| The Use of Physostigmine in the Diagnosis and Treatment of Anticholinergic Toxicity After Olanzapine Overdose: Literature Review and Case Report. | J Acad Consult Liaison Psychiatry | Second-generation antipsychotic agents are commonly used by clinicians for the treatment of various psychiatric and medical conditions. Despite their presumed safety, an overdose with olanzapine may lead to the development of anticholinergic toxicity. The anticholinergic toxidrome is characterized by both central and peripheral physical findings. Central anticholinergic syndrome, a term used to describe the symptoms that arise from reduced cholinergic activity in the central nervous system, is characterized primarily by signs and symptoms consistent with hyperactive delirium. Signs of peripheral anticholinergia include mydriasis and blurred vision, tremors, ataxia, fever/hyperthermia, flushed and dry skin, dry oral mucosa, decreased bowel sounds, constipation, and urinary retention, among other symptoms. In extreme cases, central anticholinergic syndrome can be associated with seizures, coma, respiratory failure, and cardiovascular collapse.To provide scientific evidence regarding the efficacy and safety of physostigmine use in cases of anticholinergic toxicity.We conducted a comprehensive review of the published literature on the symptoms, diagnosis, and treatment of anticholinergic toxicity.Currently the recommended treatment for olanzapine overdose, as is the case of most severe anticholinergic toxicity cases, involves supportive care, along with cardiac, neurological, and respiratory status monitoring. In addition, we detail the symptoms characteristic of anticholinergic toxicity, using the case of a patient experiencing central anticholinergic syndrome after an overdose with olanzapine.Physostigmine, a tertiary acetylcholinesterase inhibitor, can be used to assist in the both the diagnosis and management of severe anticholinergic toxicity associated with an olanzapine overdose, which might be applicable to the antimuscarinic toxidrome associated with the ingestion of agents with significant anticholinergic activity. |
| 2021 | Endophytic Fungal Community of : Diversity and Relevance to the Production of Huperzine A by the Plant Host. | Molecules | As the population ages globally, there seem to be more people with Alzheimer's disease. Unfortunately, there is currently no specific treatment for the disease. At present, Huperzine A (HupA) is one of the best drugs used for the treatment of Alzheimer's disease and has been used in clinical trials for several years in China. HupA was first separated from , a traditional medicinal herb that is used to cure fever, contusions, strains, hematuria, schizophrenia, and snakebite for several hundreds of years in China, and has been confirmed to have acetylcholinesterase inhibitory activity. With the very slow growth of , resources are becoming too scarce to meet the need for clinical treatment. Some endophytic fungal strains that produce HupA were isolated from in previous studies. In this article, the diversity of the endophytic fungal community within was observed and the relevance to the production of HupA by the host plant was further analyzed. A total of 1167 strains were obtained from the leaves of followed by the stems (1045) and roots (824). The richness as well as diversity of endophytic fungi within the leaf and stem were higher than in the root. The endophytic fungal community was similar within stems as well as in leaves at all taxonomic levels. The 11 genera (, , , , , , , , , , and ) were positively correlated with HupA content. The correlation index of with HupA contents displayed the highest value (CI = 0.92), whereas showed the lowest value (CI = 0.02). Through electrospray ionization mass spectrometry (ESI-MS), it was confirmed that the HS7-1 strain could produce HupA and the total alkaloid concentration was 3.7 ug/g. This study will enable us to screen and isolate the strain that can produce HupA and to figure out the correlation between endophytic fungal diversity with HupA content in different plant organs. This can provide new insights into the screening of strains that can produce HupA more effectively. |
| 2021 | Advances in the design and discovery of novel small molecule drugs for the treatment of Dravet Syndrome. | Expert Opin Drug Discov | : Dravet syndrome (severe myoclonic epilepsy in infancy) begins in the first year of life characterized by generalized or unilateral clonic seizures that are frequently triggered by high fever. A subsequent worsening stage occurs (in years 1-4 of life) and seizure activity is accompanied by disturbed psychomotor development. The third stage of the disease, known as the 'stabilization phase,' is associated with seizures and intellectual impairment. Of note, a mutation in the voltage-gated sodium-channel gene α 1 subunit (SCN1A) has been found in around 85% of patients with Dravet syndrome.: The authors review the current treatment strategies as well as potential drugs in the initial stages of clinical evaluation. The authors also review drugs with protective activity in mice models of Dravet syndrome.: Experimental data and results from initial clinical studies have brought attention to several drugs with various mechanisms of action including: ataluren (a suppressant of premature stop codons; under clinical evaluation), EPX-100, EPX-200, fenfluramine (serotonin modulators), soticlestat (an 24-hydroxylase cholesterol enzyme inhibitor), SPN-817 (an inhibitor of acetylcholinesterase), verapamil (a voltage-dependent calcium channel inhibitor) and STK-001 (an antisense oligonucleotide). The latter is scheduled for clinical evaluation. |
| 2020 | Chemical composition, insecticidal and biochemical effects of two plant oils and their major fractions against , the common vector of dengue fever. | Heliyon | In an attempt to reduce the massive application of the toxic chemical pesticides, essential oils (EOs) of and were obtained through hydrodistillation and analyzed using (GC-FID) and (GC-MS). α-terpinene and -cymene were detected as the major components in the EO of , while eugenol and -caryophyllene were the major constituents in the EO of . The plant EOs and major fractions act as considerable mosquitocides against L, the common transmitter of Dengue fever. The EOs and major fractions were tested at 6.25, 12.5, 25, 50 and 100 μl/l. Insect mortality was time and dose-dependent, and the adult stage was more sensitive than larvae. At a concentration of 50 μl/l, 24 post treatment larval and adult mortality ranged between (40.3 and 89.3%) and (51.4 and 95.6%), respectively. The LC values ranged between 12.2 and 70.1 μl/l against larvae and between 10.1 and 63.12 μl/l against adults. All of the crude EOs were more potent than their major fractions. Eugenol and -caryophyllene showed strong mosquitocidal activity than -cymene and α-terpinene. The corrected percentage mortality was increased over time with all of the test materials. In terms of lethal time required to kill 50% of the population (LT), a concentration of 100 μl/l of EO showed LT values of 2.3 and 1.7 h against larvae and adult, respectively. The EOs induced considerable inhibition of acetylcholinesterase activity, where crude oil (IC = 13.12mM) and eugenol (IC = 19.65mM) were the most potent. Results proved that the test plant oils and their major fractions could be developed as natural pest control agents to control . |
| 2020 | Status of oxidative stress, trace elements, sialic acid and cholinesterase activity in cattle naturally infected with Babesia bigemina. | Comp Immunol Microbiol Infect Dis | Babesia bigemina infection (also known as Texas fever) is reported as the most prevalent and main causative agent of bovine babesiosis, worldwide. The current study was undertaken to assess indicators of oxidative stress including activities of antioxidant enzymes and total antioxidant capacity (TAC), oxidation status of biomolecules and serum levels of trace elements as well as indicators of inflammation including sialic acid (SA) contents and cholinesterase activity in cattle naturally infected with B. bigemina. An infected group comprised of 20 crossbred Holstein cattle (3-4 years old) were diagnosed to be positive by both microscopy and nested PCR assay. The infected animals were subdivided into two groups according to their parasitemia rates (<20 % and>20 %). Furthermore, 10 healthy cattle were included as the control. The infection caused severe anemia in a parasitemia-burden dependent fashion. The activities of catalase and glucose-6-phosphate dehydrogenase as well as the levels of TAC, zinc, selenium, copper and manganese were significantly decreased as the parasitemia increased, accordingly. However, the activity of superoxide dismutase as well as the levels of malondialdehyde, protein carbonylation, DNA damage and iron, were significantly elevated in a parasitemeia-burden dependent manner. Additionally, glutathione peroxidase activity was significantly elevated with the lower rate of parasitemia, but the higher rate had no significant effect as compared to control. Moreover, total, protein and lipid binding SA contents were significantly increased but the activities of acetylcholinesterase and butyrylcholinesterase were significantly reduced, parasitemia dependently. Conclusively, the infection was remarkably associated with the induction of anemia, oxidative stress and inflammation. |
| 2019 | Isolation of bioactive compounds from Bergenia ciliata (haw.) Sternb rhizome and their antioxidant and anticholinesterase activities. | BMC Complement Altern Med | Bergenia ciliata is a medicinal plant used for the treatment of diarrhea, vomiting, fever, cough, diabetes, cancer, pulmonary disorders and wound healing.In this study, Bergenia ciliata crude extract, subfractions, and isolated compounds were evaluated for their antioxidant and anticholinesterase potential. The free radical scavenging capacities of the extracts determined using DPPH and ABTS assays. The anticholinesterase potentials were determined using acetylcholine esterase and butyryl choline esterase enzymes. To determine the phytochemical composition, the extracts were subjected to HPLC analysis and silica gel column isolation. Based on HPLC fingerprinting results, the ethyl acetate fraction was found to have more bioactive compounds and was therefore subjected to silica gel column isolation. As a result, three compounds; pyrogallol, rutin, and morin were isolated in the pure state. The structures of the isolated compounds were elucidated using spectroscopic techniques like H-NMR, IR and UV-Visible.The crude extract showed maximum anticholinesterase (acetylcholinesterase = 90.22 ± 1.15% and butyrylcholinesterase = 88.22 ± 0.71%) and free radical scavenging (87.37 ± 2.45 and 83.50 ± 0.70% respectively against DPPH and ABTS radicals) potentials. The total phenolic contents (expressed as equivalent of gallic acid; mgGAE/g) were higher in ethyl acetate fraction (80.96 ± 1.74) followed by crude extract (70.65 ± 0.86) while the flavonoid contents (expressed as quercetin equivalent; mgQE/g) and were higher in crude extract (88.40 ± 1.12) followed by n-butanol fraction (60.10 ± 1.86). The isolated bioactive compounds pyrogallol, rutin, and morin were found active against ABTS and DPPH free radicals. Amongst them, pyrogallol was more active against both free radicals. Reasonable anticholinesterase activities were recorded for pyrogallol against selected enzymes.The extracts and isolated compounds showed antioxidant and acetylcholinesterase inhibitory potentials. It was concluded that this plant could be helpful in the treatment of oxidative stress and neurological disorders if used in the form of extracts. |
| 2019 | Isolation, pharmacological evaluation and molecular docking studies of bioactive compounds from . | Drug Des Devel Ther | Traditionally, is widely used for the treatment of many diseases like dysentery, fever, typhoid, diarrhea, eczema, smallpox, malaria and cough.Shade-dried roots of were extracted with methanol. Based on HPLC results, chloroform and ethyl acetate fractions were subjected to silica column isolation and four compounds: glutaric acid , 3,5 dihydroxy phenyl acrylic acid , (2,5 dihydroxy phenyl) 3',6',8'-trihydroxyl-4H chromen-4'-one and hexanedioic acid were isolated in pure form. Ellman's assay was used to determine the anticholinesterase potential of isolated compounds while their antioxidant potential was estimated by DPPH and ABTS scavenging assays.Amongst the isolated compounds, and exhibited excellent percent inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) (83.23±1.11, 82.72±2.20 and 82.11±2.11, 82.23±1.21, respectively, at 1000 µg/mL) with IC of 76, 90, 78 and 92 µg/mL, respectively. Highest percent radicals scavenging against DPPH and ABTS (87.41±1.20 and 86.13±2.31) with IC of 64 and 65 µg/mL, respectively, were observed for compound . Molecular docking studies also supported the binding of compound and with the target enzyme. The para-hydroxyl group of the phenolic moiety is formed hydrogen bonds with the active site water molecule and the side chain carbonyl and hydroxyl residues of enzyme.The isolated compounds inhibited the DPPH and ABTS-free radicals, and AChE and BChE enzymes. It was concluded that these compounds could be used in relieving the oxidative stress and pathological symptoms associated with excessive hydrolysis of acetyl and butyryl choline. The results of the study were supported by docking studies for compounds and . |
| 2020 | Chemical composition and larvicidal activity against Aedes mosquitoes of essential oils from Arisaema fargesii. | Pest Manag Sci | Dengue fever is caused by the spread of dengue virus by Aedes mosquito vectors. Currently, the most effective way to control dengue is by preventing mosquitoes from spreading the disease. Arisaema fargesii is a Chinese herbal medicine commonly used to repel mosquitoes. In our laboratory, anti-mosquito chemical components were extracted from A. fargesii, and the effects of these substances on mosquito larvae were examined.In total, 48 compounds corresponding to 98.79% of the total oil were identified and the major compounds identified were linalool (12.38%), carvacrol (8.27%), eugenol (5.21%), and β-selinene (5.36%). Essential oil had larvicidal activity against Ae. aegypti and Ae. albopictus with LC values of 40.49 mg/L, 47.01 mg/L, respectively. The LC values of carvacrol, eugenol, linalool and β-selinene were 32.78, 56.34, 70.56, 136.03 mg/L against Ae. aegypti larvae, and 39.08, 52.07, 82.34, 151.74 mg/L, respectively, against Ae. albopictus larvae. Biochemical assays of Aedes larvae showed that the activities of acetylcholinesterase (AChE), monooxygenases (MO), glutathione-S-transferase (GST), p-Nitrophenyl acetate (p-NPA) esterase, α-esterase and β-esterase were significantly affected by carvacrol. Essential oil induced the detoxification mechanism for the action of GST and MO.The result indicates that essential oil of A. fargesii and its isolated constituent have good inhibitory effects on the defense enzymes of Aedes mosquito larvae. A. fargesii essential oil can be used to control Aedes mosquito larvae to prevent the spread of dengue fever. © 2019 Society of Chemical Industry. |
| 2019 | Baculoviral Expression of Presumptive OP-Resistance Mutations in BmAChE1 of Rhipicephalus (Boophilus) microplus (Ixodida: Ixodidae) and Biochemical Resistance to OP Inhibition. | J Med Entomol | The southern cattle tick, Rhipicephalus (Boophilus) microplus (Canestrini), transmits bovine babesiosis and anaplasmosis, and is endemic to Mexico, Latin and South America. Rhipicephalus (B.) microplus infestations within the United States are a continuing threat to U.S. cattle producers. An importation barrier between Texas and Mexico keeps the ticks from re-entering the United States. All cattle imported into the United States are dipped in an organophosphate (OP) acaricide and hand inspected for presence of ticks. Tick resistance has developed to most available acaricides, including coumaphos, the OP used in the cattle dip vats. OP-resistance can result from one or more mutations in the gene encoding the enzyme, acetylcholinesterase (AChE), resulting in production of an altered AChE resistant to OP inhibition. Previous research reported a large number of BmAChE1 mutations associated with OP resistance. We report baculovirus expression of recombinant tick BmAChE1 (rBmAChE) enzymes containing a single resistance-associated mutation, to assess their contribution to OP inhibition resistance. Surprisingly, of the naturally occurring BmAChE1 resistance-associated mutations, only D188G resulted in markedly reduced sensitivity to OP-inhibition suggesting that OP-insensitivity in BmAChE1 may result from the D188G mutation, or may possibly result from multiple mutations, each contributing a small decrease in OP sensitivity. Furthermore, an OP-insensitivity mutation (G119S) found in mosquitoes was expressed in rBmAChE1, resulting in 500-2000-fold decreased sensitivity to OP inhibition. Recombinant BmAChE1 with the G119S mutation demonstrated the lack of any structural prohibition to broad and high-level OP-insensitivity, suggesting potential increases in tick OP-resistance that would threaten the U.S. importation barrier to ticks. |
| 2019 | Hierarchical Virtual Screening of Potential Insectides Inhibitors of Acetylcholinesterase and Juvenile Hormone from Temephos. | Pharmaceuticals (Basel) | (Linnaeus, 1762; Diptera: Culicidae) is the main vector transmitting viral diseases such as dengue fever, dengue haemorrhagic fever, urban yellow fever, zika and chikungunya. Worldwide, especially in the Americas and Brazil, many cases of dengue have been reported in recent years, which have shown significant growth. The main control strategy is the elimination of the vector, carried out through various education programs, to change human habits, but the most usual is biological control, together with environmental management and chemical control. The most commonly insecticide used is temephos (an organophosphorus compound), but populations have shown resistance and the product is highly toxic, so we chose it as a template molecule to perform a ligand-based virtual screening in the ChemBrigde (DIVERSet-CL subcollection) database, searching for derivatives with similarity in shape (ROCS) and electrostatic potential (EON). Thus, fourty-five molecules were filtered based on their pharmacokinetic and toxicological properties and 11 molecules were selected by a molecular docking study, including binding affinity and mode of interaction. The L46, L66 and L68 molecules show potential inhibitory activity for both the insect (-9.28, -10.08 and -6.78 Kcal/mol, respectively) and human (-6.05, 6.25 and 7.2 Kcal/mol respectively) enzymes, as well as the juvenile hormone protein (-9.2; -10.96 and -8.16 kcal/mol, respectively), showing a significant difference in comparison to the template molecule temephos. Molecules L46, L66 and L68 interacted with important amino acids at each catalytic site of the enzyme reported in the literature. Thus, the molecules here investigated are potential inhibitors for both the acetylcholinesterase enzymes and juvenile hormone protein-from insect and humans, characterizing them as a potential insecticide against the mosquito. |
| 2019 | Insecticide resistance genes affect Culex quinquefasciatus vector competence for West Nile virus. | Proc Biol Sci | Insecticide resistance has been reported to impact the interactions between mosquitoes and the pathogens they transmit. However, the effect on vector competence for arboviruses still remained to be investigated. We examined the influence of two insecticide resistance mechanisms on vector competence of the mosquito Culex quinquefasciatus for two arboviruses, Rift Valley Fever virus (RVFV) and West Nile virus (WNV). Three Cx. quinquefasciatus lines sharing a common genetic background were used: two insecticide-resistant lines, one homozygous for amplification of the Ester locus (SA2), the other homozygous for the acetylcholinesterase ace-1 G119S mutation (SR) and the insecticide-susceptible reference line Slab. Statistical analyses revealed no significant effect of insecticide-resistant mechanisms on vector competence for RVFV. However, both insecticide resistance mechanisms significantly influenced the outcome of WNV infections by increasing the dissemination of WNV in the mosquito body, therefore leading to an increase in transmission efficiency by resistant mosquitoes. These results showed that insecticide resistance mechanisms enhanced vector competence for WNV and may have a significant impact on transmission dynamics of arboviruses. Our findings highlight the importance of understanding the impacts of insecticide resistance on the vectorial capacity parameters to assess the overall consequence on transmission. |
| 2019 | Detrimental Effects of Induced Antibodies on Aedes aegypti Reproduction. | Neotrop Entomol | Aedes aegypti (Linnaeus) (Diptera: Culicidae) is the main vector of viruses causing dengue, chikungunya, Zika, and yellow fever, worldwide. This report focuses on immuno-blocking four critical proteins in the female mosquito when fed on blood containing antibodies against ferritin, transferrin, one amino acid transporter (NAAT1), and acetylcholinesterase (AchE). Peptides from these proteins were selected, synthetized, conjugated to carrier proteins, and used as antigens to immunize New Zealand rabbits. After rabbits were immunized, a minimum of 20 female mosquitos were fed on each rabbit, per replicate. No effect in their viability was observed after blood-feeding; however, the number of infertile females was 20% higher than the control when fed on AchE-immunized rabbits. The oviposition period was significantly longer in females fed on immunized rabbits than those fed on control (non-immunized) rabbits. Fecundity (eggs/female) of treated mosquitoes was significantly reduced (about 50%) in all four treatments, as compared with the control. Fertility (hatched larvae) was also significantly reduced in all four treatments, as compared with the control, being the effect on AchE and transferrin the highest, by reducing hatching between 70 and 80%. Survival to the adult stage of the hatched larvae showed no significant effect, as more than 95% survival was observed in all treatments, including the control. In conclusion, immuno-blocking of these four proteins caused detrimental effects on the mosquito reproduction, being the effect on AchE the most significant. |
| 2019 | Identification of Potential Inhibitors from Pyriproxyfen with Insecticidal Activity by Virtual Screening. | Pharmaceuticals (Basel) | is the main vector of dengue fever transmission, yellow fever, Zika, and chikungunya in tropical and subtropical regions and it is considered to cause health risks to millions of people in the world. In this study, we search to obtain new molecules with insecticidal potential against via virtual screening. Pyriproxyfen was chosen as a template compound to search molecules in the database Zinc_Natural_Stock (ZNSt) with structural similarity using ROCS (rapid overlay of chemical structures) and EON (electrostatic similarity) software, and in the final search, the top 100 were selected. Subsequently, in silico pharmacokinetic and toxicological properties were determined resulting in a total of 14 molecules, and these were submitted to the PASS online server for the prediction of biological insecticide and acetylcholinesterase activities, and only two selected molecules followed for the molecular docking study to evaluate the binding free energy and interaction mode. After these procedures were performed, toxicity risk assessment such as LD values in mg/kg and toxicity class using the PROTOX online server, were undertaken. Molecule ZINC00001624 presented potential for inhibition for the acetylcholinesterase enzyme (insect and human) with a binding affinity value of -10.5 and -10.3 kcal/mol, respectively. The interaction with the juvenile hormone was -11.4 kcal/mol for the molecule ZINC00001021. Molecules ZINC00001021 and ZINC00001624 had excellent predictions in all the steps of the study and may be indicated as the most promising molecules resulting from the virtual screening of new insecticidal agents. |
| 2019 | Hwangryunhaedok-Tang Exerts Neuropreventive Effect on Memory Impairment by Reducing Cholinergic System Dysfunction and Inflammatory Response in a Vascular Dementia Rat Model. | Molecules | Hwangryunhaedok-tang (HRT) is a traditional oriental herbal formula used in Asian countries for treating inflammatory diseases and controlling fever. Our present study aimed to determine whether HRT has therapeutic effects for patients with vascular dementia (VaD) using a bilateral common carotid artery occlusion (BCCAO) rat model and assessing spatial memory impairment and activation of neuroinflammation. BCCAO was performed in male Sprague Dawley rats to induce VaD, and oral HRT was administered daily for 30 d. Our data showed that HRT ameliorated BCCAO-induced memory and cognitive impairment in behavioral tests. In addition, HRT reversed cholinergic dysfunction and neuronal damage in the hippocampus of BCCAO rats. Furthermore, HRT attenuated microglial activation and reduced the phosphorylation of p38 mitogen-activated protein kinase and c-Jun N-terminal kinase (JNK) induced by BCCAO. Simultaneous high-performance liquid chromatography analysis of HRT using index compounds from the herbal composition revealed that both HRT ethanol extract and commercial HRT granules primarily comprise geniposide, baicalin, and berberine. Our study showed that HRT administration resulted in the prevention of neuronal injury induced by BCCAO through improvement of cholinergic dysfunction and inhibition of neuroinflammatory responses, suggesting that HRT may have potential as a treatment for VaD. |
| 2018 | Biological activities of extracts from Aspidosperma subincanum Mart. and in silico prediction for inhibition of acetylcholinesterase. | Phytother Res | Species of Aspidosperma are traditionally used to treat malaria, leishmaniasis, microbial, and inflammatory diseases. Aspidosperma subincanum Mart. known as "guatambu" is used in Brazilian traditional medicine to treat diabetes, hypercholesterolemia, and digestive diseases. Its tonic properties have been employed by the indigenous populations to stimulate the circulatory and genitourinary tracts and to improve respiratory function as well as to relieve spasms and to reduce fever. The species is known to contain antitumoural and antimalarial indole alkaloids. In the present study, various less explored biological activities of extracts from leaves and branches of A. subincanum were investigated, that is, inhibition of acetylcholinesterase as well as antioxidant and antibacterial activity. Twenty-one known indole alkaloids from this species were targeted for predicting the inhibition of acetylcholinesterase, and their biological activities were collected from the literature. Through in silico the prediction, the indole alkaloids uleine and derivatives demonstrated a strong probability of being able to inhibit the acetylcholinesterase enzyme, as well as the olivacine derivatives 3,4-dihydroolivacine and N-methyl-tetrahydro-olivacine (guatambuine), and the subincanadines C and E. Indeed, the extracts of A. subincanum showed acetylcholinesterase inhibitory activity, antioxidant activity in the lipid peroxidation assay, and antimicrobial activity against Staphylococcus aureus ATCC 25923, and their pharmacological properties should be explored further. |
| 2017 | Phytochemical Quantification and the In Vitro Acetylcholinesterase Inhibitory Activity of Phellodendron chinense and Its Components. | Molecules | The dried bark of has been used as a traditional herbal medicine to remove damp heat, relieve consumptive fever, and cure dysentery and diarrhea. In the present study, we performed quantitative analyses of the two components of , phellodendrine and berberine, using high-performance liquid chromatography. A 70% ethanol extract of was prepared and the two components were separated on a C-18 analytical column using a gradient solvent system of acetonitrile and 0.1% (/) aqueous trifluoroacetic acid. The ultraviolet wavelength used for detection was 200 nm for phellodendrine and 226 nm for berberine. The analytical method established here showed high linearity (correlation coefficient, ≥0.9991). The amount of phellodendrine and berberine used was 22.255 ± 0.123 mg/g and 269.651 ± 1.257 mg/g, respectively. Moreover, we performed an in vitro acetylcholinesterase (AChE) activity assay and an amyloid-β aggregation test to examine the biological properties of phellodendrine and berberine as therapeutic drugs for Alzheimer's disease. Phellodendrine and berberine inhibited AChE activity in a dose-dependent manner (IC = 36.51 and 0.44 μM, respectively). In contrast, neither phellodendrine nor berberine had an effect on amyloid-β aggregation. The extract and phellodendrine, but not berberine, exhibited antioxidant activity by increasing radical scavenging activity. Moreover, demonstrated a neuroprotective effect in hydrogen peroxide-treated HT22 hippocampal cells. Overall, our findings suggest that has potential as an anti-Alzheimer's agent via the suppression of the enzymatic activity of acetylcholinesterase and the stimulation of antioxidant activity. |
| 2017 | [Cases of acute pesticide poisoning in Colonia Puerto Pirapó, Itapúa, Paraguay, February, 2014]. | Biomedica | In Paraguay, pesticides are the causative agent in 13.7% of poisonings, especially organophosphorus compounds. Such poisoning produces the inhibition of acetylcholinesterase generating three possible clinical conditions: acute poisoning, intermediate syndrome or late neurotoxicity. We present 15 cases of acute poisoning, ten women and five men from a rural community between 5 and 67 years of age, whose symptoms began after using water contaminated by pesticides from the community network. The most common symptoms were nausea and vomiting, followed by abdominal pain, headache, fever, itching, red eyes and sweating. Five patients underwent blood tests for blood count, renal and liver function and serum cholinesterase, with results within the reference values; just one patient had high liver enzymes.In two samples from the community water supply network the active compound detected was profenophos. It is essential to train primary health care personnel to identify cases of acute pesticide poisoning in a timely manner to provide appropriate treatment, especially in rural areas. Additionally, it is necessary that responsible institutions monitor compliance with environmental regulations in these areas to avoid such incidents. |
| 2016 | Evaluation of Antioxidant, Anticholinesterase, and Antidiabetic Potential of Dry Leaves and Stems in Tamarix aphylla Growing Wild in Tunisia. | Chem Biodivers | Tamarix aphylla (L.) Karst. has a wide geographic distribution and was employed in traditional medicine as astringent, anti-rheumatic and to treat fever. T. aphylla leaves and stems extracts were studied from both chemical and biological points of view to assess the antidiabetic, anticholinesterase and antioxidant potential of this species. The HPLC/Diode Array Detector (DAD) analysis showed the presence of 14 phenolic compounds (gallic, caffeic, p-coumaric, ferulic and ellagic acids, kaempferol, quercetin, quercetin 3-O-galactoside and six flavonol derivatives). This is the first study reporting a comparative study of the biological activities of different extracts from T. aphylla. High activities were obtained against DPPH radical, superoxide anion radical (O2∙-) and nitric oxide radical ( NO) in a concentration-dependent manner, the most active extracts being the polar ones. T. aphylla also showed moderate protective effects against acetylcholinesterase, but no effects were observed against butyrylcholinesterase. Against α-glucosidase the MeOH extracts displayed IC values from 8.41 to 24.81 μg/ml. |
| 2016 | Inhibition and Larvicidal Activity of Phenylpropanoids from Piper sarmentosum on Acetylcholinesterase against Mosquito Vectors and Their Binding Mode of Interaction. | PLoS One | Aedes aegypti, Aedes albopictus and Culex quinquefasciatus are vectors of dengue fever and West Nile virus diseases. This study was conducted to determine the toxicity, mechanism of action and the binding interaction of three active phenylpropanoids from Piper sarmentosum (Piperaceae) toward late 3rd or early 4th larvae of above vectors. A bioassay guided-fractionation on the hexane extract from the roots of Piper sarmentosum led to the isolation and identification of three active phenylpropanoids; asaricin 1, isoasarone 2 and trans-asarone 3. The current study involved evaluation of the toxicity and acetylcholinesterase (AChE) inhibition of these compounds against Aedes aegypti, Aedes albopictus and Culex quinquefasciatus larvae. Asaricin 1 and isoasarone 2 were highly potent against Aedes aegypti, Aedes albopictus and Culex quinquefasciatus larvae causing up to 100% mortality at ≤ 15 μg/mL concentration. The ovicidal activity of asaricin 1, isoasarone 2 and trans-asarone 3 were evaluated through egg hatching. Asaricin 1 and isoasarone 2 showed potent ovicidal activity. Ovicidal activity for both compounds was up to 95% at 25μg/mL. Asaricin 1 and isoasarone 2 showed strong inhibition on acetylcholinesterase with relative IC50 values of 0.73 to 1.87 μg/mL respectively. These findings coupled with the high AChE inhibition may suggest that asaricin 1 and isoasarone 2 are neuron toxic compounds toward Aedes aegypti, Aedes albopictus and Culex quinquefasciatus. Further computational docking with Autodock Vina elaborates the possible interaction of asaricin 1 and isoasarone 2 with three possible binding sites of AChE which includes catalytic triads (CAS: S238, E367, H480), the peripheral sites (PAS: E72, W271) and anionic binding site (W83). The binding affinity of asaricin 1 and isoasarone 2 were relatively strong with asaricin 1 showed a higher binding affinity in the anionic pocket. |
| 2016 | Huperzine A as a neuroprotective and antiepileptic drug: a review of preclinical research. | Expert Rev Neurother | Huperzine A (HupA) is an acetylcholinesterase (AChE) inhibitor extracted from Huperzia Serrata, a firmoss, which has been used for various diseases in traditional Chinese medicine for fever and inflammation. More recently, it has been used in Alzheimer's disease and other forms of dementia with a presumed mechanism of action via central nicotinic and muscarinic receptors. HupA is marketed as a dietary supplement in the U.S. This article reviews newly proposed neuroprotective and anticonvulsant HupA properties based on animal studies. HupA exerts its effects mainly via α7nAChRs and α4β2nAChRs, thereby producing a potent anti-inflammatory response by decreasing IL-1β, TNF-α protein expression, and suppressing transcriptional activation of NF-κB signaling. Thus, it provides protection from excitotoxicity and neuronal death as well as increase in GABAergic transmission associated with anticonvulsant activity. |
| 2015 | Acetylcholinesterases from the Disease Vectors Aedes aegypti and Anopheles gambiae: Functional Characterization and Comparisons with Vertebrate Orthologues. | PLoS One | Mosquitoes of the Anopheles (An.) and Aedes (Ae.) genus are principal vectors of human diseases including malaria, dengue and yellow fever. Insecticide-based vector control is an established and important way of preventing transmission of such infections. Currently used insecticides can efficiently control mosquito populations, but there are growing concerns about emerging resistance, off-target toxicity and their ability to alter ecosystems. A potential target for the development of insecticides with reduced off-target toxicity is the cholinergic enzyme acetylcholinesterase (AChE). Herein, we report cloning, baculoviral expression and functional characterization of the wild-type AChE genes (ace-1) from An. gambiae and Ae. aegypti, including a naturally occurring insecticide-resistant (G119S) mutant of An. gambiae. Using enzymatic digestion and liquid chromatography-tandem mass spectrometry we found that the secreted proteins were post-translationally modified. The Michaelis-Menten constants and turnover numbers of the mosquito enzymes were lower than those of the orthologous AChEs from Mus musculus and Homo sapiens. We also found that the G119S substitution reduced the turnover rate of substrates and the potency of selected covalent inhibitors. Furthermore, non-covalent inhibitors were less sensitive to the G119S substitution and differentiate the mosquito enzymes from corresponding vertebrate enzymes. Our findings indicate that it may be possible to develop selective non-covalent inhibitors that effectively target both the wild-type and insecticide resistant mutants of mosquito AChE. |
| 2015 | Susceptibility status of Aedes aegypti (L.) (Diptera: Culicidae) to temephos from three districts of Tamil Nadu, India. | J Vector Borne Dis | Dengue is the most rapidly expanding arboviral disease in India. Aedes aegypti is the primary vector of dengue fever. Chemical insecticides have long been used in the vector control programmes along with other control measures. However, continuous use of insecticides targeting Ae. aegypti may lead to development of insecticide resistance. Though resistance in Ae. aegypti has been reported, the mutation in ace-1 gene associated with temephos resistance is not reported in natural populations. The present study aims to evaluate the susceptibility/resistance status of Ae. aegypti to temephos from three districts of Tamil Nadu.Ae. aegypti larvae were sampled from different locations in three districts, viz., Dharmapuri, Salem and Namakkal. The standard WHO larval bioassay, biochemical assays and spotting of specific mutation (G119S) in the acetylcholinesterase gene, which is associated with organophosphate resistance, were carried out by PCR and sequencing.The results showed that larvae from Namakkal (NKL) population had an alteration in their susceptibility status (RR = 6.9 fold), while the other populations were moderately susceptible to insecticides. Biochemical assay showed increased activity for α- and β-esterase in NKL, as well as evidence of acetylcholinesterase insensitivity. G119S mutation was detected in this population with high frequency of 0.24.The high activity of esterase, mixed-function oxidase (MFO) and ace-1 mutation frequency were closely associated with temephos resistance. Early detection of resistance alleles in natural vector population could be useful for the successful implementation of insecticide resistance management strategies. The results of this study provide baseline data on temephos resistance in Ae. aegypti populations. |
| 2015 | Acetylcholinesterase 1 in populations of organophosphate-resistant North American strains of the cattle tick, Rhipicephalus microplus (Acari: Ixodidae). | Parasitol Res | Rhipicephalus microplus, the cattle fever tick, is a global economic problem to the cattle industry due to direct infestation of cattle and pathogens transmitted during feeding. Cattle fever tick outbreaks continue to occur along the Mexico-US border even though the tick has been eradicated from the USA. The organophosphate (OP) coumaphos targets acetylcholinesterase (AChE) and is the approved acaricide for eradicating cattle fever tick outbreaks. There is evidence for coumaphos resistance developing in cattle ticks in Mexico, and OP-resistant R. microplus ticks were discovered in outbreak populations of Texas in 2005. The molecular basis of coumaphos resistance is not known, and our study was established to gather further information on whether AChE1 is involved in the resistance mechanism. We also sought information on allele diversity in tick populations with different levels of coumaphos resistance. The overarching project goal was to define OP resistance-associated gene mutations such that a DNA-based diagnostic assay could be developed to assist the management of resistance. Three different AChE transcripts have been reported in R. microplus, and supporting genomic and transcriptomic data are available at CattleTickBase. Here, we report the complete R. microplus AChE1 gene ascertained by sequencing a bacterial artificial chromosome clone containing the entire coding region and the flanking 5' and 3' regions. We also report AChE1 sequences of larval ticks from R. microplus strains having different sensitivities to OP. To accomplish this, we sequenced a 669-bp region of the AChE1 gene corresponding to a 223 amino acid region of exon 2 to assess alleles in seven strains of R. microplus with varying OP resistance phenotypes. We identified 72 AChE1 sequence variants, 2 of which are strongly associated with OP-resistant phenotypes. Esterase-like sequences from the R. microplus transcriptome RmiTr Version 1.0 were compared to the available sequence databases to identify other transcripts with similarity to AChE1. |
| 2015 | Larvicidal activity and possible mode of action of four flavonoids and two fatty acids identified in Millettia pinnata seed toward three mosquito species. | Parasit Vectors | Aedes aegypti and Aedes albopictus and Culex pipiens pallens mosquitoes transmit dengue fever and West Nile virus diseases, respectively. This study was conducted to determine the toxicity and mechanism of action of four flavonoids and two fatty acids from Millettia pinnata (Fabaceae) seed as well as six pure fatty acids and four fatty acid esters toward third instar larvae from insecticide-susceptible C. pipiens pallens and A. aegypti as well as wild A. albopictus. Efficacy of 12 experimental liquid formulations containing M. pinnata seed methanol extract and hydrodistillate (0.5-10.0% liquids) was also assessed.The contact toxicities of all compounds and 12 formulations were compared with those of two larvicides, temephos and fenthion and the commercial temephos 200 g/L emulsifiable concentrate (EC). The possible mode of larvicidal action of the constituents was elucidated using biochemical methods. Larval mortality and cAMP level were analyzed by the Bonferroni multiple-comparison method.Potent toxicity was produced by karanjin, oleic acid, karanjachromene, linoleic acid, linolenic acid, pongamol, pongarotene, and elaidic acid toward C. pipiens pallens larvae (24 h LC50, 14.61-28.22 mg/L) and A. aegypti larvae (16.13-37.61 mg/L). Against wild A. albopictus larvae, oleic acid (LC50, 18.79 mg/L) and karanjin (35.26 mg/L) exhibited potent toxicity. All constituents were less toxic than either temephos or fenthion. Structure-activity relationship indicates that the degree of saturation, the side chain length, and the geometric isomerism of fatty acids appear to play a role in determining the fatty acid toxicity. Acetylcholinesterase (AChE) is the main site of action of the flavonoids, oleic acid, and palmitic acid. The mechanism of larvicidal action of elaidic acid, arachidic acid, and behenic acid might be due to interference with the octopaminergic system. Linoleic acid and linolenic acid might act on both AChE and octopaminergic receptor. M. pinnata seed extract or hydrodistillate applied as 10% liquid provided 100% mortality toward the three mosquito species larvae and the efficacy of the liquids was comparable to that of temephos 200 g/L EC.Further studies will warrant possible applications of M. pinnata seed-derived products as potential larvicides for the control of mosquito populations. |
| 2015 | Acute systemic LPS-mediated inflammation induces lasting changes in mouse cortical neuromodulation and behavior. | Neurosci Lett | Systemic lipopolysaccharide (LPS) is widely used to induce a neuroinflammatory response that is associated with short-term 'sickness'-behavior that can include fever, loss of activity, loss of appetite, impaired cognition, anxiety and depression. If large enough or left unchecked, this neuroinflammatory response can become self-perpetuating and lead to long-term neurodegenerative processes. In this study, we assess the longer-term effects of a single systemic LPS injection on electrophysiological neuromodulator effects and basic behavioral analysis in mice. Five months after LPS injection, we find a mild reduction in cortical inhibition and altered temporal dynamics of acetylcholine but not norepinephrine or serotonin neuromodulator effects. Consistent with electrophysiological findings, LPS treated mice showed a deficit in memory performance in the novel object recognition test with no effect on measures of anxiety or despair as measured in the open field test and tail suspension test, respectively. Furthermore, LPS-treated mice showed an increase in acetylcholinesterase activity. As increased acetylcholinesterase activity is associated with reduced acetylcholine signaling and impaired cognitive ability, these studies demonstrate the potential for a single inflammatory event to initiate processes that may lead to long-term neurodegeneration. |
| 2014 | Anti-diabetic and spasmolytic potential of Farsetia hamiltonii Royle from Cholistan desert. | J Ethnopharmacol | Folk herbal practitioners of the Cholistan desert claim Farsetia hamiltonii Royle (Brassicaceae) to treat diabetes, oxidative damages, diarrhea, fever, and abdominal cramps. The aim of this study was to scientifically find the potential of Farsetia hamiltonii in treating diabetes and gastrointestinal diseases.In vivo anti-diabetic activity of Farsetia hamiltonii was studied on alloxan induced diabetic rats to justify its traditional use. The in vitro antispasmodic activity on isolated tissues of rabbit jejunum was also evaluated. In addition, several enzyme inhibition studies (lipoxygenase, tyrosinase, acetylcholinesterase (AchE), carbonic II anhydrase and phosphodiesterase I) and antioxidant activity of plant extracts were also conducted.In vivo experiments, Farsetia hamiltonii methanol extract (300 mg/kg) significantly lowered the fasting blood glucose (107.6 ± 1.249 mg/dL up to 4th day) comparable to positive control (Glibenclamide) throughout the study period. The in vitro antispasmodic activity on isolated tissues of rabbit jejunum on methanol extract showed concentration dependent (0.01-0.3 mg/ml) relaxation of spontaneous contractions with EC₅₀ value 0.011 µM and high K(+) (80 mM) induced contraction (0.01-0.1 mg/ml) with EC₅₀ value 0.066 mg/ml. Farsetia hamiltonii DCM and methanol extracts exhibited some antilipoxygenase activities while tyrosinase, acetylcholinesterase (AchE), carbonic II anhydrase, phosphodiesterase I, and antioxidant activity of plant extracts were not significant.Our results validate the traditional use of Farsetia hamiltonii for the traditional therapeutic potential in treating diabetes and gastrointestinal diseases. |
| 2014 | Design, synthesis, acetylcholinesterase inhibition and larvicidal activity of girgensohnine analogs on Aedes aegypti, vector of dengue fever. | Eur J Med Chem | Girgensohnine alkaloid was used as a natural model in the design and generation of new alkaloid-like α-aminonitrile series that was completed by the use of SSA-catalyzed Strecker reaction between commercial and inexpensive substituted benzaldehydes, piperidine (pyrrolidine, morpholine and N-methylpiperazine) and acetone cyanohydrin. Calculated ADMETox parameters of the designed analogs revealed their good pharmacokinetic profiles indicating lipophilic characteristics. In vitro AChE enzyme test showed that obtained α-aminonitriles could be considered as AChEIs with micromolar IC50 values ranging from 42.0 to 478.0 μM (10.3-124.0 μg/mL). Among this series, the best AChE inhibitor was the pyrrolidine α-aminonitrile 3 (IC50 = 42 μM), followed by the piperidine α-aminonitriles 2 and 6 (IC50 = 45 μM and IC50 = 51 μM, respectively), and the compound 7 (IC50 = 51 μM). In vivo insecticidal activity of more active AChEIs against Aedes aegypti larvae was also performed showing a good larvicidal activity at concentrations less than 140 ppm, highlighting products 2 and 7 that could serve as lead compounds to develop new potent and selective insecticides. |
| 2013 | Inhibitor profile of (n)-tacrines -methylcarbamates on acetylcholinesterase from and | Pestic Biochem Physiol | The cattle tick, (), and the sand fly, are disease vectors to cattle and humans, respectively. The purpose of this study was to characterize the inhibitor profile of acetylcholinesterases from (AChE1) and (AChE) compared to human and bovine AChE, in order to identify divergent pharmacology that might lead to selective inhibitors. Results indicate that AChE has low sensitivity (IC = 200 μM) toward tacrine, a monovalent catalytic site inhibitor with sub micromolar blocking potency in all previous species tested. Similarly, a series of (n)-tacrine dimer series, bivalent inhibitors and peripheral site AChE inhibitors possess poor potency toward AChE. Molecular homology models suggest the rAChE enzyme possesses a W384F orthologous substitution near the catalytic site, where the larger tryptophan side chain obstructs the access of larger ligands to the active site, but functional analysis of this mutation suggests it only partially explains the low sensitivity to tacrine. In addition, AChE1 and AChE have low nanomolar sensitivity to some experimental carbamate anticholinesterases originally designed for control of the malaria mosquito, . One experimental compound, 2-((2-ethylbutyl)thio)phenyl methylcarbamate, possesses >300-fold selectivity for AChE1 and AChE over human AChE, and a mouse oral LD of >1500 mg/kg, thus providing an excellent new lead for vector control. |
| 2012 | Pharmacological properties and protein binding capacity of phenolic extracts of some Venda medicinal plants used against cough and fever. | J Ethnopharmacol | Several ailments are caused by infectious bacteria and in other diseases; they act as co-infection which complicate human life by causing health hazards. In Venda (South Africa), many plants are used in traditional medicine to treat cough and fever.This study was aimed at evaluating the antibacterial and antifungal properties, cyclooxygenases (COX), acetylcholinesterase (AChE) enzyme inhibitory effects and the phenolic composition as well as mutagenic properties of six medicinal plants used by the Venda people of Limpopo Province of South Africa against cough and fever.The petroleum ether (PE), dichloromethane (DCM), 80% ethanol (EtOH) and water extracts of six plants were tested against four infectious bacteria (Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus) and a fungus Candida albicans. The same extracts were evaluated for their ability to inhibit COX-1 and -2 enzymes. Methanolic and water extracts of the same plant were tested for acetylcholinesterase inhibitory effects. Total phenolics, flavonoids, gallotannins and condensed tannins were determined. The ability of the extracts to bind and precipitate proteins was also investigated. The extracts were investigated for genotoxicity with and without S9 (metabolic activation) against three Salmonella typhimurium tester strains TA98, TA100 and TA102.The organic extracts of Rhus lancea leaves exhibited the best antibacterial activity with minimum inhibitory concentration (MIC) values ranging from 0.0061 to 0.049mg/ml. The best antifungal activity was observed from a DCM extract of Syzygium cordatum leaves with a MIC value of 0.195mg/ml. The methanolic and water extracts of the same plant exhibited high inhibitory effects towards AChE with IC(50) values of 0.22 and 0.26mg/ml, respectively. The highest levels of flavonoids and gallotannins were detected in Spirostachys africana bark; 11.57 and 48.88μg/g, respectively. The highest percentages (1.2%) of condensed tannins were detected in Uvaria caffra leaves. The high levels of phenolic compounds may have been responsible for high antimicrobial activities for extracts of S. africana bark and U. caffra leaves. S. cordatum leaves represented the highest affinity for protein binding with 93%. All the extracts were non-mutagenic towards the three tested strains with and without S9 metabolic activation.The result obtained in this study goes a long way in validating the ethnobotanical usage of these medicinal plants in the treatment of cough and fever by the Venda people. However, more evidence obtainable from other assays not performed here are urgently required to confirm these results. |
| 2012 | Effect of Moringa oleifera flower extract on larval trypsin and acetylcholinesterase activities in Aedes aegypti. | Arch Insect Biochem Physiol | Aedes aegypti control is crucial to reducing dengue fever. Aedes aegypti larvae have developed resistance to organophosporous insecticides and the use of natural larvicides may help manage larval resistance by increasing elements in insecticide rotation programs. Here, we report on larvicidal activity of Moringa oleifera flower extract against A. aegypti L(1), L(2), L(3), and L(4) as well as the effect of flower extract on gut trypsin and whole-larval acetylcholinesterase from L(4.) In addition, the heated flower extract was investigated for larvicidal activity against L(4) and effect on larval gut trypsin. Moringa oleifera flower extract contains a proteinaceous trypsin inhibitor (M. oleifera flower trypsin inhibitor, MoFTI), triterpene (β-amyrin), sterol (β-sitosterol) as well as flavonoids (kaempferol and quercetin). Larvicidal activity was detected against L(2), L(3), and L(4) (LC(50) of 1.72%, 1.67%, and 0.92%, respectively). Flower extract inhibited L(4) gut trypsin (MoFTI K(i) = 0.6 nM) and did not affect acetylcholinesterase activity. In vivo assay showed that gut trypsin activity from L(4) treated with M. oleifera flower extract decreased over time (0-1,440 min) and was strongly inhibited (98.6%) after 310 min incubation; acetylcholinesterase activity was not affected. Thermal treatment resulted in a loss of trypsin inhibitor and larvicidal activities, supporting the hypothesis that flower extract contains a proteinaceous trypsin inhibitor that may be responsible for the deleterious effects on larval mortality. |
| 2012 | Withdrawal syndrome after donepezil cessation in a patient with dementia. | Neurol Sci | We describe a 62-year-old female diagnosed with Alzheimer's disease, who had been treated with donepezil for approximately 1 year. When she developed a low-grade fever and digestive complaints, her family physician interpreted these symptoms as side effects of the drug and ordered donepezil to be discontinued. Not only was there no improvement of the somatic symptoms after discontinuation of donepezil, but there was also a worsening of the dementia symptoms, culminating in delirium. When donepezil was re-prescribed, the delirium resolved and the patient's mental state stabilized. The authors urge great caution in discontinuing treatment with acetylcholinesterase inhibitors such as donepezil. |
| 2010 | Insect-specific irreversible inhibitors of acetylcholinesterase in pests including the bed bug, the eastern yellowjacket, German and American cockroaches, and the confused flour beetle. | Chem Biol Interact | Insecticides directed against acetylcholinesterase (AChE) are facing increased resistance among target species as well as increasing concerns for human toxicity. The result has been a resurgence of disease vectors, insects destructive to agriculture, and residential pests. We previously reported a free cysteine (Cys) residue at the entrance to the AChE active site in some insects but not higher vertebrates. We also reported Cys-targeting methanethiosulfonate molecules (AMTSn), which, under conditions that spared human AChE, caused total irreversible inhibition of aphid AChE, 95% inhibition of AChE from the malaria vector mosquito (Anopheles gambia), and >80% inhibition of activity from the yellow fever mosquito (Aedes aegypti) and northern house mosquito (Culex pipiens). We now find the same compounds inhibit AChE from cockroaches (Blattella germanica and Periplaneta americana), the flour beetle (Tribolium confusum), the multi-colored Asian ladybird beetle (Harmonia axyridis), the bed bug (Cimex lectularius), and a wasp (Vespula maculifrons), with IC(50) values of approximately 1-11muM. Our results support further study of Cys-targeting inhibitors as conceptually novel insecticides that may be free of resistance in a range of insect pests and disease vectors and, compared with current compounds, should demonstrate much lower toxicity to mammals, birds, and fish. |
| 2010 | Long-term follow-up in patients with congenital myasthenic syndrome due to CHAT mutations. | Eur J Paediatr Neurol | Congenital myasthenic syndromes (CMSs) are a group of clinically and genetically heterogeneous inherited disorders of the neuromuscular junction. Mutations in the acetylcholine transferase (CHAT) gene cause a pre-synaptic CMS, typically associated with episodic apnoea and worsening of myasthenic symptoms during crises caused by infections, fever or stress. Between crises symptoms may be mild and variable. Acetylcholinesterase - inhibitor therapy is reported to improve clinical symptoms and reduce crises.We present data on the long-term follow-up of 11 patients with a congenital myasthenic syndrome due to nine different CHAT mutations; ten of the patients have not been previously reported.Manifestation varied from the neonatal period to the age of two years, follow-up time from nine months to 12 years. This cohort of CHAT patients studied here enabled us to describe two distinct phenotypes: The neonatal-onset group suffers from apnoeic crises, respirator dependency and bulbar weakness. Apnoea should be carefully distinguished from seizures; a CMS should be taken into account early to start appropriate therapy. Infantile-onset patients show mild permanent weakness, but experience apnoeic crises and worsening which resolve with Acetylcholinesterase - inhibitor treatment. However, after several years of treatment proximal muscle strength may decrease and lead to wheelchair dependency despite the continuation of Acetylcholinesterase - inhibitor therapy. |
| 2009 | Selective and irreversible inhibitors of mosquito acetylcholinesterases for controlling malaria and other mosquito-borne diseases. | PLoS One | New insecticides are urgently needed because resistance to current insecticides allows resurgence of disease-transmitting mosquitoes while concerns for human toxicity from current compounds are growing. We previously reported the finding of a free cysteine (Cys) residue at the entrance of the active site of acetylcholinesterase (AChE) in some insects but not in mammals, birds, and fish. These insects have two AChE genes (AP and AO), and only AP-AChE carries the Cys residue. Most of these insects are disease vectors such as the African malaria mosquito (Anopheles gambiae sensu stricto) or crop pests such as aphids. Recently we reported a Cys-targeting small molecule that irreversibly inhibited all AChE activity extracted from aphids while an identical exposure caused no effect on the human AChE. Full inhibition of AChE in aphids indicates that AP-AChE contributes most of the enzymatic activity and suggests that the Cys residue might serve as a target for developing better aphicides. It is therefore worth investigating whether the Cys-targeting strategy is applicable to mosquitocides. Herein, we report that, under conditions that spare the human AChE, a methanethiosulfonate-containing molecule at 6 microM irreversibly inhibited 95% of the AChE activity extracted from An. gambiae s. str. and >80% of the activity from the yellow fever mosquito (Aedes aegypti L.) or the northern house mosquito (Culex pipiens L.) that is a vector of St. Louis encephalitis. This type of inhibition is fast ( approximately 30 min) and due to conjugation of the inhibitor to the active-site Cys of mosquito AP-AChE, according to our observed reactivation of the methanethiosulfonate-inhibited AChE by 2-mercaptoethanol. We also note that our sulfhydryl agents partially and irreversibly inhibited the human AChE after prolonged exposure (>4 hr). This slow inhibition is due to partial enzyme denaturation by the inhibitor and/or micelles of the inhibitor, according to our studies using atomic force microscopy, circular dichroism spectroscopy, X-ray crystallography, time-resolved fluorescence spectroscopy, and liquid chromatography triple quadrupole mass spectrometry. These results support our view that the mosquito-specific Cys is a viable target for developing new mosquitocides to control disease vectors and to alleviate resistance problems with reduced toxicity toward non-target species. |
| 2007 | Molecular cloning and characterization of the complete acetylcholinesterase gene (Ace1) from the mosquito Aedes aegypti with implications for comparative genome analysis. | Insect Biochem Mol Biol | Insensitive acetylcholinesterase (AChE) has been shown to be responsible for resistance to organophosphates and carbamates in a number of arthropod species. Some arthropod genomes contain a single Ace gene, while others including mosquitoes contain two genes, but only one confers insecticide resistance. Here we report the isolation of the full-length cDNA and characterization of the complete genomic DNA sequence for the Ace1 gene in the yellow fever mosquito, Aedes aegypti. The Ace1 homolog in other mosquito species has been associated with insecticide resistance. The full-length cDNA consists of 2721bp and contains a 2109bp open reading frame that encodes a 702 amino acid protein. The amino acid sequence is highly conserved with that of other mosquitoes, including greater than 90% identity with Culex spp. and about 80% identity with Anopheles gambiae. The genomic DNA sequence includes 138,970bp and consists of eight exons with seven introns ranging from 59 to 114,350bp. Exons 2 and 8 show reduced amino acid conservation across mosquito species, while exons 3-7 are highly conserved. The Ace1 introns in Ae. aegypti reflect a high frequency of repetitive sequences that comprise about 45% of the total intron sequence. The Ace1 locus maps to the p-arm of chromosome 3, which corresponds to the orthologous genome regions in Culex spp. and An. gambiae. |
| 2006 | Biochemical diagnosis of organophosphate-insensitivity with neural acetylcholinesterase extracted by sonication from the adult tick synganglion. | Vet Parasitol | A sonication method for the homogeneous extraction of acetylcholinesterase (AChE) from the synganglia of adult ticks is described. The method provides for the extraction of sufficient AChE for multiple assays of enzyme activity in the presence of specific organophosphate (OP) inhibitors for the rapid diagnosis of OP-insensitivity and assignment of homozygous susceptible (SS), heterozygous resistant (RS), and homozygous resistant (RR) genotypes to individual ticks. A single synganglion from adult ticks of either gender and various stages of feeding can successfully be used for AChE extraction. The study presents the results of diagnostic screening of four Boophilus microplus strains for OP-insensitivity. The extraction method and these findings should find utility in support of researchers involved in the mitigation of acaricide resistance in tick populations worldwide, and in particular, the Cattle Fever Tick Surveillance and Quarantine Program maintained by USDA-APHIS/Veterinary Services along the south Texas border that prevents reentry of Boophilus spp. into the United States from endemic populations in Mexico. |
| 2005 | Carbaryl resistance in Mexican strains of the southern cattle tick (Acari: Ixodidae). | J Econ Entomol | Susceptibility to carbaryl in six Mexican strains of the southern cattle tick, Boophilus microplus (Canestrini), was evaluated with the Food and Agricultural Organization larval packet test. Tick strains from the cattle fever tick quarantine zone in Texas were more susceptible to carbaryl than to coumaphos or diazinon. Compared with the susceptible reference (Gonzalez) strain, Mexican tick strains demonstrated 10.9-59.5-fold resistance to carbaryl. Significant cross-resistance was found between carbaryl and the organophosphate acaricides coumaphos and diazinon. Bioassay results with synergists suggested that metabolic detoxification mechanisms did not play a major role in carbaryl resistance. Resistance to carbaryl was likely conferred by insensitive acetylcholinesterase. The implications of carbaryl resistance in tick eradication and control also are discussed. |
| 2003 | The psychopharmacology of huperzine A: an alkaloid with cognitive enhancing and neuroprotective properties of interest in the treatment of Alzheimer's disease. | Pharmacol Biochem Behav | Huperzine A (HupA), extracted from a club moss (Huperzia serrata), is a sesquiterpene alkaloid and a powerful and reversible inhibitor of acetylcholinesterase (AChE). It has been used in China for centuries for the treatment of swelling, fever and blood disorders. It has demonstrated both memory enhancement in animal and clinical trials and neuroprotective effects. Recently it has undergone double-blind, placebo-controlled clinical trials in patients with Alzheimer's disease (AD), with significant improvements both to cognitive function and the quality of life. Most of the clinical trials are from China, but HupA and derivatives are attracting considerable interest in the West, where AD is a major and growing concern. Furthermore, both animal and human safety evaluations have demonstrated that HupA is devoid of unexpected toxicity. Other interesting aspects of HupA pharmacological profile relate to its neuroprotective properties: it has been shown in animal studies that HupA can be used as a protective agent against organophosphate (OP) intoxication and that it reduces glutamate-induced cell death. |
| 2003 | Influence of gender on thermoregulation and cholinesterase inhibition in the long-evans rat exposed to diazinon. | J Toxicol Environ Health A | Diazinon is an organophosphate (OP)-based, anticholinesterase insecticide that irreversibly inhibits acetylcholinesterase activity and produces cholinergic stimulation in central nervous system (CNS) and peripheral tissues. Our laboratory has found that OPs administered orally in rats induce a transient period of hypothermia followed by a delayed fever that persists for several days after exposure. There is little information on the thermoregulatory effects of diazinon. Core temperature (Tc) and motor activity (MA) were monitored by radiotelemetry in male and female rats of the Long-Evans strain dosed orally with diazinon (0 [corn-oil vehicle], 100, 200, or 300 mg/kg in males and 0, 50, 100, or 200 mg/kg in females). There was a dose-dependent decrease in Tc during the first night after treatment, with females exhibiting slightly greater sensitivity than males. MA was unaffected in females exposed to diazinon at doses of 50 to 200 mg/kg; MA of males was reduced during the first night after dosing with 300 mg/kg. There was a delayed elevation in Tc of males dosed with 200 and 300 mg/kg and females dosed with 50, 100, and 200 mg/kg diazinon. The elevated Tc was only manifested during d 2 and 3 after diazinon. Administration of 200 mg/kg sodium salicylate to females 48 h after being treated with 200 mg/kg diazinon led to a rapid abatement of the fever. Diazinon doses of 50 to 300 mg/kg led to 40% to 50% inhibition in plasma cholinesterase (ChE) activity 4 h after dosing, and females displayed a significantly slower recovery of ChE activity compared to males. When compared on a molar basis, the hypothermic response to diazinon was relatively small compared to other OPs such as chlorpyrifos. The delayed fever and efficacy of sodium salicylate to block diazinon-induced fever are similar to the effects of OPs chlorpyrifos and diisopropyl fluoro-phosphate (DFP). |
| 2002 | Microbiological, biological, and chemical weapons of warfare and terrorism. | Am J Med Sci | Microbiological, biological, and chemical toxins have been employed in warfare and in terrorist attacks. In this era, it is imperative that health care providers are familiar with illnesses caused by these agents. Botulinum toxin produces a descending flaccid paralysis. Staphylococcal enterotoxin B produces a syndrome of fever, nausea, and diarrhea and may produce a pulmonary syndrome if aerosolized. Clostridium perfringens epsilon-toxin could possibly be aerosolized to produce acute pulmonary edema. Ricin intoxication can manifest as gastrointestinal hemorrhage after ingestion, severe muscle necrosis after intramuscular injection, and acute pulmonary disease after inhalation. Nerve agents inhibit acetylcholinesterase and thus produce symptoms of increased cholinergic activity. Ammonia, chlorine, vinyl chloride, phosgene, sulfur dioxide, and nitrogen dioxide, tear gas, and zinc chloride primarily injure the upper respiratory tract and the lungs. Sulfur mustard (and nitrogen mustard) are vesicant and alkylating agents. Cyanide poisoning ranges from sudden-onset headache and drowsiness to severe hypoxemia, cardiovascular collapse, and death. Health care providers should be familiar with the medical consequences of toxin exposure, and understand the pathophysiology and management of resulting illness. |
| 1998 | Huperzine A--an interesting anticholinesterase compound from the Chinese herbal medicine. | Acta Medica (Hradec Kralove) | Huperzine A, alkaloid from the Chinese herbal medicine Qian Ceng Ta, which is prepared from the moss Huperzia serrata, has been used in China for centuries to treat fever and inflammation. Huperzine A is a strong inhibitor of cholinesterases with high selectivity to acetylcholinesterase and in China is developed as therapeutic against Alzheimer's disease. May be that huperzine A will be better than other centrally active anticholinesterases in treating this neurodegenerative disorder. Huperzine A appears to have additional pharmacological properties that make it an attractive candidate therapy for clinical trials. |
| Molecular mapping of insecticide resistance genes in the yellow fever mosquito (Aedes aegypti). | J Hered | Several loci conferring insecticide resistance in the yellow fever mosquito (Aedes aegypti) have previously been mapped by simple recombinational mapping. Here we describe correlation of these resistance phenotypes with molecular gene probes for insecticide target sites by RFLP mapping. The para sodium channel gene homologue and the GABA receptor gene Resistance to dieldrin map to the same genome regions as the DDT/pyrethroid and cyclodiene resistance loci, respectively. Although the acetylcholinesterase (target site of organophosphorus and carbamate insecticides) gene Ace does not map to any known resistance locus, it maps very close to the sex-determining locus. We discuss the possibilities that, if identified, Ace-mediated resistance in A. aegypti will be sex linked or that, as suggested for anopheline mosquitoes, two independent Ace loci may exist, one of which is autosomal. These results support the importance of target site insensitivity as an insecticide resistance mechanism in mosquitoes. |
| 1997 | Site-directed mutagenesis of an acetylcholinesterase gene from the yellow fever mosquito Aedes aegypti confers insecticide insensitivity. | Exp Parasitol | Insecticide resistance is a serious problem facing the effective control of insect vectors of disease. Insensitive acetylcholinesterase (AChE) confers resistance to organophosphorus (OP) and carbamate insecticides and is a widespread resistance mechanism in vector mosquitoes. Although the point mutations that underlie AChE insensitivity have been described from Drosophila, the Colorado potato beetle, and house flies, no resistance associated mutations have been documented from mosquitoes to date. We are therefore using a cloned acetylcholinesterase gene from the yellow fever mosquito Aedes aegypti as a model in which to perform site directed mutagenesis in order to understand the effects of potential resistance associated mutations. The same resistance associated amino-acid replacements as found in other insects also confer OP and carbamate resistance to the mosquito enzyme. Here we describe the levels of resistance conferred by different combinations of these mutations and the effects of these mutations on the kinetics of the AChE enzyme. Over-expression of these constructs in baculovirus will facilitate purification of each of the mutant enzymes and a more detailed analysis of their associated inhibition kinetics. |
| 1997 | Hypothermia and delayed fever in the male and female rat exposed to chlorpyrifos. | Toxicology | Chlorpyrifos (CHL) is a commonly used organophosphate (OP) pesticide which irreversibly inhibits acetylcholinesterase activity in the CNS. Little is known regarding the thermoregulatory effects of CHL when administered orally and whether the sensitivity to CHL is affected by sex. To address these issues, male and female rats of the Long-Evans strain were administered 0, 10, 50, or 80 mg/kg CHL by gavage while core temperature (T(c)) and motor activity (MA) were monitored continuously by telemetry. Females were generally more sensitive than males to CHL. Significant hypothermic responses to CHL were observed in males administered 80 mg/kg and in females administered 10-80 mg/kg. Following recovery from hypothermia T(c) of both males and females underwent a significant elevation during the light phase 1-2 days after CHL exposure. CHL-induced hyperthermia was blocked in male and female rats by administration of 200 mg/kg sodium salicylate (SS), an antipyretic agent. Male castrated rats were markedly more sensitive to the hypothermic and hyperthermic effects of CHL compared to sham operated controls. On the other hand, ovariectomized female rats responded to CHL in a similar fashion as the sham operated controls. Thus, testicular function may be important in determining greater resistance to CHL in male rats. It appears that exposure to CHL leads to a delayed fever which involves activation of CNS pathways normally involved in fever. This mechanism could be responsible for the febrile response to OP pesticides commonly observed in humans exposed to OPs. |
| Thermoregulatory aspects of environmental exposure to anticholinesterase agents. | Rev Environ Health | Anticholinesterase (antiChE) agents can be highly toxic to birds and mammals and constitute a major proportion of the pesticides used throughout the world. AntiChEs consist of the organophosphates (OP), which irreversibly inhibit the enzyme acetylcholinesterase (AChE), and the carbamates (CB), which reversibly inhibit AChE. AChE inhibition elicits cholinergic stimulation in the central nervous system and in peripheral tissues and organs, which can lead to marked dysfunction of homeostatic systems, including temperature regulation. The control of body temperature uses cholinergic pathways in the integration and central processing of thermal information, as well as in the control of thermoeffector responses. Hence, the cholinergic stimulation elicited from exposure to antiChEs has profound effects on body temperature at rest as well as during exercise. Ambient heat and cold stress can also modulate the animal's sensitivity to antiChE exposure. After exposure to most OPs, rodents and other small species undergo a marked hypothermic response lasting up to 24 hours. On the other hand, humans exposed to OP pesticides rarely become hypothermic but rather experience a fever that may last many days. Recent studies monitoring body temperature in OP-exposed, telemetered rats demonstrated that the initial hypothermic response is followed by a period of hyperthermia lasting several days. That the hyperthermia can be blocked with administration of sodium salicylate suggests that the hyperthermia is a fever. Thus, the antiChE-induced effects on body temperature and other physiological systems cannot be explained solely by the immediate consequences of AChE inhibition and stimulation of cholinergic systems. Research into the mechanisms of action of antiChE toxicity will be improved with a better understanding of their effects on temperature regulation. |
| 1995 | Sarin poisoning in Matsumoto, Japan. | Lancet | A presumed terrorist attack with sarin occurred in a residential area of the city of Matsumoto, Japan, on June 27, 1994. About 600 residents and rescue staff were poisoned; 58 were admitted to hospitals, and 7 died. We examined clinical and laboratory findings of 264 people who sought treatment and the results of health examinations on 155 residents done 3 weeks after the poisoning. Findings for severely poisoned people were decreases in serum cholinesterase, acetylcholinesterase in erythrocytes, serum triglyceride, serum potassium and chloride; and increases in serum creatine kinase, leucocytes, and ketones in urine. Slight fever and epileptiform abnormalities on electroencephalogram were present for up to 30 days. Examination revealed no persisting abnormal physical findings in any individual. Acetylcholinesterase returned to normal within 3 months in all people examined. Although subclinical miosis and neuropathy were present 30 days after exposure, almost all symptoms of sarin exposure disappeared rapidly and left no sequelae in most people. |
| 1995 | Cloning, sequencing and functional expression of an acetylcholinesterase gene from the yellow fever mosquito Aedes aegypti. | FEBS Lett | A degenerate PCR strategy was used to isolate a fragment of the acetylcholinesterase gene (Ace) homolog from Aedes aegypti and screen for a cDNA clone containing the complete open reading frame of the gene. The predicted amino acid sequence of the Aedes gene shares 64% identity with Ace from Drosophila and 87% identity with the acetylcholinesterase gene from another mosquito species Anopheles stephensi. High levels of expression of the Aedes gene were achieved by infection of Sf21 cells with a recombinant baculovirus containing the Aedes Ace cDNA. The catalytic properties and sensitivity of the recombinant enzyme to insecticide inhibition are described and discussed in relation to the role of insensitive AChE in conferring resistance to organophosphorus and carbamate insecticides. |
| 1991 | Taiwan National Poison Center survey of glyphosate--surfactant herbicide ingestions. | J Toxicol Clin Toxicol | Between January, 1986 and September, 1988, the Taiwan National Poison Center recorded 97 telephone consultations (49 male, 48 female) on cases of ingestion of glyphosate-surfactant herbicide concentrate containing the isopropylamine salt of glyphosate (N-phosphonomethyl glycine, CAS 1071-83-6) and a non-ionic tallow amine surfactant. Eleven of the cases resulted in fatalities, all among those attempting suicide. The average amount ingested by survivors was 120 +/- 112 mL and by nonsurvivors was 263 +/- 100 mL (p less than or equal to 0.0001). The average age of survivors was 35 +/- 15 years compared to 54 +/- 11 years for fatalities (p less than or equal to 0.0002). Irritation of the oral mucous membrane and gastrointestinal tract was the most frequently reported effect. Other effects recorded were pulmonary dysfunction, oliguria, metabolic acidosis, hypotension, leukocytosis and fever. Fourteen patients received either atropine or pralidoxime plus atropine despite the fact that glyphosate does not inhibit acetylcholinesterase. Thirteen percent of patients received a urine test for paraquat or treatment customarily used for paraquat ingestion, possibly reflecting similar initial presentations following ingestion of these two herbicides. Laboratory differentiation is essential if any doubt exists about which herbicide was ingested. Patients ingesting large volumes of concentrated glyphosate-surfactant herbicide formulations require close observation and supportive treatment. |