Inhibition Of Enzyme Acetylcholinesterase Research Articles

<p>Phytochemical and pharmacological investigation of <em>Teucrium muscatense</em></p>

<p>The effect of enzyme inhibition, anticancer, antifungal, antioxidants activities of the extracts of <em>Teucrium muscatense </em>obtained with different organic solvents was investigated. Chloroform fraction exhibited promising inhibition (64%) with IC<sub>50 </sub>value (390 ± 2.0 μg/mL) against urease, while other fractions displayed moderate activity. In case of α-glucosidase and acetyl cholinesterase enzyme inhibition assays, all fractions were found inactive at a concentration of 1.0 mg/mL. The <em>n</em>-hexane fraction of <em>Teucrium muscatense </em>exhibited highest anticancer activity against breast cancer cell (MDAMB231) line at high (100 µg/mL) concentration and also inhibited the growth of <em>F. oxysporum </em>up to 64.3% in case of antifungal activity. EtOAc fraction showed highiest DPPH (70.6%) and ABTS (76.7%) radical scavenging activity at highest concentration (1000 μg/mL). Bioassay guided isolation of EtOAc fraction afforded two flavonoids (<strong>1</strong> and <strong>2</strong>). Both compounds showed highiest ABTS activity and could be a significant markers in the EtOAc fraction. Anti-lipid peroxidation assay was also performed in which aqueous fraction showed highest percentage of 73.2% at higher concentration (1000 μg/mL) followed by n-BuOH (64.1%) and EtOAc (51.4%) fractions. GC/MS analysis of the essential oil of <em>T. mascatense</em> showed higher percentage of linalool (34.18%), limonene (13.45%), linalyl acetate (10.04%), and β-eudesmol (9.21%). Proximate composition of <em>Teucrium muscatense </em>showed that it contained high amount of ash (19.6%), protein (10.3%), and fiber (17.5%).</p>

Evaluation of essential oils from<em> Boswellia sacra</em> and <em>Teucrium mascatense</em> against acetyl cholinesterase enzyme and urease enzyme

<p>Enzyme inhibition is one of the most important areas of pharmaceutical research which resulted in the discoveries of several useful drugs. The prime aim of this study is to identify effective natural inhibitors against pharmacologically important enzymes such as acetylcholinesterase enzyme and urease enzyme. In present study, we evaluated the essential oils extracted from medicinally important plants including <em>Boswellia sacra</em><strong> </strong>Flückiger (frankincense) and <em>Teucrium mascatense </em>Boiss.<em> </em>Two major constituents of frankincense essential oil including (+)-α-pinene and (R)-+-limonene<strong> </strong>were also investigated against these enzymes. The essential oils were extracted from <em>Boswellia sacra </em>and <em>Teucrium mascatense</em> which are<strong> </strong>native plants to the southern and northern areas of Oman, respectively. In this study, the essential oil of frankincense exhibited significant inhibition with IC<sub>50</sub> value of 0.043±0.02 mg/mL, against acetylcholinesterase enzyme while against urease enzyme it has shown good inhibition with IC<sub>50</sub> value of 0.17 ± 0.05 mg/mL. The essential oil obtained from the<em> Teucrium mascatense</em> was found to be in active against both the enzymes. On acetylcholinesterase enzyme inhibition assay, the (+)-α- pinene exhibited significant inhibition (IC<sub>50</sub> = 0.094±0.01 mg/mL) while (R)-+- limonene<strong> </strong>was found to be inactive on this assay. Against urease enzyme (+)-α- pinene and (R)-+- limonene<strong> </strong>showed moderate activity 40.06±1.03 % and 19.5±1.00 %, respectively. Interestingly, the mixture of equal concentration of (+)-α- pinene and (R)-+- limonene<strong> </strong>exhibited 70% inhibition with IC<sub>50</sub> value of (0.195 ± 0.10 mg/mL) which shows the synergistic relationship between them. Promising inhibitory potential of frankincense essential oil and (+)-α-pinene, against acetylcholinesterase enzyme and urease enzyme indicated their potential therapeutic role to manage Alzheimer’s disease and stomach ulcers, respectively.</p>

Synthesis of Novel Pyrazolines, Their Boron-Fluorine Complexes, and Investigation of Antibacterial, Antioxidant, and Enzyme Inhibition Activities.

New 3,5-disubstituted-2-pyrazoline derivatives (4-6), their boron-fluorine complexes (boron (3-(2'-aminophenyl),5-(2'-/3'-/4'-pyridyl)pyrazoline, BOAPPY) (7-9) and boron 1,2'-diazaflavone complex (BODAF) (11) were synthesized starting from azachalcones (1-3) to diazaflavone (10), respectively. Biological evaluation of compounds 4-9 and 11 showed remarkable antioxidant, antibacterial, and acetylcholinesterase and tyrosinase enzyme inhibition activities. All newly synthesized compounds 4-9 and 11 showed respectable antibacterial effect with minimum inhibitory concentrations in the range of 4.7-150 μg/mL.

Novel Enzymatic Potentiometric Approaches for Surfactant Analysis

AbstractThe present study described a novel application of simple potentiometric enzymatic method for analysis of surfactants based on their inhibitory effect on acetylcholinesterase enzyme (AChE). The enzymatic activity was measured through monitoring hydrolysis of acetylcholine (ACh) with a disposable acetylcholine potentiometric sensor. Comprehensive investigations were carried out including the effect of incubation time, cholinesterase enzyme and the working calibration ranges. Based on inhibition of AChE, different cationic, anionic and nonionic surfactants were determined in the concentration range from 0 to 40 μg mL−1 with detection limits reaching 0.07 μg mL−1 depending on the nature of surfactants. The degree of AChE inhibition caused by different tested surfactants were as follows: cetylpyridinium chloride (CPC)>benzyldimethylhexadecyl ammonium chloride (BDHAC)>Hyamine (Hy)>cetyltrimethylammonium bromide (CTAB)>Triton X‐100 (TX‐100)>sodium dodecyl sulphate (SDS). The proposed method was applied for determination of surfactants in pharmaceutical formulation, detergents products and environmental samples with acceptable sensitivity and reproducibility.

Dose and Time-dependent Alterations in Various Cholinergic and Non-cholinergic Markers after Organophosphate Poisoning: Possible Role in Diagnosis

Toxicity of organophosphates (OP) is mainly ascribed to inhibition of acetylcholinesterase (AChE) enzyme at the cholinergic synapses. This results in cholinergic crisis leading to various muscarinic, nicotinic and central effects. Additionally, there are several non-cholinergic effects of OP which are likely to exacerbate the toxicity and complicate diagnosis. The present study reports the dose (0.125 - 4.0 LD50) and time (1 h - 14 d)- dependent acute effect of diisopropyl phosphorofluoridate (DFP) on mice body weight, organ-body weight index (brain), butyrylcholinesterase (BChE) and β-glucoronidase (BG) activity in plasma, AChE activity, reduced glutathione (GSH) and malondialdehyde (MDA) levels in brain, and DNA damage in brain (agarose gel electrophoresis) and blood (comet assay). The study reveals a dose and time- dependent BChE inhibition up to 24 h and AChE inhibition up to 7 d. However, elevated BG levels were observed up to 1 h only after 1.0, 2.0, and 4.0 LD50 DFP. Diminished GSH levels up to 24 h and increased MDA levels at 4 h indicated oxidative stress. None of the treatments produced any DNA damage in soft tissues. In addition to cholinesterase, the study suggests possible relevance of measuring BG levels (non-cholinergic marker) in the diagnosis of OP poisoning.

Chlorpyrifos Toxicity in Mouse Cultured Cerebellar Granule Neurons at Different Stages of Development: Additive Effect on Glutamate-Induced Excitotoxicity.

Chlorpyrifos (CPF) is a neurotoxic organophosphorus (OP) insecticide. Its mechanism of action includes oxidative stress, excitotoxicity, and inhibition of the acetylcholinesterase enzyme (AChE). The aim of the present study is to investigate CPF toxicity in mature and immature cerebellar granule neurons (CGNs), as well as its effect on glutamate induced excitotoxicity. This study was an in vitro experimental study performed on mice cultured CGNs. Immature and mature neurons were exposed to different concentrations of CPF (1-1000 µM) and glutamate (10-600 µM) for 48 hours after which we used the MTT assay to measure cytotoxicity. Immature neurons had exposure to CPF for 5 days in order to evaluate the cytotoxic effect on developing neurons. Mature neurons received sub-lethal concentrations of CPF (10, 100 µM) combined with different concentrations of glutamate. AChE activity and reactive oxygen species (ROS) generation were assessed after treatments. Immature CGNs had increased sensitivity to CPF toxicity compared to mature neurons. We observed significantly greater ROS production in immature compared to mature neurons, however AChE activity was more inhibited in mature neurons. Although CPF toxicity was not well correlated with AChE inhibition, it correlated well with ROS production. Glutamate toxicity was potentiated by sub-lethal concentration of CPF, however glutamate induced ROS production was not affected. The results suggested that CPF potentiated glutamate toxicity by mechanisms other than oxidative stress. CPF toxicity differed in mature and immature neurons. Potentiated glutamate toxicity by CPF implied that CPF exposure might be a risk factor for neurodegenerative disease.

English

Bauhinia ungulata L. species, belongs to the genus Bauhinia, popularly known as pata de vaca, is among the species of medicinal employ in Brazil, used to treat diabetes. The aim of this study was to characterize the chemical composition, antimicrobial activity, toxicity on Artemia salina and acetylcholinesterase enzyme inhibition by essential oil from B. ungulata L. The chromatographic analysis revealed 18 components, the majority were the β-caryophyllene (15.9%), caryophyllene oxide (9.2%), α-humulene (8.1%), epi-γ-eudesmol (7.5%), α-bisabolol (4.7%), copaene (3.5%), nerolidol (3.3%), α-bisabolol oxide B (2.5%), spathulenol (2.1%). The essential oil showed high toxicity compared to the tests with Artemia salina and inhibited 95.96%±0.62 of the acetylcholinesterase enzyme. The microorganisms show antimicrobial inhibition with Candida albicans (85%), Bacillus cereus (65.5%) and Staphylococcus aureus (66.4%), Salmonella typhimurium (68.7%) and Citrobacter freundii (46.1%). The oil showed great potential when tested in bioassays. Key words: Volatile oil, cytotoxicity on microcrustacean, antifungal, antibacterial, neurodegenerative disease.

In vitro characterization of pralidoxime transport and acetylcholinesterase reactivation across MDCK cells and stem cell-derived human brain microvascular endothelial cells (BC1-hBMECs).

BackgroundCurrent therapies for organophosphate poisoning involve administration of oximes, such as pralidoxime (2-PAM), that reactivate the enzyme acetylcholinesterase. Studies in animal models have shown a low concentration in the brain following systemic injection.MethodsTo assess 2-PAM transport, we studied transwell permeability in three Madin-Darby canine kidney (MDCKII) cell lines and stem cell-derived human brain microvascular endothelial cells (BC1-hBMECs). To determine whether 2-PAM is a substrate for common brain efflux pumps, experiments were performed in the MDCKII-MDR1 cell line, transfected to overexpress the P-gp efflux pump, and the MDCKII-FLuc-ABCG2 cell line, transfected to overexpress the BCRP efflux pump. To determine how transcellular transport influences enzyme reactivation, we developed a modified transwell assay where the inhibited acetylcholinesterase enzyme, substrate, and reporter are introduced into the basolateral chamber. Enzymatic activity was inhibited using paraoxon and parathion.ResultsThe permeability of 2-PAM is about 2 × 10−6 cm s−1 in MDCK cells and about 1 × 10−6 cm s−1 in BC1-hBMECs. Permeability is not influenced by pre-treatment with atropine. In addition, 2-PAM is not a substrate for the P-gp or BCRP efflux pumps.ConclusionsThe low permeability explains poor brain penetration of 2-PAM and therefore the slow enzyme reactivation. This elucidates one of the reasons for the necessity of sustained intravascular (IV) infusion in response to organophosphate poisoning.Electronic supplementary materialThe online version of this article (doi:10.1186/s12987-016-0035-0) contains supplementary material, which is available to authorized users.

β-glucan attenuated scopolamine induced cognitive impairment via hippocampal acetylcholinesterase inhibition in rats

β-glucan (polysaccharide) rich diet has been reported to enhance cognition in humans but the mechanism remained elusive. Keeping this in mind, the present study was designed to investigate the interaction of β-glucan with central cholinergic system. Briefly, in-silico analysis revealed promising interactions of β-glucan with the catalytic residues of acetylcholinesterase (AChE) enzyme. In line with this outcome, the in vitro assay (Ellman's method) also exhibited inhibition of AChE by β-glucan (IC50=0.68±0.08μg/µl). Furthermore, the in vivo study (Morris water maze) showed significant dose dependent reversal of the amnesic effect of scopolamine (2mg/kg i.p.) by β-glucan treatment (5, 25, 50 and 100mg/kg, i.p.). Finally, the hippocampi of aforementioned treated animals also revealed dose dependent inhibition of AChE enzyme. Hence, it can be deduced that β-glucan possesses potential to enhance central cholinergic tone via inhibiting AChE enzyme. In conclusion, the present study provides mechanistic insight to the cognition enhancing potential of β-glucan. Keeping in mind its dietary use and abundance in nature, it can be considered as economic therapeutic option against cognitive ailments associated with decline in cholinergic neurotransmission.

Synthesis and inhibitory properties of some carbamates on carbonic anhydrase and acetylcholine esterase

A series of carbamate derivatives were synthesized and their carbonic anhydrase I and II isoenzymes and acetylcholinesterase enzyme (AChE) inhibitory effects were investigated. All carbamates were synthesized from the corresponding carboxylic acids via the Curtius reactions of the acids with diphenyl phosphoryl azide followed by addition of benzyl alcohol. The carbamates were determined to be very good inhibitors against for AChE and hCA I, and II isoenzymes. AChE inhibition was determined in the range 0.209–0.291 nM. On the other hand, tacrine, which is used in the treatment of Alzheimer’s disease possessed lower inhibition effect (Ki: 0.398 nM). Also, hCA I and II isoenzymes were effectively inhibited by the carbamates, with inhibition constants (Ki) in the range of 4.49–5.61 nM for hCA I, and 4.94–7.66 nM for hCA II, respectively. Acetazolamide, which was clinically used carbonic anhydrase (CA) inhibitor demonstrated Ki values of 281.33 nM for hCA I and 9.07 nM for hCA II. The results clearly showed that AChE and both CA isoenzymes were effectively inhibited by carbamates at the low nanomolar levels.

Biological evaluation of the toxicity and the cell cycle interruption by some benzimidazole derivatives

In this work, the in vitro tests of biological activity of benzimidazoles were conducted. This group of benzimidazole derivatives was evaluated as potential bioreductive agents and their characteristic pro-apoptosis activity and cell cycle interruption on the human lung adenocarcinoma A549 cells were discussed. Their toxicity on the healthy human erythrocytes and their influence on the healthy human erythrocytes acetylcholinesterase enzyme (AChE) were established. Their apoptosis activity on A549 cells line was determined by Annexin V-APC test, and it was visualized by Hoechst test. In the next stage, their influence on the cell cycle interruption was determined by using the ribonuclease reagent. The AChE inhibition test was defined by the Ellman method, and the red blood cell lysis was defined by erythrotoxicity test. The results proved the pro-apoptosis properties of all tested compounds in normoxia and hypoxia. The DNA content assay showed that the benzimidazoles possess the ability to interrupt S phase of tumor cell cycle. The best activity in this action was presented by compound 1, especially in hypoxia, and it proves that the N-oxide analogs are predispositioned to the hypoxic target. In this study, the benzimidazoles were found as potentially biocompatible and their inhibition of acetylcholinesterase was lower than tirapazamine and much lower than tacrine which constitutes their desired effect of potential biological activity.

Anticholinesterase and Antioxidant Effects of Traditional Herbal Medicines used in the Management of Neurodegenerative Diseases in Mauritius

Bioactive plant constituents from traditional herbal medicines can simultaneously protect neurons against oxidative stress and act as cholinesterase inhibitors, two key factors involved in the pathogenesis of neurodegenerative diseases. This study thus aimed at investigating the antioxidant and anticholinesterase activities of five herbal medicines, including 3 polyherbal formulas (F1, F2, F4) and 2 singleherb formulas (F3 and F5), currently used in Mauritius. Antioxidant activities were determined by the reducing potential, scavenging and chelating properties while the pro-oxidant effects was characterized by the copper-phenanthroline assay. While all extracts exhibited antioxidant activity, different extent of such property was observed in each assay. F3 containing Gingko biloba L. demonstrated a higher ferric reducing antioxidant potential (1654 ± 37.8 μmol Fe (II) equivalent/g dry weight) compared to the other extracts. The elixir F2 consisting of Gingko biloba L., Hypericum perforatum L. and Salvia miltiorrhiza Bunge was a potent scavenger of hypochlorous acid and hydroxyl radical and was a strong iron (II) chelator. All extracts inhibited acetylcholinesterase enzyme in a dose-dependent manner, which correlated strongly with total phenolics (r=0.894, p<0.01) and total proanthocyanidins (r=0.937, p<0.01). These findings suggested that activities of the locally available herbal drugs used to slow the progression of neurodegenerative disorder might be partly ascribed to their antioxidant and anticholinesterase activity. KEY WORDS : Cholinesterase inhibitors; Oxidative stress; Pro-oxidant activities; Traditional herbal medicine; Neurodegenerative diseases

Downregulation of nicotinic and muscarinic receptor function in rats after subchronic exposure to diazinon.

Diazinon (DZN) is an organophosphate insecticide which exerts its effect through the inhibition of acetylcholinesterase enzyme (AChE). In this work, we studied the development of tolerance to subchronic p.o. administration of DZN in rats, under both in vivo and in vitro conditions. A group of 20 rats (2 groups, n=10) was administered p.o. the 1/10 of established LD50 DZN (namely 55.87mg/kgbw) for 28days. On the 14th and 28th day of study with isolated diaphragm and ileum, we examined the downregulation of nicotinic and muscarinic receptor function through Electrical Field Stimulation (EFS). Maximum contractility of the diaphragm was recorded on the 14th day of the study (25% higher compared to the non-treated rats), while on the 28th day the contractions almost did not differ from the values found in non-treated rats. EFS of isolated ileum on the 14th day of study caused significantly higher contractions compared to the non-treated rats, but after 28days, ileum contractions decreased approximately to the level of contractions in non-treated rats. On the 14th study day, we also recorded increased amplitude of spontaneous ileum contractions, compared to non-treated rats. The application of increasing ACh concentrations caused dose-dependent ileum contractions, without statistically significant differences of median effective concentration (EC50) values in non-treated and treated rats. Tolerance to subchronic DZN administration develops due to various adaptation mechanisms, including the most important one-downregulation of nicotinic and muscarinic receptor function.

Synthesis, Biological Evaluation and Molecular Docking Study of Hydrazone-Containing Pyridinium Salts as Cholinesterase Inhibitors.

A series of pyridinium salts bearing alkylphenyl groups at 1 position and hydrazone structure at 4 position of the pyridinium ring were synthesized and evaluated for the inhibition of both acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) enzymes. The cholinesterase (ChE) inhibitory activity studies were carried out by using the Ellman's colorimetric method. All compounds displayed considerable AChE and BuChE inhibitory activity and some of the compounds manifested remarkable anti-AChE activity compared to the reference compound, galantamine. Among the title compounds, the series including benzofuran aromatic ring exhibited the best inhibitory activity both on AChE and BuChE enzymes. Compound 3b, 4-[2-(1-(benzofuran-2-yl)ethylidene)hydrazinyl]-1-(3-phenylpropyl)pyridinium bromide, was the most active compound with IC50 value of 0.23 (0.24) µM against enantiomeric excess (ee)AChE (human (h)AChE) while compound 3a, 4-[2-(1-(benzofuran-2-yl)ethylidene)hydrazinyl]-1-phenethylpyridinium bromide, was the most active compound with IC50 value of 0.95 µM against BuChE. Moreover, 3a and b exhibited higher activity than the reference compound galantamine (eeAChE (hAChE) IC50 0.43 (0.52) µM; BuChE IC50 14.92 µM). Molecular docking studies were carried out on 3b having highest inhibitory activity against AChE.

Clinical profile of organophosphate poisoning at a tertiary-care center

Background: Nowadays, organophosphate (OP) compounds are widely used in agricultural field as an insecticide. Toxicity with these compounds is owing to inhibition of acetylcholinesterase enzyme. Patients are presented with muscarinic and nicotinic side effects. Red blood cells and plasma acetylcholinesterase enzyme (AChE) levels are helpful in diagnosis of the patients. It may cause life-threatening acute and chronic complications. All poisoned patients are required intensive care and treatment with injections atropine and PAM. Objective: To study the clinical aspect of OP poisoning in detail with hospital stay, clinical course, complication, and recovery and mortality in OP poisoning. Materials and Methods: This study was done at PDU Medical College, Rajkot, Gujarat, India, comprising 50 cases of OP poisoning. After taking written consent, personal history of the patients was taken. Then, a detailed history regarding poison and clinical symptoms was taken. Then, general and systematic examinations of patients were carried out, and blood samples were sent for investigations. We followed up the patients till discharge or expired. Result: In our study, maximum incidence of OP poisoning was in between 20 and 40 years age group (60%), and male to female ratio was 2:1. Clinical signs such as bradycardia and tachycardia were present in 20% cases. Miosis was present in 70% cases, and it is more dangerous. Low serum AchE level was found in 68% cases, with mortality in 44.62% among them. Type-I paralysis (52%) and acute respiratory failure (32%) were found as life-threatening complications. In our study, 64% patients survived. Conclusion: Detailed history and thorough clinical examination of patients are helpful in diagnosing the patients of OP poisoning. Life-threatening complications occurred in these patients. Early detection and immediate treatment in intensive care units with injections atropine and PAM can increase the chances of survival rate of patients.

Acetyl-cholinesterase Enzyme Inhibitory Effect of &lt;i&gt;Calophyllum&lt;/i&gt; species

Purpose: To search for new acetylcholinesterase enzyme inhibitors from Calopyllum species. Methods: Six stem bark extracts of Calophyllum inophyllum , C. soulattri , C. teysmannii , C. lowii , C. benjaminum and C. javanicum were subjected to anti-cholinesterase analysis against acetylcholinesterase (AChE) enzyme using Ellman’s method. Results: Most of the extracts showed promising inhibitory activity against AChE at concentrations of 100 μg/mL, with the methanol extract of C. inophyllum demonstrating the strongest inhibitory effect of 81.28 % followed by the methanol extract of C. benjaminum with 74.32 % inhibition. The methanol extracts of Calophyllum inophyllum and Calophyllum bejaminum also showed significant inhibitory activity towards the acetylcholinesterase (AChE) enzyme. Conclusion: Calophyllum species is capable of yielding potential lead compounds for the development for acetyl-cholinesterase enzyme inhibition drugs. Keywords: Calophyllum species, Acetylcholinesterase, Inhibitors

New Tacrine Hybrids with Natural-Based Cysteine Derivatives as Multitargeted Drugs for Potential Treatment of Alzheimer's Disease.

Alzheimer's disease (AD) is a devastating age-dependent neurodegenerative disorder. The main hallmarks are impairment of cholinergic system and accumulation in brain of beta-amyloid (Aβ) aggregates, which have been associated with oxidative damage and dyshomeostasis of redox-active biometals. The absence of an efficient treatment that could delay or cure AD has been attributed to the complexity and multifactorial nature of this disease. With this in mind and the recent interest on natural-based drugs, we have explored a set of natural-based hybrid compounds by conjugation of a tacrine moiety with an S-allylcysteine (garlic constituent) or S-propargylcysteine moiety aimed at improving the cholinergic system and neuroprotective capacity. The docking modeling studies allowed the selection of linkers to optimize the bimodal drug interaction with acetylcholinesterase enzyme (AChE) active site. The compounds were evaluated for some representative biological properties, including AChE activity and Aβ aggregation inhibition, as well as for their neuroprotective activity to Aβ- and ROS-induced cellular toxicity. The most promising results were achieved by compounds 9d for the AChE inhibition and 9l for the remarkable prevention of superoxide production and Aβ-induced cellular toxicity.

Reduced expression of exocytotic proteins caused by anti-cholinesterase pesticides in Brachionus calyciflorus (Rotifera: Monogononta).

The organophosphate and carbamate pesticides methyl-parathion and carbaryl have a common action mechanism: they inhibit acetylcholinesterase enzyme by blocking the transmission of nerve impulses. However, they can alter the expression of exocytotic membrane proteins (SNARE), by modifying release of neurotransmitters and other substances. This study evaluated the adverse effects of the pesticides methyl-parathion and carbaryl on expression of SNARE proteins: Syntaxin-1, Syntaxin-4 and SNAP-23 in freshwater rotifer Brachionus calyciflorus. Protein expression of these three proteins was analyzed before and after exposure to these two pesticides by Western Blot. The expression of Syntaxin-1, Syntaxin-4 and SNAP-23 proteins in B. calyciflorussignificantly decreases with increasing concentration of either pesticides. This suggests that organophosphates and carbamates have adverse effects on expression of membrane proteins of exocytosis by altering the recognition, docking and fusion of presynaptic and vesicular membranes involved in exocytosis of neurotransmitters. Our results demonstrate that the neurotoxic effect of anticholinesterase pesticides influences the interaction of syntaxins and SNAP-25 and the proper assembly of the SNARE complex.

English

Plants from Annona (Annonaceae) genus are present in tropical regions, where they have economic and medicinal potential. Information on the fatty acids profile and bioactivity from seed oil of Annona species are incipient. The objective of this work was to investigate Annona hypoglauca seeds oil in terms of its yield, composition and biological activity (acetylcholinesterase enzyme inhibition, bactericidal and fungicidal activity). Fatty acids profiles were determined by Gas Chromatography equipped with Flame Ionization Detector. Oil yield reached about 15% and the major constituents detected were ω-9 oleic acid (42.65%) and ω-6 linoleic acid (29.63%). A. hypoglauca oil was potent for acetylcholinesterase inhibition (79.55%), and presented high and selective bioactivity against Candida albicans . Keywords: Annona hypoglauca , ω-9 Oleic Acid, ω-6 Linoleic Acid, Acetylcholinesterase, Candida albicans

Toxicity and biochemical efficacy of chemically characterized Rosmarinus officinalis essential oil against Sitophilus oryzae and Oryzaephilus surinamensis

The study explores the efficacy of Rosmarinus officinalis essential oil (EO) as a plant based insecticide and its effect on acetylcholinesterase (AChE) and antioxidant enzyme system in Sitophilus oryzae and Oryzaephilus surinamensis. GC–MS result revealed 2-methoxy-3-(2-propenyl)-phenol, 1,8-cineole, and camphor as the major component of the EO. As a fumigant, at 0.15μl/ml EO exhibited 100% toxicity and antifeedant activity against the test insect pests without affecting seed germination. EO inhibited acetylcholinesterase enzyme activity (>40%) in both test insect pest. A significant impairment in the antioxidant enzyme system; superoxide dismutase (SOD), and catalase (CAT), along with the decrease in reduced glutathione (GSH) level was observed. However, in the case of O. surinamensis GSH level showed a biphasic response with an initial increase followed by a decline in its level. The findings revealed that the toxicity of EO might be associated with inhibition of AChE activity and oxidative imbalance. In view of the strong fumigant toxicity and antifeedant activity, test EO may be recommended as an eco-friendly alternative to synthetic insecticides.