Enzyme AChE Research Articles

Exploring the potential of Fabiana imbricata Ruiz et Pav. (“Pichi”) against pest insects and pathogenic microorganisms for crop protection

• Fabiana imbricata extracts represents green insecticides for fruit fly control • Scopoletin is the main constituent of Fabiana imbricata active extract • Leaf fractions show repellency activity against Acanthoscelides obtectus adults • The extract has effect on detoxifiying enzimes such as carbolxyl esterases and acetylcholinesterase of Tenebrio molitor . • the components of these fractions could not inhibit the expression of acid and alkaline phosphatase in the intestine of T. molitor The loss of agricultural products by pests and microorganisms is intensely fought with synthetic products that can pose a serious threat to the environment, health, and foods. The use of plant-derived products in the management of these organisms is a sustainable and safe alternative. In this study, we investigated Fabiana imbricata , a very well-known species of Solanaceae found in the Patagonian region. The toxicological effects of its fractions were tested against Drosophila melanogaster and Tenebrio molitor . These fractions were also screened for repellency on Acanthoscelides obtectus and antimicrobial activity. Additionally, the mortality assay of D. melanogaster larvae revealed higher activity for the stem (LC 50 value of 7.5 µg/mL) and leaf (LC 50 value of 19.8 µg/mL) petroleum benzine fractions. T. molitor larvae needed to be exposed to a high concentration of stem fractions (200 and 300 µg/mL) to observe about 50 and 90% mortality, respectively. Moreover, repellency after 4 h of exposure was mainly observed with the stem dichloromethane fraction (conc. 100 µg/mL). The acetate fraction of the stem (FE-C) was responsible for the greatest growth inhibition of the tested bacteria ( E. coli, L. monocytogenes, L. innocua, Salmonella sp., and S. aureus ). Based on the findings, stem fractions were selected for studies of toxicity in non-target organisms and systemic effects on proteins and detoxification enzymes from T. molitor larvae. The fractions tested against adult bees were safe up to 500 µg/mL for 4 h of exposure and 48 h of observation. Total proteins and enzymes AChE, GST/GSH, and Carboxylase were significantly reduced, mainly with FE-C. In contrast, ACP and ALP were up-regulated, with the same fraction as the major inducer. The chemical profiles of the fractions analyzed by GC-MS and NMR showed that FE-C had scopoletin as the main component. Therefore, we selected this compound for in silico analysis of AChE docking, qualitative and quantitative study of insecticide-likeness, and toxicity prediction. The results indicated that scopoletin efficiently docked with the active site of AChE. Due to the high values ​​of Relative Drug Likelihood (RDL) (2.77) and Gaussian Scoring Function (GAU) (4.19) values, ​​it can consider as potential insecticide-likeness and the toxicity prediction study showed that this compound has low toxicity to mammals. These results demonstrate that FE-C has potential as an insecticidal agent against insect pests and can be of help in combating pathogenic microorganisms present in food.

Alkaloid Composition and Biological Activities of the Amaryllidaceae Species Ismene amancaes (Ker Gawl.) Herb.

Natural products have always played a significant role in the search for new drugs. One of the most relevant alkaloid-containing plant groups is the Amaryllidaceae family, a source of exclusive structures with a wide variety of pharmacological activities. The aim of this work was to determine the alkaloid composition and biological potential of an extract from the bulbs of an endemic Peruvian Amaryllidaceae species Ismene amancaes (Ker Gawl.) Herb. The alkaloid profiling was carried out by GC-MS, which revealed the presence of 13 compounds, 2 of them unidentified. The plant extract was found to contain high amounts of lycoramine, a galanthamine-type alkaloid. The extract also presented low inhibitory potential against the enzymes AChE and BuChE, with IC50 values of 14.6 ± 0.6 and 37.6 ± 1.4 μg·mL−1, respectively, and good to moderate inhibitory activity against the protozoan Plasmodium falciparum strain FCR-3 (chloroquine-resistant), with IC50 values of 3.78 ± 0.3 μg·mL−1. This is the first report of the alkaloid profile of a plant of the Ismene genus, which could be an interesting source of bioactive compounds.

Determination of acute median lethal concentration and sublethal effects on AChE activity of Gymnotus carapo (Teleostei: Gymnotidae) exposed to trichlorfon

Trichlorfon (TRF) is a pesticide widely used in aquaculture to control fish ectoparasites. This pesticide is an inhibitor of acetylcholinesterase, an essential enzyme for termination of nerve impulses. High rates of TRF use generate risks to the environment and human health. In the environment, pesticides can affect the local fauna and generate an ecological breakdown. There are several studies performed with fish production; however, gaps are created for native fish with other commercial values. The tuvira (Gymnotus carapo) is a fish native to Brazilian fauna and has great commercial importance in sport fishing. The present study aimed to determine the lethal concentration of trichlorfon (Masoten) in Gymnotus carapo and its sublethal effects on the enzyme AChE. In this study, the acute toxicity (the concentrations to kill 50% of the fish LC50) of TRF in tuviras (Gymnotus carapo) and acetylcholinesterase inhibition in liver and muscle tissue of tuviras submitted to sublethal concentrations were evaluated. For the acute assay, concentrations of 0.0, 5.0, 7.5, 15, 22.5, 30, 37.5 and 45 mg L-1 were used for a period of 96 h. After the acute exposure period, a LC50 of 6.38 mg L-1 was determined. In the sublethal assay, concentrations of 0.0, 0.238, 0.438 and 0.638 mg L-1 were used, based on 10% of the LC50, over a period of 14 days. Two collections were performed: one at seven days and the other at the end (day 14). Inhibition of acetylcholinesterase in the liver was only shown (p < 0.05) for the treatment with 0.638 mg L-1 after 14 days of exposure. At seven days, muscle activity showed a significant difference only for the treatments 0.438 and 0.638 mg L-1, compared with the treatment 0.238 mg L-1 and control. At 14 days of exposure, only the treatment 0.638 mg L-1 showed significant differences in relation to the other groups, thus showing that enzyme recovery had occurred. The value found in the acute test allowed the conclusion that TRF presents moderately toxic characteristics to Gymnotus carapo. The toxicity parameter values calculated in the present study assisted in estimation of maximum allowable limits in bodies of water when combined with test data from other non-target organisms.

Synthesis, preliminarily biological evaluation and molecular docking study of new Olaparib analogues as multifunctional PARP-1 and cholinesterase inhibitors

A series of new Olaparib derivatives was designed and synthesized, and their inhibitory activities against poly (ADP-ribose) polymerases-1 (PARP-1) enzyme and cancer cell line MDA-MB-436 in vitro were evaluated. The results showed that compound 5l exhibited the most potent inhibitory effects on PARP-1 enzyme (16.10 ± 1.25 nM) and MDA-MB-436 cancer cell (11.62 ± 2.15 μM), which was close to that of Olaparib. As a PARP-1 inhibitor had been reported to be viable to neuroprotection, in order to search for new multitarget-directed ligands (MTDLs) for the treatment of Alzheimer’s disease (AD), the inhibitory activities of the synthesized compounds against the enzymes AChE (from electric eel) and BChE (from equine serum) were also tested. Compound 5l displayed moderate BChE inhibitory activity (9.16 ± 0.91 μM) which was stronger than neostigmine (12.01 ± 0.45 μM) and exhibited selectivity for BChE over AChE to some degree. Molecular docking studies indicated that 5l could bind simultaneously to the catalytic active of PARP-1, but it could not interact well with huBChE. For pursuit of PARP-1 and BChE dual-targeted inhibitors against AD, small and flexible non-polar groups introduced to the compound seemed to be conducive to improving its inhibitory potency on huBChE, while keeping phthalazine-1-one moiety unchanged which was mainly responsible for PARP-1 inhibitory activity. Our research gave a clue to search for new agents based on AChE and PARP-1 dual-inhibited activities to treat Alzheimer’s disease.

HPLC characterization of molluscicidal component of Tamarindus indica and its mode of action on nervous tissue of Lymnaea acuminata

BackgroundFasciolosis is a water-borne disease with gastropods snail (Lymnaea acuminata) act as key-link is still burden for mankind especially in developing countries. Snail control is one of the important tools to trim down the frequency of fasciolosis. ObjectiveTo evaluate the toxic effect and inhibitory potential of plant Tamarindus indica and their active constituent on the key enzyme of nervous tissue of snail L. acuminata. MethodThe present study deals with the chromatographic isolation and identification of molluscicidal component from Tamarindus indica bark and its effects on enzymes activities of vector snail L. acuminata. ResultThe toxicity study reveals that among all organic extract ethanol extract of T. indica bark (96 h LC50:127.4 mgL−1) was more effective than other organic extracts. The 96 h LC50 of column purified fraction of T. indica bark was 13.78 mgL−1 respectively. Saponin was isolated, characterized and identified as active molluscicidal component in the bark of T. indica by column chromatography, TLC and HPLC chromatographic methods. The in vivo and in vitro treatment of column purified fraction and saponin has significant inhibition in enzyme AChE, ACP and ALP activities. The study of inhibition kinetics indicates that inhibition of AChE and ALP is competitive, while ACP is uncompetitive in both the treatments. ConclusionThus inhibition of these enzyme activities by T. indica bark column purified fraction and saponin in the snail L. acuminata may be the cause of its molluscicidal activity which leads snail death.

Investigation of Anticholinesterase Activity of a Series of Salvia Extracts and the Constituents of Salvia staminea

In continuation of our studies on the genus Salvia fourteen alcoholic extracts of Salvia species were evaluated for their anticholinesterase activity. Among them, the most active extract at 200 μg/mL was found to be S. staminea with the inhibition of 55.17 and 79.75% against enzymes AChE and BChE, respectively. Pure isolated compounds from S. staminea were investigated for anticholinesterase activity at 200 μM, and the abietane diterpenoids ferruginol and taxodione were found to be the most promising isolates, which were then further investigated at five different concentrations, and both diterpenoids exhibited high activity, particularly against BChE enzyme with IC50 values of 7.73 and 10.52 μM, respectively. Salvia chrysophylla and Salvia poculata extracts also exhibited moderate anticholinesterase activity.

On the multifunctionality of cholinesterases

Here we present novel information on non-classical functions of cholinesterases and on a cross-talk linking the two enzymes AChE and BChE. The first part of the article is focussed on the regulation of ChEs and the effects acquired when one of the proteins is knocked down (siRNA for BChE, AChE knock-out mouse). In the second part evidence is presented showing that AChE may exert adhesive properties through its binding to laminin, thus being involved in cell–matrix or cell–cell communication.

Evidence against a generalized membrane defect in dystrophic mice platelets.

The response of the membrane-bound enzyme AChE to changes in temperatures was investigated to test the applicability of the "generalized membrane defect" hypothesis proposed for human myotonic and Duchenne muscular dystrophies to the two forms of muscular dystrophy expressed in mice. For intact platelets from homozygous normal and dystrophic mice of both strains, a break (Tc) occurred in the Arrhenius plot of AChE activity at approximately 22 C. Solubilization of membrane-bound AChE by Triton X-100 produced a nonlinear Arrhenius plot over the temperature range (7.7 C to 37 C) in normal and dystrophic mice of both strains. However, in the presence of phospholipase A2 + C and Triton X-100, a linear Arrhenius plot was produced indicating that the membrane-bound enzyme is normally modulated by a bulk lipid domain as well as by a tightly bound (immobilized) phospholipid domain. The temperature response of platelet AChE from normal and dystrophic mice of both strains was not significantly different. These results showing normal temperature kinetics of AChE do not lend support to the theory of a membrane defect in the platelets of dystrophic mice.