Abstract:
Alzheimer’s disease (AD) is an advancing age-related neurodegenerative disease that is depicted by the decline of acetylcholine neurotransmitter leading to cognitive decline. Inhibition of acetylcholinesterase (AChE) is deemed as a promising tactic in the administration of AD. The shortcoming of presently approved drugs in use for AD is inherent toxicity and side effects compromising the drug efficacy studies. The present study was designed to investigate the cytotoxic and anticholinesterase potential of 24 extracts of three plant species, namely Argyrolobium roseum, Zygophyllum fabago and Citrullus colocynthis. In vitro bioactivity screening was performed for various plant extracts obtained through detailed fractionation of crude plant extracts. Anticholinesterase potential was evaluated by Ellman’s method and cytotoxic activity was assessed by Brine shrimp lethality assay and MTT (3-(4,5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide) cell proliferation assay using 2 human cancer cell lines (HUH-liver & MCF-7-breast). Eight extracted fractions of plant species, revealed promising inhibition as above 50% on AChE at concentration of 100μg/ml. While three butanol fractions of C.colocynthis and Z.fabago plant displayed significant IC50 values 32.35, 36.02, 36.89 (μg/ml) compared with standard Galanthamine IC50 8.97 μg/ml. Brine shrimp lethality assay identified presence of cytotoxic constituents of plants and revealed hexane extract of A.roseum to be most toxic possessing median lethal concentration value of 40.04 μg/ml. MTT assay results presented that plants are not cytotoxic against cell lines. In conclusion, the plant extracts exhibited occurrence of bioactive compounds with significant AChE inhibition reinforcing their consumption in the management of AD and supreme effective of all for AD treatment are the extracted BuOH fractions of C.colocynthis and Z.Fabago as they shown no cytotoxicity against both cell lines and maximum inhibition of acetyl cholinesterase enzyme.
