Toxicological, anticholinesterase, antilipidemic, antidiabetic and antioxidant potentials of Grewia optiva Drummond ex Burret extracts.

Background In this study, Grewia optiva Drummond ex Burret root extracts were assessed for use as a remedy for oxidative stress, diabetes mellitus and neurological disorders. Methods The antioxidative potentials of the extracts were determined using DPPH and ABTS assays, whereas their enzyme inhibitory potentials were determined against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), α-glucosidase and α-amylase. In the in vivo experiments, methanol extract was orally administered to mice (n = 5) at four doses of 200, 300, 400 and 500 mg kg-1 for 30 days and its effect on glucose, triglycerides, total cholesterol, etc. were investigated. Results The highest free radical scavenging activities against DPPH and ABTS radicals were recorded for the methanol and ethyl acetate extracts, and their respective IC50 values were 75 and 88 μg/mL. In addition, these two fractions were highly active in inhibiting AChE and BChE, with IC50 values of 120 and 185 μg/mL, respectively. Moderate inhibition (μg/mL) was recorded against α-glucosidase (69.02 ± 1.02 and 64.29 ± 2.41) and α-amylase (65.12 ± 2.02 and 63.29 ± 1.41) and these were comparable to the inhibitory activities exhibited by the standard, acarbose. All the extracts showed high phenolic and flavonoid contents, which correlated with their antioxidant, anticholinesterase, α-glucosidase and α-amylase activities. The phenolic compounds in the crude extract and fractions were determined using the standard HPLC method and bioactive compounds, namely, morin, ellagic acid, kaempferol-3-(p-coumaroyl-diglucoside)-7-glucoside, apigenin-7-O-rutinoside, quercetin-3-(caffeoyl-diglucoside)-7-glucoside, etc., which were detected at various retention times. Significant decrease in cholesterol, triglyceride and blood glucose levels were observed. Conclusion G. optiva is a good source of antioxidants and other phytochemicals, some of which possess anticholinesterase, anti-glucosidase, and anti-amylase activities, and can be used to treat different health conditions such as oxidative stress, neurological disorders, and diabetes mellitus.