Enzyme Inhibitory Effect and Antioxidant Properties of Astragalus lagurus Extracts

Antioxidant and enzyme inhibitory effects (against cholinesterase, tyrosinase, α-amylase and α-glucosidase) of ethyl acetate, methanol, and aqueous extracts from Astragalus lagurus (Fabaceae) were investigated with spectrophotometric methods. Antioxidant capacity were evaluated by using different assay including free radical scavenging (DPPH and ABTS), reducing power (FRAP and CUPRAC), phosphomolybdenum, and metal chelating experiments. Total phenolic and flavonoid content was also determined as 20.34-20.72 mg GAEs/g and 19.58-31.10 mg REs/g, respectively. Generally, A. lagurus ethyl acetate and aqueous extracts were observed to possess higher antioxidant and enzyme inhibitory effects compared to methanol extract. The aqueous extract exhibited the strongest free radical scavenging activity on DPPH (20.65 mg TEs/g) and ABTS (67.43 mg TEs/g) as well as on reducing power tests (73.98 mg TEs/g for CUPRAC and 53.49 mg TEs/g for FRAP). α-Amylase and α-glucosidase inhibition were found to be 0.12-0.56 and 1.45-1.82 mmol ACAEs/g. These findings suggest that A. lagurus could provide natural biologically active agents to be used in food and pharmaceutical industry.