α-Glucosidase, α-Amylase and Antioxidant Evaluations of Isolated Bioactives from Wild Strawberry

Abstract

Diabetes mellitus is a metabolic disorder and is a global challenge to the current medicinal chemists and pharmacologists. This research has been designed to isolate and evaluate antidiabetic bioactives from <i>Fragaria indica</i>. The crude extracts, semi-purified and pure bioactives have been used in all in vitro assays. The in vitro α-glucosidase, α-amylase and DPPH free radical activities have been performed on all plant samples. The initial activities showed that ethyl acetate (<b>Fi.EtAc</b>) was the potent fraction in all the assays. This fraction was initially semi-purified to obtain <b>Fi.EtAc 1</b>-<b>3</b>. Among the semi-purified fractions, <b>Fi.EtAc 2</b> was dominant, exhibiting potent IC₅₀ values in all the in vitro assays. Based on the potency and availability of materials, <b>Fi.EtAc 2</b> was subjected to further purification to obtain compounds <b>1</b> (2,4-dichloro-6-hydroxy-3,5-dimethoxytoluene) and <b>2</b> (2-methyl-6-(4-methylphenyl)-2-hepten-4-one). The two isolated compounds were characterized by mass and NMR analyses. The compounds <b>1</b> and <b>2</b> showed excellent inhibitions against α-glucosidase (21.45 for <b>1</b> and 15.03 for <b>2</b> μg/mL), α-amylase (17.65 and 16.56 μg/mL) and DPPH free radicals (7.62 and 14.30 μg/mL). Our study provides baseline research for the antidiabetic bioactives exploration from <i>Fragaria indica</i>. The bioactive compounds can be evaluated in animals-based antidiabetic activity in future.