Identification of a new α-glucosidase inhibitor: Alkyl ferulate ester derived from unripe fruits of Solanum torvum Swartz

Abstract

In this study, the phytochemical compositions and a-glucosidase inhibitory activity of the ethyl acetate extract derived from the unripe fruits of Solanum torvum Swartz have been investigated. The investigation led to the isolation of a new isoferulate fatty alkyl ester, solacanin B (1), in addition to eight known compounds, including lyciumol A (2), ethyl caffeate (3), caffeic acid (4), scopo- letin (5), p-hydroxybenzaldehyde (6), p-hydroxybenzoic acid (7), vanillic acid (8) and 1-0-palmitoylglycerol (9). The structural elucidation of these compounds was achieved through extensive spectroscopic analyses and reference literature. Bioactivity assay of all compounds demonstrated that compounds 1-4, and 7 showed more potent a-glucosidase inhibition activities, with ICso values of 48.4, 29.3, 38.8, 95.0, and 186.6 µm, respectively, than that of positive control acarbose (1C50, 214.5 μμ).