Placovinane: 1″β-Ethoxy-6,4′-dimethoxy-3″,3″-dimethyl-1″,2″-dihydropyranoisoflavone, a New Isoflavone Derivative

Abstract

Isoflavonoids possess a 3-phenylchroman skeleton and are the biologically active secondary metabolites of various plants that are used for different health promoting and restoring effects through a variety of mechanisms. Chromatographic separation of the n-hexane extract from the stems of Placolobium vietnamense led to the isolation of a new isoflavone derivative, placovinane (1), together with four known compounds (2–5). The structures of isolated compounds were identified from their spectroscopic data and by comparison with the literature. All isolated compounds were evaluated for their α-glucosidase inhibition. They all exhibited potent α-glucosidase inhibition with IC50 values ranging from 11.0 to 87.3 µM, which was significantly less than the positive control acarbose (IC50 179 µM). The cytotoxicity of 1 was evaluated against KB, Hep G2, and MCF7 cell lines, and displayed weak cytotoxicity toward KB and Hep G2 cell lines, with the IC50 values of 89.6 and 93.8 μM, respectively.