Catechin, taxifolin, and proanthocyanidin derivatives from Entada elephantina rhizome and their antimicrobial activity assessment

Abstract

Twenty-two compounds, predominantly catechin, taxifolin, and proanthocyanidin derivatives, were isolated and characterized from the methanol extract of Entada elephantina tuberous rhizomes. Five taxifolin-based metabolites, elephantinosides A–E (1–5) and one proanthocyanidin, elephantinoside F (19), were previously undescribed. Their structures were elucidated primarily based on 1D- and 2D-NMR and HRESIMS data. The absolute configuration of isolates was determined via NOESY NMR technique and experimental and calculated ECD analyses. None of the tested compounds 3–6, 8–10, 13–17, and 19 exhibited antimicrobial activity against a panel of bacterial and fungal strains.