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

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.