A roselle (Hibiscus sabdariffa Linn.) tea extract was found to have high inhibitory activity against porcine pancreatic α-amylase. Hibiscus acid and its 6-methyl ester were respectively isolated as active principles from the 50% methanol and acetone extracts of roselle tea. The activity of each isolate was compared to that of structurally related citric acid, a previously known inhibitor of fungal α-amylase.
