Hibiscus acid, an alpha -amylase inhibitor isolated from roselle tea, and i
ts derivatives were compared in an inhibition test for starch digestion. An
alpha -amylase-added Caco-2 system was established as a useful model to ev
aluate the effects of alpha -glucosidase inhibitors on starch digestion. Hi
biscus acid showed weak inhibition in this model system, and the methyl est
er derivatives showed even weaker or no acitivity.