Biologically Active Iridoids from Hedyotis diffusa

Two new iridoids, 10-O-benzoyl-6′-O-α-L-arabino(16)-β-D-glucopyranosylgeniposidic acid (1), deacetyl-6-ethoxyasperulosidic acid methyl ester (2), along with 14 other known iridoids, were isolated from the whole plant of Hedyotis diffusaWilld. Their structures were determined on the basis of spectroscopic analysis. The short-term-memory-enhancement activities of compounds 1, 7–9, 11, and 13 were evaluated on an Aβ transgenic drosophila model.