Bioactive Diarylheptanoids from Alpinia coriandriodora

Eight new diarylheptanoids,coriandralpinins A-H(1-8),were isolated from the rhizomes of Alpinia coriandriodora,an edible plant of the ginger family.Their structures,including the absolute configurations,were established by extensive spectroscopic analysis and ECD calculations.Compounds 1-8 have a 1,5-O-bridged diarylheptanoid structure featuring polyoxygenated aryl units.When evaluated for intracellular antioxidant activity using t-BHP stressed RAW264.7 mac-rophages,all these compounds scavenged reactive oxygen species(ROS)in a concentration-dependent manner.Compounds 3 and 5 also showed inhibitory activity against NO release in LPS-induced RAW 264.7 cells.Six known flavonols,7,4′-di-O-methylkaempferol,7-O-methylquercetin,7,4′-di-O-methylquercetin,7,3′,4′-tri-O-methylquercetin,kaempferol 3-O-β-d-(6-O-α-l-rhamnopyranosyl)glucopyranoside,and 3-O-β-d-glucopyranuronosylquercetin were also isolated and characterized from the rhizomes.