Two new lignan glucosides from the fruit of Vitex cannabifolia

Two new phenyldihydronaphthalene-type lignan glucosides, vitecannasides A (1) and B (2) were isolated from the fruit of Vitex cannabifolia Sieb. et. Zucc. (Verbenaceae) along with the six known lignan derivatives (3–8), four known iridoid glucosides (9–12), three known flavonoids (13–15), and one known phenylbutanone glucoside (16). Their chemical structures were determined on the basis of spectroscopic data as well as chemical evidence. The scavenging effect of 1, 2, and 11–16 on the stable free radical 1,1-diphenyl-2-picrylhydrazyl was examined. Compounds 1, 2, 14, and 15 exhibited stronger activity than that of l-cysteine. Especially, 14 and 15 showed more potent activity than that of α-tocopherol.