Determination of the absolute configurations and anti-angiogenic activities of new diarylheptanoid glucosides from Curcuma phaeocaulis

Diarylheptanoids, potential therapeutic agents and dietary supplements, are the main active compounds in the genus Curcuma, however, determination of the absolute configurations of the flexible polyhydric main chains in linear diarylheptanoids is still a challenge. In this study, an exploration of the phytochemical constituents of Curcuma phaeocaulis led to the isolation of eight novel linear diarylheptanoids (1-8). Enzymatic hydrolysis, preparation of acetonide derivatives, preparation of MTPA esters, and electronic circular dichroism calculations were comprehensively performed in order to determine their absolute configurations. In in vitro assays, compounds 2, 3, and 6 exhibited anti-angiogenic activities, and compounds 2, 3, and their aglycones inhibited the proliferation of HepG2 cells. These findings suggest that diarylheptanoid glucosides of C. phaeocaulis may be useful for suppression of hepatoma growth and metastasis.