Activity-Guided Isolation of Resveratrol Oligomers from a Grapevine-Shoot Extract Using Countercurrent Chromatography

An activity-guided isolation of bioactive stilbenes has been carried out with the grapevine-shoot extract Vineatrol 30. After hexane precipitation of the polymeric constituents, the stilbene mixture was separated on a preparative scale using low-speed rotary countercurrent chromatography (LSRCCC). The antiproliferative activity of the separated LSRCCC fractions was then screened in the human cancer cell line A-431, and trans-resveratrol, trans-epsilon-viniferin, r-2-viniferin, hopeaphenol, and miyabenol C were identified as active principles. In addition, a new class of stilbene derivatives, which exhibit a gamma-lactam ring structure and exert a weak growth-inhibiting activity in A-431 cells, has been identified.