Absolute Configuration of New Flavan-3-ol from Uncaria longiflora var.pteropoda (Miq.) Ridsd

摘要

A novel flavonoid, (-)-2R,3R-3,5,4’-trihydoxyflavan-[6,7:5”,6”]-2”-pyranone/ (-)-2R,3R-pyrano-5”,6”:6,7]-3,5,4’-trihydoxyflavan-2”-one named uncarinol (1) was isolated from the methanolic extract of the leaves of Uncaria longiflora var.pteropoda (Miq.) Ridsd. along with the known (-)-epiafzelechin (2) and (-)-epicatechin (3). Structures of the flavonoids wereelucidated by 1D and 2D NMR, FTIR, UV, MS and CD data. The absolute configuration of the new uncarinol was establishedby comparison of its experimental and calculated electronic circular dichroism (ECD) data.