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 were
elucidated by 1D and 2D NMR, FTIR, UV, MS and CD data. The absolute configuration of the new uncarinol was established
by comparison of its experimental and calculated electronic circular dichroism (ECD) data.