Withangulatin I, a new cytotoxic withanolide from Physalis angulata

[[abstract]]A new withanolide, withangulatin 1 (2), was isolated from the whole plant of Physalis angulata. Its structure was established as (20S,22R)-15 alpha-acetoxy-5 beta,6 beta-epoxy-14 alpha-hydroxy-1,4-dioxo-witha-2,16,24-trienolide on the basis of chemical and spectroscopic methods including 2D-NMR and circular dichroism (CD) experiments. Withangulatin A (1) and withangulatin I (2) were tested for their cytotoxic activities against two human cancer cell lines, colorectal carcinoma COLO 205 and gastric carcinoma AGS, in vitro. Compounds 1 and 2 exhibited inhibitory activities against these two human cancer cells with IC50 values of 16.6 and 1.8 and 53.6 and 65.4 mu M, respectively.[[fileno]]2010336010006[[department]]化學