Source
Program for Collaborative Research in the Pharmaceutical Sciences and Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, 833 South Wood Street, Chicago, Illinois 60612, USA.
Abstract
Activity-guided fractionation of an ethyl acetate extract of the twigs of Hernandia ovigera, using a soft agar assay with JB6 murine epidermal cells, led to the isolation of two new naturally occurring aryltetralin lignans, (7R,8S,7'R,8'R)-(+)-7'-acetyl-5'-methoxypicropodophyllin (1) and (7R,8S,7'R,8'R)-(+)-7'-acetylpicropodophyllin (2), of which 2 was previously identified as a synthetic product, along with eight known compounds, epiyangambin (3), caruilignan C, diasesartemin, (+)-epimagnolin A, N-methylcorydaldine, (-)-5'-methoxyyatein, (+)-syringaresinol dimethyl ether, and (-)-yatein. The structures and stereochemistry of 1 and 2 were determined using spectroscopic methods. Compounds 2 and 3 exhibited significant inhibition of the transformation of murine epidermal JB6 cells, with IC50 values of 0.15 and 0.4 microg/mL, respectively, while the other isolates were regarded as inactive (IC50 >4 microg/mL).