Bioactive constituents of the roots of Cynanchum atratum

A novel biphenylneolignan, 2,6,2 ' ,6 ' -tetramethoxy-4,4 ' -bis(2,3-epoxy- 1-hydroxypropyl)biphenyl (1), and two new glycosides named atratoglaucoside s A (2) and B (3), were isolated from the roots of Cynanchum atratum, and t heir structures were determined on the basis of chemical and spectroscopic evidence. The aglycons of 2 and 3 were identified as glaucogenin C and 7-de soxyneocynapanogenin A, a new disecopregnane. A known compound, glaucogenin C 3-O-beta -D-cymaropyranosyl-(1 --> -4)-alpha -L-diginopyranosyl(1 -->4)- beta -D-thevetopyranoside (4), isolated from the same source, showed a sign ificant cytotoxic effect against 212 cells. This substance also gave a sign ificant inhibitory effect on TNF-alpha (tumor necrosis factor-alpha) format ion from the RAW 264.7 mouse macrophage-like cell line stimulated with LPS (lipopolysaccharide) and on the N9 microglial cell line stimulated with LPS /IFN-gamma (interferon-gamma).