Seco-iridoid and lignans from Gymnosporia acuminata.

From the ethanol extract of Gymnosporia acuminata (syn. Maytenus hookeri), a new seco-iridoid derivative (1) and four lignans (2-5) were obtained. Significantly, the absolute configurations of the methoxypinoresinol derivatives 2 and 3 were unambiguously established for the first time by analysis of 2D NMR data combined with ECD calculations, identifying them as the 9'R and 9'S enantiomers. Meanwhile, compounds 4 and 5 exhibited moderate cytotoxic effects on HCT116 cells, with IC50 values of 41.0 and 49.0 μM.