Antioxidant iridoid glucosides from Wendlandia formosana.

Two new iridoid glucosides of 10-O-caffeoyl scandoside methyl ester (3), and 6-methoxy scandoside methyl ester (4) besides the known compounds of scandoside methyl ester (1), methyl deacetyl asperulosidate (2), 10-O-caffeoyl daphylloside (5), phytol (6), and ursolic acid (7) were isolated from the leaves of Wendlandia formosana. Structure elucidation of the new iridoid glucosides was based on interpretation of high-resolution 1D and 2D NMR spectral data and chemical conversions. Antioxidant activity of Compounds (1-5) against diphenylpicrylhydrazyl (DPPH) and hydroxyl radical, and peroxynitrite was reported.