Peroxynitrite-Scavenging Glycosides from the Stem Bark of Catalpa ovata

Ten new glycosides, 6,10-O-di-trans-feruloyl catalpol (1), 6,6'-O-di-trans-feruloyl catalpol (2), 3,4-dihydro-6-O-di-trans-feruloyl catalpol (10), (8R,7'S,8'R)-lariciresinol 9'-O-β-d-(6-O-trans-feruloyl)glucopyranoside (17), and ovatosides A-F (18-22, 24), were isolated from the stem bark of Catalpa ovata along with 19 known compounds. All isolates, except 6 (catalposide) and 9 (6-O-veratroyl catalpol), were found to scavenge peroxynitrite (ONOO^-) formed by 3-morpholinosydnonimine. In particular, 12 compounds showed potent activity, with IC₅₀ values in the range 0.14-2.2 μM.