Iridoid glycosides from Gmelina philippensis

Six new iridoids, 6-O-alpha-L-(2"-O-, 3"-O-, 4"-O-tribenzoyl)rhamnopyranosy lcatalpol, 6-O-alpha-L-(2"-O-, 3"-O-dibenzoyl, 4"-O-cis-p-coumaroyl)rhamnop yranosylcatalpol, 6-O-alpha-L-(2"-O-, 3"-O-dibenzoyl, 4"-O-trans-p-coumaroy l)rhamnopyranosylcatalpol, 6-O-alpha-L-(2"-O-benzoyl, 3"-O-trans-p-coumaroy l)rhamnopyranosylcatalpol, 6-O-alpha-L-(2"-O-, 3"-O-dibenzoyl)rhamnopyranos ylcatalpol, and gmephiloside as well as five known monoacyl and diacyl rham nopyranosylcatalpol derivatives were isolated from the aerial parts of Gmel ina philippensis. Their structures were established by spectroscopic means. Additionally, the known iridoids catalpol, geniposidic acid, gardoside, an d 8-epi-loganic acid were identified and quantified by GC and GC-MS. The ta xonomic significance of rhamnopyranosylcatarpol derivatives and iridoid aci ds as chemical characters is discussed. (C) 2000 Elsevier Science Ltd. All rights reserved.