Iridoid glycosides from Globularia trichosantha

A new iridoid glycoside, deacetylalpinoside (2), was isolated from the aerial parts of Globularia trichosantha together with nine known iridoid glycosides: catalpol, 10-O-benzoyl-catalpol, aucubin, asperuloside, deacetylasperuloside, asperulosidic acid, scandoside, geniposidic acid, and alpinoside (1). From the underground parts of the same plant, two new bisiridoid glycosides, globulosides A (3) and B (4); a known iridoid glycoside, globularidin; a lignan glycoside, liriodendrin; and seven phenylethanoid glycosides, arenarioside, verbascoside (= acteoside), isoacteoside, crenatoside, isocrenatoside, and trichosanthosides A and B, were isolated. Compounds 2-4 are new iridoids containing an 8,9 double bond representing a rare carbon skeleton. Their structures were established by spectroscopic methods.