Iridoid and Phenylethanoid Glucosides from Veronica (sect. Hebe) lavaudiana

From an extract of Veronica (sect. Hebe) lavaudiana we have identified mannitol and isolated eleven iridoid glucosides, the carbohydrate ester hebitol II, and four esters of phenylethanoid glycosides. Five of the iridoid glycosides are new; of these, lavaudioside A, B, and C (2a, 3a, and 4) are 1-mannityl esters of 8-epiloganic acid while two (7e and 7f) were 6'-O-caffeoyl derivatives of catalpol. Three of the phenylethanoid glycoside esters, named helioside A, B, and C (8b-8d) were also new, being 6'-xylosyl derivatives of aragoside. The structures of the new compounds were elucidated mainly by spectroscopic analysis, but also by chemical degradation. In the course of the present work, we have demonstrated that the structures of the known glycosides globularitol as well as hebitols I and II should be revised. These compounds are derivatives of mannitol and not glucitol as previously believed.