Structure-activity studies of some oleanane triterpenoid glycosides and their related compounds from the leaves of Tetrapanax papyriferum on anti-inflammatory activities.

The anti-inflammatory activities of oleanane triterpenoid glycosides, papyrioside L-IIa, L-IIb, L-IIc and L-IId, extracted from Tetrapanax papyriferum (Araliaceae), and their aglycones, papyriogenin A and C and propapyriogenin A1 and A2, were investigated by using the carrageenin-induced edema and the cotton pellet granuloma tests in mice. Of these compounds, papyriogenin A and C (30 mg/kg p.o.) manifested in these tests almost the same potency as prednisolone (25 mg/kg p.o.). The structure-activity relationships of these and related triterpenes have been investigated. This takes into account particularly variation in the oxygen function and the molecular conformation. We have found that the anti-inflammatory activity of these triterpenes was favoured when the molecules tended to take a planar conformation; this was induced by the heteroanulardiene group between C and D ring.