Anti-inflammatory glycoterpenoids from Scrophularia auriculata

The activity of the four glycoterpenoids: two saponins, verbascosaponin A and verbascosaponin, and two iridoids, scropolioside A and scrovalentinoside, isolated from Scrophularia auriculata ssp. pseudoauriculata, were studied in different models of acute and chronic inflammation. Both saponins significantly inhibited the mouse paw edema induced by carrageenan and ear edema induced by single and multiple doses of 12-O-tetradecanoylphorbol 13-acetate (TPA). Verbascosaponin A showed a potency twice as high as that of indomethacin in the acute TPA model. Verbascosaponin A and scropolioside A were active after a long latency period against ethyl phenylpropiolate edema, as are glucocorticoids. When the putative corticoid-like mechanism of the two compounds was studied, verbascosaponin A activity was notably reduced by the mRNA synthesis inhibitor, actinomycin D, while the effect of scropolioside A was partially interfered with by the anti-glucocorticoid drugs used. Both iridoids were active on the delayed type hypersensitivity reaction. They significantly reduced the inflammatory lesion and suppressed the cellular infiltration.