The anti-inflammatory potential of alpha-hederin (monodesmoside) and hederasaponin-C from Hedera helix, and hederacolchisides-E and -F (bidesmosides) from H. colchica was investigated in carrageenan-induced acute paw edema in rats. Saponins and indomethacin were given orally in concentrations of 0.02 and 20 mg/kg body wt. For the first phase of acute inflammation, indomethacin was found as the most potent drug. a-hederin and hederasaponin-C were found ineffective, while hederacolchisides-E and -F showed slight anti-inflammatory effects on the first phase. For the second phase of acute inflammation, indomethacin and hederacolchiside-F were determined as very potent compounds. a-hederin was found ineffective for the second phase, either. Despite hederasaponin-C and -E were found effective in the second phase of inflammation, they were not found as effective as indomethacin and hederacolchiside-F. As a conclusion, hederasaponin-C, -E and -F, may exert their anti-inflammatory effects by blocking bradykinin or other inflammation mediators. The latter affect may occur via affecting prostaglandin pathways. Regarding the structure activity relationship, it is likely that sugars at C-3 position and Rha7-Glc1-6Glc moiety at C-28 position are essential for the acute anti-inflammatory effect. (c) 2005 Elsevier GmbH. All rights reserved.