Total alcoholic extract of Desmodium gangeticum, which exhibited significant anti-inflammatory activity, was evaluated for the possible mode of action by studying its antioxidant potential in adjuvant-induced arthritic rats. Activity guided fractionation and isolation were carried out. The phenolics fraction showed maximum potency. Solid phase extraction followed by preparative HPLC of the active phenolic fraction yielded for the first time two potent antioxidant compounds, caffeic acid and chlorogenic acid, from this plant. The biological antioxidant defense system involving the superoxide dismutase, glutathione and catalase, showed a significant increase with their levels close to the normal control with a decrease in the lipid peroxide content upon administration of D. gangeticum extract (100 mg kg-1) and its phenolics (50 mg kg-1) in arthritic rats, thereby indicating the extracts antioxidant property under arthritic conditions.Ispitivan je mogući mehanizam protuupalnog djelovanja alkoholnog ekstrakta biljke Desmodium gangeticum na artritičnim štakorima. Nakon frakcioniranja, najjače djelovanje pokazale su fenolne frakcije. Ekstrakcijom i preparativnom HPLC kromatografijom iz fenolne frakcije izolirana su, prvi put iz te biljke, dva spoja sa snažnim antioksidativnim djelovanjem, kavena i klorogena kiselina. Biološki antioksidativni obrambeni sustav koji se sastoji od superoksidismutaze, glutationa i katalaze značajno je porastao u odnosu na kontrolnu skupinu, nakon davanja ekstrakta D. gangeticum (100 mg kg-1) i njegovih fenola (50 mg kg-1) artritičnim štakorima. Istovremeno se smanjio sadržaj peroksida u lipidima. To ukazuje da ekstrakt djeluje antioksidativno u stanju upale
