ANTIMICROBIAL AND ANTIOXIDANT COMPOUNDS FROM THE INFUSION AND METHANOLIC EXTRACT OF Baccharis incarum (WEDD.) PERKINS

Abstract

In the traditional medicine of the South American highlands, the infusion and decoction of aerial parts of “tola”, Baccharis incarum (Wedd.) Perkins (Asteraceae) is orally taken as an antiseptic, antipyretic and digestive or externally applied to relieve pain and inflammation. A plant infusion and methanolic (MeOH) extract of the aerial parts were compared for main constituents by HPLC-MS as well as assessed for antimicrobial and free radical scavenging activities. Assay-guided fractionation of the polar extracts was carried out using the ABTS•+ autographic as well as methicillin-resistant Staphylococcus aureus and Enterococcus faecalis bioautographic test. Seven compounds were isolated from the polar extracts and identified as chlorogenic acid, 3’,4’,5,7-tetrahydroxyflavone; dicaffeoyl quinic acid; 3’,4’,5,7-tetrahydroxy-3,6-dimethoxyflavone; 3’,4’,5,7-tetrahydroxy-3,6,8-trimethoxy flavone, 4’,5,7trihydroxy-3’,3,6,8-tetramethoxyflavone and 4’,5-dihydroxy-3’,3,6,7,8-pentamethoxyflavone . The main constituents from the methanol extract and infusion were caffeic acid derivatives. This is the first report on the constituents of B. incarum infusion and show clear differences with previous phytochemical studies on the same plant. All isolated compounds showed antioxidant activity with SC 50 values of 1 to 10 µg/ml. The isolated flavones were active against methicillin-resistant Staphylococcus aureus and Enterococcus faecalis with MICs in the range 100 and >200 µg/ml.