Eupatorin

Methanol and ethanol (analytical grade), acetonitrile and formic acid (HPLC grade) were purchased from Merck, Petaling Jaya, (Malaysia). 2,2-diphenyl-1-picrylhydrazyl, quercetin, gallic acid, aluminium chloride, bovine serum albumin, copper sulphate, folin-ciocalteu’s reagent, anthrone, sodium carbonate and potassium tartrate were purchased from Sigma-Aldrich, (Germany). The reference compounds rosmarinic acid, 3′-hydroxy-5,6,7,4′-tetramethoxyflavone, sinensetin and eupatorin were purchased from ChromaDex, (USA). Deionised water for HPLC was prepared using ultra pure water purifier system Thermo Scientific, (USA). The reverse phase Acclaim Polar Advantage II C18 column (3 μm, 3 × 150 mm) was purchased from Dionex, Thermo scientific, (USA). 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide, potassium chloride, potassium dihydrogen phosphate, dimethyl sulfoxide and sodium chloride were purchased from Sigma-Aldrich, (USA). Disodium hydrogen phosphate was purchased from Fluka, (Switzerland).