The total flavonoid contents were measured by a colorimetric assay (Zhishen et al. 1999; Zou et al., 2004). A-100.0 µl aliquot of extracts or fractions in methanol was added to a 10 ml volumetric flask containing 4 ml of distilled water. At zero time, 0.3 ml 5% sodium nitrite was added to the flask. After 5 min, 0.3 ml of 10% aluminium chloride was added. At 6 min, 2 ml of 1 M sodium hydroxide was added to the mixture. Immediately, the mixture was diluted to volume with the addition of 2.4 ml distilled water and thoroughly mixed. Absorbance of the mixture, pink in color, was determined at 510 nm versus a blank containing all reagents except samples of extracts or fractions. Rutin was used as standard for the calibration curve. Total flavonoid content of the extracts and fractions were expressed as mg rutin equivalents (RE) per gram of sample (mg/g).