Total flavonoid content was determined by a colorimetric method (Bao et al., 2005) with minor modification. Aliquots (0.5 mL) of appropriately diluted extracts or standard solutions were pipetted into 15-mL polypropylene conical tubes containing 2 mL double distilled H2O and mixed with 0.15 mL 5% NaNO2. After 5 min, 0.15 mL 10% AlCl3$6H2O solution was added, and the mixture was allowed to stand for another 5 min, and then 1 mL 1 M NaOH was added. The reaction solution was well mixed, kept for 15 min, and the absorbance was determined at 415 nm. Total flavonoid content was calculated using the standard rutin curve, and expressed as mg rutin equivalent (mg RE) per 100 g of dry weight.