The TFC were assessed following a previously reported spectrophotometric method with minor modification10. Briefly, for each samples, an aliquot of 500 μL extract were diluted with 3.2 mL of water. Initially, 150 μL of 5% NaNO2 solution was added to each sample. After 5 minutes, 150 μL of 10% AlCl3 was added. Then, 6 minutes later, 1 mL of 1.0M NaOH was then added and mixed well. Absorbance was read at 510 nm. Quercetin was taken as standard for the calibrating curve. The total flavonoid content was calibrated using the calibration curve based linear equation. The total flavonoid content was expressed as mg quercetin equivalent/g dry extract.