Total flavonoid contents of all vegetable extracts were determined according as aluminium chloride
colorimetric method described by Marinova et al. (2005).[12] Briefly, a 1 millilitre sample of the vegetable
extract was pipetted into a flask containing 4 ml of distilled water and mixed with 0.3 ml 5% NaNO2. After 5
min, 0.3 ml of 10% AlCl3 was added. This mixture was mixed with 2 ml of 1 M NaOH after standing for
another 6 min. Then, the mixture volume was adjusted to 10 ml by adding distilled water. The mixture was
well mixed and the reaction mixture absorbance was measured at 510 nm. The results were expressed as mg
of rutin equivalent (RE)/g fresh matter of vegetable