2.4.4. Total flavonoid content
The total flavonoid contents of the spice extracts were determined
by a modified colorimetric method described by Sakanaka et al.
(2005), using quercetin as a standard. Extracts or standard solutions
(250 μl) weremixed with distilled water (1.25 ml) and 75 μl of5%sodium
nitrite (NaNO2) solution followed by the addition of 150 μl of 10%
aluminum chloride (AlCl3) solution 5 min later. After 6 min, 0.5 ml of
1 M sodium hydroxide (NaOH) and 0.6 ml distilled water were added.
The solutions were then mixed and absorbance was measured at
510 nm. The results were expressed as mg quercetin/g of sample. All
determinations were performed in triplicate.