Total Flavonoid Content
The Total Flavonoid Content was estimated using aluminium
nitrate assay [32,33]. 500 lL of the diluted sample was mixed thoroughly
with 0.1 mL of 10% aluminium nitrate, 0.1 mL of 1 M potassium
acetate and 4.3 mL of distilled water and allowed to stand at
room temperature for 40 min. A change in colour of the prepared
samples from colourless to yellow indicated the presence of flavonoids.
Absorbance was measured at 415 nm (Lambda 25, Perkin
Elmer, USA) against a reagent blank prepared similarly without
the extract. A standard curve was prepared using quercetin and
the results were expressed as mg quercetin equivalent per mL of
solvent (mgQE/mL). All the assays were repeated three times and
the average values were used for further analysis