The values for TPC are expressed in mg gallic acid equivalents
(GAE) per g dried sample (dry weight, dw).
The total flavonoid content (TFC) was evaluated by the protocol
of Chang, Yang, Wen, and Chern (2002). Briefly, 10 ll of 5% sodium
nitrate (NaNO3) was added to 100 ll of the original stock solution
(1 mg/ml) of the samples. The mixture was incubated in the dark
for 5 min. A 10 ll volume of aluminium chloride (AlCl3, 10%) was
added to the mixture and incubated for a further 5 min in the dark.
A 100 ll of NaOH, 1 M, was added to the resulting mixture
followed by addition of 30 ll of distilled water. The absorbance
was read at 510 nm. The total flavonoid content of the sample
was expressed in milligram quercetin equivalents (per g dried
weight). All analyses were carried out in triplicate.