Determination of total flavonoid content
The total flavonoid content (TFC) was
determined using the Dowd method [17]. Briefly,
100 μl of 2 % AlCl3 in methanol was mixed with
100 μl of the sample solution. The absorbance of
the mixture was measured at 415 nm using
Pelkin Elmer UV-VIS lambda 25
spectrophotometer after 10 min against a blank
sample consisting of methanol. The TFC was
determined using a standard curve of quercetin
(5 - 30 μg/ml). The mean of three readings was
used and expressed as milligrams of quercetin
equivalents (QE)/l g of extract.