Determination of the total flavonoids content (TFC)
The aluminum chloride colorimetric method was used to determine
the total content of flavonoids. The total flavonoids content
were determined using the method described in (Sun et al., 2011)
with slight modifications. Briefly, 200L of the extract or quercetin
was mixed with 300L of 5% sodium nitrite. After 6min, 500L of
10% aluminum chloride was added, and the mixture was allowed to
stand for a further 5min. Then, 1000L of 10% NaOH was added to
the above mixture. After the mixture had been incubated at room
temperature for 15 min, the absorbance was measured at 510 nm.
Quercetin was used as standard. Results were expressed as mg/L of
extract