The flavonoid contents of the ethanolic and ethyl acetate
extracts of I. viscosa were assessed using the method of Lamaison
and Carnat based on the formation of a complex flavonoidaluminium[
16]. Briefly, 1 mL of diluted sample (20 μg/mL) was
mixed with 1 mL of 2% aluminium chloride methanolic solution,
after incubation for 10 min at room temperature. The absorbance
was read at 430 nm and the flavonoids content was expressed in μg
quercetin equivalent (QE) per mg of dry extract.