2.4. Aniline hydroxylase inhibitory assay
Aniline hydroxylase assay was performed by the
method described by Mazel (Mazel, 1971). The enzyme
was induced in rats by the oral administration of
phenobarbital (80 mg/kg) for 5 days. The animals were
sacrificed after an overnight fasting by ether anesthesia
and the liver was excised. A 10% homogenate prepared
was used for the assay. Various concentrations of the
extract were added to the reaction mixture and incubated
for 2 h at 37 °C. P-aminophenol formed during
the enzyme action reacts with phenol in alkaline
medium to form a blue coloured product, which was
measured at 630 nm. The percentage inhibition of
aniline hydroxylase was calculated by comparing the
absorbency of control and that of drug treated samples.