Inhibition of xanthine oxidase by an aqueous extract of banaba leaves (Lagerstroemia speciosa)

The inhibitory effect of an aqueous extract of Lagerstroemia speciosa leave s, known as the name of banaba in the Philippines, on xanthine oxidase (XOD ) was compared with that of green tea. rooibos tea and tochu tea. A spectro scopic technique to measure the increasing UV absorbance at 295 nm was used to estimate the formation of uric acid from xanthine. On the sample tested , banaba extract was shown to have the strongest potential in inhibiting XO D. The fractionation of the banaba extract with DIAION HP-20 resin resulted in enhancing the inhibitory effect on XOD. It was revealed that ellagic ac id. main polyphenolic component in banaba extract, was one of the substance having the inhibitory effect on XOD.