Inhibitory activity of xanthine oxidase and superoxide-scavenging activity in some taxa of the lichen family Graphidaceae.

Results on the screening of species of the lichen family Graphidaceae for superoxide-scavenging activity (SSA) and xanthine-oxidase inhibitory (IXO) activity have been presented. The potential of the extracts for scavenging of superoxide and inhibition of xanthine-oxidase under various physiological conditions has been evaluated. The methanolic extracts of the species of family Graphidaceae showed inhibitory properties of xanthine oxidase (IC50 = 2.0 to 5.26 microg/ml) with an additional superoxide scavenging capacity (IC50 = 3.63 to 13.88 microg/ml). The potential of the methanolic extracts for scavenging of superoxide and inhibition of xanthine oxidase remained stable at 4 degrees C. Thus the extracts can be maintained for longer periods for their therapeutic uses.