Targeting xanthine oxidase inhibition has been a prime strategy for exploration and development of non-purine based drugs for anti-hyperuricemic therapy. Recent studies from our laboratory have suggested that fungal endophytes from medicinal plants could play a pivotal role in exploration of novel therapeutic moieties. In the present study, 19 fungal endophytes were isolated from the medicinal plant Tinospora cordifolia and evaluated for their XO inhibitory activity. In the qualitative assay, Out of 19 fungal endophytes, 7 endophytes exhibited > 30% XO inhibition, of which isolates #1 TCSTITPLM, #53 TCSTITPLM, #105 TCSTITPLM and #83 TCSTITPLM were found to exhibit XO inhibition in the range of 38-45%. Further, ethyl acetate extract of #1TCSTITPLM exhibited 69% XO inhibitory activity followed by chloroform extract of #53 TCSTITPLM with 63% XOI activity in the in vitro uric acid estimation assay. In the quantitative NBT titer plate assay, both extracts exhibited 85% of XO inhibition. The present study is the first report of fungal endophytes isolated from T. cordifolia exhibiting XO inhibitory activity. Ethyl acetate and chloroform extract of #1 TCSTITPLM and #53 TCSTITPLM demonstrated potent XO inhibitory action. Further studies are warranted for purification and characterization of the XO inhibiting moieties.
Keywords: Endophytic fungi; Enzyme inhibition; Hyperuricemia; Uric acid; Xanthine oxidase.