Xanthine oxidase inhibitory and antioxidant potential of Indian Muscodor species

Xanthine oxidase is a key enzyme responsible for hyperuricemia, a pre-disposing factor for Gout and oxidative stress-related diseases. Only two clinically approved xanthine oxidase inhibitors Allopurinol and Febuxostat are currently used for treatment of hyperuricemia. However, owing to their side effects there is a need for new non-purine-based selective inhibitors of xanthine oxidase. In the process of exploring novel xanthine oxidase inhibitors and anti-oxidants, we screened the culture filtrate of 07 novel species of Muscodor, a sterile endophytic fungi isolated from Cinnamomum and Aegle marmelos. Chloroform extract of M. darjeelingensis exhibited the maximum xanthine oxidase inhibition in the qualitative and quantitative assays. The IC(50) of chloroform extract of M. darjeelingensis was 0.54 µg/ml which was much lower to Allopurinol but higher when compared to Febuxostat. 88% reduction in uric acid production was recorded by M. darjeelingensis chloroform extract which was similar to allopurinol. The maximum anti-oxidant activity was exhibited by M. indica against the gallic acid standard in the DPPH-free radical assay. Anti-oxidant activity index of M. indica was 7.7, which was followed by M. kashayum with 5.4. M. darjeelingensis exhibited a moderate anti-oxidant activity with anti-oxidant activity index of 1.63 in the DPPH assay. The present study is the very first report of Muscodor species exhibiting xanthine oxidase inhibitory and anti-oxidant activity together. Chloroform extract of M. darjeelingensis and M. indica stand out as potential candidates for isolation and characterization of the xanthine oxidase inhibitor and anti-oxidant compound, respectively.