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 IC₅₀ 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.