In silico xanthine oxidase inhibitory activities of alkaloids isolated from Alphonsea sp.

Abstract

Xanthine oxidase is an enzyme responsible for the build-up of excess uric acid that causes gout, one of the most common inflammatory arthritis found in Malaysia. The present study investigate in silico xanthine oxidase inhibitory activities of alkaloids isolated from Alphonsea cylindrica and Alphonsea elliptica. Serial column chromatography led to the isolation of compounds which were characterized as kinabaline, atherospermidine, cyathocaline, and N-methylouregidione on the basis of various spectroscopic techniques. Binding orientation and binding energy of all compounds were predicted via docking studies. Docking simulations revealed that kinabaline has the lowest binding energy at 6.9040 kcal/mol. All compounds revealed at least one hydrogen bond to key amino acids. Docking study showed that atherospermidine and cyathocaline bind to active sites which suggest they are competitive inhibitors while the other two compounds are non-competitive inhibitors. The findings of this study reveal the potential of Alphonsea sp. as remedy for gout.