Flavonoids and anthranquinones as xanthine oxidase and monoamine oxidase inhibitors: A new approach towards inflammation and oxidative stress

The development of xanthine oxidase and monoamine oxidase inhibitors led to important breakthroughs in the therapy of oxidative damage, hyperuricemia, gout, neurological, neuropsychiatric disorders and management of reperfusion injury. Drugs obtained from natural sources play an important role in the treatment of various pathological disorders and act as a lead compound for the discovery of new synthetic drug substances. In this review, various pharmacological effects produced by the inhibition of xanthine oxidase and monoamine oxidase through natural and synthetic flavonoids as well as anthraquinones are discussed in detail. Several methods have been designed for monitoring enzymatic activity and its inhibitor screening of bioactive natural and synthetic flavonoids and anthraquinones. In this review, all the in-vitro and other computational approaches are critically discussed which provided the clue about structure activity requirements for further precise modifications on the basic scaffold.