A PLAUSIBLE CHEMICAL MECHANISM OF THE BIOACTIVITIES OF MANGIFERIN

A plausible chemical mechanism of the observed bioactivities of mangif erin, a naturally occurring C-glucosylxanthone (1), is depicted. The m echanism focuses its capacity to provide cellular protection as an ant ioxidant and a radical captodative agent. Mangiferin performs its anti oxidant function at different levels of systemic oxidation sequence. A s far as membrane lipid peroxidation and consequent immunomodulations are concerned, it acts by (i) decreasing localized O-2 concentration t hereby generating, in concert, mangiferin phenoxy radicals (2); (ii) b y binding metal ions (Fe-2+/3+) in forms 3 and 4 that will not allow t he generation of such tissue damaging species as hydroxyl and highly r eactive oxo-ferryl radicals; (iii) regulating polymer chain lengthenin g (membrane lipids) by interacting with the reactive oxygen species; ( iv) chain breaking (by 2), i.e. scavanging intermediate radicals (such as lipid peroxy and alkoxy radicals) to prevent continued H abstracti on from cellular lipid molecules; and (v) maintaining systemic oxidant -antioxidant balance (by 1 and 2). Chemical evidence in support of the above postulate has been sought and obtained in the form of a complex polymer (5) through the intermediates 2 to 4.