Constitution of mangiferin

Abstract

Mangiferin, C₁₉H₁₈O₁₁, has been isolated from the leaves, heartwood and stem-bark of Mangifera indica. Its properties indicate that it is a stable C-glycoside of the xanthone group. Reductive hydrolysis with hydriodic acid and oxidation with ferric chloride yield 1,3,6,7-tetrahydroxyxanthone and glucose respectively indicating that it is a glucoside of the former and oxidation with periodic acid reveals that the sugar is in the pyranose form. The position of linkage has been shown to be 2 by oxidizing mangiferin tri and tetra methyl ethers with periodate to the corresponding α-hydroxyacetaldehydes of trimethoxy and tetramethoxyxanthones and comparing them with synthetic samples obtained from the appropriate 2-allylxanthones. This has been further supported by oxidation of mangiferin tetra methyl ether and 2-allyl-1,3,6,7-tetramethoxyxanthone with permanganate yielding 1,3,6,7-tetramethoxyxanthone-2-carboxylic acid.