Further studies on the biosynthesis of mangiferin in Anemarrhena asphodeloides: hydroxylation of the shikimate-derived ring

The hydroxylation at C-3′ of maclurin, an intermediate in mangiferin biosynthesis, has been studied. Labelled cinnamic acid, p-coumaric acid, caffeic acid, iriflophenone and maclurin were fed to Anemarrhena asphodeloides. Cinnamic acid and p-coumaric acid were better precursors than caffeic acid for mangiferin, and iriflophenone as well as maclurin was effectively incorporated into mangiferin and isomangiferin. These results show that maclurin is biosynthesized via hydroxylation of iriflophenone derived from p-coumarate in this plant.