Enzymatic Sulfation of Phenolic Hydroxy Groups of Various Plant Metabolites by an Arylsulfotransferase

The bacterial arylsulfate sulfotransferase (AST) from Desulfitobacterium hafniense was used as a catalytic tool to derivatize poorly sol. arom. compds. (polyphenols)​. As examples, we sulfated the natural occurring compds. p-​coumaric acid, 6-​hydroxyflavone, resveratrol, phloretin, and quercetin, using p-​nitrophenylsulfate as the sulfate donor. The water-​sol. sulfate esters were purified and characterized. Depending on the nature of the compd., one or more sulfate groups could be introduced in a stepwise order. The sulfation of resveratrol resulted in two different monosulfates (4'- and 3-​sulfates)​, the 3,​4'-​disulfate, and the 3,​5,​4'-​trisulfate. Sulfation of phloretin resulted in a monosulfate (4'-​sulfate) and a disulfate (4,​4'-​disulfate)​. Although quercetin has five hydroxy groups that could be sulfated, surprisingly this enzyme system primarily catalyzes the sulfation only at the 4' position. This simple enzymic one-​step sulfation method is easy to use, and it allows a convenient and simple prodn. of sulfated compds. with improved soly.