Lipase-catalyzed regioselective protection/deprotection of hydroxyl groups of the isoflavone irilone isolated fromIris germanica

The regioselective acylation of irilone, isolated from Iris germanica, with vinylacetate and propenylacetate and deacylation of irilone diacetate with n-butanol were studied using lipases from Aspergillus niger, Mucor miehei, Pseudomonas cepacia, Candida cylindracea, porcine pancreas and Candida antarctica. Significant conversion of irilone to 4'-O-acetylirilone was achieved using P. cepacia lipase, while irilone diacetate was converted to 5-O-acetylirilone by the enzymatic action of lipases from M. miechei, P. cepacia and porcine pancreas under different experimental conditions. This preferential protection/deprotection furnishes an opportunity to modify the structure of irilone by selective derivatization that may help to change its biological activities by modifying its amphiphilic/lipophilic balance.