Glycosylation of Methylflavonoids in the Cultures of Entomopathogenic Filamentous Fungi as a Tool for Obtaining New Biologically Active Compounds

Abstract

Flavonoid compounds are secondary plant metabolites with numerous biological activi-ties; they naturally occur mainly in the form of glycosides. The glucosyl moiety attached to the flavonoid core makes them more stable and water‐soluble. The methyl derivatives of flavonoids also show increased stability and intestinal absorption. Our study showed that such flavonoids can be obtained by combined chemical and biotechnological methods with entomopathogenic filamentous fungi as glycosylation biocatalysts. In the current paper, two flavonoids, i.e., 2′‐hydroxy‐4‐methyl-chalcone and 4′‐methylflavone, have been synthesized and biotransformed in the cultures of two strains of entomopathogenic filamentous fungi Isaria fumosorosea KCH J2 and Beauveria bassiana KCH J1.5. Biotransformation of 2′‐hydroxy‐4‐methylchalcone resulted in the formation of two dihydro-chalcone glucopyranoside derivatives in the culture of I. fumosorosea KCH J2 and chalcone glucopy-ranoside derivative in the case of B. bassiana KCH J1.5. 4′‐Methylflavone was transformed in the culture of I. fumosorosea KCH J2 into four products, i.e., 4′‐hydroxymethylflavone, flavone 4′‐meth-ylene‐O‐β‐D‐(4″‐O‐methyl)‐glucopyranoside, flavone 4′‐carboxylic acid, and 4′‐methylflavone 3‐O-β‐D‐(4″‐O‐methyl)‐glucopyranoside. 4′‐Methylflavone was not efficiently biotransformed in the culture of B. bassiana KCH J1.5. The computer‐aided simulations based on the chemical structures of the obtained compounds showed their improved physicochemical properties and antimicrobial, an-ticarcinogenic, hepatoprotective, and cardioprotective potential.