Biotransformation of the Phenolic Constituents from Licorice and Cytotoxicity Evaluation of Their Metabolites.

Biotransformation of four bioactive phenolic constituents from licorice, namely licoisoflavanone (), glycyrrhisoflavone (), echinatin (), and isobavachalcone (), was performed by the selected fungal strain KCCM 60332, leading to the isolation of seventeen metabolites (-). Structures of the isolated compounds were determined on the basis of extensive spectroscopic methods, twelve of which (-, - and ) have been previously undescribed. A series of reactions including hydroxylation, hydrogenation, epoxidation, hydrolysis, reduction, cyclization, and alkylation was observed in the biotransformation process. All compounds were tested for their cytotoxic activities against three different human cancer cell lines including A375P, MCF-7, and HT-29. Compounds and exhibited most considerable cytotoxic activities against all the cell lines investigated, while compounds and were moderately cytotoxic. These findings will contribute to expanding the chemical diversity of phenolic compounds, and compounds and may serve as leads for the development of potential cancer chemopreventive agents.