Mapping the Biotransformation of Coumarins through Filamentous Fungi

Abstract

Natural coumarins are present in remarkable amounts as secondary metabolites in edible and medicinal plants, where they display interesting bioactivities. Considering the wide enzymatic arsenal of filamentous fungi, studies on the biotransformation of coumarins using these microorganisms have great importance in green chemical derivatization. Several reports on the biotransformation of coumarins using fungi have highlighted the achievement of chemical analogs with high selectivity by using mild and ecofriendly conditions. Prompted by the enormous pharmacological, alimentary, and chemical interest in coumarin-like compounds, this study evaluated the biotransformation of nine coumarin scaffolds using Cunninghamella elegans ATCC 10028b and Aspergillus brasiliensis ATCC 16404. The chemical reactions which were catalyzed by the microorganisms were highly selective. Among the nine studied coumarins, only two of them were biotransformed. One of the coumarins, 7-hydroxy-2,3-dihydrocyclopenta[c]chromen-4(1H)-one, was biotransformed into the new 7,9-dihydroxy-2,3-dihydrocyclopenta[c]chromen-4(1H)-one, which was generated by selective hydroxylation in an unactivated carbon. Our results highlight some chemical features of coumarin cores that are important to biotransformation using filamentous fungi.

Multi-Level Optimization and Strategies in Microbial Biotransformation of Nature Products

“…Subsequently, the crude was separated to give three new metabolites, of which β -chamigren-1 β ,8 α -diol was the major product (46.2% in isolated yield) [ 61 ] ( Figure 2 a). Coumarins dissolved in dimethyl sulfoxide was added to the Koch’·s K1 medium, Cunninghamella elegans ATCC 10028b and Aspergillus brasiliensis ATCC 16404 could convert coumarins 7-hydroxy-2,3-dihydrocyclopenta[c]chromen-4(1H)-one to 7,9-dihydroxy-2,3-dihydrocyclopenta[c]chromen- 4(1H)-one at 28 °C for 72 h with shaking at 120 rpm·min −1 [ 62 ] ( Figure 2 a). Glycyrrhetinic acid ( Glycyrrhiza glabra ) (5 mg) dissolved in Tween 80-H 2 O (0.5 mL; 1:3 v / v ) added into the medium, and Cunninghamella blakesleeana could convert glycyrrhetinic acid to 3-oxo-7β-hydroxy-glycyrrhetinic acid (GA-1) and 7 β -hydroxy-glycyrrhetinic acid (GA-2) at 30 °C for 5 days with shaking at 180 r·min −1 [ 63 ] ( Figure 2 a).…”