A versatile tailoring tool for pentacyclic triterpenes of Penicillium griseofulvum CICC 40293

Abstract In the biosynthetic pathway of pentacyclic triterpenes (PTs), tailoring reactions can produce a wide range of end products from a small number of common scaffolds and the microbial transformation has also been established as an alternative technique for this purpose. In this study, we explored the tailoring reactions involved in the microbial transformation of pentacyclic triterpenes by Penicillium griseofulvum CICC 40293. Preparative biotransformation of eight different PTs from three scaffolds resulted in the isolation of thirteen metabolites. The structures of metabolites were elucidated by HR-ESI-MS, 1D, and 2D NMR spectroscopy. We discovered the highly efficient regio- and stereo-selective hydroxylation of inactivated sp3 CH2 and CH3 on the position of 2α, 7β, 15α, 21β, 23(angular methyl), and 30−COOH glycosylation, this versatile tailoring system for PTs would provide an effective method for expanding their structural diversities. In addition, all compounds were subjected to the bioassay on the model of lipopolysaccharide (LPS)-stimulated RAW 264.7 cells to evaluate their anti-inflammatory activity through nitric oxide (NO) inhibition activity. Compounds 2a and 5a exhibited excellent NO inhibitory activity with IC50 values of 8.35 ± 2.81 μM and 19.60 ± 4.25 μM, respectively.