Discovery of the Endophytic Fungi from Polygonum cuspidatum and Biotransformation of Resveratrol to Pterostillbene by the Endophyte Penicillium sp. F5

In this study, fungal endophytes were screened from samples of Polygonum cuspidatum and 24 endophytes were obtained. The fungal endophytes were allocated to 6 orders and 9 genera by phylogenetic analysis. Based on the ability of fungal endophytes to induce biotransformation, Penicillium sp. F5 was selected for the biotransformation of resveratrol. Fermentation of media using Penicillium sp. F5 yielded transformation products, giving a main product that was purified using silica gel column chromatography. The structure of main product was established as pterostilbene (trans-3,5-dimethoxy-4'-hydroxystilbene) by using H-1-NMR, C-13 -NMR, HSQC and HMBC spectroscopy. Pterostilbene plays an important role in resisting disease in humans and shows more metabolic stability, stronger pharmacological activities, and longer half-life when compared with resveratrol.