Heterologous biosynthesis of prenylated resveratrol and evaluation of antioxidant activity

Prenylated stilbenoids are good candidates of nutraceuticals presented in food resources. The levels of natural prenylated stilbenoids are usually low. Biotransformation is a promising synthesis strategy to produce novel bioactive compounds. However, information regarding biosynthesis of prenylated stilbenoids is rare. In this work, prenyltransferase and geranyl diphosphate biosynthesispathway were overexpressed in E. coli. Multiple prenyltransferase genes were tested and Ambp1 was found to be effective on resveratrol geranylation. The products were identified by mass spectrometry and nuclear magnetic resonance spectroscopy as 4-C-geranyl resveratrol (1) and 3-O-geranyl resveratrol (2, novel chemical). By optimization of culture conditions, a yield of 36.9% was achieved for the conversion to geranylated resveratrol from resveratrol. These two compounds demonstrated good antioxidant activities with IC50 values of 28.09 μM for 4-C-geranyl resveratrol and 403.88 μM for 3-O-geranyl resveratrol. The results were helpful for developing novel technique to produce prenylated phenolics.