Estimation of resveratrol content in peanut pericarp and its relation to the in vitro inhibitory activity on carbohydrate metabolizing enzymes.

The aim of this work was the estimation of resveratrol content in two successive extracts (EtOAc and MeOH) of peanuts (Arachis hypogaea L.) pericarp of Egypt, by TLC and HPLC methods. Results showed the presence of 3.0 and 0.5 microg/mL resveratrol in EtOAc and MeOH extracts respectively. The in vitro carbohydrate hydrolyzing enzyme inhibition activity showed higher percentage of inhibition of alpha-amylase, alpha-glucosidase and beta-galactosidase with EtOAc (4.32, 5.93 and 13.7%) than with MeOH extract (3.9, 4.9 and 14.1%) but lower than the standard resveratrol concentration (5.18, 5.94 and 13.26%) and the reference acarbose (5.88, 5.9 and 13.0%). It could be concluded that the content of resveratrol in peanut pericarp is related to the percentage of inhibition activity of carbohydrate hydrolyzing enzymes. These results strongly reflect the benefit of using peanut pericarp, the waste product, as a natural antidiabetic agent.