Extraction of polydatin and resveratrol from Polygonum cuspidatum root: Kinetics and modeling

The biochemical activities of polydatin and resveratrol have been proven to own considerable medicinal potential. However, the extraction processes are yet to be fully characterized. This study explores particularly the optimization and kinetics of polydatin and resveratrol extraction from Rhizoma Et Radix Polygoni Cuspidati (the root of Polygonum cuspidatum) in agitation extractions by ethanol and water mixtures. The effects of the parameters on several extraction processes have been fully investigated. The optimized condition for polydatin was found at 0.4 mole fraction of ethanol as the extraction solvents, temperature 323 K, agitation speed 500 rpm and solid to solvent ratio of 1:90. However, the optimized condition for resveratrol was 0.4 mole fraction of ethanol, temperature 323 K, agitation speed 800 rpm, solid to solvent ratio of 1:120. Furthermore, the extraction kinetics behavior of polydatin and resveratrol follows a first order kinetics with diffusion coefficient ranging from 3.59 × 10^-11 to 7.53 × 10^-11 m² s^-1 and 3.90 × 10^-11 to 10.10 × 10^-11 m² s^-1 for polydatin and resveratrol respectively. The values of activation energy for the extraction were found to be 3.96 kJ mol^-1 for polydatin and 17.83 kJ mol^-1 for resveratrol.