Extraction of total phenolics and flavonoids from the leaf of Ribes odoratum Wendl.and its antioxidant activity

Objective: To obtain the optimum microwave- assisted extraction process for total phenolics and flavonoids from the leaf of Ribes odoratum Wendl. and to examine the antioxidant activity. Method: Based on single factor tests,effects of various factors on total phenolics and flavonoids contents were analyzed through response surface methodology( RSM).The optimal conditions for microwave extraction of total phenolics and flavonoids from the leaf of Ribes odoratum Wendl.were discussed.And the comparison between different extraction methods,such as ultrasonic extraction and soxhlet extraction were also investigated.Moreover,the DPPH radical scavenging capacity and FRAP total antioxidant activity tests were carried out to determine its potential antioxidant activity. Result: The optimum conditions for microwave- assisted extraction were determined as follows:extraction temperature 58 ℃,liquid- to- solid ratio 39 ∶ 1 m L / g,ethanol concentration 57%,extraction time 15 min and microwave power 600 W.The extraction yields of total phenolics and flavonoids were up to 99.89 mg / g and 38.16 mg / g under the optimal conditions. The antioxidant tests showed that the total phenolics and flavonoids extracted from the leaf of Ribes odoratum Wendl.had a potent scavenging effect on DPPH free radicals with IC50 value of 0.0445 mg / m L and FRAP ferric reducing antioxidant power with value of 4.832 mmo L / g.Conclusion: The microwave- assisted extraction of total phenolics and flavonoids from the leaf of Ribes odoratum Wendl.was stable and feasible,and the extracts by this method also exhibited a betterantioxidant activity.The study could provide a certain scientific basis for research and development of Ribes odoratum Wendl..