Research On Extration、Purification And Free Radical Scavenging Activity Of Polyphenols In Dendrobium Chrysotoxum

Dendrobium chrysotoxum,a precious resource for traditional medicine in our country.And they were used for the treatment of fever, ophthalmic disorders, throat inflammation and chronic superficial gastritis for a long time.Recent years, many researches have uncovered that the polyphenols extract from Dendrobium chrysotoxum has good potential for antioxidant activity.And inhibits the growth of Hela cells.The polyphenols compounds from Dendrobium chrysotoxum was extracted, isolated and purified in this project. We purified phenolic compounds by macroporous adsorptive resin(NKA-9);investigated the antioxidation activity in vitro by evaluations of hydroxyl radical scavenging activity, DPPH radical scavenging activity, and ABTS radical scavenging activity.Therefore,an important theory basis for development and utilization of Dendrobium chrysotoxum polyphenols was provided.(1)The optimization of extraction technology of polyphenols from Dendrobium chrysotoxum by response surface methodology, On the basis of single-factor test, Response surfacemethodology was used to investigate the effects of processing parameters, including ethanol concentration,ph value,and solvent/material ratio.The extraction rate of polyphenols was chosen as response value, mathematical model was established by implementing three factors and three levels.The optimum technological conditions was ethanol concentration 76%(v/v), ratio of water to raw material 1:52 (g/mL), ph 6.(2)NKA-9 macroporous adsorptive resin can putify the Dendrobium chrysotoxum polyphenols,under appropriate parameters the polyphenol purity was 58.92%.The best purify process conditions were determined by the static and dynamic absorptive and desorptive performance:the time of polyphenols passed through NKA-9 is 4h, the eluant is 90% ethanol and pH value of 6 after saturated absorption.(3)The antioxidant test in vitro showed that Dendrobium chrysotoxum polyphenols had significant ABTS radical scavenging activity, DPPH radical scavenging activity and hydroxyl radical scavenging activity.Vitamin C have stronger effect on radical scavenging activity than Dendrobium chrysotoxum polyphenols in the same concentration.After purified, the scavenging effect to DPPH radicals of polyphenols increased.From the results of the free radical scavenging assay,we could see that the polyphenols from Dendrobium chrysotoxum had a high radical scavenging activity on ABTS radicals,DPPH radical,hydroxyl radicals and reducing power.Therefore we could conclude that the polyphenols from Dendrobium chrysotoxum could be explored as a novel potential antioxidant.In summary, the research studied the extraction and purification of polyphenols from Dendrobium chrysotoxum, optimized the optimum parameters of ultrasonic assisted extraction of polyphenols from Dendrobium chrysotoxum; used different antioxidant systems to evaluate the radical scavenging activity in vitro of Dendrobium chrysotoxum polyphenols.