Research On The Effects Of Protection And Renovation Of Apple Polyphenols On UVB-Induced HepG₂ Cell Injury

UVB is mid-ultraviolet and its wavelength is 280 to 320nm. The damage of UVB radiation to human is rising because of destroying to ozone layer. UVB irradiation can induce the formation of reactive oxygen species(ROS),and induce the change of cell biology, gene mutation, carcinogenesis and cell death. Apple is one of the most important edible fruits in our country. Apple is rich of polysaccharides that has multiple pharmacological activities. Recently, Apple polyphenols (AP) is being paied great attention by scientists because of its antioxidant and free radical scavenging . In this dissertation, the author conducted a series of studies on Apple polyphenols, which were isolated and purified from Apple, and protection and ranovation of HepG₂ cell damage, in the hope of providing elementary data and theoretical bases for the actual application and development of AP extracting technology.Taking the Ralls apple as the research material, this research established the optimun technological parameters of mixture solvent extracting corditions of AP using response surface methodology. Time on the extraction of AP is 60.04min,the temperature on the extraction of AP is 40.03℃,ratio of solvent to apple on the extraction of AP is 1:6.02 (mL/g), ratio of solvent on the extraction of AP is 1:1.18. After mixture solvent extracting, flocculation and deposition, the author have the crude product of AP. For the purification of AP, the silica gel column chromatography was used. Mobile phase is ethyl acetate-n-Butanol, recovery rate of AP could reach to 45.42%,purify of AP could reach to 62.5%.In the present study, the effect of anti-UVB on human liver cancer in vitro was investigated and was determined by MTT assay. In vitro cell experiments, the AP's IC50 is 286.54μg/ml. HepG₂ cell was used as the cell model in vitro, and the relationship between the proliferation of HepG₂ cell and the different doses of UVB irradiation with the methods of MTT coloripetry. It was showed that low intensity UVB could promote HepG₂ cell proliferation and high intensity UVB could damage HepG₂ cell proliferation and high intensity UVB could damage HepG₂ cell; and that UVB 111s was the dosage of half HepG₂ cell death. This study showed that 100μg/ml of apple polyphenols is the best protection and 150μg/ml of apple polyphenols is the best renovation by protect and renovate experiment. More, DNA damage induced by UVB irradiation was determined by DNA-Ladder. The cell DNA extracted display ladder bands in DNA agarose gel electropheresis.