Protective Effect Of Schisandra Chinensis Fruit On Ultraviolet B-induced Damage In HaCaT Keratinocytes

The main components of Schisandra chinensis(Turez.) Baill are lignans which possess anti-oxidation, anti-fatigue, anti-inflammatory and anti-carcinogenic effects, et al. It’s reported that the extract of Schisandra chinensis can improve the glutathione defense system, improve the activity of glutathione peroxidase, increase the level of glutathione, and even inhibit in the formation of cellular peroxide, but its UV protection effect has rarely been reported. This thesis takes its extracts as research object and studies the protective effect and its mechanism.The S. chinensis fruits which are main material in this paper were extracted with methanol by ultrasonic wave for 3 times. The residue obtained was suspended in different solutions to yield the petroleum ether layer, ethyl acetate layer, the n-Bu OH layer, respectively, as well as the water layer. The different layers were qualitatively analyzed employing HPLC method. Our results found that lignans were only detected in the petroleum ether layer(PEL) and ethyl acetate layer(EAL). MTT was conduct to detect the influence of the extracts which contain Lignans on Ha Ca T cell viability. We found that the cytotoxic of PEL was higher than EAL. In addition, we investigate the causes of cell damage by UVB radiation and get the corresponding experimental parameters. We finally established the damage model according to condition of the laboratory. MTT was conduct to detect the influence of the extracts which contain Lignans on UVB radiation. UVB-induced cell growth inhibition was significantly prevented by pretreatment with EAL in a dose-dependent manner.To understand the mechanisms, the protective effect of EAL on UVB-induced damage was evaluated by measuring ROS generation, DNA damage, cell apoptosis and apoptosis protein. The EAL could inhibit UVB-induced oxidative damage, eliminate the ROS, reduce DNA damage and cell apoptosis induced by UVB irradiation. Moreover, it also inhibit the activation of apoptosis protein such as caspase-3、caspase-8. In a word, the extract of Schisandra chinensis is of hopeful to develope as natural antioxidants and ultraviolet protecting agent applying to the product of medicine or cosmetic to protect from UVB damage.