The Potential Mechanism Of Quercetin On Prevention Of DNA Damage And Apoptosis Induction Of Melanoma Cloudman S91 Cell Line

Quercetin (3, 3 , 4, 5, 7-hydroxyl flavonoid) is one of ubiquitous flavonoids which belong to an extensive group of polyphenolic substances. Quercetin exists in most plants and is concentrated in seeds, fruit peel, bark, and flowers. A great number of herbal medicines contain quercetin. Quercetin has been reported by many authors with potential vasodilatory, anti-inflammatory, antithrombotic, antibacterial, antiviral, antiallergic, antimutagenic and antineoplastic activities. Epidemiologic-al and molecular biological researches suggested that quercetin had lower toxicity and less side effects than most of the clinical anticancer drugs applied up to date. Quercetin might be used as a potential anti-tumor agent in the future.This study is to investigate the mechanisms of biological effects of quercetin on cancer prevention and tumor treatment. Quercetin might induce the apoptosis of Cloudman S91 cell line from murine melanoma, inhibit CYP1A1 activities in L-02 cell line and human liver microsomes, and prevent DNA damages in murine peripheral blood lymphocyte induced by B[a]P.PART ONEThe Potential Mechanism of Quercetin on Apoptosis Induction of Cloudman S91 Cell Line from Murine MelanomaUsing MTT reduction assay, fluorescence straining with AO/ EB, flow cytometrical analysis and Western blotting, we explored the biological effects of quercetin on Cloudman S91 cell line from murine melanoma. Results showed that cell growth inhibition of Cloudman S91 cell line by quercetin was a dose- and time-dependent manner. A typical apoptotic morphological and a hypodiploidal peak before GI phase occurred after the cells were treated with 40-120 umol/L quercetin for 72h. I concluded that Quercetin arrested Cloudman S91 cells in G0/G1 phase. Results from Western blotting showed that quercetin strongly inhibited the expression of p53 and Bcl-2 in a dose-dependent manner after 48h treatment. These evidences suggested that quercetin induced apoptosis of Cloudman S91 cell line from murine melanoma that might be related to the G0/G1 arrest, and down-regulate of p53 and Bcl-2 expressions in Cloudman S91 cell line.