Study On Purification And Antitumor Activity Of Polysaccharide From Natural Portulaca Oleracea L.

According to 2014 World Cancer Report,the incidence of the liver cancer is increasing dramatically in the world,especially in China,the increasing number of new cases of liver cancer and the number of deaths result from the liver cancer both become the world’s first.Hepatocellular carcinoma is a kind of malignant tumor which occurs in the liver,including primarily hepatoma and metastatic hepatic carcinoma,primary hepatoma is the most common malignant tumor in our country,accounting for more than 80%.The Methods of liver cancer treatment usually include(except surgery)radiation and chemo therapy treatment.The increasing interest has been attracted for the development and utilization of new anti-liver cancer agents with high efficiency and low toxicity from natural substances because of the higher cost,greater side effects and stronger drug resistance of chemotherapy drugs.Portulaca oleracea L.polysaccharides(POP),which is one of the main active ingredients of Portulaca oleracea L.,has been reported to possess a variety of bioactivities such as anti-oxidant,anti-inflammatory,anti-diabetes and anti-cancer.Previous researches generally focused on extraction,isolation,antioxidant,anticancer of POP,so far.However,the study on the molecular mechanism of antitumor effect of POP acting on Human hepatoma cell line HepG2 remains unknown.Therefore,the study on enzymatic removal of protein from POP was optimized and the study on the structure of POP-A were preliminary analysised,then antitumor function of POP-A were investigated by using cellular and molecular biology technique.The optimal response of enzymatic removal of protein from polysaccharide: the ratio of papain’s liquid to polysaccharides’ s liquid is 0.2:1,enzymolysis time is 3.03 h,enzymolysis temperature is 62.45 ℃,enzymolysis pH is 5.98.The clearance rate of protein is 78.4%.The molecular weight of polysaccharides was identified by HPGPC,the molecular weight of POP-A and POP-B is 11 kD and 9.1 kD,respectively.PMP pre column Derivatization High performance liquid chromatography method for analysis monosaccharide composition of POP-A are mannose,rhamnose,glycuronic acid,galacturonic acid,glucose,galactose and glucose in Arabia.And Infrared spectrum indicated that pyranose is the major component of the polysaccharide in POP-A,with two glycoside configurations,α-hemiacetal hydroxy and β-hemiacetal hydroxy,coexiste.The molecular mechanism about anti tumor effect of POP-A in HepG2 hepatoma carcinoma cells was studied.Results showed that compared with the control group,POP-A can inhibit the proliferation of hepatocellular carcinoma cells significantly,and the potential mechanism may be related to regulate cellular immune response and improve the expression of p53,Bax,Bcl-2 genes and proteins.The process of deproteinization optimization,structure analysis,immune response regulation,and the molecular mechanisms of anticancer of POP-A were discussed in this paper.The results of this study can provide the theoretical foundation for the development of functional foods or drugs with anti tumor effect.