| Potato is the fourth largest food product in the world,which not only provides us with energy,but also has a certain degree of nutrition and health value.Purple potato is one of the most common coloured potato,and its figure is much smaller than the common potato,with skin appearing dark purple,and it has a high nutritional value.It contains a lot of healthy ingredients,including anthocyanins,vitamin C,polyphenols,with ideal edible and medical function.Purple potato is active on anti-oxidation,free radical scavenging,anti-aging,anti mutation,anti-inflammatory which can suppress tumor and benefit human a lot on healthcare.Prostate cancer is the second most common cancer in men in western countries,and its mortality rate is the second highest in the world.In recent years,the incidence of prostate cancer in China has increased significantly.Prostate cancer will eventually deteriorate into hormone independent prostate cancer or hormone resistant prostate cancer,which can not be cured by chemotherapy,and will induce death.By extraction and purification of anthocyanin extracts from different parts of purple potato,We got three main substances:anyhocyanin extracts from flesh of purple potato(AEFP),anyhocyanin extracts from peel of purple potato(AEPP),and anyhocyanin monomer one from flesh of purple potato(AMFP).Regarding these three substances as the research object,this paper studied on their antioxidant activity and correlation with antioxidant active substance,and their mechanism of inducing cell cycle arrest,apoptosis and proliferation inhibition of androgen independent prostate cancer cells PC-3 and Du-145.The results of this study provides a theoretical basis for preventing prostate cancer in vitro,and it can be used as a reference for developing new natural medicine against prostate cancer in the future.The main contents are as follows:(1)The purple potato peel and flesh powders were extracted by ultrasonic extraction with citric acid as extraction agent,and the extract was purified by macroporous resin D101,after concentrating and freeze drying,lyophilized powders of anyhocyanin extracts from flesh and peel of purple potato were gathered.Two monomers of anthocyanin were separated from lyophilized powders of purple potato by Pre-HPLC.The monomer one was identified by MS and NMR as Petunidin-3-p-coumaroylrutinoside-5-glucoside.The monomer two was identified by MS as Peonidin-3-p-coumaroylrutinoside-5-glucoside.UPLC analysis showed both purity were higher than 95%.(2)The main antioxidant contents of anyhocyanin extracts from peel and flesh of purple potato were measured.Content of total phenolics,total flavones and total anthocyanins from lyophilized powders of anyhocyanin extracts from peel was significantly higher than that in lyophilized powders of anyhocyanin extracts from flesh(p<0.05).Antioxidant capacity of anyhocyanin extracts from peel of purple potato(AEPP),anyhocyanin extracts from flesh of purple potato(AEFP)and anyhocyanin monomer one from flesh of purple potato(AMFP)were evaluated by By DPPH,ORAC,ABTS+,FRAP,and the result showed that these three substances did reveal antioxidant activity,and antioxidant strength was AEPP>AEFP>AMFP,and that the antioxidant activity was positively correlated with the antioxidant substance.(3)The effect of anthocyanin extracts from the peel and flesh of purple potato,anyhocyanin monomer one from flesh of purple potato on proliferation inhibition of androgen independent prostate cancer cells Du-145 and PC-3 were detected by MTT assay,and the result revealed all the three appearing proliferation inhibition effect,and revealed dose dependent effect,and the result was significant(p<0.05).The inhibitory effect of three substances on two cancer cells was AEPP>AEFP>AMFP.AEPP,AEFP,AMFP blocked the cell cycle of PC-3 cells in the Go/Gi phase,and then delayed the cells into the S phase preventing DNA replication,and reduced the number of cells into the G2/M phase,thereby inhibiting the proliferation of malignant cells.PI/Annexin-V FITC double staining showed that AEPP,AEFP and AMFP could induce apoptosis of PC-3 cells.Western blot experiment showed AEPP,AEFP,AMFP could up-regulate p53 protein expression both in Du-145 and PC-3 cells.AEPP,AEFP could up-regulate Bax protein expression in PC-3 cells.Therefore,AMFP may block PC-3 cells in G0/G1 phase and induced cell apoptosis by up regulating p53 protein while AEPP and AEFP may do likewise by up regulating p53 protein and Bax expression.AEPP,AEFP and AMFP may induce apoptosis of Du-145 cells by up regulating p53 protein. |
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