Study On Anti-cancer Activity Of Anthocvanin-rich Extracts From Specialty Potatoes In Vitro

Specialty potatoes(Solanum tuberosum L.) are new developed varieties in recent years with the function of nutrition, health care and pigment source. Due to their high content of anthocyanins, specialty potatoes have the function of both medcine and food. In this study, the extraction and purification of anthocyanin-rich extracts from flesh and peel of colored (Yongzi Ⅰ), purple (Yongzi Ⅱ) and common yellow fished potaoes have been investigated. The antiproliferative properties of extracts from flesh and peel of Yongzi Ⅰ against huaman prostate, gastric, lung, liver and breast cancer cells as well as normal cells, the antiproliferative properties and effcet on the cycle distribution of different extracts against human prostate cancer and normal cells have been emphatically studied. This study can provide theory basis for the development of health care products from specialty potatoes and for their preventive and therapeutic function against cancers. The results were as follows:(1) Extraction method using citric acid solution and ultrasonic as assist was effective, whose recovery rate was higher than75%-80%; Purification by macroporous resin D-101could significantly increace the content of anthocyanin; Freeze-dried power was obtained by vacuum freeze drying, in which the content of athocyanins were about25%and were the active principles inhibiting the growth of cancer cells. Analysis of extracts by HPLC indicated that the varieties of anthocyanins were different in extracts from different kind of specialty potatoes, while the varieties were the same but the proportion differed in the extracts from different part of the same variety; The extracts were effectively degermed using microfiltration membrane filter and could be used for cell experiment.(2) The antiproliferative properties of extracts from flesh and peel of Yongzi I against huaman prostate(Du145, PC-3), gastric(AGS), lung(A549), liver(HepG2) and breast(Bcap-37) cancer cells and their corresponding normal cells were determined by MTT method. Drug susceptibility of different cell lines differed greatly:Du145presented the most intense susceptibility with IC50values of85μg/mL and27μg/mL to the extracts from flesh and peel, respectively; While AGS and HepG2presented the least intense susceptibility to the extracts from flesh and peel, respectively. The growth inhibition effects against normal cells were significantly slighter, whose IC50values were at least double of their corresponding cancer cells, indicating the little side-effect of natural products.(3) The antiproliferative properties of extracts from flesh and peel of Yongzi Ⅰ, Yongzi Ⅱ and normal yellow fleshed potaoes against huaman prostate cancer line Du145and its corresponding normal cell line were evaluated. The varieties and proportion of anthocyanins differed in extracts from different variety and part of potatoes, leading to the difference in the antiproliferative activities. The antiproliferative activities of extracts from fleshes were:Yongzi Ⅱ>yellow-fleshed> Yongzi Ⅰ, while the activities of extracts from peels were:yellow-fleshed> Yongzi Ⅱ> Yongzi Ⅰ; Extracts from peels presented better antiproliferative activities, whose IC50values were less than1/3of extracts from fleshs; The growth inhibition effects against normal cells were significantly slighter. All the results were comparative to the results in other researches at home and abroad.(4) The effects of extracts from flesh and peel of Yongzi Ⅰ, Yongzi Ⅱand normal yellow fleshed potaoes on the cycle distribution of huaman prostate cancer line and its corresponding normal cell line were evaluated. No significant apoptosis was found, indicating that the inhibitory effect may be caused by necrosis; The effects of extracts on the change of cycle distribution were more significant to cancer cells causing G2phase retardation, but less significant to normal cells presenting a integral cytotoxicity effect with a prevalent change of G1/G2, G2/M and S phase; The chemopreventive mechanisms of anthocyanin-rich extracts from specialty potatoes may be due to their oxygen inhibiton as well as promotion effects under different conditions, and can be related to caspase mechanism and male sex hormone.