Two exopolysaccharides, NPS and APS, were isolated from L. plantarum WLPL09 and purified by ion-exchange chromatography. The structural analyses showed that molecular weight of NPS and APS were 72.60 kDa and 33.22 kDa, respectively. NPS was mainly composed of mannose and glucose, in molar ratio of 85.35:14.65, while APS was composed of mannose, glucose and galactose, in molar ratio of 89.69:8.65:1.66. In in vitro antitumor assays, APS displayed strong anti-proliferative effect against HepG2 hepatocellular carcinoma cells and HCT-8 colon adenocarcinoma cells in a dose-dependent manner. Morphological and flow cytometry analyses revealed that APS strongly induced apoptosis of HepG2 and HCT-8, especially for HCT-8. Furthermore, APS significantly up-regulated the mRNA level of apoptosis-related genes in cancer cells, and remarkably improved the activities of caspase-3, -8 and -9 in HepG2, caspase-3 and -8 in HCT-8. These results suggest APS might be explored as a potential, natural antitumor agent for functional food.

从植物乳杆菌中分离出两种胞外多糖NPS和APSWLPL09，并通过离子交换色谱法纯化。结构分析表明，NPS和APS的分子量分别为72.60 kDa和33.22 kDa。NPS主要由甘露糖和葡萄糖组成，摩尔比为85.35：14.65，而APS由甘露糖，葡萄糖和半乳糖组成，摩尔比为89.69：8.65：1.66。在体外抗肿瘤试验中，APS对HepG2肝癌细胞和HCT-8结肠腺癌细胞具有强剂量依赖性的抗增殖作用。形态和流式细胞仪分析表明，APS强烈诱导了HepG2和HCT-8的凋亡，尤其是HCT-8。此外，APS显着上调了癌细胞凋亡相关基因的mRNA水平，并显着提高了HepG2中caspase-3，-8和-9，HCT-8中caspase-3和-8的活性。