Structural characteristics and anti-tumor/-oxidant activity in vitro of an acidic polysaccharide from Gynostemma pentaphyllum

In this paper, a novel acidic polysaccharide (CPS-1) was successively prepared from Gynostemma pentaphyllum using hot water isolation method to explore its antitumor and antioxidant activities. Structural characteristics of CPS-1 were evaluated by SEM, HPGPC, HPAEC-PAD, FT-IR, and NMR. The results indicated: CPS-1 was mainly composed of Ara, Gal, Glc, Xyl, Man, GalA and GlcA in a molar ratio of 1.23:2.14:0.67:0.2:0.29:0.16:0.04 with molecular weight of 3297 kDa. Combining with the results of FT-IR and NMR, it was inferred that CPS-1 was mainly possessed the five main linkages including α-D-Ara, α-D-Gal, α-D-Man, α-D-Xyl and β-D-Glc. Furthermore, MTT results exhibited that the IC50 value of CPS-1 for inhibitive effect on SPC-A-1 and MGC-803 cells for 24 h were 284.36 and 365.27 μg/mL, respectively. Microscopic observations showed that the cells exhibited significant apoptotic characteristics, such as cell shrinkage, the decreased of cell adherence and the appearance of apoptotic bodies. It was shown that CPS-1 had significant anti-tumor activity. In addition, the ability of CPS-1 to scavenge superoxide radical, ABTS and DPPH radicals was also enhanced with the increased of concentration. Therefore, it was revealed that CPS-1 might be used as a natural anticancer and antioxidant component.