Physicochemical properties of polysaccharides separated from Camellia oleifera Abel seed cake and its hypoglycemic activity on streptozotocin-induced diabetic mice

Two homogeneous polysaccharide fractions named SCP-1 (7.16 × 106 Da) and SCP-2 (2.00 × 104 Da) were purified by DEAE-52 cellulose and Sephadex G-200 column chromatography successively from Camellia oleifera Abel seed cake. They were characterized by Fourier transformed infrared (FT-IR), high performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR) spectroscopy and differential scanning calorimetry (DSC). The monosaccharide compositions of SCP-1 were d‑mannose, d‑glucose and l‑xylose with a molar ratio of 1.77:0.93:1 and that of the SCP-2 were d‑mannose, l‑rhamnose, d‑glucose and l‑xylose with a molar ratio of 5.27:1.21:0.16:1. Animal experiments suggested that the plasma glucose levels in hyperglycemia mice were reduced by 11.34%, 30.70%, 46.83% after administration of high, medium and low doses of SCP-1, and reduced by 16.67%, 23.93% and 33.00% after administration of high, medium and low doses of SCP-2, respectively. SCP-1 and SCP-2 also increased the activities of glutathione peroxidase (GSH-Px), catalase (CAT) and superoxide dismutase (SOD), as well as decreased the content of malondialdehyde (MDA) in the hyperglycemia mice. These results suggested that SCP-1 and SCP-2 possessed strong hypoglycemic activities in streptozotocin-induced model mice. In addition, the hypoglycemic activity of SCP-1 was stronger than that of SCP-2.