Preparation Of A Momordica Charantia L.polysaccharide Chromium(Ⅲ) Complex And Study On Its Anti-hyperglycemic Activity

Polysaccharide is one of the main active ingredients in Momordica charantia(M.charantia).Our laboratory has reported in the previous work that Momordica charantia polysaccharide(MCP)has certain effects such as anti-oxidation and blood sugar lowering,and can significantly increase the density of islet particles and repair damaged islet tissue.And possible targets have been found in the hepatic glucose metabolism pathway,but the hypoglycemic effect of M.charantia L.is less stable than chemical drugs.The hypoglycemic effect of plant polysaccharides similar to M.charantia has been reported for many years,but the difference in the blood glucose lowering activity of natural products compared with chemical synthetic drugs is still significant.At present,it is reported that the chemical modification of polysaccharides can improve the biological activity of polysaccharides,and the combination of trace elements and polysaccharides related to the treatment of diabetes can form synergistic hypoglycemic effects,which has great application value for the treatment of diabetes.Trivalent chromium ion is one of the essential trace elements of the human body.It is closely related to diabetes.It can help insulin to lower blood sugar.Appropriate chromium supplement can alleviate the symptoms related to diabetes,and organic chromium is more easily absorbed than inorganic chromium.In this study,M.charantia was used as raw material to extract polysaccharides with hypoglycemic activity from M.charantia,and combined with trivalent chromium ions under certain conditions to prepare MCP chromium complex.Based on this,inductively coupled plasma was used to measure chromium.And the molecular weight and monosaccharide composition were measured by gel chromatography and gas chromatography-mass spectrometry.The binding sites of chromium ions and polysaccharide backbone were speculated by infrared chromatography,and the bitter melon formed by complex analysis was observed by circular dichroism and atomic force microscopy.The spatial conformation of polysaccharide derivatives was studied.The hypoglycemic activity of MCP chromium complex was studied by establishing a mouse model of diabetes mellitus.The possible hypoglycemic mechanism was discussed and the structure-activity relationship was analyzed.This topic has the following results:1.MCP chromium complex was successfully prepared by complexation of MCP with trivalent chromium ion,and the yield was 49.42%.It is made up of rhamnose(3.4): arabinose(12.8): xylose(4.5): mannose(3.8): glucose(15.2): galactose(59.1): rock sugar(0.98),the chromium content is 14.68 ± 0.35% of a dark green solid with a molecular weight of 8.3× 104 Da.2.By comparing the infrared spectra of MCP and its chromium complex,it is shown that the MCP chromium complex has a red shift to 3427cm-1 from 3420 cm-1,and new features peak appear at 530.34 cm-1.It is speculated that the chromium ion is successfully bound to the MCPe and attached to the hydroxyl group of the MCP.Combined circular dichroism and atomic force microscopy analyses indicated that after linking with chromium ions,the flexibility of the three-dimensional structure of the polysaccharide increased,which is more conducive to the biological activity.3.By the treatment of MCP chromium complex for four weeks,the mice with STZ-induced DM exhibited significantly lower fasting blood glucose levels,whereas higher insulin levels and antioxidant enzyme activity than in the diabetic group.Optimal effects wereobtained with a dosage of 30 mg/kg MCP chromium complex body weight.Moreover,an effective dosage of MCP chromium complex was more than ten times lower than that of MCP.Histological analysis indicated that MCP chromium complex alleviated the oxidative tissue damage in STZ-lesioned mice.An acute toxicity experiment indicated that MCP chromium complex was safe at a dose of 1500 mg/kg in normal mice.In summary,these results indicate that the MCP chromium complex may be a functional food for preventing diabetes,which is effective,safe and economical.