| Corn silk is a kind of often-used functional food, and a kind of Chinese herbal medicine as well. Corn silk would be of great value, but often it is abandoned. These years, study of the chemical composition and the pharmacological action of corn silk has been gradually deeper. According to the results, corn silk, as a kind of medicine, has a bright prospect. Corn silk polysaccharide content up to 4% in corn silk, it is one of the most important water-soluble components.Corn hybrid of Zhenghong series, due to the high yield, excellent quality, strong resistance and wide adaptability, has become the leading variety in southwest of China, especially in sichuan. This research would take eight maize varieties of Zhenghong series as the subject, to analyze its polysaccharide content differences, structure and anti-oxidation function, and multiple discussed the structure of corn silk polysaccharide of Zhenghong 505 and the function of lowering blood sugar, to make clear the chemical value of the corn silk of Zhenghong 505. This research also points to the additional value of Zhenghong 505, to promote its application and to provide another reference direction. The results are below:1. This research took the Water-extraction and alcohol-precipitation method to pick up the polysaccharide of eight maize varieties of Zhenghong series, the results showed that the contents of corn silk polysaccharide are different among these varieties, and CSP311, CSP505, CSP211 is relatively high, CSP002, CSP115 and CSP102 content relatively low, the rest in the middle.2. This research took advantages of FTIRto preliminary study the structures of the 8 polysaccharides, and then took the comprehensive application of HPLC,NMR, GC-MS to study the monosaccharide constitution of corn silk polysaccharides CSP505. Results show that the structure of Zhenghong series of 8 maize corn silk polysaccharide. in addition to the glycosidic bond configuration in CSP002 and CSP211 polysaccharide as an alpha type, the rest 6 polysaccharide of glycosidic bond configuration for the beta type, showed that the eight main body structure of the polysaccharide corn silk are basically identical. In addition, the GC-MS result showed that corn silk polysaccharide CSP505 may be made up of arabinose and galactose, and the peak area ratio is 3 to 2. NMR results showed that ZZ-311 could be composed of two kinds of monosaccharide, with the similar chemical shifts of ?-arabinose and?-galactose in the 13CNMR spectrum.3. By using the MTT test, the antioxidant activity of the 8 polysaccharides was studied, the results showed that compared with model group, polysaccharide CSP006, CSP102, CSP115, CSP211, CSP311, CSP505 high dose group showed the significant effect (P<0.05), and compared with model group, high dose group of CSP211 and CSP115 polysaccharides has the extremely significant difference (P<0.01),capacity free from cell by H2O2 damage reached 47.64%,62.73% respectively.4. We took the MTT to study the corn silk polysaccharide's hypoglycemic activity to the rat islet cell RINm5F and human liver cell HepG2, and the results showed that, With the increase of polysaccharide concentrations, RINm5F cells survive ability also enhanced, dosing of polysaccharide in 200,500,1000 ugˇmL-1 concentration and combination of alloxan, the cell survival rate increased by 16.1%,16.1% and 16.1% respectively, the effect is very obvious (P<0.01).Along with the increase of the concentration of the polysaccharide, HepG2 cells survive ability is enhanced, dosing of polysaccharide, respectively in 200,500,1000 ugˇmL-1 concentration effects on cell, cell survival were 100.4%,101.4% and 103.3% respectively.Compared with negative control group, under the effect of three concentration gradient of polysaccharide in the dosing group, the concentration of adenylate cyclase (ADCY4), GPBB and GYS2 showed significant or very significant difference, while the cAMP concentration in the 1000 ugˇmL-1 also showed significant differences.the results indicates that the polysaccharide can promote the synthesis of adenylate cyclase (ADCY4) and cAMP to make insulin secretion to increase, and have the effect of lowering blood by Inhibiting glycogen decomposition and promoting the synthesis of glycogen.To make a summary, the content of corn silk polysaccharide CSP505 is relatively high, and may be a kind of ? polysaccharide formed by D-arabinose and D-galactose with the ratio of arabinose and galactose 3:2. CSP505 can protect the islet cells from oxidative damage, and can also obviously increase cell survival fraction, decreasing the resistance of insulin HepG2. In the aspect of clinical application, CSP505 has a good application prospect to the disease such as diabetes. |
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