| The last Porphyra haitanensis was abandoned as it was ugly, rough texture and had low price. In this paper, the abandoned Porphyra haitanensis cultivated in Guangdong Province was studied for the first time. The main nutritional composition of abandoned P. haitanensis and shanshui P. haitanensis were analyzed and compared. The extraction technology of polysaccharide from abandoned P. haitanensis was optimized. The polysaccharide extracted by direct hot water and assisted by microwave were purified, and the purified polysaccharides were analyzed preliminarily with the contents of chemical components analysis, UV spectrum, IR and 2D-NMR. Last, the function on in-vitro anti-oxidative and hypoglycemic effect were studied.Nutritional components analysis showed that: compared with the shanshui P. haitanensis, the contents of crude fat , crude protein and crude fiber of abandoned P. haitanensis were higher, while the ash, total carbohydrate and polysaccharide were lower. The abandoned P. haitanensis was also rich in kinds of amino acids, and contained seven essential amino acids(EAA), the quality of protein was good. The contents of K, Na, Mg, Ca and Fe, Zn, Cu ,et al were rich . The content of Hg was lower than national standards , but the contents of As and Pb were a little higher. So it should be considered to remove the As and Pb during the exploitation and utilization process.The optimum extraction conditions were obtained as microwave treatment time of 4min, ratio of water to material of 50:1, water extraction time of 2h, water extraction temperature of 100℃, under which the yield of polysaccharide was 10.81%.The chemical components and structure of polysaccharide , which extracted by direct hot water (WP) and assisted by microwave (MP) , were compared. Two polysaccharides were isolated and purified by DEAE-52 and Sephadex G-150 column chromatography, one fraction was got respectively finally. UV spectrum showed they were sterling. Chemical components analysis showed the contents of molecular weight, sulfate and 3,6-inner ether-galactose had little difference. IR and 2D-NMR spectroscopy further proved they were both sulfated galactan. The results showed that there were no obvious change between WP and MP.The in-vitro anti-oxidative function of the polysaccharide(crude and purified)extracted from P. haitanensis were showed that: both of the polysaccharides had a certain reducing capacity and anti-oxidative effect, which were lower than the capacity of the control, vitamin C. A certain ability to scavenging·OH,·O2- and DPPH·had been found in purified polysaccharide. A strong ability to scavenging DPPH·and a certain ability to scaveng·O2- had been found in crude polysaccharide, but didn't show some scavenging·OH activity. Hypoglycemic effect of abandoned P. haitanensis polysaccharide(APHP) inalloxan-induced diabetic mice was studied. Compared with untreated diabetic mice,the administration of the APHP for 21 days caused a significant decrease in blood glucose levels (p <0 .05) , the index numbers of pancreas, kidney, liver and thymus,spleen were increased, it seemed APHP could protect internal organ and function.. Simultaneously, the concentration of serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL) were significant decrease(p <0 .05), triglyceride (TG) was apparent decrease and high-density lipoprotein cholesterol (HDL) level was apparent increase; In addition, the contents of T-AOC and enzymic antioxidants(SOD,GSH-Px and GSH) in serum, liver, kidney were significant increased (p <0 .05), content of MDA was significant decrease (p <0 .05). The tissues (pancreas, kidney, liver, thymus and spleen) of mice, which were stained with hematoxylin & eosin, were repaired to some extent. The results showed that the administration of APHP could reduce the blood glucose levels, improve lipid metabolism and activities of antioxidant, reduce the tissue damage and restore tissues in alloxan-induced diabetics mice. |
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