Preparation Of C-phycocyanin And Polysaccharides From Spirulina Platensis And Their Biological Activities

Spirulina is multicellular and filamentous cyanobacteria that have achieved a considerable popularity in the health care and food industry.However,the main application of industry is sale of dry powder,capsules,tablets,etc.,and it is difficult to achieve high value-added products.In this study,the different molecular weights of PSP and different purity of C-PC from Spirulina platensis were prepared.Then,the anti-fatigue and anti-diabetic activities of C-PC and PSP were evaluated in vitro and in vivo.The results were summarized as follows:?1?Preparation of polysaccharides from Spirulina platensis and its biological activities:the degradation of polysaccharides from PSP1 was investigated.Two low molecular weight polysaccharides PSP2 and PSP3 were obtained using H₂O₂-Vc system combined with ultrafiltration.The physicochemical properties indicated that the solubility and sulfate content of polysaccharides were increased after degradation,and the IR spectrum implied that the structure of polysaccharides did not change.In vitro antioxidant activity and inhibition of?-glucosidase activity experiments showed that the degraded sample with lower molecular weight possessed higher bioactivities.PSP3 had the best bioactivities.?2?Isolation and purification of phycocyanin from Spirulina platensis:C-PC?was obtained by repeated freezing and thawing with a purity(A₆₂₀/A₂₈₀)of 0.56.Then,three different purity phycocyanins C-PC_II,C-PC_III and C-PC?were prepared by precipitation with ammonium sulfate,aqueous two-phase system?ATPE?and precipitation with ammonium sulfate combined with ATPE.The optimum saturation of ammonium sulfate was 40%.Under this condition,C-PC_II was obtained with a purity of 1.08 and a yield of83%.The optimum extraction process for aqueous two phase system was PEG 4000 12.3%?m/m?,the KHP was 15.1%?m/m?and pH was 5.9,the purity of C-PC?was 2.33 and with the recovery rate was 79%.The highest purity of C-PC?was obtained by salting out combined with ATPE,and the final recovery of C-PC?was 63%with the purity of 3.47.?3?Anti-fatigue activity of C-PC from Spirulina platensis:the exhaustive swimming test in mice showed that C-PC with different purity could increase the exhaustion time of mice.C-PC_IVV medium dose?200 mg/kg?group had the longest swimming time,which increased by 82.4%compared with the positive control.At the same time,it was found that four different purity of C-PC can increase LDH,LG levels and reduce BLA,BUN levels.The test of atmospheric pressure tolerance showed that phycocyanin could improve the hypoxia tolerance of mice.With the increase of the purity of C-PC,the anti-fatigue activity was better.C-PC?had the best anti-fatigue effects,however it had no significant difference compared with C-PC?.?4?Hypoglycemic activity of C-PC and PSP:3T3-L1 adipocyte insulin resistance model experiments were established.The results showed that PSP1,PSP2 and PSP3polysaccharides had no toxic side effects on 3T3-L1 preadipocytes.At the same time,it was found that three different molecular weight polysaccharides could improve the insulin resistance of 3T3-L1 adipocytes and increased the sugar uptake capacity of 3T3-L1 insulin resistance model cel s.And PSP3 had the best effects.Then,the PSP3,C-PC_III and CPM were administered by intraperitoneal injection to the STZ-induced diabetic male ICR mice.After 28 d administration,the hypoglycemic effect was evaluated by testing the fast blood glucose level,fasting serum insulin and blood lipids,and oxidative stress.The results showed that all three samples could reduce fasting blood glucose levels in diabetic mice.Compared with the model group,the blood glucose level of mice in the C-PC_III 200 mg/kg group was reduced by 60.35%.PSP3,C-PC?and CPM could improve diabetes induced dyslipidemia in mice by reducing serum TC,TG,and LDL-c levels and increasing HDL-c levels.After administration,diabetic mice could significantly increase FINS levels and decreased HOMA-IR.The date of ALT,AST and?-GGT in serum and activities of antioxidant enzymes?SOD,GSH-Px and CAT?indicated that PSP3,C-PC?and CPM had beneficial effects on the improvement in the activities of oxidative stress.And,C-PC?had the best hypoglycemic effects.