| Chlorococcum sphacosum GD contains a large number of bio-active substance,including lipids,pigments,polysaccharides,and polyphenols etc.The algal polysaccharide,as one of the most natural active substances,has been reported to have various biological activities such as antioxidant,anti-inflammatory,anti-clotting,anti-tumor,hypoglycemic and hypolipidemic.As the Chlorococcum sphacosum GD has many advantages including simple culture conditionsthe high yield,and the easy preparation of polysaccharide,making the Chlorococcum sphacosum GD polysaccharides become an important potential natural polysaccharide for developing pharmaceuticals and health products.At present,the research on the biological activity of Chlorococcum sphacosum GD polysaccharides is mostly in vitro biological activity research,however,the research on its in vivo biological activity is still less,and there is not much experimental basis for development and utilization.In this thesis,Chlorococcum sphacosum GD polysaccharides were extracted by hot water extraction.The antioxidant and anti-inflammatory activities of the Chlorococcum sphacosum GD polysaccharides were investigated in vivo and in vitro using the zebrafish model,tissue culture model.And its antihypoglycemic and hypolipidemic activity has been examined byin vitro assays.The main findings are as follows.(1)There was no toxicity to RAW264.7 cells when cells were treated with Chlorococcum sphacosum GD polysaccharide at concentrations of 0-400 μg/mL.The minimum concentration of 20 μg/mL of Chlorococcum sphacosum GD polysaccharide effectively inhibit the cytotoxic effect of LPS,and the improvement effect increased with increasing concentration of Chlorococcum sphacosum GD polysaccharide.Treatment of oxidatively stressed cells with Chlorococcum sphacosum GD polysaccharides at concentrations of 5-100 μg/mL was able to reduce the cellular ROS content,and within this concentration range was able to increase the activity of SOD,CAT,and GSH-PX enzymes in oxidatively stressed cells.(2)According to the optimum concentration of Chlorococcum sphacosum GD polysaccharide in zebrafish,the subsequent treatment concentrations of Chlorococcum sphacosum GD polysaccharide for zebrafish were determined to be 20,50 and 100 μg/mL.Treatment with Chlorococcum sphacosum GD polysaccharides at concentrations of20-100 μg/mL largely improved LPS-induced rapid heart rate and high ROS content,and significantly reduced lipid peroxidation rate and cell mortality in zebrafish.Mechnically,it can increase the expression of SOD,CAT,GSH-PX,HO-1,Keap1,Nrf2 at the m RNA level.(3)The polysaccharide of Chlorococcum sphacosum GD efficiently inhibited the movement of neutrophils to neuromast induced by copper sulfate.As well,it inhibited the movement of macrophages and neutrophils towards the fin wound after fin clicking in zebrafish larvae.Consistently,it reduced the expression of inflammatory factors TNF-α,TNF-β,IL-6,IL-8,IL-1β,COX-2,and thus reduced the level of inflammation in zebrafish.(4)The Chlorococcum sphacosum GD polysaccharide inhibited the activity ofα-amylase and α-glucose as showed in in vitro experiments,inhibited the body’s absorption of starch and glycogen,and slowed down the rise time of blood sugar in the body.It inhibited the activity of pancreatic lipase and cholesterol esterase,inhibited the body’s absorption of fat and cholesterol,and reduceed the plasma levels of cholesterol and fat.In addition,the Chlorococcum sphacosum GD polysaccharides had a high binding rate to cholate and promoted the conversion of cholesterol to bile acids and achieved a lipid-lowering effect.In summary,this study combined in vivo and in vitro experiments to evaluate the biological activities of Chlorococcum sphacosum GD polysaccharides,filling the gap in the study of various biological activities of Chlorococcum sphacosum GD polysaccharides in vivo and providing an experimental basis for the development and utilization of Chlorococcum sphacosum GD polysaccharides as health products and pharmaceuticals. |
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