Preparation,Physicochemical Properties And Protective Effects On Acute Alcoholic Liver Damage Of Polysaccharides From Corbicula Fluminea

Alcoholic liver damage(ALD),a liver disease caused by excessive alcohol consumption,has become a significant problem endangering people’s health.Polysaccharides are a kind of important physicological active substances,having showed a broad spectrum of biological activities including anti-oxidation,anti-tumor and immunoregulation.In this study,a novel enzyme-assisted three-phase partitioning(TPP)method was used to extract and separate polysaccharide(PSP)from Corbicula fluminea,and the optimum extraction parameters were determined by response surface methodology(RSM).Subsequently,the physicochemical properties and in vitro antioxidant activities of PSP were compared with the polysaccharide(E-PSP),extracted by conventional enzyme method,and PSP demonstrated much higher bioactivity.Therefore,the protective effects of the PSP on acute alcohol-induced liver damage in mice were evaluated,and the mechanism based on oxidative stress was preliminarily revealed.The main results are as follows:(1)Enzyme-assisted TPP was used to extract PSP.Results showed that the optimal PSP extraction conditions by single factor experiments and RSM optimization were ammonium sulfate 15.74%(w/v),t-butanol to crude extract ratio 1.4:1.0(v/v),extraction time 30 min,and temperature 37.10 ℃.The extraction yield of PSP was9.18 ± 0.37% under the optimal conditions.(2)The physicochemical properties and antioxidant activities of PSP and E-PSP were comparatively analyzed.Results showed that compared with E-PSP,the extraction yield(9.18%)and carbohydrate content(81.71%)of the PSP increased20.63% and 1.84%,respectively,and the extraction time was significantly reduced to0.5 h from 14 h for the E-PSP extraction.In addition,PSP had the lower soluble protein content as compared to the E-PSP.Both PSP and E-PSP are proteoglycans with similar basic chemical structure,and contain the same monosaccharide types,but different monosaccharide ratios.Moreover,they were comprised of a high molecular weight(high-MW)fraction and a low molecular weight(low-MW)fraction,the latter being much higher than the former.According to in vitro antioxidant activity assays,PSP exhibited much stronger free radical-scavenging ability and antioxidant capacity than E-PSP.(3)The acute alcohol-induced liver damage in mice was established through continuous gavage with 50%(v/v)ethanol-water solution.Compared with the modelgroup,PSP showed significant protection on the alcohol-induced liver damage,decreasing the liver index and increasing thymus and spleen indices dramatically.It also effectively reduced the activities of ALT and AST,and the contents of TG,MDA,IL-6,IL-10,IL-1β and TNF-α.Meanwhile,enhanced activities of SOD,GSH-Px,and CAT and the content of GSH were also detected.(4)The obvious intervention on acute alcoholic liver damage in mice by PSP may be attributed to the fact that PSP can regulate key enzymes in ethanol metabolism.It is well known that PSP can inhibit the expression of CYP2E1,reduce the amount of harmful free radicals produced by the living organism,thus avoiding alcohol damage to the liver.Apart from that,PSP can also activate the expression of HO-1,enhance the body’s antioxidant capacity,and relieve the lipid peroxidation caused by ethanol metabolism,all contributing to the protection against the damage to the liver cell.