Gelation Characteristics,Formation Mechanism Of Polysaccharide From Mesona Blumes And Its Protective Effect On Acute Liver Injury Induced By Carbon Tetrachloride In Mice

Mesona blumes is an annual herbaceous plant from Lamiaceae family that has somefunctions such as relieving summer heat,clearing heat and detoxifying.The commonly known as often"cool powder"are made in the folk by cooking the stems of Mesona blumesin water and then adding diluted starch to make it gelation.Polysaccharide is the main active substance of Mesona blumes,it has good rheological behavior,gelation properties,and the effect of scavenging free radicals.However,the gel mechanisms of polysaccharides and polysaccharide with other macromolecular compounding systems are still unclear.In addition,there are few reports on the liver protection activity of the Mesona blumes polysaccharides?MBP?.Therefore,in this study,the physicochemical properties of MBP were determined,the gel properties,interactions and microstructures of MBP and MBP-soy protein isolate?SPI?gels were analyzed.Gel mechanisms were established after that.In addition,the hepatoprotective activity of MBP was evaluated.The main results are as follows:1.The MBP was extracted by 0.5%sodium carbonate aqueous solution,and its physical and chemical properties were analyzedafter ethanol precipitation and lyophilization.Firstly,the results revealed that the contents of carbohydrate and protein were81.12%?52.45%uronic acid content and 28.67%neutral sugar content?and 14.07±0.90%,respectively.The results of HPGPC indicated that the molecular weight of the polysaccharide was about 3.75×10⁵ Da.The HPAEC-PAD showed that the polysaccharide was mainly composed of rhamnose?Rha?,arabinose?Ara?,galactose?Gal?,glucose?Glc?,xylose?Xyl?and glucuronic acid?Gala?with molecular ratio of 1.38:1.64:2.16:4.90:0.42:6.75.Secondly,the FT-IR spectrumof MBP showedthe specific absorption peak of the carbohydrate in the range of4000-400 cm^-1.Finally,the results of TGA showed that the MBP possessed thermal stability,and the mass remained 20.7%when the temperature was raised to 600°C.2.The effects of salt ions on the rheological and gel properties of MBP and the compounded systemof MBP-SPI were investigated.The results revealed that 3%MBP showed a weak gel propertie,and the additions of calcium ion?3-9 mM?could significantly improve the gel properties?P<0.05?.In addition,calcium ions also significantly increased the thermal decomposition temperature of the MBP gel,and makeit smoother in microstructure.The addition of salt ions also has a significant effect on the compositegel.The resultsshowed that the storage modulus?G??and loss modulus?G??were significantlyincresed when salt ion at lower concentrations?0.005-0.01 M?.In addition,the gel strength and water holding capacity of the compositegels were also significantly increased.However,when the salt ion concentration was raised to 0.015 M,the gel properties were distinct weakening.3.The rheological method of relaxation modulus was used to analyze the gelling mechanism of MBP.The results showed that hydrogen bonding played a major role in the gel formation process.In addition,the"calcium bridge"formed by calcium and the carboxyl groups of MBP plays an important role in the gel formation process.The presence of electrostatic interactions also promoted the formation of the gel network,but it does not play a major role.We also analyzed the interaction of the compositegel and the results showed that hydrophobic interaction,electrostatic interaction and disulfide bond were the main forcesto maintain the gel network structure.As a polysaccharide gel with a wide range of biological activities,MBP contributes to the innovative application of soy isolate protein.4.After 7 days of environmental adaptation,the mice?18-22 g?were divided randomly into 7 groups with 10 mice for each group.MBP group?100,200,300mg/kg body weight?;BD group?200 mg/kg body weight?;BD+MBP group?BM??100+100 mg/kg body weight?;Mice in MBP group,BD group and BM group were given polysaccharide and BD at the above concentration orally every day.Normal group and CC1₄ group were given the same amount of physiological saline?0.9%NaCl?.Afterthe 18 days of treatment,mice were received 0.5%CCl₄/peanut oil mixture?0.1 mL/10 g?while the normal group was received only peanut oil.After 2 h,all mice were fasted but could free access enough water.All mice were killed and blood samples were collected by removing the eyeballs after 12 h.After the experiment,the serum and liver of the mice were analyzed.The results showed that the MBP significantly reduced the levels of serum alanine aminotransferase?ALT?and aspartate aminotransferase?AST?induced by CCl₄ treatment?P<0.05?.Compared tothe CCl₄-induced acute liver injury model,moderate and highdose MBP treatments?200 mg/kg body weight,300 mg/kg body weight?not only significantly increased the levels of antioxidant enzymes?superoxide dismutase,SOD?,Non-enzymatic antioxidants?glutathione,GSH?were alsosignificantly reduced?P<0.05?.In addition,MBP couldsignificantly reduce the level of lipid peroxidation in liver tissue caused by CCl₄ treatment.In addition,medium and high doses of MBP significantly increased TNF-?and IL-1?levels?P<0.05?.Therefore,this study showed that MBP had a protective effect on CCl₄-induced acute liver injury.