Preparation Of Crude Old Tea Extract And Its Hypoglycemic, Lipid-lowering And Hepatoprotective Effects On Diabetic Mice

Objectives:To establish the best extraction process for extracting WECOT and COTCP from crude tea leaves,determine the content of WECOT and COTCP components,detect heavy metal content and pesticide residues,and explore the effects of WECOT and COTCP on blood sugar,blood lipids,and islets of diabetic mice ? cell function and the role of internal organs.Methods:Using water extraction method,single factor experiment and orthogonal experiment,the best extraction process of WECOT was determined,and COTCP was obtained by water extraction and alcohol precipitation method.The moisture content in WECOT and COTCP was determined by drying method,the content of tea polyphenols in WECOT and COTCP was determined by Folin method,the content of free amino acids in WECOT and COTCP was determined by ninhydrin colorimetric method,and the content of free amino acids in WECOT and COTCP was determined by Coomassie brilliant blue method.The protein content in COTCP,the anthrone-sulfuric acid method to determine the neutral polysaccharide content in WECOT and COTCP,the meta-hydroxybiphenyl method to determine the acid polysaccharide in WECOT and COTCP,and the ultraviolet-visible spectrophotometric method to determine the tea pigment in WECOT and COTCP.Content,ICP-MS method to determine the heavy metal content in WECOT,COTCP,LC-MS,GC-MS method to determine the pesticide residues in WECOT,COTCP.A mouse diabetes model was induced by intraperitoneal injection of streptozotocin,and the effects of WECOT and COTCP on blood glucose,body weight,water and diet,and organ index of diabetic mice were investigated.The automatic biochemical analyzer measures the liver function indexes and blood lipids of the mice,and the enzyme-linked immunoassay measures the serum insulin of the mice,and then calculates the related indexes.Results:The optimal extraction conditions of WECOT were obtained through single factor experiments and orthogonal design experiments.The optimal extraction conditions of COTCP were obtained by water extraction and alcohol precipitation;the moisture content in WECOT was 0.65%and the moisture content in COTCP was determined by drying method.1.00%;the content of tea polyphenols in WECOT is 21.83%determined by the Folin method,and the content of tea polyphenols in COTCP is 0.25%;the content of free amino acids in WECOT determined by the ninhydrin colorimetric method is 0.13%,and the content of tea polyphenols in COTCP is 0.13%.The content of free amino acids is 0.13%;the content of soluble protein in WECOT is 3.17%by the Coomassie brilliant blue method,and the content of soluble protein in COTCP is 3.30%;the content of neutral polysaccharides in WECOT is 15.83%by the anthrone-sulfuric acid method,and the content of COTCP is determined by COTCP.The neutral polysaccharide content of COTCP was 6.40%;the acidic polysaccharide content of COTCP measured by meta-hydroxybiphenyl method was 4.60%;the content of theaflavins,thearubicin,and thefuscin in WECOT measured by UV-Vis spectrophotometry was 0.37,respectively.%,6.85%,28.73%;UV-visible spectrophotometric determination of theaflavins,thearubicin,and theafuscin content in COTCP were 0.15%,0.90%,and 27.27%;ICP-MS determined WECOT,COTCP The content of heavy metals in the product did not exceed the limit and met the standard requirements;the pesticide residues in WECOT and COTCP determined by LC-MS and GC-MS methods did not exceed the limit and met the standard requirements.The effect of WECOT and COTCP on diabetic mice showed that the high and medium doses of WECOT group can significantly reduce the blood sugar of diabetic mice(P<0.01),and there is no statistical difference compared with the metformin group(P>0.05).The WECOT group can also reduce blood sugar in diabetic mice(P<0.05).There was no statistical difference between the high,medium,and low COTCP groups compared with the model group(P>0.05).The high and medium dose WECOT groups have the effect of reducing the area under the blood glucose curve and improving glucose tolerance(P<0.01 or P<0.05).High and medium dose WECOT group,high,medium and low dose COTCP group can effectively reduce the total cholesterol of diabetic mice(P<0.05);low dose WECOT group,medium and low dose COTCP group can reduce triglyceride in diabetic mice The content of ester(P<0.05);neither WECOT nor COTCP can reduce the VLDL in the serum of diabetic mice(P>0.05).High,medium,and low dose WECOT groups can increase the serum insulin content of diabetic mice,but there is no statistical difference(P>0.05).High,medium,and low doses of WECOT can also improve the insulin sensitivity index of diabetic mice(P<0.05).The COTCP group has no effect on the serum insulin content,insulin secretion index and insulin sensitivity index of diabetic mice(P>0.05).WECOT high and medium dose groups can reduce the liver index of diabetic mice(P<0.05);the spleen index and thymus index of diabetic mice are not abnormal;the high dose WECOT group can reduce the ALT of diabetic mice(P<0.05),Compared with the normal group,there was no statistical difference(P>0.05);the AST and GGT of diabetic mice were not different from those of the normal group(P>0.05).The high-dose WECOT group can improve the symptoms of polyphagia in diabetic mice,while the other WECOT and COTCP groups have no effect on diabetic mice.Neither WECOT nor COTCP can improve the weight loss of diabetic mice.Conclusions:In this study,the best technology for extracting WECOT and COTCP from crude old tea leaves was established.Through content determination,it was found that WECOT is a mixture containing tea polyphenols,tea polysaccharides,amino acids,proteins,tea pigments and other substances.The content of polyphenols,tea polysaccharides and tea pigments was significantly reduced.The heavy metal content and pesticide residues in WECOT and COTCP did not exceed the limits,which met the standard requirements.WECOT improves the body's glucose tolerance,increases serum insulin,enhances the body's sensitivity to insulin,reduces ALT in the liver,reduces liver inflammation,reduces serum CHO and TG,increases serum HDL,and relieves polydipsia and polyphagia Urinary symptoms can lower blood sugar,protect liver,and improve diabetes symptoms.COTCP can reduce CHO and TG in diabetic mice,but it does not reduce blood sugar,enhance pancreatic ?-cell function,improve "three more and one less" symptoms,and protect the liver.