Comprehensive Utilization,Antidiabetic And Lipid-lowering Activity Of The Active Ingredient From The Exocarpium Citri Grandis

This study systematically evaluated the extraction,isolation,purification,comprehensive utilization,and antidiabetic and lipid-lowering activity of essential oil,flavonoids and polysaccharide from the Exocarpium citri Grandis.This provides a reference for the comprehensive development and utilization of Exocarpium citri Grandis.The specific findings are as follows:1.First,the Exocarpium Citri Grandisis essential oil?EEO?was extracted by steam distillation.When the solid-to-liquid ratio was 1:10g/mL and the extraction time was 10 h,the yield of EEO reached 2.63mL/150g.The results of GC-MS analysis shown that 21 components of EEO were identified and grouped as follows:?-Pinene,?-myrcene,limonene,m-mentha-4,8-diene and other.Cyclodextrin-EEO inclusion complex??-CD-EEO?was prepared.The inclusion complex was characterized by UV spectroscopy,microscopic imaging,scanning electron microscope?SEM?and Thermogravimetric Analysis?TG?analysis.The antioxidant experiment showed that when the EEO concentration was 0.033mL/mL,the DPPH clearance rate was 90.09%.High concentration of EEO scavenged DPPH free radicals faster than low concentrations.DPPH scavenging ability of the inclusion complexes was higher than that of the EEO.2.The polysaccharide was extracted from filtrate and filter residue by water extraction and alcohol precipitation.Crude polysaccharide of Exocarpium Citri Grandis?ECP?was obtained by alcohol precipitation,deproteinization and dialysis.Then,ECP was purified by quaternary ammonium salt to obtain polysaccharides EAP,ENP and ELP with contents of 59.61%,83.80%and 92.26%,respectively.The results of HPGPC indicated that EAP may be a homogeneous polysaccharide.In order to improve the activity of polysaccharide,the polysaccharide was modified by carboxymethylation.The results showed that the four polysaccharides had been modified by Carboxymethyl and had a high degree of substitution.3.At the 282 nm,the determination of total flavonoids in Exocarpium Citri Grandis with naringin as a standard has good accuracy and specificity.The results of LC-MS indicated that TF contained naringin,rhoifolin,poncirin,naringen and bergaptol.Using the method of combining macroporous resin with recrystallization,Naringin was obtained from the filter residue and filtrate of the extracted polysaccharide,and its content was 98.01%.Then,naringen was obtained by using naringin as raw material and optimizing acid hydrolysis by response surface methodology.The optimized extractionconditions were as followings:reaction time of 5.7 h,solid-liquid ratio of 1:50 g/mL,acid concentration of 3.0%.Under above conditions,the transformation rate reached 97.43%.The content of naringen obtained by the purification was98.90%,and the yield of naringen was 70.22%.4.The results of in vitro antioxidant test showed that the active substances of Exocarpium Citri Grandis have good scavenging effect on DPPH and hydroxyl radical,and good reducing power.The results of enzyme inhibition showed that EAP(IC₅₀=0.841 mg/mL)and naringen(IC₅₀=0.214 mg/mL)inhibited the activity of?-glucosidase more strongly than the acarbose(IC₅₀=1.038 mg/mL).The inhibition effect on?-glucosidase activity by ENP and ELP increased significantly after carboxymethylation modification.When the concentration was 6.0mg/mL,the inhibition rate of ENP on?-glucosidase increased from 3.79%to 99.40%,and that of ELP on?-glucosidase increased from 3.68%to46.80%.In addition,the polysaccharide,total flavonoids and naringen of Exocarpium Citri Grandis also showed a certain inhibition effect on?-amylase activity.Among them,EAP was the most significant(IC₅₀=4.568 mg/mL).After carboxymethylation modification,the inhibition effect on?-amylase activity by ENP increased significantly.Animal experiment results showed that compared with diabetic mice,EAP can reduce fasting blood sugar,improve glucose tolerance,regulate insulin levels,reduce Total Cholesterol?TC?,Triglyceride?TG?and low density lipoprotein cholesterol?LDL-C?levels,and improve liver and kidney swelling in diabetic mice.In addition,TF and naringin have no significant effect on blood glucose regulation in diabetic mice,but have a regulatory effect on blood lipid levels,which can reduce the levels of TC,TG and LDL-C and increase the levels of HDL-C.They also can improve liver and kidney swelling.In summary,polysaccharides,flavonoids and naringin in the Exocarpium Citri Grandis have a certain hypoglycemic effect.Among them,EAP has the most significant and comprehensive antidiabetic and lipid-lowering activity...