Study On The Extraction Process Of Total Flavonoids And The Pharmacological Effects For Anti-type 2 Diabetes Mellitus From The Leaves Of Dimocarpus Longan Lour

Objective:?1?To study the optimum extraction process of total flavonoids from the leaves of Dimocarpus longan Lour.and find the best method of its content determination.?2?Screening the active parts of anti-type 2 diabetes mellitus and studying on its pharmacological effects and mechanism,which can provide some scientific basis for further study from the leaves of Dimocarpus longan Lour..Methods:?1?The effects of ethanol concentration,ethanol dosage and extraction time on the extraction process of total flavonoids from the leaves of Dimocarpus longan Lour.were studied by single factor experiment and Box-Behnken response surface method.Based on this,the content was determined.?2??1?In order to get the total extracts,use the percolation method to extract the leaves of Dimocarpus longan Lour.,and followed by extraction using petroleum ether,ethyl acetate,n-butanol to get the different polar parts.?2?For observing the toxicity,the acute toxicity test was carried out on total extracts and different polar parts from the leaves of Dimocarpus longan Lour..?3?To investigate the hypoglycemic effects of different polar parts on high glucose and high fat diets combined with streptozotocin?STZ?induced type 2 diabetic mice.After 28 days of administration,the growth and weight of the mice were observed.The fasting blood glucose was measured and the mice were tested for oral glucose tolerance.The serum total cholesterol?TC?,triglyceride?TG?,high density?HDL-C?and low density lipoprotein?LDL-C?were measured.The results were compared with those of the control group.The active site of the anti-type 2 diabetes mellitus was selected.?3?To study the pharmacological effects of the leaves of Dimocarpus longan Lour.ethyl acetate extracts on type 2 diabetic rats:After 28 days of administration,the growth and body weight of the rats were observed and the fasting blood glucose was measured,The oral glucose tolerance test was carried out;The activities of superoxide dismutase?SOD?,malondialdehyde?MDA?and blood lipid were measured by enzyme-linked immunosorbent assay;The levels of serum insulin?INS?,tumor necrosis factor?TNF-a?and interleukin-6?IL-6?were measured by ELISA;The weight index of the rat thymus was calculated;Rats were stained with HE and the pathological changes of pancreatic islet cells were observed,Through the above experiments to explore its main hypoglycemic mechanism.Results:?1?The optimum extraction conditions were as follows:ethanol concentration 53%,ethanol dosage 57ml,extract time 83min,the total flavonoid content was 15.479%under this condition,and the difference was slightly different from the predicted value.?2??1?The total extracts from the leaves of Dimocarpus longan Lour.were 3150g,the petroleum ether extracts were 514g,the ethyl acetateextracts were 504.7g,the n-butanol extracts were 677.4g,the aqueous extractwere 552g.?2?Through acute toxicity experiments:The aqueous extracts with significant toxicity,the LD₅₀0 was calculated as 740g?crude drug?/kg;The rest of the parts have no obvious toxic reactions,The MTD of the total extracts was 101.4?crude drug?/kg,the MTD petroleum ether extracts was 888.8?crude?/kg,the MTD of ethyl acetate extracts was 320?crude?/kg,the MTD n-butanol extracts was 316?crude?/Kg.?3?Through the anti-type 2 diabetes active site screening experiments we found that the total extracts from the leaves of Dimocarpus longan Lour.can reduce the blood glucose of diabetic mice?p<0.05?,But have little effects on the weight of mice;The ethyl acetate extracts can be a good way to reduce the blood glucose of diabetic mice?p<0.01?,improve model mice's body weight,enhances them glucose tolerance,and can regulate the lipid disorders.Then-butanolextractsondiabeticmice also have hypoglycemic pharmacological effects,but the effect is not as obvious as the ethyl acetate extracts.The petroleum ether extracts and aqueous extracts did not see a significant hypoglycemic effect.?3?The study of ethyl acetate extracts anti-type 2 diabetes mellitus pharmacological effects shows that:?1?It can reduce the blood glucose of diabetic rats?p<0.01?,and enhance the rats tolerance to glucose in a certain extent.And can improve the insulin resistance by increasing the insulin concentration of the model rats and improve the insulin sensitivity index,which can regulate the insulin resistance of the rats.?2?It can increase the activities of SOD and decrease the contents of MDA in diabetic rats and inhibit the thymic atrophy of diabetic rats to a certain extent.?3?It Can regulate the dyslipidemia of diabetic rats and reduce the secretion of TNF-a and IL-6 inflammatory factors in rat serum.and the pathological features of pancreas in diabetic rats were also improved.Conclusion:?1?Using Box-Behnken response surface method to optimize the extraction process is not only high extraction rate but also simple and feasible,which can provide theoretical reference for further study of the leaves of Dimocarpus longan Lour..?2?The total extracts,ethyl acetate extracts and n-butanol extracts from the leaves of Dimocarpus longan Lour.had some hypoglycemic effects on diabetic mice,which could be used for later experimental study.?3?The ethyl acetate extracts have a good anti-type 2 diabetes effect,the mechanism may be related to the repair of islet injury,inhibition of inflammation.