Study On Extraction, Purification And Hypolipidemic Effects Of Phenolics From Chestnut Burs In Hyperlipidemic Diabetic Rats

Chestnut is one of the most important forestry resources, which is widely cultivated in China. As a result of chestnut harvesting and shelling, the chestnuts are left as waste product with high quantity. To explore the potential utilities of chestnut burs is significant for the systematic development of chestnut industry. Further more, there are plenty of phenols inside chestnut burs, and phenols have been proved to possess different functions including anti-tumor, anti-virus, antioxidant, anti-aging. Other researches indicate that phenols not only prevent the rising of blood lipid level, but also to prevent the increasing of HDL-cholesterol level. There are few related research involved phenols in chestnut burs, so this thesis focuses on the primary study of extracting, separating, purifying and the hypolipidemic effect of total phenols in mice. Results are as follows:1) Through repeated trials, the method was established for optimizing the best of extracting process with ethanol solvent:First step,10times of50%ethanol was added to raw material of chestnut burs. Then the same procedure was carried out on water bath extraction under the temperature of80℃for3times,1hour each time. Final step, the extracting solution was concentrated under reduced pressure and was dried by freezing drying apparatus with the temperature of-50℃.2) In this study, the purification of total phenols and tannins from chestnut burs was optimized to obtain the optimal solvent. AB-8macroporous resin was selected for the purification. After extraction and purification, the content of total phenols and total tannins in final extract were over80%and60%.3) Diabetic model was induced by high fat diet and low dose streptozotocin (STZ) injection. Rats were randomly divided into five groups:normal rats group, model rats group, tolbutamide treated model group and CMPE treated model groups with dose of150mg/kg and300mg/kg respectively. Rats were given intragastrically (ig) with aqueous extract for8consecutive weeks and serum glucose, triglyceride (TG), total cholesterol (TC), HDL-and LDL-cholesterol (HDL-C and LDL-C) level were measured spectrophotometrically.4) Compared with the normal group, the TC, TG, LDL-C and glucose levels were significantly increased and HDL-C levels were significantly decreased in type2diabetic model rats group. Oral administration of CMPE could significantly modulate the glucose and lipid levels and improve the glucose and lipid profiles in model rats. CMPE could adjust lipid and glucose metabolism in type2diabetic rats, and could be further developed as a drug for the treatment of diabetes. This results indicate that the extractive of chestnut burs capable of decreasing blood lipid level, but do not disclose and explain the metabolism of blood lipid level effect. Subsequent experiment can focus on the research of metabolism.