碩士 / 國立臺灣師範大學 / 人類發展與家庭學系 / 101 / According the statistics report of Department of Health in Taiwan, diabetes mellitus (DM) is the fifth among the top ten leading causes of death. Among them, 95% of diabetes patients are Type 2 DM, which is characterized by hyperinsulinemia resulted from insulin resistance. Taiwan is becoming to be an aging society and the life expectancy of people is increasing year by year. Thus, the dementia in elderly has been attached great importance to society country. Most dementia is Alzheimer’s disease (AD). The growing evidences indicate that high fat diet is the major risk factor of AD. Furthermore, the protective effect of phenolic acids on hypoglycermia and neuronal has been reported.
The result from cell viability test revealed that the maxium safe dosage of phenolic acids is 12.5 μM on neuroblastoma Neuro 2a cells. The insulin resistant cell model was used as a platform for screening the anti-insulin resistance potential phenolic acids. Among the tested samples, caffeic acid exhibited the highest glucose uptake enhancing activity in insulin resistant cells. Then effect of caffeic acid on ameliorating carbohydrate metabolism, insulin resistance and memory impairment and learning ability in high fat diet (HFD)-induced hyperinsulinemic rats were investigated.
The results show that orally administered with caffeic acid once a day at a dosage of 30mg/kg B.W. for 30 weeks significantly improved the glucose tolerance and abdominal fat in high-fat diet (HFD) fed male SD rats. The Western blot analysis reveals that caffeic acid increases the expression of glycolysis-associated enzymes, including hexokinase, phosphofructokinase and aldolase in hippocampus and cortex of HFD rats. Moreover, caffeic acid increases the protein expression of insulin signaling-associated proteins, including insulin receptor (IR), phosphatidylinositol-3-kinase (PI3K), AKT/Protein kinase B (AKT/ PKB), glucose transporter-3 (GLUT-3) and insulin degrading enzyme (IDE) in hippocampus and cortex of HFD rats. Additionally, caffeic acid increases the protein expression of leptin signaling-associated proteins, including leptin receptor (LEPR), pJAK2Tyr813/JAK2. The results from passive avoidance test also revealed that caffeic acid significantly improved the memory impairment in HFD rats.
Above investigation elucidates that caffeic acid may alleviate brain insulin resistance and improve glucose metabolism thus ameliorate memory impairment and lraening ability in HFD rats.
| Identifer | oai:union.ndltd.org:TW/101NTNU5261027 |
| Date | January 2013 |
| Creators | Kuo, Po-Ling, 郭柏伶 |
| Contributors | Shen, Szu-Chuan, Wu, James Swi-Bea, 沈賜川, 吳瑞碧 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 147 |
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