http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/78 2026-03-24T20:44:12Z http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/33203 標題: 龍鬚菜之酵素降解; Enzymatic Degradation of Gracilaria 作者: Yung-Te Hou; 侯詠德 摘要: 本研究探討以纖維素水解酶(Cellulase)水解醣類生質(蔗渣、龍鬚菜)的最佳條件(溫度50℃，pH 4.6)。並且比較醣類生質未經前處理及經過酸處理(基質加入0.2 M H2SO4，以殺菌釜加溫至121℃處理半小時)、冷凍前處理(基質加入去離子水浸泡，並於-10℃下靜置20分鐘)後的酵素水解速率差異。醣類生質經酵素水解成單醣、雙醣及寡醣後，再利用DNS (Dinitrosalicylic acid)定量還原端產生的量，以推估酵素水解效率。另外，利用酚-硫酸法以及葡萄糖感測器來定量酵素水解後產生的總醣濃度及葡萄糖濃度。本研究所開發的海藻生質，在經過冷凍前處理後確實提高了酵素水解速率以及醣類增加量，可望有效應用於生質能源領域。; Lignocellulosic biomass has been utilized to produce ethanol in the last two decades. The main process involved in this conversion is hydrolysis of cellulose in the lignocellulosic materials to produce reducing sugars. Due to the recalcitrant nature, the biomass can not be easily converted to monomeric sugars. Therefore, the low yield and high cost of the hydrolysis process are the major challenges in biomass energy development. In our research, marine seaweeds Gracilaria is used as the biomass. Owing to their hydration ability, an “Ice-crystal pretreatment” is developed to enhance the hydrolysis of cellulosic biomass. The enzymatic hydrolysate of biomass was measured by three methods. Reducing sugars is determined by the dinitrosalicylic method (DNS). Total soluble sugars is determined by the phenol-sulphuric acid method. Glucose is determined by the glucose biosensor. In our result, the validity of “Ice-crystal pretreatment” were confirmed. The effect of “Ice-crystal pretreatment” was also compared with acid pretreatment. In conclusion, marine seaweeds Gracilaria with “Ice-crystal pretreatment” may be a new approach to biomass energy development in the future. 2006-01-01T00:00:00Z http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/58633 標題: 龍葵葉片95%酒精萃取物之抗氧化能力及抗醣化作用分析; Antioxidation and antiglycation of 95% ethanolic extracts prepared from the leaves of Solanum nigrum 作者: Tsung-Han Hou; 侯宗翰 摘要: 最終醣化蛋白(advanced glycation end-products, AGEs)的形成，導致發炎反應的發生與胰島素抗性(insulin resistance)的產生。有證據顯示抗氧化劑可以抑制活性氧(reactive oxygen species, ROS)的形成，經由抑制糖基化(glycation)減少醣化終產物的生成。龍葵(Solanum nigrum)可以作為改善血糖的藥用食物，然而其活性成分與作用機轉仍然不清楚。本研究結果顯示，龍葵95%乙醇萃取物的抗氧化活性高於龍葵50%乙醇萃取物和龍葵水萃取物。此外，龍葵95%乙醇萃取物具有抑制糖基化的活性，可以抑制果糖胺(fructosamine)與α-二羰基化合物(α-dicarbonylcompiund)的生成。在每毫克龍葵95%乙醇萃取物中，solasonine與solamargine的量分別為0.484毫克和0.183毫克。基於上述，龍葵具備當作萃取抗糖基化和抗糖尿病活性成分的潛力。; Solanum nigrum are recently not only considered to be the brand-new source of functional ingredients that exerts antiglycation and anti-diabetes activities but also to be kind of medicinal food for improving blood glucose. However, there are only few identities of the active compounds and how those above-mentioned compounds counteract diabetes are still unknown. To induces insulin resistance occurs in an inflammatory response that requires the hyperglycemia results in the formation of advanced glycation end-products (AGEs). Evidence indicates that antioxidants can suppress the formation of reactive oxygen species, decrease levels of AGEs by inhibiting glycation. In this research demonstrates that 95% ethanolic extracts of Solanum nigrum exerted significant antioxidative activity compared with 50% ethanolic extracts and aqueous extracts. Moreover, 95% ethanolic extracts of S. nigrum produced antiglycative activity, which contributed to the inhibition of fructosamine and generation of α-dicarbonyl compounds. The results indicate that 95% ethanolic extracts of S. nigrum are with great bioactivities on antiglycation and anti-diabetes. 2013-01-01T00:00:00Z http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/35167 標題: 龍眼花萃取物抗氧化性之探討; Studies on the Antioxidative Activities of Longan (Dimorcarpus longan Lour.) Flower Extracts 作者: Yi-Jane Shen; 沈宜蓁 摘要: 近年來，許多慢性疾病的發生與氧化壓力具有很大的相關性，例如癌症、動脈粥狀硬化、老化等，當體內氧化物與抗氧化物不平衡時即會造成氧化傷害，因此需有足夠的抗氧化物質俾能抵抗氧化壓力的產生。本研究目的主要以抗氧化活性之化學檢測方法及體外生物活性檢測方法評估龍眼花不同溶劑粗萃物之抗氧化活性，期能找出具最佳抗氧化力的龍眼花粗萃物，並進一步分析龍眼花中提供抗氧化力之有效區分層及提供抗氧化力之可能有效成分，以提高龍眼花之利用價值。 本實驗龍眼花之萃取方式為沸點下熱水迴流萃取及室溫下以95%乙醇、甲醇、乙酸乙酯與正己烷四種溶劑之攪拌萃取。再以七種抗氧化活性評估方法檢測此五種龍眼花不同溶劑之粗萃物，包括清除DPPH自由基、TEAC (Trolox equivalent antioxidant capacity)、氧自由基吸收能力 (Oxygen radical absorbance capacity, ORAC)、還原力、抑制微脂粒 (liposome) 過氧化、抑制銅離子誘導低密度脂蛋白 (low density lipoprotein, LDL) 氧化與以TGF-β1 (transforming growth factor-β1) 誘導肝癌細胞Hep 3B產生氧化損傷之保護效果。 實驗結果顯示，龍眼花水粗萃物於各抗氧化實驗中皆展現較高之抗氧化力，其清除DPPH自由基之EC50為3.69±0.16 μg/mL，TEAC值為1.22 mM Trolox equiv.，ORAC值為7.28 mM Trolox equiv.，還原力方面於50 μg/mL時A700 =1.84，抑制微脂粒過氧化之IC50為54.46±1.61 μg/mL，且延緩銅離子誘導LDL氧化之效果最佳，為同濃度下Trolox之0.62倍；以TGF-β1誘導肝癌細胞Hep 3B產生氧化損傷實驗中，其於100 μg/mL濃度時達約64.3±3.4%的回復率。整體而言抗氧化活性以水粗萃物最佳，其次為甲醇、乙醇與乙酸乙酯粗萃物，而正己烷粗萃物則幾乎無抗氧化效果。 進一步分析龍眼花不同溶劑粗萃物之抗氧化成分，結果顯示，水粗萃物中的總酚類化合物 (548.2±12.7 mg gallic acid equivalent / g of dry weight) 與没食子酸 (10.4 ± 0.3 mg gallic acid /g of dry weight) 含量最多，因此推測其抗氧化力可能來自於龍眼花中之酚類物質。再進ㄧ步將龍眼花水萃物經Sephadex LH-20管柱層析分離得到八個區分層，並進行抑制銅離子誘導LDL氧化測定，結果以fraction 7之100%甲醇沖提區分層之效果最佳。本研究結果顯示龍眼花中提供抗氧化性的有效成分可能為一些極性較高的酚類物質。; Recently, many chronic diseases such as cancer, atherosclerosis, and aging were found to be associated with oxidative damage. The imbalance between the concentration of reactive oxygen and nitrogen species and defense mechanisms of the body would cause oxidative damage, and antioxidants enhancement would reduce oxidative damage. Therefore, dietary supplementation of antioxidants was thought to be beneficial to health. The purpose of this study is to locate the most antioxidative solvent extract of Longan (Dimorcarpus longan Lour.) flower by various antioxidative assays, and to further investigate the most efficient antioxidative fraction after chromatographic separation by the assay of Cu2+-induced low density lipoprotein (LDL) oxidation. First, the crude extracts were prepared by extracting Longan flower with boiling water and four solvents (95% ethanol, methanol, ethyl acetate and n-hexane) at room temperature. Then the five different solvent extracts of Longan flower were tested for various antioxidative assays, including DPPH free radical scavenging effect, Trolox equivalent antioxidant capacity (TEAC) assay, oxygen radical absorbance capacity (ORAC) assay, reducing power, inhibition of peroxidation in a liposome model system, Cu2+-induced oxidation of human LDL and recovery effect of TGF-β1 induced oxidative damage in Hep 3B cells. The results of antioxidative assays revealed that the best effect was exhibited by the water extract, followed by methanol, ethanol, ethyl acetate and n-hexane extracts of Longan flower. The EC50 value of water extract in scavenging DPPH radicals was 3.69±0.16 μg/mL. Results of TEAC and ORAC assays revealed that water extract gave the highest TEAC value (1.22 mM Trolox equivalent) and ORAC value (7.28 mM Trolox equivalent). With regard to reducing power, at sample concentration of 50 μg/mL, water extract gave the best effect. Concerning inhibition of peroxidation in a liposome model system, the IC50 of water extract in inhibiting the peroxidation was 54.46±1.61 μg/mL, which was the lowest among all the extracts. As for the effect of Cu2+-induced oxidation of human LDL, water extract showed the best effect in delaying LDL oxidation. Finally, water extract gave the best recovery effect of TGF-β1 induced oxidative damage in Hep 3B cells at concentration of 100 μg/mL. Water extract of Longan flower contained the most abundant amount of total polyphenol (548.2±12.7 mg gallic acid equivalent / g of dry weight) and gallic acid (10.4 ± 0.3 mg gallic acid /g of dry weight). According to the results of antioxidative assays, water extract showed the highest antioxidant capacity and we presumed that this could probably be related to the phenolic compounds. Then Sephadex LH-20 gel chromatography was employed to fractionate the water extract; eight fractions were obtained and tested for Cu2+-induced oxidation of human LDL. The result of antioxidative experiment revealed that fraction 7 showed the best effect in delaying LDL oxidation. We presumed that antioxidative capacity of Longan flower could probably be related to phenol compounds having higher polarity. 2005-01-01T00:00:00Z http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/28825 標題: 龍眼花水萃物對高果糖誘發代謝症候群大鼠之影響; Effect of Longan (Dimocarpus longan Lour.) Flower Water Extract on Metabolic Syndrome in Fructose-Fed Rats 作者: Hui-Yun Tsai; 蔡蕙芸 摘要: 代謝症候群是近年來受到重視的健康議題，其症狀包括高胰島素血症、胰島素阻抗、高三酸甘油酯血症和高血壓等，此些危險因子的叢聚現象與第二型糖尿病和心血管疾病有密切的相關性。前人研究也證實，於飲食中多攝取抗氧化物質有助於預防代謝症候群因而降低心血管疾病的發生。本研究室於先前的研究發現龍眼 (Dimocarpus longan Lour.) 花在體外具有很好的抗氧化活性，因此本研究目的在探討龍眼花粗萃物的高抗氧化活性是否能改善代謝症候群之諸多症狀。 實驗第一階段為體外抗氧化性試驗，先將龍眼花粉末分別以沸水萃取及室溫下以95%乙醇或甲醇溶劑攪拌萃取。再以兩種抗氧化活性評估方法，包括清除DPPH自由基能力試驗和抑制銅離子誘導人類低密度脂蛋白氧化檢測此三種不同溶劑之龍眼花粗萃物。實驗結果顯示，龍眼花水萃物於此二種抗氧化實驗中皆展現較高之抗氧化力，其清除DPPH自由基之EC50值為3.75±0.61 μg/mL，且延緩銅離子誘導LDL氧化效果為同濃度下正控制組trolox之1.57倍。整體而言抗氧化活性以水萃物最佳，其次為乙醇和甲醇萃取物。 第二階段為對大鼠進行急性灌食試驗，觀察龍眼花粗萃物對其耐糖能力的影響。急性試驗中，以龍眼花粗萃物125或250 mg/kg body weight (BW) 的劑量灌食正常Sprague-Dawley大鼠，同時進行口服葡萄糖耐受性試驗。結果顯示，大鼠灌食龍眼花水萃物250 mg/kg BW，在第30分鐘的血漿葡萄糖值顯著低於對照組，但胰島素濃度在各時間點則無顯著差異。此外，灌食龍眼花乙醇萃物125或250 mg/kg BW的劑量，不論在血漿葡萄糖或胰島素濃度與對照組比較皆無顯著差異。顯示大鼠急性灌食龍眼花水萃物可以減緩血糖上升的速度，其作用不在於改善胰島素敏感性，可能與延緩或干擾腸道對糖分的吸收有關。 第三階段為長效性試驗，以高果糖飼料誘發大鼠產生代謝症候群，觀察龍眼花水萃物是否能改善其症狀。將體重約250克Sprague-Dawley大鼠隨機分為4組：C組給予標準飼料；F組給予高果糖飼料；L組除了高果糖飼料外，每隻每天灌食龍眼花水萃物 125 mg/kg BW，為低劑量組；H組除了高果糖飼料外，每隻每天灌食龍眼花水萃物 250 mg/kg BW，為高劑量組，C組與F組則以灌食去離子水作為對照。實驗期為14週。F組自第2週起，收縮壓、禁食狀態血漿三酸甘油酯和胰島素皆明顯開始上升，但血漿葡萄糖濃度仍維持正常；於第4週進行口服葡萄糖耐受性試驗，已有胰島素阻抗之情況發生，顯示長期餵飼高果糖飼料已明顯誘導大鼠產生代謝症候群之症狀。在體內抗氧化能力試驗中，餵飼高果糖飼料14週後，會造成體內氧化壓力增加，血漿脂質過氧化物TBARS濃度明顯上升且肝臟抗氧化酵素活性下降。 給予低劑量125 mg/kg BW龍眼花水萃物的組別，可降低高血壓，於實驗11和12週血壓已明顯低於F組。在胰島素敏感性方面，於4、8和12週的口服葡萄糖耐受性試驗中，有改善胰島素阻抗的現象，但效果並不明顯。對於禁食血漿三酸甘油酯濃度仍不具有調節作用。在體內抗氧化能力試驗中可提升肝臟抗氧化酵素Glutathione reductase的活性，而在血漿脂質過氧化物TBARS濃度則無差異。 給予高劑量250 mg/kg BW龍眼花水萃物的組別，降血壓效果顯著，於實驗第7週開始已明顯低於F組。在胰島素敏感性方面，於第4週口服葡萄糖耐受性試驗中即開始有改善胰島素阻抗之現象。而給予高劑量的龍眼花水萃物仍無法降低禁食血漿三酸甘油酯濃度。在體內抗氧化能力試驗中可提升肝臟抗氧化酵素Glutathione reductase的活性，且可降低血漿脂質過氧化物TBARS的濃度。 分析脂肪細胞胰島素訊息傳遞相關蛋白質表現量的結果顯示，給予高果糖飼料會造成insulin receptor substrate (IRS-1)、Akt和glucose transporter 4 (GLUT 4)表現量降低，導致胰島素受體對胰島素之敏感性降低。而給予低劑量龍眼花水萃物14週後有增加IRS-1的表現量，而給予高劑量龍眼花水萃物14週後更提升了IRS-1和GLUT 4的表現量，此結果顯示龍眼花水萃物可藉由增加胰島素訊息傳遞相關蛋白質之表現量，使胰島素敏感性增加。 本研究結果顯示，龍眼花水萃物具有很好的抗氧化活性，且可改善高血壓、高胰島素血症、胰島素阻抗和降低體內氧化壓力。; Metabolic syndrome is a cluster of disorders, including hyperinsulinemia, insulin resistance, hypertriglyceridemia and hypertension that increase one's risk for type 2 diabetes and cardiovascular disease . Natural antioxidants were reported to ameliorate metabolic syndrome. Previous study in our laboratory has shown that Longan (Dimocarpus longan Lour.) flower had strong antioxidant activity in vitro. Therefore, the objective of this study was to evaluate the effect of the supplemention of Longan flower extract on metabolic syndrome. The first stage of this study was to analyze the antioxidative activity of Longan flower in vitro, the crude extracts were prepared by extracting Longan flower with boiling water and two solvents (95% ethanol, methanol) at room temperature. Then, the three different solvent extracts of Longan flower were tested for two different antioxidant assays, including DPPH free radical scavenging effect and the inhibition of Cu2+-induced oxidation of human LDL. The results of antioxidant assays revealed that the best effect was exhibited by the water extract, followed by ethanol and methanol. The EC50 value of water extract in scavenging DPPH radicals was 3.75±0.61 µg/mL, and its effect on delaying LDL oxidation is 1.57 times better than trolox at the same concentration level (1 µg/mL). The second stage of the study was to observe the glucose tolerance of rats after the acute treatment with Longan flower crude extract (125 mg/kg or 250 mg/kg) and glucose. Results of oral glucose tolerance test (OGTT) in rats showed that the plasma glucose levels of the Sprague-Dawley rats administered 250 mg/kg BW of Longan flower water extract (LFWE) were lower than the control group after 30 minutes of ingestion but insulin concentrations showed no difference with the control group at each time intervals . However, both the plasma glucose and insulin levels of the rats ingested Longan flower ethanol extract showed no significant difference with control group. These findings suggest that Longan flower water extract may delay or interference with the sugar absorption in the gastrointestinal tract without changing insulin secretion and its action. The third stage is to investigate the effect of long-term treatment of LFWE on rats with metabolic syndrome induced by high fructose diet. Male Sprague-Dawley rats of body weight around 250 g were randomly divided into four groups: group C, fed with standard Purina chow; group F, fed with high fructose diet alone; group L, fed with high fructose diet plus LFWE 125 mg/kg BW per day by gavage (a low dose group) and group H, fed high fructose diet plus LFWE 250 mg/kg BW per day by gavage (a high dose group). The dietary manipulation lasted for 14 weeks. Results of our study showed that, high fructose feeding for 2 weeks cause significant increase in sytosolic blood pressure, fasting plasma triglyceride and insulin levels without elevating fasting plasma glucose. And insulin resistance was demonstrated after the 4th week by OGTT. These results indicated that fructose-rich diet could cause a cluster of disorders in metabolic syndrome. In antioxidative capacity analyses, at the end of the 12-week experiment high fructose diet increased plasma TBARS and significantly decreased liver antioxidant enzyme activity . The supplementation of LFWE ameliorated insulin resistance by enhancing the expression of insulin signaling pathway related proteins, including GLUT 4 and insulin receptor substrate-1. LFWE supplementation was also found to decrease SBP and ameliorated oxidative stress. These findings indicate that Longan flower water extract may improve the symptoms of the metabolic syndrome in fructose-fed rats. 2007-01-01T00:00:00Z