台灣鄉土蔬菜~蕺菜之安全性試驗及生理代謝

Studies of safety and metabolic effects

陳珮菁(Pei-Ching Chen)

指導教授 ： 劉 珍 芳

臺北醫學大學/公共衛生暨營養學院/保健營養學研究所/碩士(2001年)

摘要

本研究以乾燥蕺菜粉末為材料，以鼠為實驗模式評估蕺菜之食用安全性，並探討蕺菜中多酚類被吸收、代謝及生理效應。 以口服急性毒性試驗 (acute oral LD50 test) 及28天的慢性毒性試驗 (28-day feeding toxicity study) 進行安全性評估，結果顯示，在給予35隻ICR小鼠，單次胃管餵食不同量之蕺菜粉末，15 mg、75 mg、150 mg/kg Body weight，連續三天；在28天慢性毒性試驗中，24隻SD大鼠，分別餵食含0、0.2、2、5 % 蕺菜粉末之飼料28天，皆無急性及慢性毒性之發生。此外在探討蕺菜中多酚類於大鼠體中之生理代謝的情形時，48隻SD大鼠分別於飼養的第2週及第4週犧牲，結果發現血漿中多酚類含量會隨餵食週數增長而增加，且多酚類於動物體之外表吸收率 (apparent absorption) 亦會隨餵食劑量增加而提高。在肝臟解毒酵素系統Phase I 酵素之cytochrome P-450含量及NADPH-cytochrome C reductase活性之方面，2%組較其他組別高；而2%組之NADPH-cytochrome C reductase活性亦會隨餵食週數增長而增加。Phase II 酵素系統之UDP-glucuronyl transferase (UDPGT) 活性在2%組較其他組高，而glutathione S-transferase (GST) 活性則於2%及5%組較其他組高。在抗氧化效力方面，血漿總抗氧化力 (TAS) 於2%組較其他組高；肝臟中TAS會隨餵食週數增長而增加。在低密度脂蛋白氧化遲滯時間 (LDL lag time) 方面，會隨餵食含量的增加而延長氧化遲滯時間，2%組之LDL lag time隨餵食週數增長而增加。血漿中脂質過氧化指標TBARS濃度，則會隨蕺菜含量增加而顯著降低，且會隨餵食週數增長而顯著降低；而肝臟中TBARS濃度也會隨蕺菜含量增加而顯著降低。 綜合以上結果，推測蕺菜食用安全性相當高，且蕺菜中多酚類易被大鼠吸收代謝並具有抗氧化能力。

關鍵字

蕺菜 ； 安全性試驗 ； 多酚類 ； 肝臟解毒酵素系統 ； 抗氧化效力

並列摘要

The aim of this study was to evaluate the safety of Houttuynia cordata thunb, and to investigate the metabolic effects of polyphenols in Houttuynia cordata thunb in rodents. The evaluation of safety was carried out by the acute oral LD50 test and 28-day feeding toxicity study. In the acute oral LD50 test, the 35 ICR mice fed with 15, 75, 150 mg/kg body weight of Houttuynia cordata thunb powder diet respectively for 3 days. No significant changes in sign and histopathology was found in all groups. In the 28-day feeding toxicity study, 24 Sprague-Dawley rats fed with 0, 0.2, 2, 5 % Houttuynia cordata thunb powder diet for 28 days. It also did not show any toxic manipulation on the biochemical parameters. The investigation of metabolic effects of polyphenols in Houttuynia cordata thunb by examining the activity of xenobiotic -metabolic enzyme system in liver and the oxidative efficacy, 48 Sprague-Dawley rats were fed with 0, 0.2, 2, 5 % Houttuynia cordata thunb powder diet for 2 and 4 weeks. The present results showed the polyphenols contents of plasma increased while feeding time prolonged, and the apparent absorption of polyphenols in SD rats increased while feeding dose increased. The 2% group produced a significant increase in phase I enzymes which inducing the cytochrome P450 content and the NADPH -cytochrome C reductase activity. And the NADPH-cytochrome C reductase activity of the 2% group was also increased while feeding time prolonged. Phase II enzyme, the UDP-glucuronyl transferase activity of the 2% group was higher than other groups. The Glutathione S-transferase activity of the 2% and 5% group was also increased. According to the oxidative efficacy, the 2% group appeared the highest total antioxidant status (TAS) of plasma among groups. The TAS of liver increased while feeding time prolonged. LDL lag time elevated while feeding dose increased, and 2% group elevated while feeding time prolonged. The thiobarbituric acid reactive substances (TBARS) of plasma were lowered while feeding dose increased and feeding time prolonged. In the same way, TBARS of liver were also lowered while feeding dose increased. The present results show that administration of Houttuynia cordata thunb powder did not induce any toxic effect which could be detected by the methodology used in either mice and rats. The polyphenols in Houttuynia cordata thunb could be easily absorbed and metabolized. The hepatic xenobiotic -metabolic enzyme system could be modulated by diet-contained Houttuynia cordata thunb, especially at 2% group. According to the results on TBARS, TAS and LDL lag time, Houttuynia cordata thunb showed high oxidative efficacy. In conclusion, Houttuynia cordata thunb is edible harmlessly, and polyphenols in Houttuynia cordata thunb are easily absorbed and metabolized, and show the high oxidative efficacy.

並列關鍵字

Houttuynia cordata thunb ； safety ； polyphenols ； thunbxenobiotic -metabolic enzyme system ； oxidative efficacy

參考文獻

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