攝食咖啡酸、阿魏酸和香豆酸對老鼠膽固醇代謝及抗氧化活性之影響   全文下載

Dietary Caffeic Acid, Ferulic Acid and Coumaric Acid Supplements on Cholesterol Metabolism and Antioxidant Activity in Rats

酚酸（phenolic acids）廣泛存在於許多天然物中，包括日常飲食中米麥、蔬果、茶葉、咖啡，都與酚酸息息相關，本研究針對於三種酚酸化合物咖啡酸（caffeic acid）、阿魏酸（ferulic acid）和香豆酸（coumaric acid），研究其對於降低脂質及抗氧化指標活性之影響，以24 隻老鼠分成4 大組，4 大組的老鼠分別在六週內餵食3% 的膽固醇，除了控制組之外其他三組分別餵食0.2% 咖啡酸、0.2% 阿魏酸和0.2% 香豆酸，經過六週的飼養之後，在餵食咖啡酸、阿魏酸和香豆酸組別的老鼠與控制組比較，顯示可降低血液中的脂質和肝臟內之膽固醇，在抑制肝臟中HMG-CoA reductase 的活性方面，此三種酚酸皆可抑制HMG-CoA reductase 活性，惟其中以咖啡酸的效果較佳（p < 0.05），肝臟中的ACAT 活性中在餵食咖啡酸、阿魏酸和香豆酸與控制組比較都具有抑制的作用（p < 0.05），餵食咖啡酸、阿魏酸和香豆酸會增加抗氧化系統裡的指標像是肝臟中SOD 活性和GSH 之濃度（p < 0.05），並且降低肝臟和血液中TBARS 之值（p < 0.05），增加老鼠體內之抗氧化活性及老鼠糞便中的中性和酸性固醇的排放量（p < 0.05），並可以減少體內膽固醇的吸收作用，由此顯示添加咖啡酸、阿魏酸和香豆酸在老鼠的飲食中，可降低餵食高膽固醇飲食老鼠血液和肝臟中之膽固醇並增加糞便中的膽固醇的排放量，而且扮演重要的角色。

This study was designed to test the lipid-lowering and antioxidative activities of three phenolic compounds, caffeic acid, ferulic acid and coumaric acid. Four groups of rats were given a semisynthetic diet containing 3% of cholesterol for 6 weeks. The control group only received a high cholesterol diet, whereas the other three groups received a diet including 0.2% of caffeic acid, 0.2% of ferulic acid and 0.2% of coumaric acid. The caffeic acid, ferulic acid and coumaric acid significantly lowered the plasma lipid and hepatic cholesterol levels compared to those in the control (p < 0.05). The hepatic HMG-CoA reductase activity was significantly lower in the caffeic acid group than in the ferulic acid and coumaric acid groups (p < 0.05), while the hepatic ACAT activity was significantly lower in the caffeic acid, ferulic acid and coumaric acid groups compared to the control group (p < 0.05). The overall potential of the antioxidant system was significantly enhanced by the caffeic acid, ferulic acid and coumaric acid supplements as the plasma and hepatic TBARS levels were lowered while the hepatic SOD activities and GSH concentration were elevated in the high-cholesterol-fed rats (p < 0.05). Furthermore, these results indicated that the supplementation of caffeic acid, ferulic acid and coumaric acid boosted the antioxidant activity in rats and promoted the excretion of neutral sterol and acidic sterol (p < 0.05), thereby leading to a decreased absorption of dietary cholesterol as well as lower plasma, hepatic cholesterol and promoted excretion of fecal sterols.