Anti-Fatty Liver Activity and its Mechanism of Non-Methylene-Interrupted Fatty Acid

本实验研究了香榧油中富含非亚甲基中断多不饱和脂肪酸——香酸（全顺式-5,11,14-二十碳三烯酸）对大鼠脂质代谢的影响。肥胖大鼠（OLETF大鼠）用玉米油或香榧油培养2周。食用香榧油的肥胖大鼠血清和肝脏甘油三酯及血清胆固醇水平较低。此外，大鼠在含5%酒精的饲料中与香榧油、玉米或大豆油一起生长6周。食用香榧油的大鼠血清甘油三酯和胆固醇水平较低。饲喂香榧的大鼠血清GPT和GOT活性明显降低。为了解香榧油降低血浆和肝脏甘油三酯的作用机制，采用尿素加合物与脂肪酶酯化相结合的方法从香榧籽油中分离出松香酸。Sprague-Dawley （SD）雄性大鼠分别饲喂含5%和10%玉米油基础sciadonic acid的试验饲粮2周。大鼠的血清和肝脏甘油三酯水平较低。在饲喂sciadonic酸的大鼠血清和肝脏的甘油三酰和磷脂中检测到相当数量的sciadonic酸。我们还利用HepG2研究了坐骨酸和蒎烯酸（均为顺式-5,9,12-十八碳三烯酸）作为非亚甲基中断脂肪酸对人肝癌细胞生长和脂质代谢的影响。50uM以上时，坐骨酸和蒎烯酸均抑制HepG2的生长。然而，它们增加了HepG2的脂质含量。由此可见，坐骨皂酸能改变大鼠脂质代谢，抑制脂肪肝。

We investigated effects of non-methylene-interrupted polyunsaturated fatty acid, sciadonic acid (all cis-5,11,14-eicosatrienoic acid) rich in torreya oil on the lipid metabolism in rat. Fatty rats (OLETF rats) were grown with corn oil or torreya (Torreya nucifera) oil for 2 weeks. Serum and liver triacylglycerol and serum cholesterol levels were lower in fatty rats fed torreya oil. Moreover, rats were grown with 5% alcohol-containing feeds together with torreya oil, corn or soybean oil for 6 weeks. Serum triacylglycerol and cholesterol levels were lower in rats fed torreya oil. It was interesting that rats fed torreya showed lower serum GPT and GOT activities. To know the mechanism of plasma and hepatic triacylglycerol-lowering effects of torreya oil, sciadonic acid was isolated from Japanese torreya seed oil by the combination of urea-adduct with lipase-esterification. Sprague-Dawley (SD) male rats fed the experimental diets containing 5% and 10% sciadonic acid based on corn oil for 2 weeks. Serum and liver triacylglycerol levels were lower in rats fed sciadonic acid. Considerable amounts of sciadonic acid were detected in triacylglycerol and phospholipid in both serum and liver of rats fed sciadonic acid. We also investigated the effects of sciadonic acid and pinolenic acid (all cis-5,9,12-octadecatrienoic acid as non-methylene-interrupted fatty acids on the growth and lipid metabolism of human hepatic cancer cell using HepG2. Both sciadonic and pinolenic acids inhibited the growth of HepG2 at more than 50uM. However, they increased lipid contents in HepG2. From these results, it was demonstrated that sciadonic acid could modify the lipid metabolism and suppress fatty liver in rats.