Isolation and identification of kahweol palmitate and cafestol palmitate as active constituents of green coffee beans that enhance glutathione S-transferase activity in the mouse.
Isolation and identification of kahweol palmitate and cafestol palmitate as active constituents of green coffee beans that enhance glutathione S-transferase activity in the mouse.
复制标题
分离和鉴定咖啡醇棕榈酸酯和咖啡醇棕榈酸酯作为生咖啡豆的活性成分，可增强小鼠体内谷胱甘肽 S-转移酶的活性。
作者：
L. Lam;V. L. Sparnins;L. Wattenberg
谷胱甘肽（GSH）S-转移酶是一种主要的解毒酶系统，催化各种亲电体（包括化学致癌物的反应形式）与GSH的结合。饮食中喂食的绿色咖啡豆诱导小鼠小肠粘膜和肝脏中GSH S-转移酶活性增加。从绿色咖啡豆中分离出一种能诱导谷胱甘肽S-转移酶活性增加的有效化合物，并鉴定为棕榈酸咖啡豆酚酯。相应的游离醇，kahweol，及其合成的单乙酸酯也是谷胱甘肽S-转移酶活性的有效诱导剂。从绿色咖啡豆中分离出的一种类似的二萜酯棕榈酸棕榈酸酯具有活性，但活性低于棕榈酸同样，相应的醇，乙醇，和它的单乙酸酯表现出中等效力的诱导剂增加谷胱甘肽S-转移酶活性。用石油醚从绿色咖啡豆中提取棕榈酸咖啡豆酯和棕榈酸咖啡豆酯。石油醚提取物依次经制备正相和反相液相色谱分离。最后用硝酸银浸渍的薄层色谱法纯化，得到纯的棕榈酸酯和棕榈酸酯。通过酯及其母体醇的光谱数据的检查和衍生物比较确定结构。
Glutathione (GSH) S-transferase is a major detoxification enzyme system that catalyzes the binding of a variety of electrophiles, including reactive forms of chemical carcinogens, to GSH. Green coffee beans fed in the diet induced increased GSH S-transferase activity in the mucosa of the small intestine and in the liver of mice. A potent compound that induces increased GSH S-transferase activity was isolated from green coffee beans and identified as kahweol palmitate. The corresponding free alcohol, kahweol, and its synthetic monoacetate are also potent inducers of the activity of GSH S-transferase. A similar diterpene ester, cafestol palmitate, isolated from green coffee beans was active but less so than was kahweol palmitate. Likewise, the corresponding alcohol, cafestol, and its monoacetate showed moderate potency as inducers of increased GSH S-transferase activity. Kahweol palmitate and cafestol palmitate were extracted from green coffee beans into petroleum ether. The petroleum ether extract was fractionated by preparative normal-phase and reverse-phase liquid chromatographies successively. Final purification with silver nitrate-impregnated thin-layer chromatography yielded the pure palmitates of cafestol and kahweol. The structures were determined by examination of the spectroscopic data of the esters and their parent alcohols and by derivative comparison.