Lowenthal J, Vergel Rivera G M
J Pharmacol Exp Ther. 1979 Jun;209(3):330-3.
The cis and trans isomers of vitamin K1 have been prepared at a purity of better than 99.5% and tested for effect on plasma level of factor VII in coumarin anticoagulant-pretreated and vitamin K-deficient rats. Both isomers show activity, but in coumarin anticoagulant-pretreated animals the cis isomer has approximately 10% and in vitamin K-deficient approximately 1% of the activity of the trans isomer. The cis isomer also shows slower onset and rate of increase of the response. Reduction of the 2',3'-double bond of the phytyl side chain of either isomer to the same 2',3'-dihydro derivative of vitamin K1 leaves the activity of the trans isomer unchanged but increases the activity of the cis isomer to that of the trans isomer. The results suggest that the phytyl side chain not only serves to increase lipid solubility, but may play a more direct functional role.
维生素K1的顺式和反式异构体已制备至纯度高于99.5%，并在香豆素抗凝预处理和维生素K缺乏的大鼠中测试了其对因子VII血浆水平的影响。两种异构体均显示出活性，但在香豆素抗凝预处理的动物中，顺式异构体的活性约为反式异构体的10%，在维生素K缺乏的动物中约为1%。顺式异构体还显示出反应的起效较慢和增加速率较慢。将任一异构体的植基侧链的2'，3'-双键还原为相同的维生素K1的2'，3'-二氢衍生物，反式异构体的活性不变，但顺式异构体的活性增加至与反式异构体相同。结果表明，植基侧链不仅有助于增加脂溶性，而且可能发挥更直接的功能作用。
