Structure and Physiological Activity of Glycolipids from Amphibias

从牛frog （Rana catesbeiana）脑组织中分离得到三种神经节苷脂，通过核磁共振和质谱测定，分别确定了它们的结构为二二烷基神经节脂四烷基神经酰胺（I11^6NeuAclV^3NeuAc-GgOse_4Cer）、三三烷基神经节脂四烷基神经酰胺（I11^6NeuAclV^3(NeuAc)_2-GgOse_4Cer）和tertasialosyl神经节脂四烷基神经酰胺(I11^6（NeuAc)_2lV^3(NeuAc)_2-GgOse_4Cer）。这些神经节苷类在大脑半球、间脑和视叶、小脑和延髓的混合组织中也有类似的分布。黑斑蛙和树蛙的脑组织中也含有与牛蛙相同的神经节苷。另一方面，从牛蛙脑组织中分离到12种脑苷，它们被鉴定为1-组微米- β - d -半乳糖酰基神经酰胺。通过化学和光谱分析，发现其中6种的神经酰胺部分由鞘氨醇作为长链碱和6种脂肪酸组成，分别为C_<18:0>、C_<22:1>和C_<24:1>酸及其2-羟基衍生物。其他的神经酰胺部分被发现是由二氢鞘氨酸和六种脂肪酸组成的。根据两种长链碱基的醋酸酯的核磁共振谱和苯甲酯-苯酰胺衍生物的激子手性，确定其C-2和C-3的构型分别为S和R。此外，通过CD测量，确定了三种2-羟基脂肪酸的手性中心均为R。大脑半球、间脑及视叶、小脑和延髓的混合组织中可见不同的脑侧分布。

The structures of three ganglioside isolated from bullfrog (Rana catesbeiana) brain tissue have been established as disialosylgangliotetraosylceramide (I11^6NeuAclV^3NeuAc-GgOse_4Cer), trisialosvlgangliotetraosvlceramide (I11^6NeuAclV^3(NeuAc)_2-GgOse_4Cer), and tertasialosylgangliotetraosylceramide (I11^6(NeuAc)_2lV^3(NeuAc)_2-GgOse_4Cer) by NMR and mass spectral measurements. A similar distribution of these gangliosides was seen among hemisphere, dienecephalon and mixed tissue from the optic lobe, cerebellum and medulla oblongata of the brain. The brain tissues of Rana nigromaculata and Rhacophorus arboreus also included the same gangliosides as those of bullfrog.On the other hand, twelve cerebrosides were isolated from the brain tissues of the bullfrog and they were characterized as 1-omicron-beta-D-galactopyranosyl ceramides. On the basis of chemical and spectral evidence, the ceramide parts of six of them were found to be composed of a sphingosine as a long-chain base and six fatty acids consisting of C_<18:0>, C_<22:1> and C_<24:1> acids and their 2-hydroxy derivatives. The ceramide parts of the others were found to be composed of a dihydrosphingosine and the six fatty acids. The configurations at C-2 and C-3 of the two long-chain bases were determined to be S and R, respectively, on the basis of the NMR spectra of their acetates and the exciton chirality of the benzoate-benzamide derivatives. Furthermore, the chiral center of the three 2-hydroxy fatty acids was determined to be R in all cases by means of CD measurements. A different distribution of the cerebroside was seen among the hemisphere, dienecephalon and mixed tissue from the optic lobe, cerebellum and medulla oblongata of the brain.