Structure and Physiological Activity of Glycolipids from Amphibias

从牛蛙(Rana Catesbeiana)脑组织中分离得到三个神经节苷脂，其结构经核磁共振和质谱学方法确定为二唾液酸神经节苷脂(I11^6NeuAclV^3NeuAc-GgOse_4Cer)、三唾液酸神经节苷脂(I11^6NeuAclV^3(NeuAc)_2-GgOse_4Cer)和三唾液糖基神经节四糖神经酰胺(I11^6(NeuAc)_2LV^3(NeuAc)_2-GgOse_4Cer)。这些神经节苷脂在大脑半球、双脑及视叶、小脑和延髓的混合组织中也有类似的分布。黑斑林蛙和树蛙的脑组织中也含有与牛蛙相同的神经节苷脂。另一方面，从牛蛙的脑组织中分离到12个脑苷脂，鉴定为1-Omicron-β-D-半乳糖基神经酰胺。根据化学和光谱证据，其中6个神经酰胺部分由作为长链碱的鞘氨醇和6个脂肪酸组成，分别是C_&lt；18：0&gt；，C_&lt；22：1&gt；和C_&lt；24：1&gt；酸及其2-羟基衍生物。其余的神经酰胺部分由一种二氢鞘氨醇和六种脂肪酸组成。根据其乙酸酯的核磁共振谱和苯甲酸酯-苯甲酰胺衍生物的激子手性，确定了两个长链碱的C-2和C-3构型分别为S和R。此外，通过圆二色谱测定，三种2-羟基脂肪酸的手性中心均为R。在大脑半球、双脑及视叶、小脑和延髓的混合组织中，脑苷脂的分布有所不同。

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.