Structural Analysis of Glycolipids in Human Epidermis

人表皮具有脂-水屏障，其作用主要归功于含亚油酸的神经酰胺和糖脂。人表皮糖脂的酰基葡萄糖神经酰胺与猪表皮糖脂的酰基葡萄糖神经酰胺不同。为了研究人表皮中酰基葡萄糖基神经酰胺的生化功能，我们用氯仿-甲醇提取人表皮总脂，用DEAESephadexA-25和Unisil柱层析分离糖脂，然后用硅胶柱进行高效液相层析。用薄层色谱法、气相色谱法、气相色谱-质谱法和核磁共振氢谱法对糖脂的结构进行了测定，结果表明，人表皮糖脂含有酰基葡萄糖神经酰胺，由葡萄糖、亚油酸、ω-羟基脂肪酸和长链碱基组成。亚油酸以酯键和长链碱基结合在ω-羟基-脂肪酸的ω-部分上，由鞘氨醇和植物鞘氨醇组成。含有植物鞘氨醇的酰基葡萄糖神经酰胺是首次在表皮中发现的，具有这些结构的酰基葡萄糖神经酰胺是表皮中所特有的，我们将其命名为表皮苷。

Human epidermis has lipid-water barrier, the role of which owes much to seramides and glycolipids with linoleic acids. Acylglucosylceramide of glycolipids in human epidermis was different from that in pig epidermis. In order to study the biochemical function, we analyze the structure of acylglucesylceramide in human epidermis.We extracted total lipids from human epidermis with chloroform-methanol and isolated glycolipids by DEAE Sephadex A-25 and Unisil column chromatography following high pertormance lipuid chromatography with a slica gel column. Structural determination of glycolipids was performed by means of TLC, GLC, GLC-mass spectrometry and ^1H-NMR.As a result, human epidermal glycolipids contain acylglucosylceramides which consist of glucoses, linoleic acids, omega-hydroxy-fatty acids and long chain bases. Linoleic acids bound to omega-portion of omega-hydroxy-fatty acid with ester bounds and long chain bases are composed of sphingosines and phyto-sphingosines. Acylglucosylceramides containing phyto-sphingosines was first determined in epidermis.Acylglucosylceramides having those structures are unique in epidermis, and we named them Epidermosides.