Tessema Efrem N, Gebre-Mariam Tsige, Lange Stefan, Dobner Bodo, Neubert Reinhard H H
Department of Pharmaceutical Technology and Biopharmaceutics, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Wolfgang-Langenbeck Str. 4, D-06120 Halle, Saale, Germany.
Department of Pharmaceutics and Social Pharmacy, School of Pharmacy, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
J Chromatogr B Analyt Technol Biomed Life Sci. 2017 Oct 15;1065-1066:87-95. doi: 10.1016/j.jchromb.2017.09.029. Epub 2017 Sep 20.
The impaired epidermal barrier and skin dryness in chronic skin conditions such as atopic dermatitis, psoriasis and aged skin are associated with the depletion of ceramides (CERs) in the stratum corneum. Previously, the beneficial effects of phyto-CERs, mainly from wheat and rice, in replenishing the depleted epidermal CERs and restoring the skin barrier have been shown. However, very few efforts have been made to exploit CERs from other plants for dermal applications. In an attempt to explore alternative plant source of CERs, glucosylceramides (GlcCERs) were isolated from the lipid extract of Ethiopian oat grain (Avena abyssinica). The GlcCER species were separated on a reversed phase HPLC and the structure of individual GlcCERs were identified by tandem MS with atmospheric pressure chemical ionization interface. The glycosidic linkage of the GlcCERs was cleaved by acid treatment and the predominant CERs species were isolated using column chromatography and preparative LC-MS. Further structural characterization of the CERs was made by HR/ESI-MS and NMR analyses. All the detected oat-derived GlcCER species consisted of C18 dihydroxy sphingoid bases amide-linked with α-hydroxylated saturated fatty acids (C16-C24). The two predominant GlcCER species consisted of sphingenine (d18:1) amide-linked to hydroxypalmitic acid (h16:0) and hydroxyarachidic acid (h20:0). The molecular formulae of the two major CERs assigned by HR/ESI-MS were identical to the ones identified by LC/APCI-MS/MS. The structural information was also supported by H, C, H COSY NMR and HMBC spectral analyses. The amount of GlcCERs in oat grain, quantified by HPTLC, was found to be 193.5mg/kg. The results indicated the similarity of oat CERs with commercial plant CERs (with comparable GlcCER content) suggesting its potential as source of CERs for oral (as dietary supplements) as well as topical applications.
在诸如特应性皮炎、银屑病和老年皮肤等慢性皮肤疾病中，受损的表皮屏障和皮肤干燥与角质层中神经酰胺（CERs）的消耗有关。此前，已证明主要来自小麦和大米的植物神经酰胺在补充耗尽的表皮神经酰胺和恢复皮肤屏障方面具有有益作用。然而，很少有人致力于从其他植物中提取神经酰胺用于皮肤应用。为了探索神经酰胺的替代植物来源，从埃塞俄比亚燕麦籽粒（阿比西尼亚燕麦）的脂质提取物中分离出了葡萄糖神经酰胺（GlcCERs）。通过反相高效液相色谱法分离GlcCER种类，并使用具有大气压化学电离接口的串联质谱法鉴定单个GlcCERs的结构。通过酸处理裂解GlcCERs的糖苷键，并使用柱色谱法和制备型液相色谱-质谱联用技术分离主要的神经酰胺种类。通过高分辨/电喷雾电离质谱（HR/ESI-MS）和核磁共振（NMR）分析对神经酰胺进行进一步的结构表征。所有检测到的燕麦来源的GlcCER种类均由与α-羟基化饱和脂肪酸（C16 - C24）酰胺连接的C18二羟基鞘氨醇碱组成。两种主要的GlcCER种类由与羟基棕榈酸（h16:0）和羟基花生酸（h20:0）酰胺连接的鞘氨醇（d18:1）组成。通过HR/ESI-MS确定的两种主要神经酰胺的分子式与通过液相色谱/大气压化学电离串联质谱法（LC/APCI-MS/MS）鉴定的分子式相同。结构信息也得到了氢、碳、氢-氢化学位移相关谱（H, C, H COSY NMR）和异核多键相关谱（HMBC）光谱分析的支持。通过高效薄层层析法（HPTLC）定量分析发现燕麦籽粒中GlcCERs的含量为193.5mg/kg。结果表明燕麦神经酰胺与商业植物神经酰胺相似（GlcCER含量相当），这表明其作为口服（作为膳食补充剂）以及局部应用的神经酰胺来源具有潜力。
