神经酰胺功能和应用

神经酰胺是一种功能性食品和化妆品活性成分,该文主要对神经酰胺的结构、功能、及在食品、日化、医药业中应用进行综述。     

神经酰胺生理活性功能及其应用

大米是我国人民主要食粮,大米和米糠内含有诸多非常令人瞩目的生理活性物资,如γ－谷维素、阿魏酸、γ－氨基丁酸、三烯生育酚、角鲨烯、及近年令人关注的六磷酸肌醇酯（ＩＰ６）、神经鞘糖脂等。这些有效成分现已能萃取、制品化,广泛应用于医药品,化妆品、功能性食品、食品添加剂等领域。本文主要介绍由米糠和米胚芽制取神经酰胺生理活性功能及其应用。 神经酰胺系为神经鞘糖脂中的一种,１８８４年由德国医生Ｊ．Ｌ．Ｗ．Ｔｈｕｄｉｃｈｕｍ研究发现在脑中存在神经鞘脂质,现在,对于生物体内含有神经酰胺的神经鞘脂质合成、代谢途径…     

甘薯活性成分的功能及提取方法研究进展

甘薯作为重要的粮食作物，可食用率较高，主要食用部分是甘薯根茎，且大多数有益成分集中在根茎中。甘薯含有多种活性成分，这使得甘薯具有药用价值及保健功能。本文概述了甘薯活性成分的功能，并着重阐述多糖和花青素这两种主要活性成分的功能及其提取加工方法，为甘薯相关的功能性食品及工业产品的开发提供参考。     

龙眼核活性脂质的分析及其细胞增殖活性研究

研究了龙眼核活性脂质的组成及其细胞增殖活性。以龙眼核为原料,经超声辅助提取、氯仿萃取、硅胶柱层析分离后得到富含植物甾醇和神经酰胺的活性脂质组分CEP-2;定性定量分析脂质中的活性成分,并在细胞水平上考察龙眼核活性脂质对人皮肤成纤维细胞(HSF)、人永生化角质形成细胞(Ha CaT)增殖活性的影响。结果表明:CEP-2中主要含有三萜类、神经酰胺类、鞣质及酚类物质,总甾醇含量为518. 26 mg/g,神经酰胺含量为2. 65 mg/g; CEP-2在质量浓度为40μg/m L时,HSF细胞的存活率为105. 28%;在质量浓度为100μg/m L时,对HaCaT细胞表现出明显的细胞增殖活性(p 0. 001),细胞存活率为114. 21%。     

叶瓜参鞘脂抑制3T3-L1前脂肪细胞分化及构效关系研究

目的:探究叶瓜参脑苷脂、神经酰胺、长链碱等鞘脂对3T3-L1前脂肪细胞增殖分化的影响。方法:由叶瓜参制备脑苷脂、神经酰胺和长链碱,以相同浓度的3种物质或含有等量长链碱的3种物质孵育3T3-L1细胞,采用MTT法检测叶瓜参鞘脂对3T3-L1细胞增殖的影响。利用0.5 mmol/L IBMX,1μmol/L DEX及10μg/m L胰岛素诱导3T3-L1细胞分化为成熟脂肪细胞,采用油红O染色法检测叶瓜参鞘脂对脂肪细胞分化的影响。结果:叶瓜参脑苷脂、神经酰胺、长链碱均能显著抑制3T3-L1细胞的增殖及分化。海参脑苷脂由亲脂性神经酰胺及亲水性糖基两部分组成,而神经酰胺由长链脂肪酸和长链碱以酰胺键相连而成。当3种物质浓度相同时,对3T3-L1细胞增殖分化的抑制率:长链碱神经酰胺脑苷脂;而当3种物质含有等量的长链碱时,其作用效果相当。结论:叶瓜参脑苷脂、神经酰胺、长链碱等鞘脂抑制脂肪细胞的增殖分化,其活性成分为长链碱。     

树莓中活性成分及提取方法的研究进展

结合近几年树莓活性成分的研究现状,对树莓中的酚类化合物、酶类、芳香类等活性成分及功效进行了简述,同时概括了树莓中活性成分的提取方法等研究进展,总结了新技术在树莓活性成分开发方面的应用状况,期望为树莓作为一种新的医药资源和功能食品的进一步开发利用提供参考。     

黄精主要活性成分、功能及其作用机制研究进展

黄精是一种重要的药食同源植物，黄精主要活性成分包括多糖、多酚、凝集素、生物碱、皂苷等。黄精具有抗氧化、抗炎、抗癌、降血糖、抗癌、抗炎、抗疲劳、抗菌、改善记忆力、促进细胞凋亡、治疗阿尔茨海默症以及促进骨细胞分化成骨等生物功能活性，因此，黄精在保健食品和药物研发等方面具有广阔的应用前景。黄精活性成分种类繁多，作用机制复杂，且不同产地和种属的黄精活性成分含量不同，其生物功能活性也有所差别。该研究汇总黄精的主要活性物质种类和不同产地、不同种属之间的功能活性及活性物质含量，概述黄精活性物质降血糖、促进骨细胞分化、抗癌、促进细胞凋亡、治疗阿尔茨海默症以及促进骨细胞分化等的具体作用机制，为黄精资源深加工和高效利用提供参考依据。     

榆耳主要活性成分及其生物学功能研究进展

榆耳（Gloeostereum incarnatum，GI）是一种富含多种营养物质和活性成分的食药用真菌，其子实体和发酵产物具有高效的抗菌、抗炎、抗氧化、增强机体免疫力、抑制肿瘤等作用。榆耳提取物含有多糖、倍半萜类化合物和生物碱类、黄酮类、氨基酸等多种具有生物学活性的成分，其中多糖和倍半萜类化合物的生物活性最为显著，也是多种天然药物现代药理研究中最为重要的活性成分。该文对榆耳的主要活性成分及其生物学功能的研究进展进行综述，为榆耳主要活性成分的深入研究和开发利用提供参考。     

花生粕中功能活性成分提取工艺研究进展

花生粕是脱壳花生果榨油后的副产物,我国资源丰富。花生粕中含有多种功能活性成分,如蛋白质、多糖、膳食纤维、植酸、色素及黄酮等,是一种很好的营养物质,极具开发利用价值。本文综述了近年来国内花生粕功能活性成分提取工艺研究进展,并展望了其研究方向,旨在为花生粕的综合开发利用及其功能活性成分的深入研究提供参考和借鉴。     

新型乳化稳定剂复配系统在冰淇淋中的应用

<正> 冰淇淋的制造关键在于冰淇淋结构的均匀度,故此,Regency Mowbray公司研制了一种Remco 500乳化稳定剂复配系统,将乳化剂、稳定剂、增稠剂功能成分以一种特殊的加工方法完全混合。新配方除可促进配料成分发挥额外的活性,使定量的活性成分能够发挥更佳的功能,还可改进最终产品的结构和稳定性,提高产品质量。     

Ceramide binding to African-American hair fibre correlates with resistance to hair breakage

Repetitive hair-relaxing treatments often applied to African–American hair weaken the hair structure. Therefore hair breakage is a common feature of African–American hair and an important cause of hair loss. Recently, by analysing the lipids extracted from human hair, a fraction of free-ceramide was isolated in which sphinganine was predominant. This study shows that this sphinganine-derived ceramide (i.e. C18-dhCer) binds to African–American hair and protects it from weakening caused by chemicals. To show this binding, we used two methods: radioactivity detection with a microimager^TM and secondary ion mass spectrometry.
We evaluated the benefits of C18-dhCer on African–American hair fibre, relaxed by guanidine hydroxide, using a new method called the Break'in Brush Technique (BBT^®). This method determines the hair breakage resistance during a brushing. Using this technique, we have shown less breakage when applying a shampoo with ceramide.
The present study opens new prospects for the development of products able to increase the protection, provide better care and meet the needs of African–American hair thanks to the effect of ceramide binding.     

Hydrolyzed fumonisins HFB1 and HFB2 are acylated in vitro and in vivo by ceramide synthase to form cytotoxic N-acyl-metabolites

Fumonisins B1 and B2 (FB1 and FB2) are the most abundant members of the fumonisins--mycotoxins that are produced by Fusarium verticillioides and are natural inhibitors of ceramide synthase. Their hydrolyzed forms, HFB1 and HFB2 (also called AP1 and AP2) are found in some foods, and they are not only inhibitors of ceramide synthase but also undergo acylation by this enzyme. This study characterized the conversion of HFB1 and HFB2 by ceramide synthase to their respective N-acylated metabolites using rat liver microsomes and palmitoyl-CoA or nervonoyl-CoA as cosubstrates, and examined animals that had been dosed with hydrolyzed fumonisins to ascertain if acylation occurs in vivo. Using an HPLC-MS/MS method that allowed the sensitive and selective detection of the acylation products, both HFB1 and HFB2 were found to be metabolized in vitro to nervonoyl- or palmitoyl-HFB1 and -HFB2 (i.e. C24:1-HFB1/2 and C16-HFB1/2, respectively). The apparent vmax was considerably higher for formation of C24:1HFB1 (157 pmol/min/mg protein) than for formation of C16HFB1 (8.7 pmol/min/mg protein). The acylation products also inhibited ceramide synthase and significantly reduced the number of viable cells in an in vitro [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)] assay using a human colonic cell line (HT29). Furthermore, HPLC-MS/MS analysis of tissues from rats given intraperitoneal doses of HFB1 confirmed that formation of N-acyl-HFB1 occurs in vivo to produce metabolites with fatty acids of various chain lengths. The contribution of acylated HFB1 and HFB2 metabolites to fumonisin toxicity in vivo warrants further investigation.     

Influence of topically applied ceramide/phospholipid mixture on the barrier function of intact skin, atopic skin and experimentally induced barrier damage

The influence of a liposomal formulation of a ceramide/phospholipid mixture on the barrier function of the skin in atopic tests, in subjects with healthy skin, and after lipid extraction was tested. The transepidermal water loss and the stratum corneum hydration served as parameters for the evaluation of the influence of the ceramide/phospholipid-mixture treatment on the barrier function. Additionally a barrier-function test with nicotinic acid ester was performed after ceramide/phospholipid-mixture application. Stabilizing effects on the barrier function after application of ceramide/phospholipid-mixture were found only in atopic skin and after lipid extraction but not in healthy skin. The results lead us to expect positive effects of ceramide/phospholipid-mixture only if barrier damage is present.     

Synthesis of 2-N-oleoylamino-octadecane-1,3-diol: a new ceramide highly effective for the treatment of skin and hair

2-N-Oleoylamino-octadecane-1,3-diol is a new synthetic ceramide. The process enables a four-step preparation of 2-amino-octadecane-1,3-diol (D,L-erythro/threo) and a five-step synthesis of 2-N-oleoylamino-octadecane-1,3-diol (D,L-erythro/threo). The latter compound is related to ceramide 2 according to the classification of Downing. This route of synthesis is rapid, reproducible and uses low-cost starting materials. The new ceramide was analysed as follows: ¹H, ¹³C, ¹⁵N NMR spectra afforded an unambiguous characterization of the structure; additionally, these three methods identified the threo and erythro isomers. ¹H and ¹³C NMR permitted the measurement of the threo/erythro ratio (26.6/73.4 and 25.5/74.5, respectively). Chemical ionization mass spectrometry confirmed the expected mass of the pseudo-molecular ion (m/z= 566.5: [M + H]⁺) as well as the presence of different chain lengths other than the oleic moiety due to the fatty acid composition of the technical grade oleic acid used for the synthesis. Capillary gas chromatography measured the threo/erythro ratio (23.5/76.5) which agrees with the ¹H and ¹³C NMR data. Moreover, this method afforded the relative distribution of the different N-acylated chains. The properties of the new synthetic ceramide for the treatment of skin and hair were mainly assessed by two in vitro methods. The first measured the flux of water through lipid-extracted stratum corneum. The described ceramide showed high efficacy in decreasing water loss. The second recorded the friction coefficient of different types of hair: virgin, permanent-waved, and bleached. Treatment by the ceramide led to a strong decrease in this coefficient. This was particularly observed on unrinsed hair. These findings suggest two potential fields of application and beneficial contribution for the new ceramide: repairing the barrier to transepidermal water loss, and improving the surface properties of hair. Synthèse du 2-N-oleoylamino-octadécane-1,3-diol: nouveau céramide à haut potentiel dans le soin de la peau et du cheveu.     

解脂假丝酵母中神经酰胺合成的外部影响因素

为研究利用酵母发酵生产神经酰胺的可行性,利用高效液相色谱/蒸发光散射检测器作为分析手段,考察了解脂假丝酵母(Yarrowia lipolitica)在各种发酵条件下生产神经酰胺的能力.在各种可能的影响因素中,提高溶氧与乙醇刺激均能增加细胞内神经酰胺质量分数,在这两种条件下其占细胞干重的比例分别比对照提高2.5倍及3.3倍,最高可将其从占细胞干重的 0 25%提升到0 84%.其它培养条件对神经酰胺质量分数的影响则不明显或造成一定程度的下降.     

Role of ceramides 2 and 5 in the structure of the stratum corneum lipid barrier

We utilized Fourier transform infrared (FTIR) spectroscopy to investigate headgroup and chain interactions in model SC lipid barriers containing equimolar amounts of deuterated hexadecanoic acid, cholesterol, and ceramide 2 (non-hydroxy sphingosine) or ceramide 5 (alpha-hydroxy sphingosine). In the ceramide 2 model the thermotropic response of the CD _ 2 and CH _ 2 stretching modes indicates that hexadecanoic acid begins to disorder at 42 degrees C while ceramide 2 remains ordered until 52 degrees C. Additionally, splitting of the CD _ 2 bending and CH _ 2 rocking modes provides evidence for separate orthorhombic hexadecanoic acid and ceramide domains. The ceramide amide I mode (1650 cm ; -1) is split into two components indicating strong intermolecular hydrogen bonding between headgroups. In the ceramide 5 model, the CH _ 2 and CD _ 2 stretching frequencies again reveal highly conformationally ordered ceramide 5 and hexadecanoic acid chains. Splitting of both the CD _ 2 bending and CH _ 2 rocking modes is observed. However, the CH _ 2 rocking frequencies indicate distorted packing of the ceramide. The collapse of these highly ordered phases, and the onset of conformational disorder, occurs at 50 degrees C for both ceramide 5 and hexadecanoic acid. The amide I and II frequencies of ceramide 5 indicate strong H-bonding, although neither mode is split. Our results demonstrate that model SC lipid systems have quite different physical properties depending on whether they contain ceramide 2 or 5. From this we infer that ceramide 2 and 5 make distinct contributions to the structural biophysics of the SC lipid barrier. Our observation of ordered lipid domains is also consistent with the recently proposed domain mosaic model of the skin barrier.     

Elevation of ceramide in Acetobacter malorum S24 by low pH stress and high temperature stress

Acetic acid bacteria have unique and highly pure membrane lipid components, such as 2-hydroxypalmitoyl-sphinganine (dihydroceramide) and can grow and produce acetic acid at around pH 3.0, suggesting that ceramide in cell membranes may be involved in the tolerance to acidic pH. Acetobacter malorum S24 was selected for the production of ceramide and grown in YPG medium containing 0.8% ethanol. Ceramide biosynthesis was induced at pH 4 and below, suggesting that ceramide biosynthesis is induced by low pH stress. Elevation of ceramide was also induced by high temperature stress (40–70 °C). After the strain was cultured in an optimal growth medium, the cells were collected and treated at pH 3 and 40 °C for 4 days, resulting in a 30-fold elevation of both the yield and content of ceramide.     

Eucalyptus increases ceramide levels in keratinocytes and improves stratum corneum function

The objectives of this study were to identify a plant extract that would improve stratum corneum functions and to elucidate the mechanism(s) involved. Based on the information that stratum corneum functions depend on the level of ceramide in the stratum corneum, we identified a Eucalyptus extract that was able to increase the level of ceramide in human keratinocytes in culture and in human stratum corneum and that improves the stratum corneum water holding and barrier functions. Addition of the Eucalyptus extract to human keratinocytes in culture increased the level of ceramide in a dose-dependent manner and also increased the biosynthesis of ceramide, glucosylceramide and sphingomyelin. Topical application of the Eucalyptus extract on the dry skin of human subjects induced by acetone and diethylether treatment resulted in a significant increase in ceramide level in the stratum corneum, a significant improvement in its water-holding function and an improvement in its barrier function. The addition of macrocarpal A, one of the main components of the Eucalyptus extract, to human keratinocytes in culture increased the level of ceramide and the mRNA expression of serine palmitoyltransferase, acid sphingomyelinase, neutral sphingomyelinase, glucosylceramide synthase and glucocerebrosidase in a dose-dependent manner. Our results indicate that the increased content of ceramides in the stratum corneum may underlie the therapeutic effect of the Eucalyptus extract. Our results also indicate the possibility that macrocarpal A is the key component that stimulates the synthesis of ceramide in the stratum corneum.     

SOLUBILIZATION AND CHARACTERIZATION OF MICROSOMAL-ASSOCIATED PHOSPHATIDYLINOSITOL: CERAMIDE PHOSPHOINOSITOL TRANSFERASE FROM SACCHAROMYCES CEREVISIAE

The membrane associated enzyme phosphatidylinositol: ceramide phosphoinositol transferase (IPC synthase) catalyzes an essential step in the biosynthesis of yeast inositol-containing sphingolipids. A variety of solubilization agents were examined for their ability to release IPC synthase activity from yeast membranes. The most effective solubilization agent was Triton X-100 which released over 90% of the IPC synthase activity. The basic enzymological properties of the solubilized enzyme were determined using a Triton X-100/phosphatidylinositol/ceramide/enzyme mixed micellar assay system. IPC synthase activity was dependent upon the surface concentrations of phosphatidylinositol and ceramide in a phosphatidylinositol/ceramide/Triton X-100 mixed micelle. Maximal enzyme activity was measured at 30C and pH 7.0 in the presence of 5 mM Triton X-100, 1 mM manganese and 5 mM magnesium ions.     

Technical note: Characterization of ceramide in bovine lipoproteins

The hepatic synthesis and export of ceramide is enhanced in diabetic monogastrics. Moreover, ceramide in lipoproteins can mediate the development of insulin resistance. We have previously demonstrated that circulating ceramide increases during the progression of insulin resistance in postpartum dairy cows. Considering that the origins of circulating ceramide required investigation, our objective was to develop a method to characterize the ceramide profile of lipoprotein fractions collected from dairy cows. Serum was collected from 4 nonpregnant and nonlactating Holstein dairy cows. Serum lipoproteins were isolated using size exclusion chromatography by fast protein liquid chromatography (SEC-FPLC). Measurement of triacylglycerol (TAG), phospholipid, total cholesterol, and protein was performed using standard colorimetry practices. Following lipid extraction, fractions were analyzed using electrospray ionization tandem mass spectrometry. Data were analyzed as repeated measures using a mixed model. Lipoprotein isolation using SEC-FPLC and subsequent colorimetric analyses confirmed the presence of 4 distinct fractions: TAG-rich, low density (LDL), and large (buoyant) and small (dense) high density lipoprotein (HDL) subclasses. As expected, the fraction representing mixed very low density lipoproteins and chylomicrons primarily contained TAG. Low density lipoprotein fractions were equally enriched with cholesterol and phospholipid. Buoyant HDL contained elevated levels of cholesterol, phospholipid, and protein. In contrast, the fraction containing dense HDL primarily contained protein. Our method revealed that LDL are enriched with ceramides. Ceramides were also compartmentalized to a lesser extent within both HDL subclasses and TAG-rich lipoproteins. Comparable to whole serum, C16:0-ceramide was the predominant ceramide quantified in all lipoprotein subclasses. Interestingly, the proportion of C24:0-ceramide to total ceramide was elevated in TAG-rich lipoproteins, relative to all other lipoprotein subclasses. We conclude that SEC-FPLC coupled with mass spectrometry is a means to quantify ceramides in lipoprotein fractions. Moreover, ceramides are enriched within bovine LDL, and lipoprotein ceramide profiles reflect levels observed in whole serum. Future investigation will need to determine the biological importance of lipoprotein ceramides with distinct C-chains at amide residues.