超高效液相色谱-静电场轨道阱高分辨质谱鉴定核桃仁的脂质构成

利用超高效液相色谱-静电场轨道阱高分辨质谱系统鉴定了核桃的脂质组。在正负离子模式下获得脂质的一级质谱和二级质谱信息后,共鉴定出4 大类525 种脂质分子,包括250 种甘油酯、221 种磷脂、18 种糖脂、36 种鞘脂类,含量分别占总脂质的87%、12.97%、0.02%和0.01%。甘油二酯（diacylglycerol,DG）和甘油三酯（triacylglycerol,TG）是甘油酯的主要成分,分别占总脂质的45.23%和41.77%;TG分子中以TG(18:2/18:2/18:3)含量最高,DG分子中DG(18:2/18:2)含量最高,亚油酸和亚麻酸等人体必需脂肪酸是DG和TG中的主要脂肪酸。核桃中磷脂种类丰富,包括磷脂酸、磷脂酰甘油、磷脂酰丝氨酸、磷脂酰胆碱、磷脂酰乙醇胺、磷脂酰肌醇、磷脂酰肌醇二磷酸、溶血性磷脂酰胆碱、溶血性磷脂酰乙醇胺、溶血性磷脂酰甘油、溶血性磷脂酰肌醇和双磷脂酰甘油,其中磷脂酸最多,约占磷脂的43.88%。本实验构建的核桃脂质图谱,可为核桃功能开发和营养品质的深入研究提供一定理论依据。     

UPLC-Triple-TOF-MS/MS法分析中国东北地区人乳磷脂的组成

借助超高效液相色谱联用质谱(UPLC-Triple-TOF-MS/MS)分析法,对不同泌乳期人乳中的磷脂进行定性和相对定量,为中国人乳磷脂组成的研究提供参考。本研究从哈尔滨(黑龙江省)、齐齐哈尔(黑龙江省)和吉林(吉林省)地区采集到汉族人初乳(1~5 d)、过渡乳(6~20 d)和成熟乳(21 d~)共计73份。LipidView 1.2用于检索磷脂分子式,PeakView 2.2及其插件MasterView 1.1用于磷脂定性分析,MultiQuant用于磷脂相对定量分析(基于色谱峰面积)。结果显示,人乳中检出磷脂共计60种。其中,磷脂酰胆碱(PC)17种,磷脂酰乙醇胺(PE)25种,磷脂酰丝氨酸(PS)4种,磷脂酰肌醇(PI)5种,鞘磷脂(SM)9种。磷脂酰胆碱(PC)、磷脂酰乙醇胺(PE)、鞘磷脂(SM)、磷脂酰丝氨酸(PS)和磷脂酰肌醇(PI)在总磷脂中的相对含量分别为38.12%、26.97%、29.54%、4.43%和0.94%,各种磷脂的相对含量随泌乳期变化表现出不同的变化趋势,但大多数磷脂的相对含量差异并不显著。     

基于液相色谱-质谱法脂质组学研究德州驴肌肉的脂质组成

基于液相色谱-质谱法脂质组学研究三粉（Sanfen,SF）驴和乌头（Wutou,WT）驴肌肉脂质和脂肪酸组成、差异脂质、潜在生物标记物和代谢途径。结果表明,2 种驴肉均鉴定出1 101 种脂质分子,属于13 个亚类。甘油三酯为德州驴肌肉优势脂质,其次是磷脂;甘油二酯相对含量在SF驴肌肉中显著高于WT驴肌肉（P＜0.05）。SF和WT驴肌肉中所有脂肪酸组成均无显著差异（P＞0.05）。共筛选出37 种差异脂质分子（投影变量重要性值大于1和P＜0.05）,其中SF与WT驴相比,32 种上调,5 种下调。利用接收者操作特征曲线,筛选出11 种脂质分子可作为区分SF和WT驴的主要候选生物标志物。差异脂质分子主要富集的脂质代谢通路包括甘油磷脂代谢、亚油酸代谢、糖基磷脂酰肌醇-锚定生物合成途径、α-亚麻酸代谢和花生四烯酸代谢途径。本研究在脂质分子和代谢水平分析德州驴不同品种肌肉脂质的差异,筛选出潜在生物标志物。     

不同生长期威氏海链藻主要脂类成分分析

采用超高效液相色谱-四极杆-飞行时间质谱联用分析系统(UPLC-Q-TOF MS),对威氏海链藻主要脂质的种类和含量进行研究,结果表明:该藻中主要脂类包括非极性脂三酰甘油(TAG),一类甜菜碱脂DGCC,一类磷脂磷脂酰胆碱(PC)以及4种光合膜脂,即二酰甘油单半乳糖脂(MGDG)、二酰甘油双半乳糖脂(DGDG)、二酰甘油硫代糖脂(SQDG)和磷脂酰甘油(PG)。所有TAG分子含量对数期最少,平台末期大量积累。从对数期到平台期,所有的PC含量减少,而DGCC恰好相反,只是到了平台末期有部分DGCC含量开始出现下降趋势。4种光合膜脂中,大多数SQDG、MGDG和PG在对数期到平台初期时含量不断增加,SQDG和MGDG从平台初期到平台末期含量出现降低的趋势,而PG含量继续增加;整个生长过程中,一种DGDG的含量不断降低。除了PG和SQDG外,其它脂类中都富含DHA和EPA多不饱和脂肪酸,具有较高的营养价值,可作为水产生物培养的重要生物饵料。     

基于1,2-二氯乙烷体系的金枪鱼副产物中脂质提取与组学分析

为提高金枪鱼副产物的利用率,减少资源浪费,本试验基于1,2-二氯乙烷体系结合丙酮沉淀法,建立从金枪鱼副产物中同时提取脂质和鱼油的新方法。采用气相色谱法和液相色谱-质谱联用法分别对提取脂质中鱼油和磷脂进行脂质组学研究。通过调节溶剂体系得到1,2-二氯乙烷-甲醇的最佳体积比为1∶2。进一步优化提取条件,得到磷脂和鱼油的得率分别为0.944%和17.306%。利用气相色谱法分析甲酯化的鱼油中的脂肪酸甲酯成分,同时在负离子全扫描模式下利用液相色谱-质谱联用技术对磷脂分子进行分离鉴定和相对定量分析。结果显示:鱼油中主要含有DHA、棕榈酸、油酸、EPA等18种脂肪酸,其中多不饱和脂肪酸占36.678%。从磷脂样品中共检出16种磷脂酰胆碱,14种磷脂酰乙醇胺,11种磷脂酰肌醇和12种磷脂酰丝氨酸,同时,结果显示所有磷脂分子种中包含ω-3多不饱和脂肪酸链的磷脂所占比例较高。研究表明,基于1,2-二氯乙烷的提取方法可提取金枪鱼副产物中的磷脂和鱼油,相比传统方法更安全,更适用于食品加工业。     

超高效液相色谱-四极杆/静电场轨道阱高分辨质谱鉴定嗜热链球菌发酵乳中脂质构成

采用超高效液相色谱-四极杆/静电场轨道阱高分辨质谱对嗜热链球菌发酵乳中脂质组分进行分析,在正负离子模式下分析脂质构成、分子结构,从分子层次阐述嗜热链球菌发酵乳脂质组分构成。结果显示,在正负离子模式下共检测出861 个甘油酯、540 个磷脂、282 个鞘脂和33 个糖脂,总计1 716 个脂质组分,在正离子模式下,甘油酯、磷脂、鞘脂相对含量分别为95.84%、3.08%和1.08%,甘油三酯（triacylglycerol,TG）（16∶0/6∶0/14∶0）、TG（4∶0/14∶0/16∶1）、TG（10∶0/10∶0/12∶0）为主要脂质成分（＞5%）;在加热电喷雾电离源负离子模式下,磷脂、鞘脂和糖脂相对含量分别为35.34%、28.15%和36.51%,其中单半乳糖甘油一酯（2∶0）为主要脂质成分。在正离子模式下对甘油酯具有较好检测效果,在负离子模式下对磷脂、鞘脂和糖脂具有较好检测效果,采用正负离子模式可以全面了解嗜热链球菌发酵乳中脂质组分构成。该方法具有高通量、高灵敏度、高准确度等优点,可为发酵乳中脂质研究提供可靠分析技术,又为丰富乳品脂质生物学功能提供理论依据。     

虾头中磷脂提取与组学分析

研究虾头中磷脂的提取制备方法,并分别利用气相色谱法和多维度串联质谱法对样品磷脂的脂肪酸链结构进行脂质组学分析。利用乙醇浸提法制备得到虾头中的磷脂,并从乙醇体积分数、提取温度和提取时间3?个因素对提取方法进行优化,得到较优条件为乙醇体积分数90%、提取温度50?℃、提取时间30?min,磷脂的提取效果最佳,实际提取量可达到（11.58±0.03）mg/g,与优化前相比提高了83.8%。磷脂样品经甲酯化反应后用气相色谱法分析其脂肪酸链组成,并用高效液相色谱-质谱联用技术经负离子全扫描对磷脂分子实现分离鉴定和定量分析。结果显示,磷脂的脂肪酸链中主要含有棕榈酸链、亚油酸链、二十碳五烯酸和硬脂酸链等23?种脂肪酸链,其中单不饱和脂肪酸链占9.51%,多不饱和脂肪酸链占35.33%;磷脂样品中共检出磷脂酰胆碱、磷脂酰乙醇胺、磷脂酰肌醇和磷脂酰丝氨酸4?类共28?种磷脂分子,该提取方法所得各种类磷脂的脂肪酸链中存在许多不饱和度较高的脂肪酸链,如40∶8、36∶7、38∶7、O-40∶7、40∶7、34∶6、O-36∶6、36∶6、O-38∶6、38∶6、40∶6等。虾头中磷脂含量丰富,其脂肪酸链不饱和度较高,因此具有较高的开发利用价值。     

牦牛骨脂质组成及其理化性质分析

为提高牦牛骨的利用率,实现高值化利用,本文采用GC-MS和IUPAC法测定了牦牛骨脂质组成和理化指标,并进行分析。脂质组学分析共检出20种脂肪酸,其中SFA（饱和脂肪酸）含量占脂肪酸总量的41.75%,FA n:1（单不饱和脂肪酸）为53.01%,PUFA（多不饱和脂肪酸）1.46%,其他为3.79%。在负离子模式下共检测出4种脂质:Car（乙酰左旋肉碱）、SM（鞘磷脂）、PC（磷脂酰胆碱）和TAG（三脂酰甘油及中性脂肪）,含量依次是PC>SM>TAG>Car。理化指标结果表明:牦牛腿骨脂质的脂肪酸稳定性较好且饱和脂肪酸较多。从牦牛腿骨中检出了两种物质:α-三烯酚和γ-三烯酚。油脂的氧化稳定性显示,牦牛骨油脂的诱导时间为5.56 h,牦牛骨的油脂氧化稳定性比较高,具有较强的抗氧化效果。脂肪酸与骨健康密不可分,而牦牛骨脂质脂肪酸含量丰富,因此,牦牛骨可以作为维护骨健康的潜在的营养剂。     

微拟球藻总脂中甘油酯组成定量分析及EPA的存在形式研究

采用正己烷-乙醇混合溶剂提取微拟球藻总脂,分级后得到中性脂、糖脂和磷脂,采用薄层层析分离3组分,并采用气相色谱法定量分析各组分在总脂中的含量及脂肪酸组成,同时分析了EPA在各脂质中的分布。结果表明：微拟球藻总脂甘油酯的中性脂、糖脂、磷脂占比分别为3342%、38.22%和28.36%;中性脂主要组分为甘油三酯（TAG）和游离脂肪酸（FFA）,在总脂中的含量分别为9.27 g/100 g和5.79 g/100 g;糖脂主要组分为单半乳糖甘油二酯（MGDG）和双半乳糖甘油二酯（DGDG）,在总脂中的含量分别为14.03 g/100 g和5.81 g/100 g;磷脂主要组分为磷脂酰乙醇胺（PE）、磷脂酰胆碱（PC）和磷脂酰肌醇（PI）,在总脂中的含量分别为6.22、3.53 g/100 g和1.53 g/100 g。3类脂质之和占微拟球藻总脂的51.49%;不同脂类脂肪酸组成差别较大,EPA在甘油一酯（MAG）、MGDG、DGDG和PE中比例较高,分别占各组分脂肪酸总量的16.94%、3724%、1432%和10.51%,EPA在中性脂中分布最低,83.59%的EPA以糖脂形式存在。     

3种经济类海胆的脂质组成差异分析

海胆为我国名贵海珍品,营养丰富、经济价值高,但不同种类的海胆品质存在差异,本文对国内三种常见经济类海胆的脂质组成进行分析。以性腺基本指数、总脂含量、胆固醇含量、磷脂含量、甘油酯含量、脂肪酸组成、磷脂组成等为评价指标,结合统计分析技术比较不同种类海胆脂质组成的差异。结果显示,光棘球紫海胆、黄海胆和虾夷马粪海胆总脂占干基的(21.83±0.12)%~(27.21±0.10)%;其中磷脂和甘油酯是最主要的脂类组分,分别占(39.62±0.49)%~(49.39±0.73)%和(30.08±0.01)%~(38.65±0.03)%;磷脂中的主要组分为磷脂酰胆碱(Phosphatidylcholine,PC)和磷脂酰乙醇胺(Phosphatidylethanolamine,PE)和磷脂酰肌醇(Phosphatidylinositol ,PI);总脂中脂肪酸主要为C16:0、C18:0、C20:1及C20:5(Eicosapentaenoic acid,EPA)。对脂类相关数据进行标准化处理,并结合聚类分析和主成分分析,结果显示三种海胆性腺脂类物质中脂质组成、磷脂组成及脂肪酸组成差异明显。研究表明,光棘球紫海胆相对于其他两种海胆具有较高的营养价值和脂质优势,可作为C20:4n3、C20:4n6、C20:5n3、C22:6n3及磷脂等功能性脂质分子的重要膳食来源。     

我国南北城市0～12 月不同泌乳阶段母乳蛋白质和氨基酸构成的纵向研究

目的：比较我国北京（北方）和深圳（南方）两城市0～12 月不同泌乳阶段母乳蛋白质和氨基酸含量差异。方法：于北京市和深圳市各招募30 名足月分娩健康婴儿的健康乳母,纵向采集10 次母乳,包括初乳（3～5 d）、过渡乳（13～15 d）和成熟乳（3、4 周和2、3、4、6、9、12 月）,检测蛋白质和氨基酸含量并作比较分析。结果：北京和深圳母乳中蛋白质含量均为初乳中最高,随泌乳时间的延长而逐渐降低：其中,前3 周急速降低,之后降低速度减缓,但仍有显著差异（P＜0.05）,到3 月时达到稳定;两城市母乳在各泌乳阶段中均无显著差异（P＞0.05）。母乳氨基酸含量也随着泌乳时间的延长呈显著下降趋势（P＜0.05）,到12 月时总氨基酸含量、总必需氨基酸含量和总非必需氨基酸含量均下降了约58%。母乳中含量最丰富的单体氨基酸为谷氨酸、亮氨酸和天冬氨酸,含量最低的是蛋氨酸和色氨酸,两城市母乳单体氨基酸的绝对含量在除初乳和4 月成熟乳以外的其他各月均有种类和数量的差异,但随泌乳时间的延长,各单体氨基酸在总氨基酸中的比例保持稳定,必需氨基酸和非必需氨基酸分别占总氨基酸的42%和58%左右;而深圳母乳中苯丙氨酸在总氨基酸中的比例在除3～5 d以外的其他9 个时间点均高于北京母乳。结论：初乳中蛋白质和氨基酸含量均最高,随着泌乳时间的延长均呈逐渐下降趋势;蛋白质含量不受地区差异的影响,而两城市母乳中氨基酸含量及其在总氨基酸中的比例具有一定程度的差异。     

不同泌乳期人乳与牛乳中游离氨基酸的对比

利用同位素标记相对和绝对定量技术结合高效液相色谱-串联质谱技术对不同泌乳期人乳与牛乳中游离氨基酸的种类及含量进行检测及对比分析。结果表明,人乳中游离氨基酸种类较牛乳更为丰富,含量也高于牛乳,且随着泌乳时间的延长其总量呈下降趋势。牛初乳、牛常乳、人初乳和人常乳中游离氨基酸总量分别为0.32、0.16、0.63?g/L和0.37?g/L。实验测定的42?种游离氨基酸中,人常乳中检出35?种,牛常乳中测得31?种,其中人常乳中有25?种游离氨基酸的含量高于牛常乳,人乳中组氨酸、苯丙氨酸、苏氨酸等含量显著高于牛乳（P＜0.05）,游离谷氨酸在人初乳、人常乳、牛常乳中含量均为最高,而牛初乳中游离牛磺酸含量最高。本研究分析了人乳、牛乳中游离氨基酸种类和含量的差异,可为详细的研究母乳氨基酸功能和氨基酸代谢组学提供了一定的理论依据,也可为生产婴幼儿奶粉和功能性乳制品提供参考。     

泌乳期母乳脂肪酸变化及其多不饱和脂肪酸影响因素

采用气相色谱-质谱联用技术测定不同泌乳期母乳中脂肪酸的动态变化,并分析乳母血型、生育年龄、孕周、孕前身体质量指数（body mass index,BMI）、分娩方式和婴儿性别、胎次对成熟母乳中与婴儿生长发育直接相关的重要多不饱和脂肪酸（polyunsaturated fatty acid,PUFA）,亚油酸（linoleic acid,LA）、α-亚麻酸（α-linolenic acid,ALA）、花生四烯酸（arachidonic acid,AA）,二十碳五烯酸（eicosapentaenoic acid,EPA）、二十二碳六烯酸（docosahexaenoic acid,DHA）相对含量的影响。结果显示,饱和脂肪酸（saturated fatty acid,SFA）含量在初乳和成熟乳间差异显著（P＜0.05）,单不饱和脂肪酸（monounsaturated fatty acid,MUFA）含量随着泌乳期的延长逐渐降低,但差异不显著（P＞0.05）,PUFA含量在各泌乳期无显著差异（P＞0.05）,AA、DHA含量随着泌乳期的延长逐渐降低,在初乳、过渡乳中含量差异均不显著（P＞0.05）,但均显著高于成熟乳中含量（P＜0.05）;母乳中LA含量与婴儿性别有关,ALA含量与乳母孕前BMI有关,母乳中AA、EPA含量与乳母血型有关,DHA含量与乳母孕前BMI、乳母血型有关,均具有统计学意义（P＜0.05）。     

Sialyloligosaccharides in human and bovine milk and in infant formulas: variations with the progression of lactation

Several lines of research support a role for human milk oligosaccharides in the defense of breast-fed infants against pathogens. Some ofthese oligosaccharides contain at least one moiety of sialic acid and are, thus, termed sialyloligosaccharides. These constitute a significant component (>1 g/L) of human milk. It is well established that milk composition varies among species, and previous reports have indicated that one ofthe differences between human and bovine milk is precisely their contents of sialyloligosaccharides. Because most infant formulas are manufactured with bovine milk components, it follows that formula-fed and breast-fed infants ingest dissimilar quantities of these carbohydrate structures. To ascertain these differences and their impact along lactation, the contents of oligosaccharide-bound sialic acids and major sialyloligosaccharides in samples of human and bovine milk (obtained at different lactation stages) were determined. In addition, infant formulas were assayed for their sialyloligosaccharide contents. Seven sialyloligosaccharides were identified in human milk; namely, 3'-sialyl-3-fucosyllactose and sialyllacto-N-tetraoses (a and b+c), the predominant structures at all lactation stages. Five sialyloligosaccharides were identified in bovine milk, of which 6'-sialyllactosamine and 3'-sialyllactose were the most abundant. In addition, sialyloligosaccharides in human and bovine milk decreased along lactation, and infant formulas did not contain significant amounts of sialyloligosaccharides. The results point to the general conclusion that regarding both qualitative and quantitative aspects, milk from humans and cows and infant formulas have different oligosaccharide contents. In this sense, bottle-fed infants are subject to reduced sialyloligosaccharide intake as compared to breast-fed infants.     

The chemical composition of human milk from Inner Mongolia of China

In Inner Mongolia, China, the chemical composition of 66 breast milk samples at three lactation stages was analysed. Except for total nitrogen content, the contents of total solid, fat, NPN, lactose and ash were not significantly different between colostral, transitional and mature milk. Fatty acids did not vary over the three lactation stages, while unsaturated fatty acids accounted for 59.95–63.22% of the total fatty acids. Relatively low contents of vitamins were in the milk because the volunteer mothers did not take any vitamin supplementation over the entire lactation period. Besides sodium and phosphate, the concentrations of most minerals in the breast milk remained fairly constant across the three lactation stages.     

Milk quality characteristics of Boutsiko,Frisarta and Karagouniko sheep breeds reared in the mountainous and semimountainous areas of Western and Central Greece

In this study, the chemical and microbiological characteristics of ovine milk from three indigenous Greek breeds was assessed. The breeds selected for this study were Boutsiko, Frisarta and Karagouniko. The milk yield of each breed was recorded at the early, mid‐ and late stages of lactation for two consecutive years. Among the three breeds, the average milk compositions obtained were similar for protein, lactose and total solids; however, fat values were significantly lower in Frisarta milk compared with Boutsiko and Karagouniko milk. The major fatty acids (FAs) in ovine milk were palmitic and oleic. The microbiological quality of Boutsiko and Karagouniko milk was superior to Frisarta milk.     

Distribution of bovine milk sialoglycoconjugates during lactation

The sialoglycoconjugate content of human milk has been extensively studied. However, little attention has been paid to the changes occurring in these compounds in bovine milk during lactation. Since sialoglycoconjugates are very abundant in milk from the early stages of lactation, they have been suggested to be important for the nutrition of the newborn during the first months of life. The distribution of sialoglycoconjugates (expressed as glycoconjugate-bound sialic acid) from four different stages of lactation (colostrum, transitional, mature, and late-lactation milks) was investigated in four Spanish-Brown cows. All the fractions studied (total sialic acids, glycoproteins, oligosaccharides, casein, and gangliosides) showed a similar trend. We found the highest values in the colostrum, these decreasing in transitional and mature milks and increasing again in late-lactation milk. We also found a selective change in the relative contents of glycoprotein- and oligosaccharide-bound sialic acids. In mature milk, the latter increased up to 80% (59% in colostrum) and the former decreased to 3.9% (35.3% in colostrum). It would appear that the decrease in oligosaccharide-bound sialic acid is compensated by the increase in glycoprotein-bound sialic acid. From these results, it is deduced that newborn infants or calves fed with infant formulas or milk replacers, respectively, should be supplemented with sialoglycoconjugates to approximate the composition of human and cow milk as far as is practicable.     

SFC-Q-TOF-MS法鉴定4 种家畜乳甘油三酯及特征分析

对家畜乳尤其是特种家畜乳脂肪甘油三酯（triacylglycerols，TAGs）进行系统鉴定和研究。采集荷斯坦牛、山羊、蒙古马和双峰驼原奶样品31 份，用超临界流体色谱-四极杆飞行时间质谱（supercritical fluid chromatography-quadruple time-of-flight mass spectrometry，SFC-Q-TOF-MS）检测鉴定TAGs组成，并进行主成分分析（principal component analysis，PCA）。结果表明：4?种家畜乳共鉴定出145?种TAGs，相对分子质量为470～888，酰基链总碳数为24～54，双键数为0～9；由14?种碳数4～20、双键数0～3的脂肪酸构成。牛、山羊、马和骆驼乳分别鉴定出60、66、74?种和44?种TAGs。马、骆驼、牛和山羊乳不饱和TAGs相对含量依次为82.2%、61.1%、51.7%和43.8%；马乳含亚麻酸的TAGs高达45.43%；骆驼乳TAGs脂肪酸组成最简单，至少含肉豆蔻酸、棕榈酸、硬脂酸和油酸中的一种；驼乳脂肪O-P-O相对含量最高，为5.04%，山羊乳脂肪最低，仅为1.8%；山羊乳主要TAGs都由饱和脂肪酸组成。4?种家畜乳的基峰色谱图差异明显，对TAGs进行PCA?4?种家畜乳样品以物种聚类明显分离，距离远近符合物种分类学，提示TAGs可建模判别家畜乳的物种。     

L-Ergothioneine scavenges superoxide and singlet oxygen and suppresses TNF-α and MMP-1 expression in UV-irradiated human dermal fibroblasts

The hair lipid composition collected from 44 Japanese females between 1 and 81 years of age was examined for eight lipids including hydrocarbons (HCs), squalene (SQ), wax esters (WEs), triglycerides (TGs), fatty acids (FAs), cholesterol (CH), ceramides (CERs), and 18-methyl eicosanoic acid (MEA). In this study, the 5-cm length from the proximal root end of hair fibers, which had never been exposed to any chemical treatment, was used after 5-min incubation with hexane following shampooing. Hair lipids were extracted with solvent and subsequent alkali-solvent and were then analyzed by a combination of chromatography. Although the average contents of the lipids showed great fluctuations among individuals, there were significant correlations between the levels of each lipid, which allowed for the classification of the hair lipids into four groups: group A: SQ, WEs, TGs, and FAs (designated as endogenous lipids based upon their sebum origin); group B: CH and CERs (designated as endogenous lipids); group C: HC (unknown origin); and group D: MEA (the other endogenous lipid). A principal component analysis for eight lipids revealed that the hair lipid composition was characterized by a predominant negative correlation between each lipid for groups A and B. This negative correlation suggests that the endogenous lipids in group B serve as a barrier against the penetration of predominantly sebum-derived exogenous lipids (group A). Endogenous lipids consisting of CH and CERs (group B) and MEA (group D) should be designated as intrinsic internal lipids of human hair.