Neutral Lipids and their Hydrolysis Products

Long chain hydrocarbons, alcohols, aldehydes and acids are widely distributed in the plant and animal kingdoms. These aliphatic lipids contain carbon chains which may be straight and saturated or branched or imsaturated, in one or more positions. Compoimds with more than one function, such as epoxy- and hydroxy-acids, are also known. 

Alcohols, aldehydes and acids occur in nature chiefly in combined form. The esters of long chain alcohols with acids are known as (ester-) waxes. 

Aliphatic alcohols and aldehydes occur above all in combination with glycerol they form alkyl ethers and alk-l-enyl ethers ( vinyl ethers ). Acids are found as esters with glycerol, the mono-, di- and triglycerides. 

The alkyl glycerol ethers, alkenyl glycerol ethers and monoglycerides can occur as a- and j8-isomers diglycerides may be symmetrical (a,a -) or asymmetrical (a,jS-). 

It has been discovered only in recent years that esters of various short-chain diols occur in nature as well as the esters of glycerol. The discovery, isolation and characterisation of these diol lipids was rendered possible by the application of modem chromatographic methods. 

---

Fig. 129. Separation of neutral lipids and their hydrolysis products by adsorption-TLC on silica gel G [114]. Solvent petrol ether (BP 60—70° C)-diethyl ether-acetic acid (90 + 10 + 1) time of run 40 min spray reagent 2, 7 dichlorofluorescein in ethanol 20 p,g of each apphed. a 9-octadecene 6 oleyl alcohol c oleyl aldehyde d oleic acid e methyl oleate / cholesteryl oleate g monoolein Ji diolehi i triolein j trilinolein k trihnolenin I tricaproin(a) and tristearin(]5) m cholesterol n selachyl alcohol o selachyl diolein p oleyl oleate q dioleoy 1-lecithin...

Table 67. Solvents for separation of neutral lipids and their hydrolysis products by adsorption TLC on silica gel 0...

---