THE TRYACYLGLYCEROLS OF 2 SAPINDACEAE SEE D OILS - STUDY OF LITCHI-SINENSIS SONN. AND EUPHORIA-LONGANA LAM. LIPIDS

Litchi and Longan seed oils are known for their high cyclopropanic fat ty acid contents with respectively 41.5 % and 18.7 %. For these two oi ls, the predominant cyclic fatty acids are the cis-7,8-methylenehexade canoic (Mh) and cis-9,10-methyleneoctadecanoic (Mo) acids. The partiti on of these two particular fatty acids in the triacylglycerols is stud ied for the first lime in this paper. After isolation on open silica c olumn, the triacylglycerols are analysed by high performance liquid ch romatography and silver thin layer chromatography. Then, the triacylgl ycerols are submitted to a chemical hydrolysis by ethylmagnesium bromi de, reageant without structure specificity and regioselectivity. Resul t combination allowed to determine the triacylglycerol composition of the two seed oils with more interest for the position isomers having 2 (1, 3) type. The sn-2 position of the majority of the triacylglycerol molecular species is esterified by oleic acid (O) which represent 50 % of fatty acids in internal position. The litchi seed oil is characte rised by one majoritary triacylglycerol (OMoMo) with 26.1 % content. T he longan seed oil present two major triacylglycerols O(PS) and O(MoMo ) with respectively 14.0 % and 11.2 % contents (P : palmitic acid, S : stearic acid).