Lipid classes and fatty acid regiodistribution in triacylglycerols of seed oils of two Sambucus species (S. nigra L. and S. ebulus L.).

The oil content and fatty acid composition of total lipids (TLs) and main lipid classes (NLs- neutral and PLs- polar lipids) in seeds of two wild Sambucus species (S. nigra and S. ebulus) from Transylvania (Romania) were determined by capillary gas chromatography (GC-MS). In addition, the positional distribution of fatty acids in seed triacylglycerols (TAGs) was determined by hydrolysis with pancreatic lipase. The seeds were found to be rich in fat (22.40-24.90 g/100g) with high amounts of polyunsaturated fatty acids (PUFAs) ranging from 68.96% (S. ebulus) to 75.15% (S. nigra). High ratios of PUFAs/SFAs (saturated fatty acids), ranging from 7.06 (S. nigra) to 7.64 (S. ebulus), and low ratios of n-6/n-3, ranging from 0.84 (S. nigra) to 1.51 (S. ebulus), were determined in both oils. The lipid classes/subclasses analyzed (PLs, MAGs--monoacylglycerols, DAGs--diacylglycerols, FFAs--free fatty acids, TAGs and SEs--sterol esters) were separated and identified using thin-layer chromatography. The fatty acid compositions of the TAG fractions were practically identical to the profiles of TLs, with the same dominating fatty acids in both analyzed species. SEs and FFAs, were characterized by high proportions of SFAs. The sn-2 position of TAGs was esterified predominantly with linoleic acid (43.56% for S. nigra and 50.41% for S. ebulus).