IDENTIFICATION OF MINOR COMPONENTS OF SIS YMBRIUM OIL BY NMR

Twenty constituents were found by GC analysis of the fatty acid methyl esters of Sisymbrium sp. (Cruciferae) seed oil. After a first fractio nation by TLC on silica impregnated with silver nitrate and a second b y HPLC (RP 18), some of these esters were studied by H and C-13 NMR. B esides saturated components, the unsaturated fatty esters were mainly identified by the chemical shifts values of their ethylenic carbon ato ms. All the n-9 and n-7 cis monounsaturated esters were observed, with chain length of 18, 20 and 22 carbon atoms. Several polyunsaturated e sters were also identified. After chromatographic fractionations the m ain sterols were isolated and identified by NMR ft is noticeable that the two 24R and 24S epimers of 24-methylenecholest-5-en-3beta-ol were identified in this way, while for the moment they cannot be distinguis hed by GC.