Identification of nine acetylenic fatty acids, 9‐hydroxystearic acid and 9,10‐epoxystearic acid in the seed oil ofJodina rhombifolia hook et arn. (Santalaceae)

Abstract

AbstractIn addition to some usual fatty acids, the seed oil ofJodina rhombifolia (Santalaceae) contains nine acetylenic fatty acids [9‐octadecynoic acid (stearolic acid) (1.1%),trans‐10‐heptadecen‐8‐ynoic acid (pyrulic acid) (20.1%), 7‐hydroxy‐trans‐10‐heptadecen‐8‐ynoic acid (2.3%),trans‐10,16‐heptadecadien‐8‐ynoic acid (0.7%), 7‐hydroxy‐trans‐10,16‐heptadecadien‐8‐ynoic acid (0.1%),trans‐11‐octadecen‐9‐ynoic acid (ximenynic acid) (20.3%), 8‐hydroxy‐trans‐11‐octadecen‐9‐ynoic acid (12.2%),trans‐11,17‐octadecadien‐9‐ynoic acid (1.5%), 8‐hydroxy‐trans‐11,17‐octadecadien‐9‐ynoic acid (1.3%), 9‐hydroxystearic acid (<0.1%) and 9,10‐epoxystearic acid (0.7%)]. The fatty acids have been analyzed by gas chromatography/mass spectrometry of their methyl ester and 4,4‐dimethyloxazoline derivatives. The hydroxy fatty acid methyl esters have been examined also as trimethyl‐silyl ethers. Furthermore, the fatty acid methyl esters (FAME) have been fractionated according to their polarity (FAME‐A: nonhydroxy; FAME‐B: hydroxy fatty acids) and to their degree of unsaturation (FAME‐A1/A2; FAME‐B1/B2) by preparative thin‐layer chromatography and argentation chromatography, respectively. All of these fractions have been analyzed by ultraviolet and infrared spectroscopy, and the fractions FAME‐A and FAME‐B have been analyzed further by nuclear magnetic resonance (1H,13C, 2D H/C, attached proton test) spectroscopy and gas chromatography/mass spectrometry.