DETERMINATION AND IDENTIFICATION OF TRITE RPENIC ALCOHOLS IN BORAGE, BLACK-CURRANT AND EVENING PRIMROSE OILS

Borrage (Borrago officinalis L.), block-currant (Ribes nigrum L.) and evening primerose (Oenothera biennis L.) seed oils which contain high level of gamma-linolenic acid (C18:3 omega 6), had respectively an uns aponifiable matter rate of 0.74, 1.20, 1.88%. 4,4'-dimethyl sterols wa s determined by liquid chromatography with hexane/isopropanol (98.5/1. 5; v/v) on silica column. An external standard (lupeol) was used. The triterpene alcohols compositions, determined by gas chromatography and by gas chromatography-mass spectrometry as acetates on DB17 column, w ere very different and characteristic for each oil. So, borrage contai ned cycloartenol (81.0%) and 24-methylene cycloartanol (19.0%) whereas black-currant had 24-methylene cycloartanol (57.3%), cycloartenol (30 .5%), beta-amyrine (7.5%), cyclobranol (2.7%) and 24-methylene dihydro parkeol (2.0%). Evening primerose contained a large variety of triterp ene alcohols with lupeol (32.0%) as main compound. Others alcohols wer e 7,24-tirucalladienol (15.7%), cycloartenol (15.4%), butyrospermol (1 2.7%), 24-methylene cycloartanol (7.0%) and germanicol (6.0%) which is rarely encountered in oils. The differences of 4,4'-dimethyl sterol c omposition can be used to differentiate the botanical origin of oils o r their mixtures.