Preparative Chromatographic Isolation of Hydroxy Acids from Lesquerella fendleri and L. gordonii Seed Oils1

To conduct product development research on Lesquerella seed oils, we explored methods to obtain >100 g quantities of lesquerolic (14-hydroxy-cis-lleicosenoic) acid. Preliminary experiments with opencolumn silica gel chromatography showed that L. fendleri oil could be separated into 3 triglyceride (TG) fractions. The first (10%) contained nonhydroxy 16(13%) and 18-carbon acids (65% 18:1,2,3). The second fraction (15%) contained monolesquerolins (39% lesquerolie acid). The major TG fraction (73%) was mainly dilesquerolins (66% lesquerolic acid) showing that a hydroxy acid-enriched TG oil was obtainable by this procedure. Silica gel chromatography easily separated L. fendleri fatty acid methyl esters (FAME) into a hydroxy-free ester fraction (40-44%) consisting largely of 18:1 (39%), 18:2 (19%) and 18:3 (31%), and a hydroxy ester fraction (56-60%) that was largely methyllesquerolate (94%) with small amounts of auricolate (5%) (14hydroxy-cis-ll,cis-17-eicosadienoate) and traces of 18carbon hydroxy esters. This process for isolating the hydroxy FAME of Lesquerella oil was scaled up 15-to 100-fold with a preparative high performance liquid chromatograph. Thirty-gram samples of L. gordonii FAME were dissolved in eluting solvent, pumped onto the high performance liquid chromatography (HPLC) silica column and eluted with 97:3 hexane/ethyl acetate. In an 8-hr period, up to 200 g of methyl lesquerolate could be obtained with a purity >98%, the only contaminants being methyl auricolate and methyl ricinoleate.