Preparative chromatographic isolation of hydroxy acids from Lesquerella fendleri and L. gordonii seed oils.

To conduct product development research on Lesquerella seed oils, we explored methods to obtain >100 g quantities of lesquerolic (14-hydroxy- cis-11-eicosenoic) acid. Preliminary experiments with open-column 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% lesquerolic 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 methyl lesquerolate (94%) with small amounts of auricolate (5%) (14-hydroxy- cis-11, cis-17-eicosadienoate) and traces of 18-carbon 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. [ABSTRACT FROM AUTHOR]