Preparative chromatographic isolation of hydroxy acids from<i>Lesquerella fendleri</i> and<i>L. gordonii</i> seed oils

To conduct product development research on Lesquerella seed oils, we explored methods to obtain &gt;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 &gt;98%, the only contaminants being methyl auricolate and methyl ricinoleate.

Перевод пока недоступен