The 9-hexadecenoic and 11-octadecenoic acid content of natural fats and oils

The monoenoic methyl esters from numerous fats and oils which contained appreciablecis-9-hexadecenoic acid (cis-9-16∶1) were isolated by liquid-solid chromatography on silver nitrate-silica gel. Analysis of the monoenes by packed and capillary column gas-liquid chromatography showed that significant amounts ofcis-11-octadecenoic acid (cis-11-18∶1) were present in all samples. The amount ofcis-11-18∶1 found in the monoenoic methyl esters increased proportionally to logarithmic increases in thecis-9-16∶1 level. Most analyses reported in the literature also show this proportionality. This mathematical relationship suggests that chain elongation ofcis-9-16∶1 tocis-11-18∶1 is a biosynthetic pathway operative in a wide variety of species.