A simple method for the preparation of pure 9-D-hydroperoxide of linoleic acid and methyl linoleate based on the positional specificity of lipoxygenase in tomato fruit.

Incubation of linoleic acid with crude homogenate of tomato fruit gave a high yield (69%) of linoleic acid hydroperoxides with a ratio of 9- to 13-hydroperoxide isomers of 96:4. After chromatography of the products, as free acids or methyl esters, hydroperoxides with 9- to 13-isomeric ratios of greater than 99:1 were obtained. The major product was characterized as 9-D-hydroperoxy-octadeca-trans-10,cis-12-dienoic acid. The results demonstrate the positional specificity of lipoxygenase from tomato fruit.