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 >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.