"(±)11-HEDE, a racemic mixture comprising the monohydroxy fatty acids 11(S)-HEDE and 11(R)-HEDE, is synthesized from eicosadienoic acid via cyclooxygenase (COX) activity and within macrophages."
11(R)-HEDE is synthesized from 11Z,14Z-eicosadienoic acid through a lipoxygenase-type reaction mediated by COX. Spectrophotometric analysis, specifically measuring the absorbance of the conjugated diene in 11(R)-HEDE, serves as an occasional method for quantifying COX activity.