(±)12-HEPE is produced by non-enzymatic oxidation of EPA. It contains equal amounts of 12(S)-HEPE and 12(R)-HEPE. The biological activity of (±)12-HEPE is likely mediated by one of the individual isomers, most commonly the 12(S) isomer in mammalian systems. 12-HEPE inhibits platelet aggregation with the same potency as 12-HETE, exhibiting IC50 values of 24 and 25 µM, respectively. [1] These compounds are also equipotent as inhibitors of U46619-induced contraction of rat aorta (IC50s = 8.6-8.8 µM).[2]
Reference:
[1]. Takenaga, M., Hirai, A., Terano, T., et al. Comparison of the in vitro effect of eicosapentaenoic acid (EPA)-derived lipoxygenase metabolites on human platelet function with those of arachidonic acid. Thrombosis Research 37, 373-384 (1986).
[2]. Karanian, J.W., Kim, H.Y., and Salem, N., Jr. Inhibitory effects of n-6 and n-3 hydroxy fatty acids on thromboxane (U46619)-induced smooth muscle contraction. J. Pharmacol. Exp. Ther. 270(3), 1105-1109 (1994).