11-cis Retinal is a chromophore that binds to opsin in the mammalian visual system as an inverse agonist forming the inactive conformation of rhodopsin. When 11-cis retinal absorbs a photon of light, it isomerizes to form all-trans retinal beginning the phototransduction cycle, which is the basis for mammalian vision. A G121L mutation in opsin allows 11-cis retinal to bind as a partial agonist and activate rhodopsin in the absence of light. In a moth model of carotenoid deficiency-induced low visual sensitivity, 11-cis retinal application to compound eyes restored visual sensitivity almost completely.
Docosahexaenoic acid is the most abundant ω-3 fatty acid in neural tissues, especially in the brain and retina. (±)7(8)-EpDPA is an epoxide derivative of DHA that is generated by the action of cytochrome P450 epoxygenases. It is naturally occurring in plasma and brain and spinal cord tissues and is increased following dietary supplementation with ω-3 fatty acids. (±)7(8)-EpDPA and other epoxy metabolites of DHA modulate receptor and channel activities to evoke diverse effects, such as promoting vasodilation, inhibiting angiogenesis, and decreasing inflammatory and neuropathic pain. (±)7(8)-EpDPA is a substrate of soluble epoxide hydrolase (KM = 15 μM), which converts it to the corresponding diol.
(±)10-HDHA is an autoxidation product of docosahexaenoic acid (DHA) in vitro.[1][2] It is also produced from incubations of DHA in rat liver, brain, and intestinal microsomes.[3][4][5] (±)10-HDHA is a potential marker of oxidative stress in brain and retina where DHA is an abundant polyunsaturated fatty acid. Reference:[1]. VanRollins, M., and Murphy, R.C. Autooxidation of docosahexaenoic acid: Analysis of ten isomers of hydroxydocosahexaenoate. J. Lipid Res. 25(5), 507-517 (1984).[2]. Reynaud, D., Thickitt, C.P., and Pace-Asciak, C.R. Facile preparation and structural determination of monohydroxy derivatives of docosahexaenoic acid (HDoHE) by α-tocopherol-directed autoxidation. Anal. Biochem. 214(1), 165-170 (1993).[3]. VanRollins, M., Baker, R.C., Sprecher, H., et al. Oxidation of docosahexaenoic acid by rat liver microsomes. J. Biol. Chem. 259(9), 5776-5783 (1984).[4]. Yamane, M., Abe, A., and Yamane, S. High-performance liquid chromatography-thermospray mass spectrometry of epoxy polyunsaturated fatty acids and epoxyhydroxy polyunsaturated fatty acids from an incubation mixture of rat tissue homogenate. J. Chromatogr. 652(2), 123-136 (1994).[5]. Kim, H.Y., Karanian, J.W., Shingu, T., et al. Sterochemical analysis of hydroxylated docosahexaenoates produced by human platelets and rat brain homogenate. Prostaglandins 40(5), 473-490 (1990).
(±)11-HDHA is an autoxidation product of docosahexaenoic acid (DHA) in vitro. It is also produced from incubations of DHA in rat liver, brain, and intestinal microsomes. DHA is metabolized to 11(S)-HDHA by human platelets and canine retina. In addition to 11(S)-HDHA, 14(S)-HDHA is also produced by platelets. 11(S)-HDHA was shown to be an inhibitor of U-46619-induced human platelet aggregation and rabbit and rat aortic smooth muscle contraction with IC50 values of about 50, 4.7, and 7.5 μM, respectively. (±)11-HDHA is a potential marker of oxidative stress in brain and retina where DHA is an abundant polyunsaturated fatty acid.
(±)13-HDHA is an autoxidation product of docosahexaenoic acid (DHA) in vitro. It is also produced from incubations of DHA in rat liver, brain, and intestinal microsomes. Fresh water hydra was shown to metabolize DHA to 13(R)-HDHA, presumably via the 11R-lipoxygenase activity. (±)13-HDHA is a potential marker of oxidative stress in brain and retina where DHA is an abundant polyunsaturated fatty acid.