Docosahexaenoic acid is an ω-3 fatty acid that is abundant in the brain and the retina and is known to be important in early development.[1] [2] Maresin 2 (MaR2) is a 13R,14S-dihydroxy DHA formed by recombinant human macrophage 12-lipoxygenase and soluble epoxide hydrolase co-incubated with DHA. [3] At 1 ng/mouse, MaR2 was shown to reduce neutrophil infiltration by 40% in a mouse model of peritonitis, and at 10 pM, MaR2 can enhance human macrophage phagocytosis of zymosan A by 90%. [3] Analytical and biological comparisons of synthetic MaR2 with endogenously derived MaR2 have confirmed its identity as matching the natural product.[4]

Maresin conjugates in tissue regeneration 2 (MCTR2) is a specialized pro-resolving mediator (SPM) synthesized from docosahexaenoic acid in macrophages at the site of inflammation. DHA is oxidized to maresin 1 , which is converted to MCTR1 by glutathione S-transferase Mu 4 or leukotriene C4 synthase then to MCTR2 by γ-glutamyl transferase. MCTR2 accelerates tissue regeneration in planaria (1 and 100 nM). Pretreatment with MCTR2 prior to E. coli administration reduces neutrophil infiltration, shortens the inflammatory resolution period, and increases phagocytosis of E. coli by macrophages. When administered at a dose of 100 ng 12h post E. coli infection in a mouse model of peritonitis, MCTR2 selectively reduced the amount of the eicosanoids PGD2 and PGF2α in the exudate.