14,17,18-Trihydroxy-Eicosatetraenoic Acid: A Novel Pro-Resolving Lipid Mediator from Marine Microalgae

Specialized pro-resolving mediators (SPMs) are enzymatically oxygenated derivatives of polyunsaturated fatty acids that function as central immunoregulators in mammals. Among them are resolvins (Rvs) that stimulate the clearance of harmful stimuli and limit pro-inflammatory processes. Because of their beneficial features and their high potency, SPMs are promising molecules for anti-inflammatory therapy. Besides mammals, also marine algae form lipid mediators such as prostaglandins and leukotrienes. In particular, microalgae are attractive candidates for the production of bioactive high-value metabolites. Here, we identified the diatom Cylindrotheca closterium as a prolific producer of SPMs. The diatom forms RvE3 and novel structurally related eicosanoids, including 14S/R,17R,18R-trihydroxy-eicosatetraenoic acid, which displays inflammation-resolving and anti-inflammatory bioactivities. This pro-resolving compound might enable advancements in anti-inflammatory therapy in mammals.