Lipid mediators such as the leukotrienes, resolvins and protectins have been considered excellent models for the development of new anti-inflammatory drugs, due to their high potentiality. Nevertheless, only tiny amounts are available from natural sources and they have to be prepared by total synthesis. It is known that besides chemical reagents, microorganisms can also promote fatty acid oxygenation, via enzymatic reactions. In this context, the aim of this work was to produce oxylipids analogues in structure to lipid mediators employing microbial biotransformation. To this end, alpha-linolenic acid (ALA) was biotransformed by the fungi Aspergillus niger into oxylipids with different levels of oxygenation within 24 h or 48 h. The anti-inflammatory potential of products were evaluated by means of NO and TNF-alpha quantification in LPS-stimulated RAW264.7 macrophage cell line which guided the isolation of the regioisomers at m/z [M-H] 291, 9-keto-10E,12Z,15Z-octadecatrienoic acid (9-KOTE) and 13-keto9Z,11E,15Z-octadecatrienoic acid (13-KOTE). We showed that biotransformation represents a powerful strategy for the production of potentially interesting candidates for development of anti-inflammation therapies. (C)2014 Elsevier Inc. All rights reserved.