Inhibition of inflammatory response in LPS induced macrophages by 9-KOTE and 13-KOTE produced by biotransformation

• α-Linolenic acid (ALA) was biotransformed by Aspergillus niger into species with different degree of oxygenation.
• The main biotransformation products were characterized by LC-MS/MS analyses.
• Their anti-inflammatory potential was evaluated with NO and TNF-α quantification in LPS-stimulated RAW264.7 macrophages.
• The isomeric ketoacids 9-KOTE and 13-KOTE were the most active.
• Biotransformation was successfully employed for the production of potential analogs to lipid mediators.

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, α-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-α 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-keto-9Z,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.