Aporocactus flagelliformis water extract and limonin suppresses P2Y purinoceptor 14-mediated proinflammatory features in 3D4/31 porcine alveolar macrophages

Respiratory diseases have been recognized as a significant cause of reduced livestock productivity since 1995. Respiratory diseases in the swine industry caused by both biological and non-biological factors are collectively referred to as porcine respiratory disease complex (PRDC). However, there is a lack of eco-friendly anti-inflammatory drugs (AIDs) that can effectively control lung inflammation caused by PRDC. P2Y purinoreceptor 14 (P2Y₁₄) has been identified as a key regulator of macrophage inflammatory responses; however, its regulatory role in porcine lung inflammation remains unclear. In this study, we investigated the role of P2Y₁₄ in inflammation in 3D4/31 porcine macrophages and attempted to develop a novel AID. An extract of the Mexican medicinal plant Aporocactus flagelliformis water extract (AFWE) reduced reactive oxygen species production and pro-inflammatory cytokine expression in phorbol myristate acetate-stimulated 3D4/31-PAMs. It also reduced glucose uptake, glycogen accumulation, and expression of genes related to the P2Y₁₄ cascade. Polarity-based fractionation and liquid chromatography-mass spectrometry identified limonin as an anti-inflammatory compound in AFWE. Limonin reduced P2RY₁₄ and proinflammatory gene expression induced by the P2Y₁₄ ligand UDPG in 3D4/31-PAMs, demonstrating its inhibitory effect on P2Y₁₄-mediated inflammation. These results suggest that P2Y₁₄ is an inflammatory receptor in PAMs and an effective target for AID development. We also propose AFWE and limonin as candidate AIDs for pigs.