Dilinoleoylphosphatidylcholine induces the expression of the anti-inflammatory heme oxygenase-1 in RAW264.7 macrophages.

1,2-Dilinoleoyl-sn-glycero-3-phosphocholine (DLPC), the main and active component of soybean lecithin, has been reported to exert anti-inflammatory effects, but the underlying mechanisms remain to be established. It was found that DLPC could induce the expression of the anti-inflammatory heme oxygenase-1 (HO-1) through the activation of nuclear erythroid 2-related factor 2 (Nrf2) in RAW264.7 macrophages. Pretreatment with DLPC suppressed the expression of inducible nitric oxide (NO) synthase (iNOS), one of proinflammatory enzymes, and reduced NO production in lipopolysaccharide (LPS)-stimulated macrophages. Similarly, DLPC also diminished the production of tumor necrosis factor-alpha (TNF-alpha), one of proinflammatory cytokines. Interestingly, the inhibitory effects of DLPC on LPS-induced iNOS expression and TNF-alpha production were reversed by tin protoporphyrin, a HO-1 inhibitor. Thus, HO-1 expression via Nrf2 activation may be one of the possible mechanisms explaining the anti-inflammatory effects of DLPC.