Abstract
Astaxanthin, a keto-carotenoid, is known to have potent antioxidant properties. This study aims to investigate the anti-inflammatory effect of astaxanthin and its mechanism in human neutrophils. The effects of astaxanthin on lipopolysaccharide (LPS)-stimulated human neutrophils were investigated in vitro. Neutrophils were isolated from healthy volunteers and stimulated with LPS in the presence and absence of astaxanthin. We assessed cytokine production, signaling pathway activation via mitogen-activated protein kinases (MAPKs) and nuclear factor kappa B (NF-κB), and apoptosis. Astaxanthin's impact was evaluated at different concentrations, and both pretreatment and cotreatment protocols were tested. The results demonstrated that astaxanthin significantly reduced the production of pro-inflammatory cytokines TNF-α and IL-1β in LPS-stimulated neutrophils. It effectively inhibited the phosphorylation of ERK1/2 MAPK, without notably affecting p38 MAPK or NF-κB pathways. Furthermore, astaxanthin promoted apoptosis in neutrophils, counteracting the apoptosis-delaying effects of LPS. These effects were more pronounced with pretreatment. In conclusion, astaxanthin has protective effects on inflammatory responses in neutrophils by reducing cytokine production and enhancing apoptosis while selectively modulating intracellular signaling pathways. Astaxanthin demonstrates significant potential as a therapeutic agent in the management of severe inflammatory conditions.