Natural pigment zeaxanthin ameliorates lipopolysaccharides induced acute lung inflammation in both in vitro and in vivo models

Abstract

Natural pigments obtained from plants, animals, and microbes are not only a potent alternative to synthetic dyes in the food, textile, and cosmetic industries, but they also possess immense pharmacological properties. Carmine acids, carotenoids, flavonoids, indigo, anthocyanin, melanins, and curcumin are such natural pigments that have proven pharmacological properties. Zeaxanthin is one such natural water-soluble antioxidant pigment that belongs to the xanthophyll family and is predominantly accumulated in the retina of the eyes. The potency of zeaxanthin against LPS-induced inflammation in in vitro and in vivo conditions was examined. RAW264.7 cells were treated with zeaxanthin and challenged with LPS. The LPS-induced zeaxanthin-treated cells were subjected to assessments of cytotoxicity and inflammatory markers. For the in vivo study, BALB/c male mice were induced to have acute lung inflammation by LPS. The ALI-induced mice were treated with 25 and 50 mg/kg concentrations of zeaxanthin. BALF was collected from zeaxanthin-treated ALI-induced mice and was sacrificed for the excision of lung tissue. Pulmonary edema was examined in the lung tissues. Immune cell infiltration and protein content were examined in the BALF collected. Oxidative stress induction was analyzed in the lung tissue of ALI-induced mice. The inflammatory markers iNOS, COX-2, and PGE-2 were quantified in the lung tissues of zeaxanthin-treated ALI-induced mice. Zeaxanthin effectively prevented lung edema and immune cell infiltration. Oxidative stress and inflammatory cytokine synthesis induced by LPS in the lungs were significantly decreased with zeaxanthin treatment. Histopathological analysis also confirms our in vitro and in vivo biochemical analyses. Overall, our findings corroborate that zeaxanthin is a potent anti-inflammatory agent that effectively inhibits LPS-induced ALI in both in vitro and in vivo conditions.