Anti-inflammatory effect of malus domestica cv. Green ball apple peel extract on raw 264.7 macrophages

We examined the anti-inflammatory effect of the peel extract of the newly bred Korean apple (Malus domestica Borkh.) cultivar Green ball. To test its possible use as anti-inflammatory functional material, Raw 264.7 macrophages were treated with pro-inflammatory lipopolysaccharide (LPS) in the presence or absence of Green ball apple peel ethanol extract (GBE). Notably, up to 500 µg/mL of GBE did not result in any signs of inhibition on cellular metabolic activity or cytotoxicity in Raw 264.7 macrophages. Supplementation with GBE to LPS-treated Raw 264.7 macrophage significantly suppressed various pro-inflammatory responses in a dose-dependent manner, including i) nitric oxide (NO) production, ii) accumulation of inducible NO synthase and cyclooxygenase-2, iii) phosphorylation of nuclear factor-kappa B (NF-κB) subunit p65, and iv) expression of pro-inflammatory biomarker genes, including tumor necrosis factor alpha, interleukin 1 beta, interleukin 6, monocyte chemoattractant protein-1, and prostaglandin E synthase 2.