Informatics-assisted proteomics revealing the anti-inflammatory effects of satsuma orange (<i>Citrus unshiu</i>) peel flavonoid extract in LPS-stimulated RAW 264.7 cells

Abstract

Citrus unshiu peel (CUP), rich in flavonoids, has been traditionally used for its health benefits. This study investigated the anti-inflammatory effects of CUP flavonoid extract (CUPFE) in lipopolysaccharide (LPS)-activated RAW 264.7 cells through proteomics analysis. CUPFE significantly reduced the inflammatory mediators and cytokines (nitric oxide, IL-6, and CCL-2) production. Quantitative proteomics analysis using LC-MS/MS identified 140 differentially expressed proteins between the CUPFE and LPS groups, with 86 proteins upregulated and 54 downregulated. Notably, CUPFE negatively regulated 56 proteins induced by LPS. Functional enrichment analysis using gene ontology and Kyoto Encyclopedia of Genes and Genomes revealed that most of these proteins are involved in signal transduction pathways (TNF-alpha, NF-kappa B, PI3K-Akt, mTOR, and MAPK) regulating inflammatory processes. Further analysis showed that CUPFE interferes these signaling pathways in a dose-dependent manner, counteracting the LPS-induced effects. Collectively, this study reveals CUPFE's anti-inflammatory effects, laying basis for future research on treating inflammation-related conditions.