Camellia japonica L. Seed Cake Protects Inflammatory Response in Lipopolysaccharide-Induced Macrophages and Mice

Abstract

Camellia japonica L. seed oil has been widely studied and utilized for its skincare, antioxidant, and anti-inflammatory effects. However, the anti-inflammatory activity of the seed cake-a by-product obtained after oil extraction from C. japonica L. seeds-has not yet been investigated. This study explored the anti-inflammatory properties and underlying mechanisms of the butanol fraction derived from defatted C. japonica L. seed cake (BFCJ). To induce inflammation, RAW 264.7 macrophages were treated and mice were injected with lipopolysaccharide (LPS). The effects of BFCJ on inflammation were measured using nitric oxide (NO) production, ELISA, histopathological analysis, western blotting, serum biochemical analysis, and PCR. Ultraperformance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC-QTOF MS/MS) was used to characterize the constituents of BFCJ. BFCJ treatment at 5-50 mu g/mL dose-dependently decreased NO production and inflammatory cytokine levels including tumor necrosis factor-alpha, interleukin (IL)-6, and IL-1 beta in RAW 264.7 cells induced by LPS. BFCJ also downregulated the levels of nuclear factor kappa B (NF-kappa B) pathway-related proteins, such as phosphorylated NF-kappa B, inducible nitric oxide synthase, and cyclooxygenase-2. Furthermore, administration of 50 mg/kg/day BFCJ for 14 days attenuated hepatotoxicity, as observed in the histopathological analysis. Compared to LPS treatment in mice, BFCJ significantly lowered inflammatory cytokine and protein levels during NF-kappa B signaling. Furthermore, UPLC-QTOF MS/MS analysis identified four flavonoids, including kaempferol glycosides, in BFCJ. This study suggests that BFCJ, which contains flavonoids, is a potential anti-inflammatory agent. Identifying and characterizing the functional properties of this seed cake will provide a scientific basis for its development and application as a functional ingredient in food and pharmaceutical products.