Abstract
Context: Citrus unshiu Markovich (Rutaceae) peel is known to contain high concentrations of flavonoids and exerts pharmacological effects on antioxidant, anti-inflammation, allergies, diabetes and viral infections.Objective: Very little is known about potential activity of fermented dried Citrus unshiu peel extracts (FCU) using Bacillus subtilis, as well as its mechanism of action. We investigated the effects of FCU on the anti-inflammatory activities in murine macrophages and moisturizing effects in human keratinocytes.Materials and methods: We isolated the Bacillus subtilis from Cheonggukjang and FCU using these Bacillus subtilis to prepare samples. The cells were pre-treated with various extracts for 2 h and then induced with LPS for 22 h. We determined the NO assay, TNF-α, IL-6 and PGE2 in RAW 264.7 ells. The expression of SPT and Filaggrin by FCU treatment was measured in HaCaT cells.Result: We found that two types of FCU highly suppressed LPS-induced nitric oxide (NO) without exerting cytotoxic effects on RAW 264.7 cells (21.9 and 15.4% reduction). FCU inhibited the expression of LPS-induced iNOS and COX-2 proteins and their mRNAs in a concentration-dependent manner. TNF-α (59 and 30.9% reduction), IL-6 (39.1 and 65.6% reduction), and PGE2 secretion (78.6 and 82.5% reduction) were suppressed by FCU in LPS-stimulated macrophages. Furthermore, FCU can induce the production of hyaluronic acid (38 and 38.9% induction) and expression of Filaggrin and SPT in HaCaT keratinocyte cells.Discussion and conclusion: FCU potentially inhibits inflammation, improves skin moisturizing efficacy, and it may be a therapeutic candidate for the treatment of inflammation and dry skin.
Highlights
Inflammation is a complex process mediated by the activation of various immune cells
We investigated for the first time the anti-inflammatory effects of fermented dried Citrus unshiu peel extracts (FCU) in RAW 246.7 macrophages
We found that WE, WE(1-4), AL, and AL(1-4) had no effect on the cytotoxicity except for WE(2-1) and AL(21) at a concentration of 10 or 100 lg/mL (Figure 1(A))
Summary
Inflammation is a complex process mediated by the activation of various immune cells. Macrophages play an important role in various inflammatory responses by upregulating the expression of pro-inflammatory cytokines and enzymes such as tumour necrosis factor-a (TNF-a), interleukin, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) (Larsen and Henson 1983; Lawrence et al 2002; Sica et al 2008). An inducible isoform of NOS (iNOS) is only expressed after exposure to pro-inflammatory conditions. INOS is widely expressed in various cells, including vascular smooth muscle cells, hepatocytes and Kupffer cells and is highly expresses in LPS-activated macrophages (Rockey et al 1998). COX-2 is pre-eminently expressed in inflammatory cells stimulated by LPS, pro-inflammatory cytokines and tumour promoters (Meric et al 2006)
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