Thymol is a natural monoterpene phenol primarily found in thyme, oregano, and tangerine peel. It has been shown to possess anti-inflammatory property both in vivo and in vitro. In the present paper, we studied the anti-inflammatory effect of thymol in lipopolysaccharide (LPS)-stimulated mouse mammary epithelial cells (mMECs). The mMECs were stimulated with LPS in the presence or absence of thymol (10, 20, 40 μg/mL). The concentrations of tumor necrosis factor α (TNF-α), interleukin (IL)-6, and IL-1β in the supernatants of culture were determined using enzyme-linked immunosorbent assay. Cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), extracellular signal-regulated protein kinase (ERK), c-Jun N-terminal kinase (JNK), nuclear factor-κB (NF-κB), and inhibitor protein of NF-κB (IκBα) were measured using western blot. The results showed that thymol markedly inhibited the production of TNF-α and IL-6 in LPS-stimulated mMECs. The expression of iNOS and COX-2 was also suppressed by thymol in a dose-dependent manner. Furthermore, thymol blocked the phosphorylation of IκBα, NF-κB p65, ERK, JNK, and p38 mitogen-activated protein kinases (MAPKs) in LPS-stimulated mMECs. These results indicate that thymol exerted anti-inflammatory property in LPS-stimulated mMECs by interfering the activation of NF-κB and MAPK signaling pathways. Thereby, thymol may be a potential therapeutic agent against mastitis.

Alpinetin, a composition of Alpinia katsumadai Hayata, has been reported to have a number of biological properties, such as antibacterial, antitumor and other important therapeutic activities. However, the effect of alpinetin on inflammatory bowel disease (IBD) has not yet been reported. The purpose of this study was to investigate the anti-inflammatory effect and mechanism of alpinetin on dextran sulfate sodium (DSS)-induced colitis in mice. In vivo, DSS-induced mice colitis model was established by giving mice drinking water containing 5% (w/v) DSS for 7 days. Alpinetin (25, 50 and 100 mg/kg) were administered once a day by intraperitoneal injection 3 days before DSS treatment. In vitro, phorbol myristate acetate (PMA)-differentiated monocytic THP-1 macrophages were treated with alpinetin and stimulated by lipopolysaccharide (LPS). The results showed that alpinetin significantly attenuated diarrhea, colonic shortening, histological injury, myeloperoxidase (MPO) activity and the expressions of tumor necrosis factor (TNF-α) and interleukin (IL-1β) production in mice. In vitro, alpinetin markedly inhibited LPS-induced TNF-α and IL-1β production, as well as Toll-like receptor 4 (TLR4) mediated nuclear transcription factor-kappaB (NF-κB) and NOD-like receptor protein 3 (NLRP3) inflammasome activation. In conclusion, this study demonstrated that alpinetin had protective effects on DSS-induced colitis and may be a promising therapeutic reagent for colitis treatment.

Short-chain fatty acids are fermentation end products produced by gut bacteria, which have been shown to ameliorate inflammatory bowel diseases and allergic asthma. However, the mechanism involved remains largely unknown. Here, we investigate the protective effects and mechanisms of sodium butyrate (SB) on LPS-induced mastitis model. EXPERIMENTAL APPROACHEffects of increasing doses of SB on blood-milk barrier function and inflammation are studied in BALB/c mice with LPS-induced mastitis. The underlying mechanisms of anti-inflammatory effects of SB were further investigated in LPS-stimulated mouse mammary epithelial cells (mMECs). KEY RESULTSThe results show that SB decreased LPS-induced disruption in mammary tissues, infiltration of inflammatory cells and the levels of TNF-α, IL-6 and IL-1β. SB up-regulated the tight junction proteins occludin and claudin-3 and reduced blood-milk barrier permeability in LPS-induced mastitis. Studies in vitro revealed that SB inhibited LPS-induced inflammatory response by inhibition of the NF-κB signalling pathway and histone deacetylases in LPS-stimulated mMECs. CONCLUSIONS AND IMPLICATIONSIn our model, SB protected against LPS-induced mastitis by preserving blood-milk barrier function and depressing proinflammatory responses, suggesting the potential use of SB as a prophylactic agent to protect blood-milk barrier function in mastitis.

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