Thymol Inhibits LPS-Stimulated Inflammatory Response via Down-Regulation of NF-κB and MAPK Signaling Pathways in Mouse Mammary Epithelial Cells

Abstract

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.

Modulatory effects of thymol and carvacrol on inflammatory transcription factors in lipopolysaccharide-treated macrophages

“…Both thymol and carvacrol significantly decreased STAT-3 and SAPK/JNK phosphorylation in the stimulated macrophage cells (total cell extract); this suggested to us the probable ability of these agents to diminish STAT-3-and JNKmediated activity of cytokines associated with inflammatory responses (Kortylewski et al, 2009). It should be mentioned that, in a previous study on total cell extract of LPS-stimulated mouse mammary epithelial cells, thymol decreased the levels of phosphorylation of NF-jB p65, IjBa, JNK, ERK and p38 MAPK after 1 h (Liang et al, 2014). In the current study, according to results of the ELISA assays, carvacrol and thymol also inhibited phosphorylation of IjBa, JNK and STAT-3.…”

“…NF-jB is one of the most ubiquitous important transcription factors that regulate gene expression, including that of iNOS, COX-2, cytokines TNFa and IL-1b, as well as chemokines and adhesion molecules involved in regulation of inflammatory responses (Chen et al, 1999;Liang et al, 2014). We hypothesized that thymol and carvacrol could inactivate this transcription factor.…”

“…In in vivo studies, they have significantly inhibited inflammatory edema and leukocyte migration (Fachini-Queiroz et al, 2012). There are also a number of reports of thymol or carvacrol regarding their effects on key mediators of inflammation such as cyclooxygenase (COX)-2 (Landa et al, 2009), inducible nitric oxide synthase (iNOS), as well as inflammatory cytokines like TNFa and IL-1b (Liang et al, 2014). Despite this information, various aspects of the molecular mechanisms of action of thymol and carvacrol remain unclear.…”

Kazakh Ziziphora Species as Sources of Bioactive Substances

“…Z. tenuior [94] Anti-genotoxic (bleomycin-induced DNA damage) [287] Z. tenuior [94] Anti-genotoxic (bleomycin-induced DNA damage) [287] Anti-inflammatory activity in carrageenan-induced paw edema, MPO activity and peritonitis in rats [288]; anti-inflammatory activity in LPS-stimulated mouse mammary epithelial cells via inhibition of the NF-κB and MAPKs signalling pathways [289]; antiinflammatory effect in ovoalbumin-induced mouse asthma, possibly through inhibiting NF-κB activation [290]; inhibition of S. aureus internalization into bovine mammary epithelial cells by inhibiting NF-κB activation [291] Review on anti-inflammatory, antioxidant, and immunological effects [292] Protective effect on radiation-induced apoptosis in Chinese hamster lung fibroblast V79 cells [293]; DNA-protective effects against H2O2-induced DNA lesions in human hepatoma HepG2 cells [294]; hepatoprotective effect against t-BHP-induced oxidative damage in Chang liver cells [84]; protective effect against cisplatin-induced nephrotoxicity in rats [295]; protective effect against UVA-and UVB-induced lipid peroxidation in NCTC 2544 cell line Z. clinopodioides subsp. rigida (8%) [21] Z. tenuior [94] Anti-genotoxic (bleomycin-induced DNA damage) [287] Anti-inflammatory activity in carrageenan-induced paw edema, MPO activity and peritonitis in rats [288]; anti-inflammatory activity in LPS-stimulated mouse mammary epithelial cells via inhibition of the NF-κB and MAPKs signalling pathways [289]; anti-inflammatory effect in ovoalbumin-induced mouse asthma, possibly through inhibiting NF-κB activation [290]; inhibition of S. aureus internalization into bovine mammary epithelial cells by inhibiting NF-κB activation [291] Review on anti-inflammatory, antioxidant, and immunological effects [292] Protective effect on radiation-induced apoptosis in Chinese hamster lung fibroblast V79 cells [293]; DNA-protective effects against H 2 O 2 -induced DNA lesions in human hepatoma HepG2 cells [294]; hepatoprotective effect against t-BHP-induced oxidative damage in Chang liver cells [84]; protective effect against cisplatin-induced nephrotoxicity in rats [295]; protective effect against UVA-and UVB-induced lipid peroxidation in NCTC 2544 cell line...…”

Modulation of Cytokine Production and Transcription Factors Activities in Human Jurkat T Cells by Thymol and Carvacrol

“…It was shown that thymol could decrease phosphorylation of several signaling molecules such as NF-κB p65, IκBα, c-Jun NH(2)-terminal protein kinases (JNK), extracellular signal-regulated kinases (ERK) and p38 mitogenactivated protein kinases (MAPK) in these cells. 21 Considering the central role of T cells in inflammatory processes, in the present study we aimed to investigate the effects of these components on T cells in order to derive a better understanding of the mechanisms underlying their anti-inflammatory effects. In addition, as altered T cell function is often a key component associated with numerous pathologies, discerning how they may affect T cells can help scientists build upon our findings and take better advantage of these natural products.…”