Anethole has been reported to have antioxidant, antibacterial, antifungal, antiinflammatory, and anesthetic properties. In the present study, we evaluated the effects of anethole in two pain models of inflammatory origin: acute inflammation induced by carrageenan and persistent inflammation induced by Complete Freund's adjuvant. We evaluated the effects of anethole (125, 250, and 500 mg/kg) on the development of paw oedema and mechanical hypernociception. The liver was collected for histological analysis. Paw skin was collected to determine the levels of the cytokines tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-17 (IL-17), and myeloperoxidase activity. Blood was collected to assess alanine transaminase (ALT) and aspartate transaminase (AST). The chemical composition of star anise oil was determined by gas chromatography/mass spectrometry (GC/MS), showing a presence of anethole of 98.1%. Oral pretreatment with anethole in mice inhibited paw oedema, mechanical pernociception, myelopewroxidase activity, TNF-α, IL-1β and IL-17 levels in acute and persistent inflammation models. Additionally, anethole treatment did not alter prostaglandin E2-induced mechanical hypernociception. Possible side effects were also examined. Seven-day anethole treatment did not alter plasma AST and ALT levels, and the histological profile of liver tissue was normal. The present study provides evidence of the antiinflammatory and analgesic activities of anethole in acute and persistent inflammation models.

This study was designed to test the efficacy of eugenol, a compound obtained from the essential oil of cloves (Syzygium aromaticum) in collagen-induced arthritis (CIA), a well characterized murine model of rheumatoid arthritis. Macroscopic clinical evidence of CIA manifests first as periarticular erythema and edema in the hind paws. Treatment with eugenol starting at the onset of arthritis (day 25) ameliorated these clinical signs of CIA. Furthermore, eugenol inhibited mononuclear cell infiltration into the knee joints of arthritic mice and also lowered the levels of cytokines (tumor necrosis factor (TNF)-α, interferon (IFN)-γ and tumor growth factor (TGF)-β) within the ankle joints. Eugenol treatment did not affect the in vitro cell viability as assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Therefore, eugenol ameliorates experimental arthritis and could be useful as a beneficial supplement in treating human arthritis.Key words eugenol; collagen-induced arthritis; inflammation; cytokine; mononuclear cell Eugenol (4-allyl-2-methoxyphenol) is the major component in the essential oil of many aromatic plants, including clove (Zyzygium aromaticum) and it is known to possess antioxidant, analgesic and neuroprotective properties among others.1,2) In addition, eugenol and related compounds exhibit anti-inflammatory activities, e.g. inhibition of lipopolysaccharide (LPS)-stimulated nuclear factor-kappa B (NF-κB) activation, cytokine release and cyclooxygenase-2 (COX-2) expression by macrophages in vitro 3) and inhibition of 5-lipoxygenase activity in polymorphonuclear cells. 4) However, despite the anti-inflammatory effects of eugenol described previously, there is only one report of it exhibiting antirheumatic effects in a model of adjuvant arthritis. 5)This new therapeutic strategy involving natural products has been devised because the anti-inflammatory and immunosuppressive drugs currently available cause many side effects and show limited efficacy in the treatment of rheumatoid arthritis.Collagen-induced arthritis (CIA) is used as an experimental model that resembles human rheumatoid arthritis. Both T cell and B cell responses to the autoantigen as well as the production of cytokines by systemic and tissue-specific cell populations are critical for the development (and eventual diminution) of the autoimmune response to CII and to the pathology in CIA.6) Due to the paucity of information on the effect of eugenol on experimental models of arthritis, this study was undertaken to investigate the efficacy of eugenol on CIA model.

In this study, simvastatin, atorvastatin, ezetimibe, and ezetimibe + simvastatin combination were administered to arthritic rats, first to determine their effects on the inflammatory response, employing a low-dose adjuvant-induced arthritis model in rats. Arthritis was induced by the subcutaneous injection of a suspension of Mycobacterium tuberculosis (100 μg) in mineral oil [complete Freund's adjuvant used (CFA)] into the plantar surface of the hind paws. Simvastatin(40 mg/kg), atorvastatin(10 mg/kg), ezetimibe(10 mg/kg), ezetimibe(10 mg/kg) + simvastatin(20 mg/kg or 40 mg/kg) were given intragastrically and the treatment began on the day of CFA injection and continued daily up to the 28th day after arthritis induction. The ezetimibe + simvastatin combination was more effective in reducing the inflammatory response in arthritic rats than in atorvastatin, simvastatin, or ezetimibe monotherapy. The observed effect seems to be cholesterol-independent as there were no changes in plasma cholesterol levels. In spite of the benefits on joint lesions, treatment with ezetimibe + simvastatin combination caused a marked increment in liver, kidneys, spleen size, and plasma transaminases activities. Therefore, animals treated with the ezetimibe(10 mg/kg) + simvastatin(40 mg/kg) combination were also submitted to liver perfusion experiments. In this regard, ezetimibe + simvastatin did not improve the liver metabolic alterations seen in control arthritic rats, on the contrary, a worsening was observed in liver production of glucose from alanine, as well as in oxygen uptake. All of these metabolic changes appear to be induced by treatment with ezetimibe + simvastatin combination, as the same metabolic effects were observed in normal and treated arthritic animals.

Statins are hypocholesterolemic drugs that are prescribed for patients with an increased risk of cardiovascular and cerebrovascular complications. Ezetimibe has an atheroprotective activity through inhibition of the expression of vascular adhesion molecule-I and vascular CD14, a marker of the infiltration of mononuclear leukocytes. Ezetimibe reduces the amount of chemoattractant protein-1 that is available for monocytes and macrophages and alters the activity of nuclear factor κB in leukocytes. The mechanisms of action of statins complement those of ezetimibe. Previous studies have demonstrated that the combination of statins and ezetimibe has beneficial effects, including antiinflammatory activity. The present study evaluated the effects of monotherapy with ezetimibe and simvastatin compared with ezetimibe + simvastatin combined on the evolution of the inflammatory response in a rat model of Complete Freund's Adjuvant-induced arthritis. The animals were treated with 10 mg/kg ezetimibe, 40 mg/kg simvastatin, or 10 mg/kg ezetimibe + 40 mg/kg simvastatin for 1, 7, 14, or 28 days. We analyzed leukocyte rolling behavior, leukocyte adhesion to the endothelium, the number of leukocytes that were recruited to the knee joint cavity, and the concentration of cytokines that are involved in the inflammatory response. The data were analyzed using paired t tests or analysis of variance followed by Bonferroni post hoc test. The treatments reduced leukocyte rolling behavior and leukocyte adhesion. The monotherapies did not change the number of leukocytes that were recruited to the knee joint cavity, whereas the ezetimibe + simvastatin combination significantly reduced this parameter. The treatments reduced the levels of proinflammatory cytokines and increased the levels of the antiinflammatory cytokine IL-10, indicating antiinflammatory properties of these drugs in this experimental model of inflammation.

The objective of the present study was to investigate the effects of monotherapy with simvastatin or ezetimibe compared with those of an ezetimibe + simvastatin combination on the histopathologic aspects of arthritis induced by Complete Freund's Adjuvant in rats. The characteristics of diarthrosis were analyzed 7 and 28 days after arthritis induction with regard to the regularity and integrity of articular cartilage, the presence of leukocytes in blood vessels at the inflammation site, and the cytokine levels in articular tissue. Monotherapy with simvastatin or ezetimibe and the ezetimibe + simvastatin combination effectively reduced the cytokine levels (interleukin-6 and tumor necrosis factor) and articular lesions that are characteristic of this experimental disease. Although the results did not reveal significant differences between the monotherapy and the combined therapy, they suggest that these drugs have considerable antiinflammatory properties, as reflected by an attenuation of articular cartilage lesions mediated by a reduction in the levels of proinflammatory cytokines.