Ortho-eugenol exhibits anti-nociceptive and anti-inflammatory activities.

Ortho-eugenol is a much used phenylpropanoid whose ability to reduce pain and inflammation has never been studied. Researching ortho-eugenol's antinociceptive and anti-inflammatory activity, and its possible mechanisms of action is therefore of interest. The administration of vehicle, ortho-eugenol (50, 75 and 100mg/kg i.p.), morphine (6mg/kg, i.p.) or dexamethasone (2mg/kg, s.c.) occurred 30min before the completion of pharmacological tests. Pretreatment with ortho-eugenol did not change motor coordination test results, but reduced the number of writhes and licking times in the writhing test and glutamate test, respectively. The reaction time from thermal stimulus was significantly increased in the hot plate test after administration of ortho-eugenol. Treatment with yohimbine reversed the antinociceptive effect of ortho-eugenol, suggesting involvement of the adrenergic system. In anti-inflammatory tests, ortho-eugenol inhibited acetic acid induced vascular permeability and leukocyte migration, reducing TNF-α and IL-1ß by virtue of its suppression of NF-κB and p38 phosphorylated forms in the peritonitis test. From these results, ortho-eugenol antinociceptive effects mediated by the adrenergic system and anti-inflammatory activity through regulation of proinflammatory cytokines and phosphorylation of NF-kB and p38 become evident for the first time.

Anti-inflammatory activity and acute toxicity studies of hydroalcoholic extract of Herissantia tiubae

ABSTRACT Hydroalcoholic extract of aerial parts of Herissantia tiubae (K. Schum.) Brizicky, Malvaceae, was evaluated in experimental models of inflammation and toxicity. For toxicity assays, male and female Swiss mice were orally treated with hydroalcoholic extract of H. tiubae (2000 mg/kg) and analyzed by consumption of water and food, body weight, mortality and rates of major organ weights, as well as biochemical and hematological indexes. For anti-inflammatory effect, phlogistic agents such as carrageenan or acetic acid were used to evaluate paw edema, cell migration and cytokine production. It was also investigated the hydroalcoholic extract of H. tiubae in RAW 264.7 macrophage lineage by nitric oxide and cytokine productions. Swiss mice treated with hydroalcoholic extract of H. tiubae showed low toxicity and (50 or 100 mg/kg) was able to reduce significantly (p < 0.01, p < 0.001) polymorphonuclear cell migration, TNF-α and IL-1β production in the carrageenan-induced peritonitis. However the hydroalcoholic extract of H. tiubae (50, 100 or 200 mg/kg) did not reduce carrageenan-induced paw edema. Additionally, hydroalcoholic extract of H. tiubae did not present cytotoxicity at concentrations of 6.25, 12.5, 25 or 50 µg/ml but induced significantly decrease of NO, TNF-α and IL-6 production in macrophage lineage. This study suggests that hydroalcoholic extract of H. tiubae has anti-inflammatory activity by inhibiting cell migration mainly by decreasing the inflammatory cytokine levels at the inflamed site independently of the anti-edematogenic effect.

Nerolidol exhibits antinociceptive and anti-inflammatory activity: involvement of the GABAergic system and proinflammatory cytokines.

Nerolidol, an acyclic sesquiterpene found as a major constituent of several essential oils, has several pharmacological activities, but its action in pain processes has never been studied. The purpose of our research was to evaluate the antinociceptive and anti-inflammatory activities of nerolidol, as well as possible mechanisms of action, in experimental mouse models of pain. Antinociceptive activity was evaluated using the acetic acid-induced writhing test, the formalin test, and the hot-plate test. The nerolidol-treated group showed lesser acetic acid-induced abdominal contractions than the control group in all of the three doses tested (200, 300, and 400 mg/kg, p.o.). The formalin test doses of 300 and 400 mg/kg p.o. inhibited licking time, in both the first phase and the second phase. In the hot-plate test, nerolidol did not alter latency at any of the observed time points. Motor coordination, evaluated through the rotarod test, was not hindered in animals treated with nerolidol. Regarding the mechanism of action, the antinociceptive activity of nerolidol is related to the GABAergic system, and not to the opioidergic or ATP-sensitive K(+) channels. Treatment with nerolidol reduced carrageenan-induced paw edema. In the model of carrageenan-induced peritonitis, nerolidol decreased the influx of polymorphonuclear cells and also reduced levels of tumor necrosis factor (TNF-α) in peritoneal lavage. Nerolidol reduced production of interleukin 1 beta (IL-1ß) in LPS-stimulated, peritoneal macrophages. Thus, these results showed that nerolidol has antinociceptive activity with possible involvement of the GABAergic system, and anti-inflammatory activity, attributed to the suppression of TNF-α and IL-1ß proinflammatory cytokines.