Anethole and eugenol reduce in vitro and in vivo leukocyte migration induced by fMLP, LTB4, and carrageenan.

The aim of this study was to investigate the effect of anethole (AN) and eugenol (EUG) on leukocyte migration using in vitro chemotaxis and in situ microcirculation assays. BALB/c mice were used for the in vitro chemotaxis assay, and Wistar rats for the in situ microcirculation assay. We evaluated (a) the in vitro leukocyte migration in response to chemotactic factors (formyl-methionyl-leucyl-phenylalanine [fMLP] and leukotriene B4 [LTB4]) and (b) the rolling, adhesion, and migration of leukocytes induced by an injection of carrageenan (100 µg/cavity) into the scrotum of the animal. In the in vitro chemotaxis assay, AN and EUG at doses of 1, 3, 9, and 27 µg/ml significantly inhibited leukocyte migration when stimulated by the chemotactic agents fMLP and LTB4. In the in situ microcirculation assay, AN at doses of 125 and 250 mg/kg and EUG at a dose of 250 mg/kg significantly decreased the number of leukocytes that rolled, adhered, and migrated to perivascular tissue. The results indicate that AN and EUG exert inhibitory effects on leukocyte migration, highlighting their possible use to diminish excessive leukocyte migration in the inflammatory process.

Evaluation of Anti-Inflammatory Activity of Citrus latifolia Tanaka Essential Oil and Limonene in Experimental Mouse Models.

The genus Citrus (Rutaceae) includes several species of plants that produce some of the most cultivated fruits in the world, providing an appreciable content of essential oil. In folk medicine, they are used as a cholagogue, antipyretic, anti-inflammatory, sedative, and antitoxic effects. Lemon essential oil has been used since ancient times for its antiseptic, carminative, diuretic, and eupeptic effects. In this study, we investigated the anti-inflammatory activity of Citrus latifolia Tanaka essential oil (CLEO) and its main constituent LIM. In the cell viability assay, CLEO and LIM (3, 10, 30, and 90 µ g/mL) had low cytotoxicity. In zymosan-induced peritonitis, LIM (500 mg/kg) decreased the infiltration of peritoneal exudate leukocytes and decreased the number of polymorphonuclear leukocytes. In vitro chemotaxis revealed that CLEO and LIM (1, 3, and 10 µg/mL) promoted a significant reduction of neutrophil migration toward fMLP and LTB4. LIM (500 mg/kg) also reduced TNF- α levels but did not alter IL-10 levels in the peritoneal exudate. In conclusion, this study showed that LIM isolated from CLEO had potential anti-inflammatory effects, likely by inhibiting proinflammatory mediators present in inflammatory exudate and leukocyte chemotaxis.

Effects of Thymol and Carvacrol, Constituents of Thymus vulgaris L. Essential Oil, on the Inflammatory Response.

Thyme (Thymus vulgaris L., Lamiaceae) is an aromatic and medicinal plant that has been used in folk medicine, phytopharmaceutical preparations, food preservatives, and as an aromatic ingredient. The effect of Thymus vulgaris essential oil (TEO) and its isolated constituents thymol and cavacrol (CVL) were studied in the following experimental models: ear edema, carrageenan-induced pleurisy, and chemotaxis in vitro. In the pleurisy model, TEO, CVL, and thymol significantly inhibited inflammatory edema. However, only TEO and CVL inhibited leukocyte migration. In the in vitro chemotaxis experiment, CVL inhibited leukocyte migration, whereas thymol exerted a potent chemoattractant effect. In the ear edema model, CVL (10 mg/ear), applied topically, reduced edema formation, exerting a topical anti-inflammatory effect. Thymol did not reduce edema formation but rather presented an irritative response, probably dependent on histamine and prostanoid release. Our data suggest that the antiinflammatory effects of TEO and CVL are attributable to the inhibition of inflammatory edema and leukocyte migration.