The In Vivo Antinociceptive and Antiinflammatory Effects of Verbascum exuberans Hub.-Mor.

Objectives: Safe and effective drugs are still lacking for many pain therapies. In recent years, growing interest has been devoted thus on herbal drugs as an option to identify new pain killers. Based on this, extensive researches are carried out on Verbascum L. genus due to its therapeutic potency on pain and inflammation therapy. In this study, among Verbascum species, the antinociceptive effect of Verbascum exuberans Hub.-Mor., and its contributions to nitrergic, serotonergic, or opioidergic pathways as well as its antiinflammatory acitivity were investigated. Materials and Methods: Tail clip, tail flick, and hot plate tests were used to determine the central (spinal and supraspinal) antinociceptive effect, while an acetic acid-induced writhing test was used to measure the peripheral antinociceptive effect of the extract (250 and 500 mg/kg). The extract (250 mg/kg) was then combined with nω-nitro-L-arginine methyl ester, cyproheptadine, and naloxone to evaluate its involvement in nitrergic, serotonergic, or opioidergic pathways, respectively. Carrageenan-induced hind paw edema model was used to determine the antiinflammatory effect of the extract (250 mg/kg). Results: The extract shows central spinal but not central supraspinal antinociceptive effect, and presents peripheral antinociceptive effect. The antinociceptive actions of the extract is largely regulated via targeting the nitrergic pathway, while the opioidergic pathway is partly involved. Further, the extract shows antiinflammatory effect due to the significant inhibitions on the time dependent edema progression and the cytokine (tumor necrosis factor-alfa and interleukin-1beta) productions. [ABSTRACT FROM AUTHOR]