Antipruritic and antinociceptive effects of Chenopodium album L in mice.

The ethanolic extract from the fruits of Chenopodium album L. (FCAL), orally administered at doses of 100-400 mg/kg, dose-dependently inhibited scratching behavior induced by 5-HT (10 micro g per mouse, s.c.) or compound 48/80 (50 micro g per mouse, s.c.) in mice. But it failed to affect hind paw swelling induced by 5-HT or compound 48/80 in mice at doses of 100 and 200 mg/kg and only showed a relatively weak inhibition on the swelling at a higher dose of 400 mg/kg. In addition, FCAL (200 and 400 mg/kg) significantly attenuated the writhing responses induced by an intraperitoneal injection of acetic acid and the inflammatory pain response induced by an intraplantar injection of formalin in mice. At a dose of 400 mg/kg, it also inhibited the neurogenic pain response of formalin test. In conclusion, FCAL possesses antipruritic and antinociceptive activities and the antinociceptive effects are not secondary to anti-inflammatory effects. The findings support evidence for the clinical use of FCAL to treat cutaneous pruritus.