The Effect of Carvacrol on Inflammatory Pain and Motor Coordination in Rats

Carvacrol is a monoterpenic phenol and an active ingredient of the plant essential oils of the family Lamiaceae. We have investigated the analgesic effect of carvacrol, the possible dependence of the effect in relation to animal sex, and the impact of carvacrol on motor coordination in rats. Hyperalgesia was induced by formalin (1.5%), which was administered SC in the upper lip of rat. Hyperalgesia and effects of carvacrol and indomethacin were measured by using the orofacial formalin test. The influence on motor coordination in animals treated with carvacrol was investigated by using the rota-rod test. Carvacrol administered PO in pre-treatment (45 min. prior to formalin) at a single dose of 50, 75 and 100 mg /kg BW, in the male, 50 and 100 mg /kg BW, in female rats caused a dose-dependent antinociceptive effect. This effect of carvacrol was significantly higher (P<0.01, P<0.001) in male rats. Compared with indomethacin administered during pre-treatment (2 mg/kg, PO), carvacrol (100 mg/kg) exhibits significantly higher (P <0.05 and P <0.001) antinociceptive effect on formalininduced hyperalgesia in male rats. In the rota-rod test carvacrol did not disturb the motor coordination in male rats, nor the dose of carvacrol with clear antinociceptive properties exhibited depressive effect on the CNS of treated rats. Keeping in mind that the monoterpene carvacrol is of plant origin, with potentially less side effects and without residues, it is realistic to expect the possibility of its therapeutic use in the treatment of inflammatory pain in animals.