α-Terpineol reduces nociceptive behavior in mice.

α-Terpineol (TPN) is a monoterpenoid alcohol present in the essential oils of several species of the Eucalyptus genus (Myrtaceae). TPN was assessed for its antinociceptive activity in rodents. The antinociceptive effect of TPN was examined using the acetic acid writhing reflex, formalin, glutamate, and capsaicin-induced nociception tests. TPN produced a significant (P < 0.01 or P < 0.001) analgesic effect by reduction at the early and late phases of paw licking and reduced the writhing reflex in mice (formalin and writhing tests, respectively). In the glutamate test, all doses of TPN produced significant (P < 0.01) nociceptive protection. When the capsaicin-induced nociception test was conducted, TPN produced dose-related inhibition of the nociceptive behavior. In addition, the results of a hot plate test showed central analgesic properties for TPN (P < 0.01 or P < 0.001). Such results were unlikely to be provoked by motor abnormality. Our results suggest that TPN might represent an important tool for management and/or treatment of painful conditions.