Experimental evaluation of anti-inflammatory, antinociceptive and antipyretic activities of clove oil in mice.

Clove oil of Eugenia caryophyllata (Myrtaceae) is a light yellowish fluid obtained from dried flower buds. Clove oil is used traditionally to relieve toothache. The aim of the present work was to study the anti-inflammatory, antinociceptive and antipyretic potential of clove oil in mice. Analgesic activity was examined using acetic-acid-induced abdominal constrictions and the hot plate test. Carrageenan-induced paw edema and brewer's-yeast-induced pyrexia were used to investigate the anti-inflammatory activity and the antipyretic effects, respectively. The oil was administered intraperitoneally (i.p.) at a dose of 33 mg/kg body weight and the effects were compared with reference drugs. In the antinociceptive test, mice treated with clove oil exhibited significantly decreased acetic-acid-induced writhing movements by a maximum of 87.7% (p<0.01) compared with a decrease of 77.7% (p<0.01) in response to aspirin injection (100 mg/kg, intraperitoneal, i.p.). Similarly, in the hot plate test, clove oil significantly increased the reaction latency to pain after 60 min by 82.3% (p<0.05) compared with morphine value of 91.7% (p<0.01). In addition, clove oil and indomethacin produced anti-inflammatory effects, as demonstrated by respectively 50.6% (p<0.05) and 70.4% (p<0.01) inhibition of mouse paw edema induced by carrageenan. Furthermore, clove oil significantly attenuated the hyperthermia induced by yeast at ΔT-max by 2.7°C (p<0.001), and time of peak effects was 30-180 min compared with a paracetamol value ΔT-max of 3.2°C (p<0.001). The estimated i.p. LD50 of clove oil was 161.9 mg/kg. Phytochemical screening of the oil showed the presence of eugenol. The present findings demonstrate the potential pharmacological properties of clove oil and provide further a support for its reported use in folk medicine.