The effect of the essential oil of Eugenia caryophyllata in animal models of depression and locomotor activity

Abstract

Objective

The essential oil of Eugenia caryophyllata (clove oil; Family: Myrtaceae) is used in dental care as an antiseptic and analgesic. The present study investigates the effect of clove oil on animal models of depression and locomotion.

Methods

Clove oil was administered in doses of 0.025, 0.05, and 0.1 ml/kg/day, intraperitoneally (i.p.) for 3 weeks. The forced swim test (FST) and the tail suspension test (TST) were used to assess depression. To evaluate locomotor activity, the rota rod test and the photoactometer procedure were performed.

Results

In the FST, it was observed that the duration of immobility was significantly decreased (P < 0.01) in animals treated with clove oil (0.05 and 0.1 ml/kg); however, the clove oil dose of 0.025 ml/kg showed an insignificant increase in the immobile period. The TST demonstrated that pretreatment with clove oil decreases (P < 0.01) the immobile period significantly at all the three administered doses. Similarly, the photoactometer procedure showed increased locomotor activity at all the three doses, although significant (P < 0.05) only at 0.1 ml/kg. In addition, the rota rod test showed that animals treated with clove oil (0.1 ml/kg) enhanced muscle coordination as demonstrated by a significant increase (P < 0.05) in the latency to fall from the rota rod as compared to the control. However, the lowest administered dose (0.025 ml/kg, i.p.) decreased the latency to fall from the rota rod significantly (P < 0.05) compared to the control. Clove oil (0.05 ml/kg) also showed a decrease in the latency to fall from the rota rod although the result was not statistically significant.

Discussion

Thus, it can be concluded that pretreatment with clove oil decreases depression and enhances locomotor activity similar to that exhibited by psychostimulants.

Keywords:

• Clove oil
• Forced swim test
• Tail suspension test
• Rota rod
• Photoactometer

Acknowledgement

We would like to thank Dr Prem Suman for her invaluable guidance on the project.