Analgesic Effects of Alpha-Pinene on Pain Models of Writing and Plantar Tests in Rats

Pain is an unpleasant sensation. Studying natural pain reliever compounds can be beneficial. The aim of the present study was to evaluate the analgesic effects of Alpha Pinene in writing and plantar pain tests in rats.

In the present experimental study conducted in 2019, 30 male Wistar rats (270±30 gr) were used as case subjects. The mice were randomly divided into 5 groups; the first group: normal saline administered intraperitoneally (IP), the second group: diclofenac sodium administered IP at a dose of 5 mg/kg, the third group: alpha pinene administered IP at a dose of 0.1 mg/kg. The fourth group: alpha pinene administered IP with a dose of 5 mg/kg, and the fifth group: alpha pinene administered IP with a dose of 10 mg/kg. Afterwards, the writing tests and plantar test (five groups for each test) were conducted. The collected data were analyzed using the SPSS version 16 statistical tests.

The results indicated that in the writing test, the number of abdominal twists in the groups which received alpha pinene were significantly lower than the control group (P<0.05). Moreover, in the writing test, diclofenac sodium 5 mg decreased pain intensity compared to the control group (P<0.05). In the plantar test, the pain intensity in the groups that received alpha pinene 5 mg/kg and diclofenac sodium 5 mg was significantly lower than the control group (P<0.05).

Alpha-pinene in doses of 5 and 10 mg/kg of body weight could decrease the severity in the visceral pain model of writing test like diclofenac sodium with a dose of 5 mg. Furthermore, during 30 and 60 minutes in the plantar test, alpha pinene with a dose of 5 mg/kg was able to reduce the pain caused by heat compared to the control group, like diclofenac sodium with a dose of 5 mg.