Effects of the Hydro-alcoholic Extract of Clove (Dianthus deltoides) on Inflammation and Pain Response using the Xylene Test and Hot Plate Test in Mice

Clove contains large proportion of a phenolic compound called eugenol, which has antioxidant, anti-inflammatory and analgesic properties. This study aimed to evaluate the effects of hydro-alcoholic clove extract on inflammation and pain response in mice. In this experimental study, 48 male mice were classified into six groups of control (saline), positive control (dexamethasone) and treatment (receiving 42, 85, 170 and 340 mg/kg of clove extract) to investigate the effects of clove extract on inflammation. To evaluate pain perception, 160 mice were categorized into 4 groups, divided into 5 subgroups including the control (saline), positive control (morphine), recipients of 200 mg/kg clove extract, recipients of 500 mg/kg of extract, and recipients of 200 mg/kg of combined clove extract and naloxone (4 mg/kg). To assess pain response, the hot plate test was performed on each subgroup at 5, 15, 30 and 60 minutes after the injection of the herbal extract. In addition, two hours after the injection of 0.03 ml xylene into the back of the right ears of the mice, the sections obtained from both ears (7 mm) were compared in terms of weight. In the inflammation test, the most significant difference in the ear sections was observed between the control group and recipients of 42 mg/kg of extract (36±5.1 and 33±5.3 µg, respectively), while the least significant difference was observed at doses of 180 and 340 mg/kg (21±2.1 and 17 ±1.5 µg, respectively). In the hot plate test on the treatment groups, dose of 500 mg/kg caused the highest pain delay 15 minutes before the test, while the lowest delay was observed in the recipients of combined naloxone and clove extract (200 mg/kg) 5 minutes before the test (18.91±1.53 and 8.71±1.04 seconds, respectively). According to the results of this study, hydro-alcoholic clove extract could have significant anti-inflammatory and analgesic effects on mice.