In vivo evaluation of analgesic, anti-inflammatory, and neuropharmacological activities of the chemical constituent from Nepeta clarkei

The plant species of genus Nepeta are used to treat various human diseases and for ornamental purposes as well. Nepethalate B (1) was isolated as a result of phytochemical investigations of Nepeta clarkei and was subjected in the present study for investigation of analgesic, anti-inflammatory, and central nervous system (CNS) depressant activities. The percentage inhibition in phase I of the acetic acid induced writhing test of compound 1 (dose of 0.1, 0.2 and 0.4 mg/kg of body weight) was 53.3, 58.0 and 86.7 % respectively. These results were found significantly higher (P < 0.01) as compared to the negative control. Moreover, the percentage inhibitions of three phases for 0.1, 0.2 and 0.4 mg/kg were higher than the values obtained for Aspirin (positive control). In formalin test, the percentage pain inhibition between 0 and 5 min (early phase) was 68.0, 25.5, and 75.5 % for 0.1, 0.2 and 0.4 mg/kg intra-peritoneal doses of compound 1 respectively. In case of late phase (20-30 min) it was 63.0, 66.7 and 48.1 %, respectively. In comparison to aspirin, overall percentage inhibition of compound 1 was significantly higher in early and late phases. Interestingly, at all doses compound 1 showed more potent anti-inflammatory effects in terms of intensity and duration as compared to aspirin. The gross behavioral study of nepethalate B (1) was also carried out and the results revealed that it exhibited CNS depression in the mice and showed a prominent decrease in locomotor activity.