Evaluation of Analgesic Activity of Extracts of Delphinium denudatum in Animal Models: A Dose-dependent Pre-clinical Trial

Abstract

Introduction: Pain is a common symptom of majority of clinical disorders which brings patients to a physician. Many traditional medicines have been introduced for relieving the pain and one such herb, Delphinium denudatum, is claimed to have an analgesic effect. Aim: To evaluate the analgesic activity of ethanolic extract and methanol fraction of Delphinium denudatum on Wistar albino rats. Materials and Methods: This experimental study was carried out in the Department of Pharmacology, JN Medical College, Aligarh Muslim University, Aligarh, Uttar Pradesh, India. The analgesic activity was evaluated by employing the Eddy’s Hot Plate method and Tail Flick responsemethod (Orchid Scientifics, India). In both the tests, Rats of either sex weighing 150-200 g were used. The total number of animals n=36 were allocated to six groups consisting of six animals each. Group I received propylene glycol 0.3 mL/100g p.o., Group II received pentazocine 30 mg/kg i.p, Group III received ethanolic extract of Delphinium denudatum 300 mg/kg p.o., Group IV received ethanolic extract of Delphinium denudatum 600 mg/kg p.o., Group V received methanol fraction of Delphinium denudatum 200 mg/kg p.o., Group VI received methanol fraction of Delphinium denudatum 400 mg/kg p.o. The response noted in animals who were tested by hot plate method, was reaction time for licking/biting of both the paws before and after administration of control and test drugs. However, in Tail flick test, the pain threshold response was recorded before and after administration of control and test drugs. The statistical analysis was done by using one-way ANOVA. The data are expressed as Mean±SEM. p<0.05 was considered to be statistically significant. Results: A significant analgesia was produced in all the treatment groups when compared with control group in both the test models. A dose-dependent significant (p<0.001) analgesia was recorded in all the groups received ethanolic extracts and methanol fraction of Delphinium denudatum. However, a significant increase in reaction time and pain threshold in both the test models was observed in the groups who were given a higher dose of ethanolic extracts and methanol fraction of Delphinium denudatum. Interestingly, this study noted an approximately parallel degree of significant analgesia with a group who received extract of Delphinium denudatum in a dose of 600 mg/kg to a pentazocine group. Conclusion: The present study reveals the dose-dependent significant analgesic activity of the extracts of Delphinium denudatum in both the test. However, the degree of analgesia was recorded significantly higher in groups that received higher doses of extracts of Delphinium denudatum.

Keywords

• analgesia
• experimental study
• medicinal herb