Pain Management in Mice Using the Aqueous and Ethanol Extracts of Four Medicinal Plants

Abstract

There are many traditionally used analgesic plants in Ethiopia. They, however,have not been subject to scientific investigation for their efficacy and safety.Objective: To evaluate both prophylactic and relieving effects of aqueous and ethanolextracts of four traditionally used medicinal plants in Ethiopia.Design: An experimental design in which five group of albino mice weighing 30-35 gramsrepresenting positive and negative control, and extract treated groups respectively. Theextracts, standard drugs and normal saline were administered into GIT by gavage to evaluatethe analgesic effect.Setting: Department of Drug Research at Ethiopian Health and Nutrition Research Instituteand Department of Pharmacology at Faculty of Medicine, Addis Ababa university.Methods: Analgesic effects of water and ethanol extracts of four plants were evaluatedagainst distilled water and standard analgesics (morphine and acetylsalicylic acid) withacetic acid induced writhing tests in mice. The four plants used for this screening wereOcimum sauve, Ocimum lamiifolium, Lippia adoensis and Ajuga remota.Results: All extracts of the four plant materials were observed to possess both inhibiting andtreatment activities against acetic acid induced pain. Dose related analgesic effect was alsoobserved with all extracts of all plants with different potencies. Ethanol extracts of all the fourplant materials were more potent than their water extracts at all dose levels except O. sauve,and L. adoensis whose water extracts seem to be a bit more potent at low dose. The analgesicpotencies of both extracts of all the four plants were shown to be less than those of thestandard analgesics. Of all the extracts, the ethanol extract of O. lamiifolium was found to bethe most potent, while its water extract was the least. Acetic acid induced writhing wasrelieved with medium dose of both extracts in most cases and with low dose in few. Hundredpercent relief was achieved with both standard analgesics at a very low dose.Conclusion: The present study show that all the extracts of all the plant materials have gotboth inhibiting and relieving effects of pain