Pain management in mice using the aqueous and ethanol extracts of four medicinal plants.

BACKGROUND 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 ethanol extracts of four traditionally used medicinal plants in Ethiopia. DESIGN An experimental design in which five group of albino mice weighing 30-35 grams representing positive and negative control, and extract treated groups respectively. The extracts, standard drugs and normal saline were administered into GIT by gavage to evaluate the analgesic effect. SETTING Department of Drug Research at Ethiopian Health and Nutrition Research Institute and Department of Pharmacology at Faculty of Medicine, Addis Ababa university. METHODS Analgesic effects of water and ethanol extracts of four plants were evaluated against distilled water and standard analgesics (morphine and acetylsalicylic acid) with acetic acid induced writhing tests in mice. The four plants used for this screening were Ocimum sauve, Ocimum lamiifolium, Lippia adoensis and Ajuga remota. RESULTS All extracts of the four plant materials were observed to possess both inhibiting and treatment activities against acetic acid induced pain. Dose related analgesic effect was also observed with all extracts of all plants with different potencies. Ethanol extracts of all the four plant 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 analgesic potencies of both extracts of all the four plants were shown to be less than those of the standard analgesics. Of all the extracts, the ethanol extract of O. lamiifolium was found to be the most potent, while its water extract was the least. Acetic acid induced writhing was relieved with medium dose of both extracts in most cases and with low dose in few. Hundred percent 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 got both inhibiting and relieving effects of pain.