Research Area:

Natural Products

Owing to increasingly high costs of imported medicines in Nigeria, the resort to traditional medicines is on the increase. Crude extracts of various plant extracts are now widely used as antihypertensive medications. In collaboration with Botanists and Traditional Health Practitioners, researchers at the Benin site are engaged in the screening of these extracts with a view to characterizing the active principles contained therein.

Some of the extracts that have been investigating include: aqueous leaf extracts of Musanga Cecropioides - a herbal medicine used by traditional healers (in West Africa) to induce labour; Rauwolfia Vomitoria  and a wide variety of other extracts effective in reducing intraocular pressure (for the management of glaucoma). It has been reported that M. Cecropioides elicits endothelium-dependent relaxation of rat aortic smooth muscle. Investigators at the Benin site have a number of publications on a variety of subjects relating to mechanisms of vascular smooth muscle function in health and disease states. Other studies that are under way are outlined below.

Cardiovascular/Medicinal Plants Research Program

The laboratory at Benin has been involved in studies on vascular smooth muscle function that is aimed at elucidating the mechanisms of action of a variety of vasoactive agents as well as identifying possible vascular cellular alterations associated with some forms of hypertension. Vascular cellular function is assessed, largely, in vitro, employing isolated blood vessels from various laboratory animals (rats, rabbits, dogs) and humans. In the last 12 years, the laboratory has focused on human blood vessels and has shown that isolated inferior epigastric arteries obtained (during caesarean delivery) from preeclamptic women possess cellular defects and could thus be used to study the details of the pathogenesis of pregnancy-induced hypertension. Current research activities include: (a) Ethnopharmacology of Medicinal Plant extracts, with particular emphasis on extracts with potential therapeutic benefits in the management of cardiovascular disorders and (b) Vascular L-arginine-Nitric oxide system in Malaria.

Considerable experience has also been acquired in this laboratory in in vitro characterization (using pharmacologic methods) of the mode of action of a wide range of vasoactive agents (e.g. drugs and ions: hydralazine, chloroquine, cicletanine, thiopentone, Ca2+, Mg2+ Ba2+ and K+ ions) on various vascular smooth muscle preparations.

Related Studies

The laboratory at Benin is also involved in assessing, pharmacologically, the cellular mechanisms of action of a variety of vasoactive agents. Some of the compounds which have been investigated include: dichlorovos - an organophosphorous pesticide; cicletanine - an antihypertensive furopyridine compound; and thiopentone, a barbiturate anaesthetic agent. Further pharmacological characterization of these compounds is in progress. Considerable expertise has been acquired with phytochemical/chemical/analytical procedures, particularly with synthesis of biologically active compounds.

For more information on the research training sites and the current application, please click on one of the following links:

• University of Dar es Salaam, Dar es Salaam, Tanzania
• Egerton University, Njoro, Kenya
• MHIRT Participants and Research Projects
• Current Application