A Review of Phytochemical Constituents and Pharmacological Activities of Ethnomedicinal Warburgia Ugandensis Sprague Ssp. Ugandensis in East Africa
Use of indigenous medicinal plants has been practiced in East Africa for centuries and is still being widely used to-date. The genus Warburgia belongs to family Canellaceae. The species Warburgia ugandensis Sprague ssp. Ugandensis (commonly known as East African greenheart, Pepper-bark tree) is an evergreen tree distributed throughout East Africa, including in the Democratic Republic of Congo, Ethiopia, Kenya, Malawi, Tanzania, and Uganda. The plant has been used for centuries by various local communities and several traditional healers in East Africa to treat many diseases including Malaria, constipation, tooth-ache, stomach-ache, diarrhoea, coughs and colds and general muscular and other body pains. The species, very well known to local communities by its local names, grows in natural habitats and also on farmlands where it has been domesticated. The present review describes the existing data on the botany and ecology, plant parts used, phytochemical constituents, traditional uses and pharmacological activities of W. ugandensis. The review established that during the last few decades, numerous folk medicine and scientific reports on the anti-plasmodial activitiy, antimicrobial activity and antifungal activity of this species have been cited in the literature. The chemical composition of the bark and leaves is relatively well studied. Literature review confirmed several chemical constituents isolated particularly from stem bark and leaves of this species. Drimane sesquiterpenes, including muzigadial, salutariolide, warburganal, polygodial and isopolygodial and mukaadial among several others have been reported in stem bark of W. ugandensis. The sesquiterpenes of Warburgia species are known to possess insect anti-feedant, anti-microbial, anti-plasmodial, anti-fungal anti-ulcer and molluscicidal properties. Further research by pharmaceutical companies and research institution needs to be carried out on W. ugandensis species for its potential in curing and treating diseases, particularly stem bark and leaves in regard to its antiplasmodial and antimicrobial activities. Therefore, pre-clinical and clinical trials need to be done to further validate the traditional medicine applications of W. ugandensis for possible antimalarial and antibacterial drug discovery.