Useful medicinal tree species of Ethiopia: Comprehensive review

Abstract

Medicinal plants are an important element of the health system of both human and animals in many counties. This is particularly the case in Ethiopia, one of the ancient nations located in the Horn of Africa. Floristically the country is rich with more than 6500 vascular plant species. For this reason, there has been ongoing and increasing interest in ethnobotanical studies. The aim of this study was to compile a comprehensive document on the medicinal tree species of the country. Accordingly, 65 published articles and MSc theses from 2001 to 2017 were collected and data on plant part used, preparation methods, ailments and route of administration, were summarized. A total of 274 tree species belonging to 174 genera and 69 families were identified as medicinal plants in the literature. The most dominant families were Fabaceae (51 species), Euphorbiaceae (15 species), Capparidaceae (14 species), Rubiaceae (12 species) and Anacardiaceae (12 species). Most of these species were located in Oromia and Southern Nations, Nationalities and People Regions. Large numbers of tree species were categorized to treat single rather than multiple types of ailments. Leaves were the most frequently used plant parts. Most of the remedies were prepared by crushing and administered orally. The most commonly used species include Croton macrostachyus, Olea europaea subsp. cuspidata, Balanites aegyptiaca, Brucea antidysenteria and Cordia africana. The largest number of taxa was used to treat parasites, abdominal pain, and dermatological problems. This review, therefore, sheds some light on the important medicinal tree species of Ethiopia, focusing on tree species and their local uses in the healthcare system. It also shows the need for carrying out such studies in the remaining districts of the country, to document and promote conservation and propagation of these indigenous and exotic medicinal tree species. In addition, it indicates the need to work on the validation of phytochemical and pharmacological properties of the relatively more important tree species traditionally associated with treating major health problems.