Review of ethnobotanical and ethnopharmacological evidences of some Ethiopian medicinal plants traditionally used for the treatment of cancer

Abstract

Background: Ethiopia is endowed with enormous diversity of plants. However, the majority of these plants have not been scientifically investigated. Traditional knowledge on the use of plants as medicinal agents has been transferred from generation to generation, as guarded secrets, through the word of mouth, and scientific studies on these herbs have not been properly compiled.

Objectives: The main objective of this study was to review published ethnobotanical and ethnopharmacological evidences of Ethiopian medicinal plants with anticancer potentials.

Material and methods: A total of 92 articles have been reviewed. They were obtained from search engines such as PubMed, Science Direct and Google Scholar. The following keywords were used to search for the literature inside the databases: plant extract, anticancer, Ethiopia, antioxidant compounds, cytotoxic compounds and in vivo toxicity.

Results: The current literature review revealed that about 136 anticancer plants belonging to 57 families have been identified in Ethiopia. Among these, 98 plant species were reported for their traditional use to treat different types of symptomatic cancers. However, only 29 species were scientifically studied for their in vitro cytotoxic or free radical scavenging activities. Plant parts commonly used for preparation of anticancer remedies were leaves (41.4%) and roots (32.8%). Among the reported plant species, whilst the crude extracts of Artemisia annua, Acokanthera schimperi and Catha edulis were found to be potent cytotoxic agents (IC50<15 ?g/ml), the total extracts of Cassia arereh, Rubus steudneri and Thymus schimperi showed strong radical scavenging activity (IC₅₀ <15 ?g/ml). Chronic administration of Syzygium guineense hydroalcoholic leaf extract, on the other hand, induced pathological changes in liver and kidney of mice.

Conclusions: Although several Ethiopian plants traditionally used for the treatment of cancer were shown to possess cytotoxic and free radical scavenging activities, in most cases compounds responsible for such activities have not been identified. Therefore, activity-guided detailed phytochemical studies coupled with evaluation of the safety particularly on those plant extracts that demonstrated potent activities should be carried out as this may lead to the discovery of safe and cost effective anticancer agents. [Ethiop. J. Health Dev. 2017;31 (3):161-187]

Keywords: Ethiopian medicinal plants, Antioxidant, Anticancer, Ethnopharmacology, Traditional use