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This review provides an overview on the active phytochemical constituents of medicinal plants that are traditionally used to manage cancer in Ethiopia. A total of 119 articles published between 1968 and 2020 have been reviewed, using scientific search engines such as ScienceDirect, PubMed, and Google Scholar. Twenty-seven medicinal plant species that belong to eighteen families are documented along with their botanical sources, potential active constituents, and in vitro and in vivo activities against various cancer cells. The review is compiled and discusses the potential anticancer, antiproliferative, and cytotoxic agents based on the types of secondary metabolites, such as terpenoids, phenolic compounds, alkaloids, steroids, and lignans. Among the anticancer secondary metabolites reported in this review, only few have been isolated from plants that are originated and collected in Ethiopia, and the majority of compounds are reported from plants belonging to different areas of the world. Thus, based on the available bioactivity reports, extensive and more elaborate ethnopharmacology-based bioassay-guided studies have to be conducted on selected traditionally claimed Ethiopian anticancer plants, which inherited from a unique and diverse landscape, with the aim of opening a way forward to conduct anticancer drug discovery program.

Background Kniphofia foliosa is a flamboyant robust perennial herb which has dense clumps and tick upright rhizomes with leaves at the base. In Ethiopia, it has several vernacular names including Abelbila, Ashenda, Amelmela, Yeznjero Ageda, Shemetmetie and Yezinjero Ageda. The plant is endemic to Ethiopian highlands, where its rhizomes are traditionally used for the treatment of malaria, abdominal cramps and wound healing. In the present study, the 80% methanol extract of K. foliosa rhizomes and its constituents are tested against Plasmodium berghei in mice. Methods Isolation was carried out using column and preparative thin layer chromatography (PTLC). The chemical structures of the compounds were elucidated by spectroscopic methods (ESI–MS, 1D and 2D-NMR). Peters’ 4-day suppressive test against P. berghei in mice was utilized for in vivo anti-malarial evaluation of the test substances. Results Two compounds, namely knipholone and dianellin were isolated from the 80% methanolic extract of K. foliosa rhizomes, and characterized. The hydroalcoholic extract (400 mg/kg) and knipholone (200 mg/kg) showed the highest activity with chemosuppression values of 61.52 and 60.16%, respectively. From the dose–response plot, the median effective (ED50) doses of knipholone and dianellin were determined to be 81.25 and 92.31 mg/kg, respectively. Molecular docking study revealed that knipholone had a strong binding affinity to Plasmodium falciparum l-lactate dehydrogenase (pfLDH) target. Conclusion Results of the current study support the traditional use of the plant for the treatment of malaria.

Background. Despite a substantial scientific progress over the past two decades, malaria continues to be a worldwide burden. Evergrowing resistance towards the currently available antimalarial drugs is a challenge to combat malaria. Medicinal plants are a promising source of new drugs to tackle this problem. Thus, the present study aimed at evaluating the antiplasmodial activity of Terminalia brownii in Plasmodium berghei infected mice. Methods. A 4-day suppressive test was employed to evaluate the antimalarial effect of 80% methanol and aqueous bark extracts of T. brownii against P. berghei in Swiss albino mice. Results. The in vivo acute toxicity test indicated that both extracts of T. brownii did not cause mortality. The 4-day early infection test revealed that the 80% methanol and aqueous extracts exhibited a significant inhibition of parasitemia p<0.001 compared to negative control. The maximum level of chemosuppression (60.2%) was exhibited at 400 mg/kg dose of 80% methanol extract. Moreover, the 80% methanol extract showed a significant p<0.001 attenuation of anemia associated with infection in a dose-dependent manner. The aqueous extract, on the other hand, exhibited a percent inhibition of 51.1% at the highest dose (400 mg/kg/day). Conclusion. The present study indicated that hydromethanolic and aqueous bark extracts of T. brownii possess a promising antimalarial activity, with higher effect exhibited by the hydromethanolic extract.

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In the present study, we use knipholone as a prototype molecule to identify new anti-infective agents. Since knipholone is insoluble in water, which would have a detrimental effect on its bioavailability and efficacy, we synthesized and determined the in vitro antimicrobial activity of knipholone Mannich base derivatives (2-4) that have better predicted solubility against eight pathogenic bacterial and fungal strains. The chemical structures of compounds 1-4 were elucidated from their 1 H and 13 C NMR data, and their antimicrobial activity evaluation was carried out by a broth microdilution MTT assay. Compound 3 exhibited the strongest efficacy against Staphylococcus epidermidis, with MIC value of 9.7 µg/mL. While 4 exhibited the best activity against Staphylococcus aureus, with an MIC value of 19.5 µg/mL, and was the only one to significantly inhibit the fungus Trichophyton mentagrophytes (MIC = 78.2 µg/mL). The study provides evidence for the antibacterial activity of aminoalkyl derivatives of knipholone.

The present study isolated and characterized knipholone from the active 80% methanol rhizome extract of a traditionally used endemic antimalarial plant of Ethiopia, Kniphofia insignis Rendle, using preparative thin-layer chromatography for the first time. The chemical structure of the compound was elucidated on the basis spectroscopic data and in comparison with previously reported results. The standard 4-day suppressive test against Plasmodium berghei infected Swiss albino mice was used for the in vivo antimalarial assay of the extract. At all tested doses, the extract showed significant inhibition of parasitaemia. In particular, the extract demonstrated  chemosuppression values of 24.35 and 43.87% at 200 and 400 mg/kg, respectively. Results of the current study revealed that the extract of the plant has moderate in vivo antimalarial effect against P. berghei in mice.

Background: Kniphofia foliosa Hochst is endemic to Ethiopian highlands, where its rhizomes are traditionally used for the treatment of malaria, abdominal cramps and wound healing. As a continuation of our search for antimalarial compounds from Ethiopian medicinal plants, we have tested the 80% methanol extract of K. foliosa rhizomes and its constituents against Plasmodium berghei in mice. Methods: Isolation was carried out using column and preparative thin layer chromatography (PTLC). The chemical structures of the compounds were elucidated by spectroscopic methods (ESI-MS, 1D and 2D-NMR). Peters’ 4-day suppressive test against P. berghei in mice was utilized for in vivo antimalarial evaluation of the test substances. Results: Three compounds, namely knipholone, dianellin, and 12-hydroxypentadec-9-en-1-yl methyl phthalate (HPMP) were isolated and characterized from the 80% methanolic extract of K. foliosa rhizomes. The hydroalcoholic extract (400 mg/kg) and knipholone (200 mg/kg) showed the highest activity with chemosuppression values of 61.52 and 60.16%, respectively. From the dose-response plot, the median effective (ED50) doses of knipholone and dianellin were determined to be 81.25 and 92.31 mg/kg, respectively. Molecular docking study revealed that knipholone had a strong binding affinity to Plasmodium falciparum l-lactate dehydrogenase (pfLDH) target. Conclusion: Results of the current study support the traditional use of the plant for the treatment of malaria.