The West African country Nigeria features highly diverse vegetation and climatic conditions that range from rain forest bordering the Atlantic Ocean in the South to the Desert (Sahara) at the Northern extreme. Based on data from the World Conservation Monitoring Center of the United Nations Environmental Protection, Nigeria, with ~5,000 documented vascular plants, ranks amongst the top 50 countries in terms of biodiversity. Such a rich biodiversity implies that the country is rich in diverse secondary metabolites—natural products/unique chemicals produced by the plant kingdom to confer selective advantages to them. Like many tropical countries, Nigeria is also endemic to numerous infectious diseases particularly those caused by parasitic pathogens. These phytochemicals have been exploited for the treatment of diseases and as a result, a new branch of chemistry, natural product chemistry, has evolved, to try to reproduce and improve the therapeutic qualities of particular phytochemicals. In this review, we have compiled a compendium of natural products, isolated from Nigerian flora, that have been reported to be effective against certain protozoan parasites with the aim that it will stimulate interests for further investigations, and give impetus to the development of the natural products into registered drugs. In total 93 structurally characterized natural compounds have been identified with various levels of anti-parasite activity mainly from Nigerian plants. The synthesis protocol and molecular target for some of these natural anti-parasite agents have been established. For instance, the anti-plasmodial compound fagaronine (7), a benzophenanthridine alkaloid from Fagara zanthoxyloides has been successfully synthesized in the laboratory, and the anti-trypanosomal compound azaanthraquinone (55) elicits its effect by inhibiting mitochondrial electron transfer in trypanosomes. This review also discusses the barriers to developing approved drugs from phytochemicals, and the steps that should be taken in order to accelerate the development of new antiparasitics from the highlighted compounds.

The kinetoplastids are protozoa characterized by the presence of a distinctive organelle, called the kinetoplast, which contains a large amount of DNA (kinetoplast DNA (kDNA)) inside their single mitochondrion. Kinetoplastids of medical and veterinary importance include Trypanosoma spp. (the causative agents of human and animal African Trypanosomiasis and of Chagas disease) and Leishmania spp. (the causative agents of the various forms of leishmaniasis). These neglected diseases affect millions of people across the globe, but drug treatment is hampered by the challenges of toxicity and drug resistance, among others. Propolis (a natural product made by bees) and compounds isolated from it are now being investigated as novel treatments of kinetoplastid infections. The anti-kinetoplastid efficacy of propolis is probably a consequence of its reported activity against kinetoplastid parasites of bees. This article presents a review of the reported anti-kinetoplastid potential of propolis, highlighting its anti-kinetoplastid activity in vitro and in vivo regardless of geographical origin. The mode of action of propolis depends on the organism it is acting on and includes growth inhibition, immunomodulation, macrophage activation, perturbation of the cell membrane architecture, phospholipid disturbances, and mitochondrial targets. This gives ample scope for further investigations toward the rational development of sustainable anti-kinetoplastid drugs.

Terminalia catappa (Linn.) is used in traditional medicine to treat dysmenorrhea and typhoid fever in the Tiv speaking parts of Benue State, Nigeria. The aim of this study was to investigate the plant for its chemical contents that could be responsible for the reported medicinal activity. Extraction of root bark of the plant was done with n-hexane, ethyl acetate and methanol. The ethyl acetate extract was subjected to column chromatography on silica gel 60H, 200-400 mesh, eluted gradient wise with hexane:ethyl acetate. Fractions (ND95-97) obtained from hexane:ethyl acetate (60:40) were combined based on similar TLC Rf values. On standing, the combined fractions gave a white solid with melting point 230-231 o C which gave a positive result to the Liebermann-Burchard test for pentacyclic triterpenes. Its mass spectrum showed a molecular ion peak at m/z 506.3879 [M + H2O] +. On the basis of 1 H, 13 C, 2D (HMBC, HSQC, COSY) NMR spectral data, mass spectrometry, and by comparison of spectra data with literature, ND95-97 was characterized as Arjunolic acid (2,3,23-trihydroxyolean-12-en-28-oic acid). To the best of our knowledge, this is the first report of the isolation of Arjunolic acid from the root bark of Terminalia catappa.

The absence or idle state of analytical equipment such as nuclear magnetic resonance spectroscopy, mass spectrometers and chromatographic techniques has constrained natural products research in Nigeria. Presently, gas chromatography-mass spectrometry has become the more easily available method in Nigeria for the identification of natural products in extracts. This method is sometimes fraught with non-reproducible results and the identification of non-natural or biosynthesized compounds. Several of the extracts analyzed are not volatile, some of the analysts are not competent and certified reference standards are hardly used. These coupled with poor library or database matches and data processing among others lead to the identification of compounds not recognizable from the extract or plants materials under study. This review discusses some of the problems involved in the use of this method for dereplication studies of plant extracts in Nigeria and makes some suggestions for improvement.

An ethnobotanical survey of plants used in treating anaemia, haemostasis and other diseases in Tiv traditional medicine was carried out. Seventy-six traditional medicine practitioners in Gboko, Konshisha and Ushongo Local Government Areas of Benue State, Nigeria were interviewed using a structured questionnaire. Fifty-six plant species belonging to twenty-nine families were reported as being used in treating the ailments identified. Ethnobotanical indices such as Informant Consensus Factor, Use Value and Fidelity Level were used to analyze the data. The results showed that Jatropha tanjorensis, Vernonia amygdalina, Telfairia occidentalis, and Mucuna pruriens were most used for the treatment of anaemia. The plant with the highest prescription was Carica papaya for the treatment of malaria.