Compounds from African Medicinal Plants with Activities Against Selected Parasitic Diseases:Schistosomiasis,Trypanosomiasis and Leishmaniasis

Parasitic diseases continue to represent a threat on a global scale,particularly among the poorest countries in the world.This is particularly because of the absence of vaccines,and in some cases,resistance against available drugs,currently being used for their treatment.In this review emphasis is laid on natural products and scaffolds from African medicinal plants(AMPs)for lead drug discovery and possible further development of drugs for the treatment of parasitic diseases.In the discussion,emphasis has been laid on alkaloids,terpenoids,quinones,flavonoids and narrower compound classes of compounds with micromolar range activities against Schistosoma,Trypanosoma and Leishmania species.In each subparagraph,emphasis is laid on the compound subclasses with most promising in vitro and/or in vivo activities of plant extracts and isolated compounds.Suggestions for future drug development from African medicinal plants have also been provided.This review covering 167 references,including 82 compounds,provides information published within two decades(1997-2017).

A Bioactivity Versus Ethnobotanical Survey of Medicinal Plants from Nigeria, West Africa

Traditional medicinal practices play a key role in health care systems in countries with developing economies.The aim of this survey was to validate the use of traditional medicine within local Nigerian communities.In this review,we examine the ethnobotanical uses of selected plant species from the Nigerian flora and attempt to correlate the activities of the isolated bioactive principles with known uses of the plant species in African traditional medicine.Thirty-three(33)plant species were identified and about 100 out of the 120 compounds identified with these plants matched with the ethnobotanical uses of the plants.

Synthesis,Urease Inhibition and Molecular Modelling Studies of Novel Derivatives of the Naturally Occurring b-Amyrenone

Urease enzyme(UE)has been reported to be a potent virulence factor for Helicobacter pylori(HP)bacteria indicated to be responsible for various gastrointestinal diseases.Therefore,the spread of HP,currently regarded by the World Health Organization as a class 1 carcinogen,could be better controlled by targeting UE.It is in this line that we have synthesized three new derivatives(2–4)of the naturally occurring olean-12-en-3-one(1),which was previously isolated from the figs of Ficus vallis-choudae Delile(Moraceae).Among the synthesized compounds,3 and 4 contain an indole moiety.Their structures were unambiguously assigned by spectroscopic and spectrometric techniques(1D-NMR,2D-NMR and MS).The starting material and the synthesized compounds were screened for UE inhibition activity,and showed significant activities with IC50 values ranging from 14.5 to 24.6 lM,with compound(1)being the most potent as compared to the positive control thiourea(IC50=21.6 lM).Amongst the synthetic derivatives,compound 4 was the most potent(IC50-=17.9 lM),while the others showed activities close to that of the control.In addition,molecular docking study of target compounds 2–4 was performed in an attempt to explore their binding mode for the design of more potent UE inhibitors.