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This research is aimed at assessing the possibility of using a rainwater harvesting (RWH) system to supplement domestic water supply in the Mvog-Betsi neighbourhood of Yaoundé. The research made use of a 63-year long data series on the amount of rainfall available in the study area, an analysis of rainwater quality and an estimate of the population's monthly water demand in relation to the monthly harvestable rainwater supply. Rainwater supply for the months of September, October and November is 53.05 m3 which is considerably greater than the households' water demand of 25.56 m3 during the long dry season. This led to the design of a 27 m3 ferrocement tank as minimum storage requirement. Furthermore, a rainwater quality analysis showed that all tested parameters conform to water quality standards except for microbiological quality. The rainwater needs to be disinfected before consumption as potable water. Finally, cost estimates for installing RWH systems for low ($419), medium ($549) and high standard ($668) habitations were calculated. RWH can effectively serve as a water supply supplement in the Mvog-Betsi neighbourhood.

Cancer is known to be the second most common disease-related cause of death among humans. In drug discovery programs anti-cancer chemotherapy remains quite challenging due to issues related to resistance. Plants used in traditional medicine are known to contribute significantly within a large proportion of the African population. A survey of the literature has led to the identification of ~400 compounds from African medicinal plants, which have shown anti-cancer, anti-proliferation, anti-tumor and/or cytotoxic activities, tested by in vitro and in vivo assays (from mildly active to very active), mainly alkaloids, terpenoids, flavonoids, coumarins, phenolics, polyacetylates, xanthones, quinones, steroids and lignans. The first part of this review series focuses on xanthones, quinones, steroids, coumarins, phenolics and other compound classes, while part II is focused on alkaloids, terpenoids, flavonoids.

As a whole, the African continent is highly endowed with a huge floral biodiversity. Natural products which have been isolated from plants growing in this region have shown interesting chemical structures with diverse biological activities, which could serve as a starting point for drug discovery. In this study, a literature survey led to the collection of 864 secondary metabolites from 101 plant species from 57 plant families. A correlation between the known biological activities of isolated compounds and the ethnobotanical uses of the plants has been attempted. This review is a survey of the bioactivities of alkaloids and terpenoids which have been isolated from Southern African flora versus the ethnobotanical uses of the plants used in Southern African traditional medicine.

In this review series, an attempt has been made to give indepth coverage of natural products derived from West African medicinal plants with diverse biological activities. In part II of this series, emphasis has been laid on terpenoids from West African flora having remarkable biological activities, as well as a correlation between biological activities of the derived compounds and the uses of the plants in African traditional medicine. The impact of geographical distribution on the chemical contents of selected plant genera and their chemotaxonomic classifications have also been included in the discussion. Suggestions for drug discovery projects beginning with natural products from West Africa have also been provided.

This review gives an in depth coverage of the natural products derived from West African medicinal plants with diverse biological activities. Unique compound classes from West African flora having remarkable biological activities have been highlighted, as well as a correlation between the biological activities of the derived compounds and the uses of the plants in traditional African medicine, and their chemotaxonomic classifications have been included in the discussion. In the first part of the review, the focus is on alkaloids and flavonoids.

In this review, a continuation of our in-depth coverage of natural products derived from West African medicinal plants with diverse biological activities has been given. In the previous parts of this review series, the most abundant bioactive compound classes: terpenoids, flavonoids and alkaloids from West Africa were thoroughly investigated. We now focus on the least abundant compound classes (quinones, steroids, phenolics, glycosides, and other classes), having remarkable biological activities. A correlation between the biological activities of the derived compounds and the uses of the plants in African traditional medicine has been established.

Author(s): Fechner, Uli; de Graaf, Chris; Torda, Andrew E; Gussregen, Stefan; Evers, Andreas; Matter, Hans; Hessler, Gerhard; Richmond, Nicola J; Schmidtke, Peter; Segler, Marwin HS; Waller, Mark P; Pleik, Stefanie; Shea, Joan-Emma; Levine, Zachary; Mullen, Ryan; van den Broek, Karina; Epple, Matthias; Kuhn, Hubert; Truszkowski, Andreas; Zielesny, Achim; Fraaije, Johannes Hans; Gracia, Ruben Serral; Kast, Stefan M; Bulusu, Krishna C; Bender, Andreas; Yosipof, Abraham; Nahum, Oren; Senderowitz, Hanoch; Krotzky, Timo; Schulz, Robert; Wolber, Gerhard; Bietz, Stefan; Rarey, Matthias; Zimmermann, Markus O; Lange, Andreas; Ruff, Manuel; Heidrich, Johannes; Onlia, Ionut; Exner, Thomas E; Boeckler, Frank M; Bermudez, Marcel; Firaha, Dzmitry S; Holloczki, Oldamur; Kirchner, Barbara; Tautermann, Christofer S; Volkamer, Andrea; Eid, Sameh; Turk, Samo; Rippmann, Friedrich; Fulle, Simone; Saleh, Noureldin; Saladino, Giorgio; Gervasio, Francesco L; Haensele, Elke; Banting, Lee; Whitley, David C; Oliveira Santos, Jana Sopkova-de; Bureau, Ronan; Clark, Timothy; Sandmann, Achim; Lanig, Harald; Kibies, Patrick; Heil, Jochen; Hoffgaard, Franziska; Frach, Roland; Engel, Julian; Smith, Steven; Basu, Debjit; Rauh, Daniel; Kohlbacher, Oliver; Boeckler, Frank M; Essex, Jonathan W; Bodnarchuk, Michael S; Ross, Gregory A; Finkelmann, Arndt R; Goller, Andreas H; Schneider, Gisbert; Husch, Tamara; Schutter, Christoph; Balducci, Andrea; Korth, Martin; Ntie-Kang, Fidele; Gunther, Stefan; Sippl, Wolfgang; Mbaze, Luc Meva'a

The global distribution and high stability of some haloacetic acids (HAAs) has prompted concern that they will tend to accumulate in surface waters and pose threats to humans and the ecosystem. It is important to study the degradation pathways of HAAs in aqueous systems to understand their ecotoxicological effects. Previous studies involving thermal degradation reactions show relatively long lifetimes for HAAs in the natural environment. Photolysis and photocatalytic dissociation are potentially efficient routes for the degradation of HAAs such as trichloroacetic acid to hydrochloric acid, carbon dioxide and chloroform, although such processes are poorly understood in surface waters. In our present study, we have used light to degrade the HAAs in the presence of titanium dioxide suspensions. All chloro and bromo HAAs degrade in photocatalysis experiments and the rate of degradation is directly proportional to the number of halogen atoms in the acid molecule. The half-lives of the HAAs from the photodegradation at 15 degrees C in the presence of suspended titanium dioxide photocatalyst are 8, 14, 83 days for the tri-, di- and mono-bromoacetic acids. Tri-, di- and mono-chloroacectic acids have half-lives of 6, 10 and 42 days respectively. The mixed bromochloro and chlorodifluoroacetic acids degrade with half-lives of 18 and 42 days respectively. Our results therefore suggest that the photocatalytic process can provide an additional degradation pathway for the HAAs in natural waters.

Malaria is currently a public health concern in many countries in the world due to various factors which are not yet under check. Drug discovery projects targeting malaria often resort to natural sources in the search for lead compounds. A survey of the literature has led to a summary of the major findings regarding plant-derived compounds from African flora, which have shown anti-malarial/antiplasmodial activities, tested by in vitro and in vivo assays. Considerations have been given to compounds with activities ranging from “very active” to “weakly active”, leading to >500 chemical structures, mainly alkaloids, terpenoids, flavonoids, coumarins, phenolics, polyacetylenes, xanthones, quinones, steroids and lignans. However, only the compounds that showed anti-malarial activity, from “very active” to “moderately active”, are discussed in this review.

Traditional medicine caters for about 80% of the health care needs of many rural populations around the world, especially in developing countries. In addition, plant-derived compounds have played key roles in drug discovery. Malaria is currently a public health concern in many countries in the world due to factors such as chemotherapy faced by resistance, poor hygienic conditions, poorly managed vector control programmes and no approved vaccines. In this review, an attempt has been made to assess the value of African medicinal plants for drug discovery by discussing the anti-malarial virtue of the derived phytochemicals that have been tested by in vitro and in vivo assays. This survey was focused on pure compounds derived from African flora which have exhibited anti-malarial properties with activities ranging from “very active” to “weakly active”. However, only the compounds which showed anti-malarial activities from “very active” to “moderately active” are discussed in this review. The activity of 278 compounds, mainly alkaloids, terpenoids, flavonoids, coumarines, phenolics, polyacetylenes, xanthones, quinones, steroids, and lignans have been discussed. The first part of this review series covers the activity of 171 compounds belonging to the alkaloid and terpenoid classes. Data available in the literature indicated that African flora hold an enormous potential for the development of phytomedicines for malaria.

We attempt to evaluate the “drug-likeness” of a collection of ∼1500 natural products, exhibiting in vitro or in vivo activities against cancers of various forms, by using a set of calculated molecular descriptors. Compliance to Lipinski’s “Rule of Five” and Jorgensen’s “Rule of Three” have been used to assess oral availability, by making use of popular parameters like molecular weights, predicted lipophilicities, number of hydrogen bond donors/acceptors, predicted aqueous solubilities, number of primary metabolites and Caco-2 permeabilities. Meanwhile 24 descriptors have been used to predict properties related to the absorption, distribution, metabolism, elimination, and toxicity (ADMET). The ADMET profiles of the anticancer natural products have been analyzed in comparision with the range of properties for 95 % of known drugs. Our results show that the computed parameters fall within the recommended range for about 42 % of the studied compounds, while respectively 63 % and 69 % of the corresponding ‘drug-like’ and ‘lead-like’ subsets had properties predicted to fall within the recommended range for 95 % of known drugs. The aim of giving a picture of how drug-like they are and bring out the need to return to natural sources in searching for anticancer lead compounds.

Computer-aided drug design (CADD) often involves virtual screening (VS) of large compound datasets and the availability of such is vital for drug discovery protocols. We assess the bioactivity and “drug-likeness” of a relatively small but structurally diverse dataset (containing >1,000 compounds) from African medicinal plants, which have been tested and proven a wide range of biological activities. The geographical regions of collection of the medicinal plants cover the entire continent of Africa, based on data from literature sources and information from traditional healers. For each isolated compound, the three dimensional (3D) structure has been used to calculate physico-chemical properties used in the prediction of oral bioavailability on the basis of Lipinski’s “Rule of Five”. A comparative analysis has been carried out with the “drug-like”, “lead-like”, and “fragment-like” subsets, as well as with the Dictionary of Natural Products. A diversity analysis has been carried out in comparison with the ChemBridge diverse database. Furthermore, descriptors related to absorption, distribution, metabolism, excretion and toxicity (ADMET) have been used to predict the pharmacokinetic profile of the compounds within the dataset. Our results prove that drug discovery, beginning with natural products from the African flora, could be highly promising. The 3D structures are available and could be useful for virtual screening and natural product lead generation programs.

Background In Cameroon herbs are traditionally used to meet health care needs and plans are on the way to integrate traditional medicine in the health care system, even though the plans have not been put into action yet. The country however has a rich biodiversity, with ~8,620 plant species, some of which are commonly used in the treatment of several microbial infections and a range of diseases (malaria, trypanosomiasis, leishmaniasis, diabetes and tuberculosis). Methods Our survey consisted in collecting published data from the literature sources, mainly from PhD theses in Cameroonian university libraries and also using the author queries in major natural product and medicinal chemistry journals. The collected data includes plant sources, uses of plant material in traditional medicine, plant families, region of collection of plant material, isolated metabolites and type (e.g. flavonoid, terpenoid, etc.), measured biological activities of isolated compounds, and any comments on significance of isolated metabolites on the chemotaxonomic classification of the plant species. This data was compiled on a excel sheet and analysed. Results In this study, a literature survey led to the collection of data on 2,700 secondary metabolites, which have been previously isolated or derived from Cameroonian medicinal plants. This represents distinct phytochemicals derived from 312 plant species belonging to 67 plant families. The plant species are investigated in terms of chemical composition with respect to the various plant families. A correlation between the known biological activities of isolated compounds and the ethnobotanical uses of the plants is also attempted. Insight into future direction for natural product search within the Cameroonian forest and Savanna is provided. Conclusions It can be verified that a phytochemical search of active secondary metabolites, which is inspired by knowledge from the ethnobotanical uses of medicinal plants could be very vital in a drug discovery program from plant-derived bioactive compounds.

Background Computer-aided drug design (CADD) often involves virtual screening (VS) of large compound datasets and the availability of such is vital for drug discovery protocols. We present CamMedNP - a new database beginning with more than 2,500 compounds of natural origin, along with some of their derivatives which were obtained through hemisynthesis. These are pure compounds which have been previously isolated and characterized using modern spectroscopic methods and published by several research teams spread across Cameroon. Description In the present study, 224 distinct medicinal plant species belonging to 55 plant families from the Cameroonian flora have been considered. About 80 % of these have been previously published and/or referenced in internationally recognized journals. For each compound, the optimized 3D structure, drug-like properties, plant source, collection site and currently known biological activities are given, as well as literature references. We have evaluated the “drug-likeness” of this database using Lipinski’s “Rule of Five”. A diversity analysis has been carried out in comparison with the ChemBridge diverse database. Conclusion CamMedNP could be highly useful for database screening and natural product lead generation programs.

Background Drug metabolism and pharmacokinetic (DMPK) assessment has come to occupy a place of interest during the early stages of drug discovery today. Computer-based methods are slowly gaining ground in this area and are often used as initial tools to eliminate compounds likely to present uninteresting pharmacokinetic profiles and unacceptable levels of toxicity from the list of potential drug candidates, hence cutting down the cost of the discovery of a drug. Results In the present study, we present an in silico assessment of the DMPK profile of our recently published natural products database of 1,859 unique compounds derived from 224 species of medicinal plants from the Cameroonian forest. In this analysis, we have used 46 computed physico-chemical properties or molecular descriptors to predict the absorption, distribution, metabolism and elimination (ADME) of the compounds. This survey demonstrated that about 50% of the compounds within the Cameroonian medicinal plant and natural products (CamMedNP) database are compliant, having properties which fall within the range of ADME properties of >95% of currently known drugs, while >73% of the compounds have ≤2 violations. Moreover, about 72% of the compounds within the corresponding ‘drug-like’ subset showed compliance. Conclusions In addition to the previously verified levels of ‘drug-likeness’ and the diversity and the wide range of measured biological activities, the compounds in the CamMedNP database show interesting DMPK profiles and, hence, could represent an important starting point for hit/lead discovery from medicinal plants in 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.

Background Malaria is an endemic disease affecting many countries in Tropical regions. In the search for compound hits for the design and/or development of new drugs against the disease, many research teams have resorted to African medicinal plants in order to identify lead compounds. Three-dimensional molecular models were generated for anti-malarial compounds of African origin (from 'weakly' active to 'highly' active), which were identified from literature sources. Selected computed molecular descriptors related to absorption, distribution, metabolism, excretion and toxicity (ADMET) of the phytochemicals have been analysed and compared with those of known drugs in order to access the 'drug-likeness' of these compounds. Results In the present study, more than 500 anti-malarial compounds identified from 131 distinct medicinal plant species belonging to 44 plant families from the African flora have been considered. On the basis of Lipinski's 'Rule of Five', about 70% of the compounds were predicted to be orally bioavailable, while on the basis of Jorgensen's 'Rule of Three', a corresponding >80% were compliant. An overall drug-likeness parameter indicated that approximately 55% of the compounds could be potential leads for the development of drugs. Conclusions From the above analyses, it could be estimated that >50% of the compounds exhibiting anti-plasmodial/anti-malarial activities, derived from the African flora, could be starting points for drug discovery against malaria. The 3D models of the compounds have been included as an accompanying file and could be employed in virtual screening.

Purpose Drug metabolism and pharmacokinetics (DMPK) assessment has come to occupy a place of interest during the early stages of drug discovery today. The use of computer modelling to predict the DMPK and toxicity properties of a natural product library derived from medicinal plants from Central Africa (named ConMedNP). Material from some of the plant sources are currently employed in African Traditional Medicine. Methods Computer-based methods are slowly gaining ground in this area and are often used as preliminary criteria for the elimination of compounds likely to present uninteresting pharmacokinetic profiles and unacceptable levels of toxicity from the list of potential drug candidates, hence cutting down the cost of discovery of a drug. In the present study, we present an in silico assessment of the DMPK and toxicity profile of a natural product library containing ~3,200 compounds, derived from 379 species of medicinal plants from 10 countries in the Congo Basin forests and savannas, which have been published in the literature. In this analysis, we have used 46 computed physico-chemical properties or molecular descriptors to predict the absorption, distribution, metabolism and elimination and toxicity (ADMET) of the compounds. Results This survey demonstrated that about 45% of the compounds within the ConMedNP compound library are compliant, having properties which fall within the range of ADME properties of 95% of currently known drugs, while about 69% of the compounds have ≤ 2 violations. Moreover, about 73% of the compounds within the corresponding “drug-like” subset showed compliance. Conclusions In addition to the verified levels of “drug-likeness”, diversity and the wide range of measured biological activities, the compounds from medicinal plants in Central Africa show interesting DMPK profiles and hence could represent an important starting point for hit/lead discovery.