Evaluation of the fungal microflora infesting pigeon pea (Cajanus cajan L. Millspaugh) in southern Benin and associated mycological hazards

Pigeon pea is a perennial legume with a good nutritional value. Unfortunately, it is also a substrate for fungi contamination. Then, a qualitative semi-structured survey was carried out in the main production areas of pigeon pea in southern Benin. This survey was coupled with samples collection. A total of 60 samples of pigeon pea were collected and analyzed for associated fungal microflora by using a taxonomic schemes primarily based on morphological characters of mycelium and conidia. Obtained results indicated a low technological valorization of pigeon pea seeds in southern Benin and their used only in direct consumption after cooking. Microbiological analyses revealed the high contamination of pigeon pea seeds by fungi, with the most occurrence of Aspergillus (71.42%), followed by Fusarium (26.19%). Fungal species such as Aspergillus ochraceus, A. parasiticus, A. flavus and Fusarium oxysporum were also detected in analyzed samples. Taking into account the toxicity of the secondary metabolites produced by these fungi, mycological hazards are discussed and important methods for the control of mycotoxin-contamination are further provided. More attention should be paid to the mycological quality of this legume, in order to protect the consumers’ health

In vitro biological effects of two anti-diabetic medicinal plants used in Benin as folk medicine.

International audienceBACKGROUND: Extracts from Polygonum senegalensis (Polygonaceae) and Pseudocedrela kotschyi (Meliaceae) are two important traditionally used medicinal plants in rural Benin to treat many diseases and notably type 2 diabetes. The aim of the study was to investigate the alpha-glucosidase inhibition, antioxidant and antibacterial activities of those plants extract: Polygonum senegalensis leaves, and Pseudocedrela kotschyi root. METHODS: Hydro-alcoholic (50%) extracts were analyzed for their phytochemical content and tested for their inhibition potency on alpha-glucosidase from Saccharomyces cerevisiae. Antioxidant activities were assessed using the DPPH, ORAC, FRAP and DCFH-DA (cell based) assay. Finally, the antibacterial activity was evaluated using MIC determination on four Gram-positive cocci (Bacillus subtilis, Clostridium difficile, Enterococcus faecalis, Staphylococcus aureus), three Gram-negative bacilli (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae), and the yeast Candida albicans. RESULTS: Each extract presented significant alpha-glucosidase inhibition and antioxidant activities. Polygonum senegalensis leaf extracts were the most active in each in vitro assay with an IC50 = 1.5 mug/ml for alpha-glucosidase inhibition and an IC50 = 6.8 mug/ml for DPPH scavenging, - 4.5 mumol Fe II/g of dry matter - 9366 mumol Trolox / g DW - for FRAP and ORAC values, respectively. IC50 = 2.3 mug GA / ml for DCFH-DA assay. Concerning its antibacterial activity, a growth inhibitory effect was observed only against three Gram negative bacilli: B. subtilis, E. faecalis, S. aureus and the yeast C. albicans at high concentration. CONCLUSION: The results showed that the semi alcoholic extract of the two studied plants possess alpha-glucosidase inhibitory activity, antioxidant potency, and low antibacterial effect

Chemical composition and insecticidal activity of plant essential oils from Benin against Anopheles gambiae (Giles)

BACKGROUND: Insecticide resistance in sub-Saharan Africa and especially in Benin is a major public health issue hindering the control of the malaria vectors. Each Anopheles species has developed a resistance to one or several classes of the insecticides currently in use in the field. Therefore, it is urgent to find alternative compounds to conquer the vector. In this study, the efficacies of essential oils of nine plant species, which are traditionally used to avoid mosquito bites in Benin, were investigated. METHODS: Essential oils of nine plant species were extracted by hydrodistillation, and their chemical compositions were identified by GC-MS. These oils were tested on susceptible “kisumu” and resistant “ladji-Cotonou” strains of Anopheles gambiae, following WHO test procedures for insecticide resistance monitoring in malaria vector mosquitoes. RESULTS: Different chemical compositions were obtained from the essential oils of the plant species. The major constituents identified were as follows: neral and geranial for Cymbopogon citratus, Z-carveol, E-p-mentha-1(7),8-dien-2-ol and E-p-mentha-2,8-dienol for Cymbopogon giganteus, piperitone for Cymbopogon schoenanthus, citronellal and citronellol for Eucalyptus citriodora, p-cymene, caryophyllene oxide and spathulenol for Eucalyptus tereticornis, 3-tetradecanone for Cochlospermum tinctorium and Cochlospermum planchonii, methyl salicylate for Securidaca longepedunculata and ascaridole for Chenopodium ambrosioides. The diagnostic dose was 0.77% for C. citratus, 2.80% for E. tereticornis, 3.37% for E. citriodora, 4.26% for C. ambrosioides, 5.48% for C. schoenanthus and 7.36% for C. giganteus. The highest diagnostic doses were obtained with S. longepedunculata (9.84%), C. tinctorium (11.56%) and C. planchonii (15.22%), compared to permethrin 0.75%. A. gambiae cotonou, which is resistant to pyrethroids, showed significant tolerance to essential oils from C. tinctorium and S. longepedunculata as expected but was highly susceptible to all the other essential oils at the diagnostic dose. CONCLUSIONS: C. citratus, E. tereticornis, E. citriodora, C. ambrosioides and C. schoenanthus are potential promising plant sources for alternative compounds to pyrethroids, for the control of the Anopheles malaria vector in Benin. The efficacy of their essential oils is possibly based on their chemical compositions in which major and/or minor compounds have reported insecticidal activities on various pests and disease vectors such as Anopheles

Status of research results in chemistry of biologically active substances in Benin

Research on biologically active chemicals extracted from medicinal plants and essential oils from aromatic plants in the West African subregion is booming. Recognition of the clinical, pharmaceutical and economic value of herbal medicines continues to grow despite the growth of the pharmaceutical industry and the continued development of new, more effective synthetic and biological medical products. On the other hand, despite the improvement in food preservation technics, food preservatives nature remains one of the most important issues for public health. Indeed, several synthetic preservatives have been banned in some countries because of their long-term adverse toxicological effects. The current trend of consumers to seek for a more natural diet has prompted the research, development and application of new natural products with antimicrobial and antioxidant activities in order to use them as alternatives to synthetic preservatives. This review aims to do an inventory of the results of research in chemistry of biologically active substances in Benin

Etude de la qualité physico-chimique de l’eau de boisson dans deux localités du Bénin: Cotonou et Dassa-Zoumè

L’eau, source potentielle de vie, doit subir diverses analyses physico-chimiques qui définiront sa qualité pour la consommation humaine afin d’éviter les risques de maladies hydriques pour les consommateurs. La présente étude vise à déterminer la qualité physico-chimique de l’eau de boisson des populations de deux villes du Bénin : Dassa-Zoumè et Cotonou. Trois points de prélèvement ont été identifiés dans chacune des deux localités pour un total de six (06) échantillons. Dix-neuf paramètres physico-chimiques ont été évalués sur ces échantillons. Certains paramètres (température, pH, turbidité et conductivité) susceptibles de modification au cours du transport ont été déterminés "in situ". Les résultats obtenus ont montré que l’eau des deux localités que consomment les populations est de bonne qualité sur le plan physico-chimique. Néanmoins, l’eau de consommation des populations de Dassa est plus alcaline et plus dure que celle de Cotonou : soit respectivement de 390 à 480 mg/l et de 25 à 35 mg/l puis de 232 à 260 mg/l et de 15 à 27 mg/l. Ce constat pourrait expliquer le caractère moins moussant et le goût terne souvent remarqués au niveau de l’eau de Dassa et serait lié à la nature géologique des sols traversés.© 2016 International Formulae Group. All rights reservedMots clés: Qualité physico-chimique, eau de boisson, BéninEnglish Title: Study of the physico-chemical quality of drinking water in two localities of Benin: Cotonou and Dassa-ZoumèEnglish AbstractWater, potential source of life, must undergo various physico-chemical analyzes that will define its quality for human consumption in order to avoid the risk of water-borne diseases to consumers. The present study aims to determine the physico-chemical quality of population’s drinking water in two cities of Benin: Cotonou and Dassa-Zoume. Three sampling points were identified in each of the two localities for a total of six (06) samples. Nineteen physico-chemical parameters were evaluated on these samples. Some parameters (temperature, pH, turbidity and conductivity) which may be modified during transport were determined "in  situ". The results showed that the water consumed by the populations of both localities has a good physicochemical quality. Nevertheless, drinking water of Dassa’s populations was more alkaline and harder than that of Cotonou: respectively 390-480 mg/l and 232-260 mg/l for Dassa and then 25-35 mg/l and 15-17 mg/l for Cotonou. This finding may explain the less foaming character and dull taste often noticed in Dassa's water and would be linked to the geological nature of the soils traversed.© 2016 International Formulae Group. All rights reservedKeywords: Physico-chemical quality, drinking water, Beni