Effet de la salinité sur la floraison, la fructification et la qualité nutritionnelle des fruits du cultivar local Akikon de tomate (Lycopersicon esculentum Mill.) du Bénin

La tomate est l’un des légumes les plus consommés au monde et au Bénin. Il est largement établi que la salinité agit négativement sur la germination et la croissance et modifie considérablement la concentration des composés bioactives des légumes. Au Bénin, la tomate est cultivée partiellement sur les terres cultivables des régions côtières où la salinité du sol et de l’eau d’irrigation est une réalité. Cette étude visait à évaluer l’effet de la salinité sur la floraison, la fructification et la composition nutritionnelle des fruits de tomate du cultivar local Akikon. Les plantes de trois semaines ont été arrosées jusqu’à la maturité des fruits avec diverses concentrations de NaCl de 0, 30, 60 et 120 mM. La date d’apparition des premières fleurs, la date de maturation des fruits ainsi que les teneurs en protéines des fruits n’ont pas été significativement affectées par la salinité alors que le nombre de fruits par plante, le poids des fruits, les teneurs en sucres solubles totaux et en sucres réducteurs subissent une réduction significative sous l’effet du NaCl. Par contre, les teneurs en lycopène, en vitamines B6, B12 et C ont connu une augmentation significative avec l’augmentation de la concentration de NaCl. La salinité a donc réduit la production de tomate et amélioré la qualité nutritionnelle des fruits en augmentant notamment ses teneurs en vitamines et en lycopène.Mots clés: Salinité, teneur en nutriments, sucres, lycopène, vitamines.   English title:Effect of salt stress on flowering, fructification and fruit nutritional quality of Benin local tomato (Lycopersicon esculentum Mill.) cultivar AkikonTomato (Lycopersicon esculentum) is one of the most important consumable vegetable in the world and in Benin. It is widely established that salinity acts negatively on germination and growth and considerably modifies the concentration of bioactive compounds in vegetables. In Benin, tomato is partially cultivated on arable lands in coastal regions where soil and irrigation water salinity is a reality. This study investigated the impact of salinity on flowering, fructification, and fruit nutrient contents of a local cultivar of tomato Akikon. Three weeks old plants were irrigated with four NaCl concentrations: 0; 30; 60 and 120 mM NaCl till fruit ripening. The date of first flower appearance, the date of fruit ripening and fruit protein content were not affected by salinity; whereas fruit number, fruit fresh mass, fruit soluble sugars and reducing sugars contents were significantly decreased by increasing salinity. Moreover, lycopen and vitamins B6, B12 and C contents increased significantly when salinity concentration increased. Thus, salinity reduced tomato productivity but improved fruit nutritional quality by mainly increasing vitamins and lycopen contents.Keywords: Salinity, nutrients content, lycopen, sugars, vitamins

Anti-Salmonella activity of plant species in the Benin republic: Artemisia afra and Detarium senegalense with promising in vitro and in vivo activities

Non-typhoidal invasive Salmonella (NTiS) diseases are one of the most important zoonoses in the world. This study explored the antipathogenic potential of twenty-four plants used in Benin folk medicine against NTiS diseases. The in vitro antibacterial and antibiofilm activities of ethanolic plant extracts were screened against clinical resistant isolates and ATCC reference strains of Salmonella. Salmonella enterica serovar Typhimurium-infected rat model was used to examine the in vivo antibacterial potential of plant extracts. Of the 24 plants, 18 plants exhibited antibacterial activity against Salmonella enterica strains with minimum inhibitory concentrations (MICs) ranging from 0.156 to 1.25 mg/mL. Anacardium occidentale, Artemisia afra, Detarium microcarpum, Detarium senegalense, and Leucaena leucocephala were the most active plant species. Extracts from A. afra, D. microcarpum, and D. senegalense showed biofilm inhibition greater than 50% against Salmonella clinical isolates. In the rat model of infection, A. afra and D. senegalense extracts were found to have an effective dose of less than 100 mg/kg and to stop the salmonellosis after 10 days of treatment. Additionally, these extracts did not produce any toxic effects in the treated animals. These results indicate clear evidence supporting the anti-Salmonella activity of A. afra and D. senegalense. Further studies are now needed to isolate bioactive compounds and to ensure the safety of these plant species

Scientific Baseline Information for the Potential Use of Hibiscus surattensis L against Malaria: Phytochemistry and Biological Studies

Background and aim: Hibiscus surattensis L. is a medicinal plant widely used traditionally in Benin to treat malaria. This study was designed to investigate antiplasmodial activity, hemolytic power, acute toxicity, antioxidant activity and phytochemical content of H. surattensis. Methodology: Bioassay-guided isolation approach was adopted and extracts and fractions collected were continuously tested in vitro against Chloroquine-sensitive and field isolate strains of Plasmodium falciparum by immune-dosage of Plasmodium lactate dehydrogenase. Hemolytic effect and acute toxicity of extracts were evaluated respectively on human erythrocytes and according to OECD guideline N°423. 2, 2-diphenyl-1- picrylhydrazyl) radical scavenging, Ferric reducing antioxidant power, superoxyde radical scavenging and hydrogen peroxide radical scavenging methods were used to investigate antioxidant activity. Results and conclusion:  The best antiplasmodial activity was obtained with ethanolic extract of H. surattensis L. against field isolate (IC50 = 5.03±0.31 µg/mL) and Chloroquine -sensitive (IC50 = 7.55±0.59 µg/mL) whereas aqueous extract exhibited moderate activity. Bioassay-guided fractionation of ethanolic extract shows progressive decrease of the antiplasmodial activity. Both extracts exhibited strong antioxidant activity, hemolytic power less than 1%. No mortality of rats was recorded with ethanolic extract at 2000 mg/kg body weight. Flavonoids, anthraquinones, coumarins, and triterpenes are present in both extracts with tannins in the ethanolic extract. In summary, the extracts of H. surattensis have interesting antiplasmodial and antioxidant properties probably resulting from a synergetic action of their secondary metabolites, without toxicity effect on rats and human erythrocytes. These findings strengthen the traditional use of H. surattensis as antimalarial plants. Keywords: Hibiscus surattensis; antiplasmodial; antioxidant; toxicity; phytoconstituents

Artemisia annua et Artemisia afra au Bénin : un engouement récent pour deux plantes non traditionnelles

International audienceMalaria in Benin is a real public health problem, causing thousands of deaths every year, particularly among young children. To combat this disease, the Beninese population uses both conventional and traditional medicine. At the frontier between these two medicines are products that are neither part of age-old traditions nor scientific standards. Products based on Artemisia annua and Artemisia afra belong to this category, and have recently appeared in Benin. Our team conducted a survey in 2022 to determine the type of products sold, their origin, price, audience, and the knowledge and practices of those involved in the “Artemisia market”. We interviewed 128 people in 8 of Benin’s 12 departments. Four profiles of people were interviewed: producers, retailers, consumers and traditional practitioners. Thanks to this study, we were able to trace the origins of the craze for these plants, identify the key players in the sector, notably the Maison de l’Artemisia, and demonstrate the virtual absence of traditional practitioners in this sector during the survey. The diversity of products sold and their indications was also noted. The two species A. afra and A. annua seem to be used for malaria in a similar way, with no real distinction in efficacy between the two. From an economic point of view, we have not noted any clear benefit linked to the use of Artemisia teas compared with therapeutic combinations based on artemisinin derivatives. Their efficacy and safety in humans have yet to be demonstrated. In conclusion, our study provides initial data on the use of Artemisia in Benin, and also identifies various aspects to be clarified, such as the extent of use, the health impact, and the economic interest for users of Artemisia-based products sold in Benin.Le paludisme au Bénin est un réel problème de santé publique à l’origine de milliers de décès chaque année, particulièrement chez les enfants de moins de cinq ans et les femmes enceintes. Pour pallier à cette maladie, la population béninoise utilise à la fois la médecine conventionnelle et la médecine traditionnelle. À la frontière entre ces deux médecines existent des produits qui ne font ni partie de traditions séculaires, ni de standards scientifiques. Les produits à base d’Artemisia annua et d’Artemisia afra appartiennent à cette catégorie et sont apparus récemment au Bénin. Notre équipe a mené une enquête en 2022 afin de préciser le type de produits vendus, leur origine, leur prix, leur public, et les connaissances et pratiques des acteurs de la « filière Artemisia ». Nous avons interrogé 128 personnes dans 8 des 12 départements que compte le Bénin. Quatre profils de personnes ont été interrogés : des producteurs, des revendeurs, des consommateurs, et des tradipraticiens. Grâce à cette étude, nous avons pu retracer l’origine de l’engouement constaté pour ces plantes, identifier les acteurs clés du secteur, et démontrer la quasi absence des tradipraticiens de cette filière lors de l’enquête. La diversité des produits vendus et de leurs indications a également été remarquée. Les deux espèces A. afra et A. annua semblent être utilisées pour le paludisme d’une manière similaire sans réelle distinction d’efficacité entre les deux. D’un point de vue économique, nous n’avons pas noté de bénéfice clair lié à l’usage des tisanes d’Artemisia comparées aux combinaisons thérapeutiques à base des dérivés de l’artémisinine. Aussi, leur efficacité et leur innocuité chez l’homme restent toujours à démontrer. En conclusion, notre étude permet d’apporter des premières données sur l’utilisation de l’Artemisia au Bénin, et d’identifier différents aspects à éclaircir tels que l’ampleur de l’utilisation, l’impact sanitaire et l’intérêt économique pour les utilisateurs des produits à base d’Artemisia vendus au Bénin

Evidence of Immunosuppressive and Th2 Immune Polarizing Effects of Antidiabetic Momordica charantia Fruit Juice

The mechanism of action of the antidiabetic capacity of Momordica charantia is still under investigation. Here, we assessed phytochemical compositions, antioxidant activity, and effects of total and filtered fruit and leafy stem juices of Momordica charantia on human T cell proliferation and differentiation through quantification of Th1/Th2 cytokines. In the absence of stimulation, total fruit and leafy stem juices induced significant T cell proliferation. Under PHA stimulation, both juices potentiated plant-induced T cell proliferation. However, the filtered fruit and leafy stem juices significantly inhibited PHA-stimulated T cell proliferation, while neither juice influenced T cell proliferation. Moreover, total and filtered fruit juice increased IL-4 secretion, while total and filtered leafy stem juice enhanced IFN-γ production. Phytochemical screening revealed the presence of tannins, flavonoids, anthocyans, steroids, and triterpenoids in both juices. Alkaloids, quinone derivatives, cardenolides, and cyanogenic derivatives were undetectable. The saponins present in total juices were undetectable after filtration. Moreover, both juices had appreciable antioxidant capacity. Our study supports the type 1 antidiabetic effect of filtered fruit juice of M. charantia which may be related to its immunosuppressive and T-helper 2 cell inducing capacities. Due to their immune-stimulatory activities and their ability to increase T-helper 1 cell cytokines, total fruit and leafy stem juices may serve in the treatment of immunodeficiency and certain infections