Vulnérabilité et stratégies endogènes de conservation des plantes utilisées dans le traitement du diabète dans les communes de Glazoué et Savè au Centre-Bénin

Le prélèvement excessif des organes de plantes à des fins médicinales constitue un facteur de menace sur la phytodiversité. Cette étude réalisée dans les communes de Glazoué et Savè au Centre-Bénin, a pour objectif d’évaluer la vulnérabilité et les stratégies endogènes de conservation des plantes utilisées dans le traitement du diabète. A cet effet, des enquêtes ethnobotaniques ont été effectuées auprès de 126 personnes dont 35 femmes et 91 hommes. Les entretiens ont porté sur l’inventaire des plantes antidiabétiques; les différents organes utilisés et commercialisés et les stratégies endogènes de conservation desdites plantes. La méthode d’Evaluation Rapide de Vulnérabilité a été utilisée. Les résultats obtenus montrent que 144 plantes sont utilisées dans le traitement traditionnel du diabète. Trois niveaux de pression ont été distingués. Les niveaux 1 (espèces peu menacées) et 2 (espèces menacées) sont les plus représentés avec respectivement 71 et 41 espèces. Les espèces très menacées (niveau 3) sont au nombre de 18. Parmi celles-ci, Kigelia africana est l’espèce la plus menacée avec un score de 16 points. Au nombre des stratégies endogènes de conservation pratiquées, on note la conservation au champ (21 espèces concernées) et la conservation dans les jardins de case (34 espèces). 75 espèces ne bénéficient d’aucun mode de conservation. En définitive, l’étude a permis d’identifier les plantes antidiabétiques menacées, prioritaires pour la conservation.Mots clés : Gestion durable, enquêtes ethnobotaniques, plantes médicinale

Production Fruitière De Quatre Essences Ligneuses Dans La Forêt De Nassou En Zone Soudanienne Du Bénin

Rural populations are closely dependent on plant resources for their daily needs. Fruit productivity of these species is an indicator of their economic potential and their capacity to regenerate. This is also fundamental to define sustainable management strategies of species. The present study assessed the fruits and seeds productivity of four forest species such as Vitex doniana, Afraegle paniculata, Diospyros mespiliformis and Kigelia africana according to the diameter class of trees. The study was carried out in the Nassou forest in soudanian zone of Benin. 09 to 90 trees belonging to four diameter classes (10-20 cm, 20-30 cm, 30-40 cm, and≥ 40 cm) were sampled for each species. The method used is the counting of fruits fallen under the tree through a periodic collection carried out every five days from the fructification to the end of the cycle and the fall of the last fruit. Seeds were then extracted from fruits. Generalized linear models of Poisson family were used to analyse data. Results revealed that the diameter class on the one hand influence significantly (Prob. ≤ 0.01) the production of fruits of K. africana and V. doniana, and on the other hand the production of seeds of A. paniculata, D. mespiliformis and V. doniana. Overall, fruits and seeds production is higher for the biggest tress (≥ 40 cm). Therefore, the diameter of the four studied species would be very useful for genetic improvement aiming the increasing of their productivity

Identification and Larvicidal Efficacy of Mosquito-Repelling Plants Used in Malaria Vector Control in South-East Benin

After identifying issues posed by some synthetic insecticides, the scientific community is now looking for other natural products with insecticidal and/or insect repellent characteristics. This study aimed to identify the plants of the Beninese flora known for their insecticidal and/or insect repellent effects and the indigenous techniques of their use and to evaluate the combined efficacy of extracts of a few on mosquito larvae for the control of malaria vectors in the South-East of Benin. A survey was conducted and the insecticidal effects of three combinations made from Azadirachta indica, Cymbopogon nardus and Hyptis suaveolens oils on Anopheles gambiae larvae were studied. The data were analyzed using R software, and Chi-square test was used to compare death rates. Twelve (12) plant species were identified. The combinations of C. nardus and H. suaveolens oils induced the highest mortality rates (90 ± 4.15% and 68 ± 9.14% with stages 2 and 3 larvae, respectively). The application of extracts from these plants to control the malaria vectors population would reduce the use of chemical pesticides, hence the need to promote and enhance the formulations of biopesticides based on plant extracts. Keywords:    Plant species, biopesticides, mosquito-repelling plants, vectors. &nbsp

Chemical composition and seasonal variation of essential oil of Sclerocarya birrea (A. Rich.) Hochst subsp birrea leaves from Benin

Essential oils from fresh leaves of Sclerocarya birrea (A. Rich.) Hochst. were extracted by steam distillation. The oil yield from plant collected during the hot season (February) was 0.10±0.02 and 0.24±0.01% from plant collected during the cold season (August). GC/FID and GC/MS analysis allowed us to identify a total of 49 compounds, representing 98% of the hydrodistillate. The oils contained about 96% sesquiterpenes among which 38±0.034% of 7-epi-α-selinene during the hot season and 51.7±0.12% of 7-epi-α- selinene during the cold. The main components of the oil from the hot period were 7-epi-α-selinene (38±0.03%), α-muurolene (25±0.03%), valencene (17±0.06%), β-selinene (4.3±0.01), β-caryophyllene (3.2±0.02) allo-aromadendrene-epoxide (1.5±0.03) and 14-hydrox-α-humulene (1.5±0.03). The essential oil from the cold season was characterized by 7-epi-α-selinene (51.7±0.12%), β-selinene (15.1±0.2%), valencene (12.9±0.05%), α-selinene (8.1±0.03) and β-caryophyllene (1.8±0.02%). This is the first report of these components in the essential oil of Sclerocarya birrea

Chemical composition and biological activities of extracts and essential oil of Boswellia dalzielii leaves

Context: Boswellia dalzielii Hutch. (Burseraceae) is an aromatic plant. The leaves are used for beverage flavouring. Objective: This study investigates the chemical composition and biological activities of various extracts. Materials and methods: The essential oil was prepared via hydrodistillation. Identification and quantification were realized via GC-MS and GC-FID. Consecutive extractions (cyclohexane, dichloromethane, ethyl acetate and methanol) were carried out and various chemical groups (phenolics, flavonoids, tannins, antocyanins and sugar) were quantified. The volatile compounds of organic extracts were identified before and after derivatization. Antioxidant, antihyperuricemia, anti-Alzheimer, anti-inflammatory and anticancer activities were evaluated. Results: In the essential oil, 50 compounds were identified, including 3-carene (27.72%) and α-pinene (15.18%). 2,5-Dihydroxy acetophenone and β-d-xylopyranose were identified in the methanol extract. Higher phenolic (315.97 g GAE/kg dry mass) and flavonoid (37.19 g QE/kg dry mass) contents were observed in the methanol extract. The methanol extract has presented remarkable IC50 = 6.10 mg/L for antiDPPH, 35.10 mg/L for antixanthine oxidase and 28.01 mg/L for anti-5-lipoxygenase. For acetylcholinesterase inhibition, the best IC50 (76.20 and 67.10 mg/L) were observed, respectively, with an ethyl acetate extract and the essential oil. At 50 mg/L, the dichloromethane extract inhibited OVCAR-3 cell lines by 65.10%, while cyclohexane extract inhibited IGROV-1 cell lines by 92.60%. Discussion and conclusion: Biological activities were fully correlated with the chemical groups of the extracts. The ethyl acetate and methanol extracts could be considered as potential alternatives for use in dietary supplements for the prevention or treatment of diseases because of these extracts natural antioxidant, antihyperuricemic and anti-inflammatory activities

Traditional ecological knowledge-based assessment of threatened woody species and their potential substitutes in the Atakora mountain chain, a threatened hotspot of biodiversity in Northwestern Benin, West Africa

Abstract Background Atakora mountains in Benin are a unique but fragile ecosystem, harboring many endemic plant species. The ecosystem is undergoing degradation, and the woody vegetation is dramatically declining due to high anthropogenic actions and recurrent drought. This study aimed to (i) assess the diversity of threatened woody species and (ii) identify their potential substitutes in the three regions of the Atakora mountains namely East Atakora, Central Atakora, and West Atakora. Methods The data were collected during expeditions on surveyed localities through semi-structured individual interviews. Free-listing was used to record threatened woody species and which were important and why. Alpha-diversity indices were used to assess diversity of threatened and important threatened woody species. A correspondence analysis was used to determine the reason supporting their importance. Differences in species composition were assessed using analysis of similarities. A number of potential substitutes were compared among species using generalized linear models. Results A total of 117 woody species (37 families and 92 genera) were identified. The most prominent families were Fabaceae (19.66%), Combretaceae (12.82%), and Moraceae (10.26%), and the richest genera were Ficus (10 species), Combretum (6), and Terminalia (5). Most threatened species differed across regions (East Atakora, Central Atakora, and West Atakora) and included Afzelia africana, Anogeissus leiocarpa, Borassus aethiopum, Diospyros mespiliformis, Khaya senegalensis, Milicia excelsa, and Pterocarpus erinaceus. Most socio-economically important species (K. senegalensis, Parkia biglobosa, Vitellaria paradoxa, and V. doniana) were used mainly for food, timber, and fuelwood purposes. Old and adult people, and Dendi and Fulfulde sociolinguistic groups had greater knowledge of threatened woody plant species. High intercultural differentiations in species composition were detected between Bariba-Berba and Bariba-Natimba. Knowledge of substitutes also differed across regions with P. erinaceus, Isoberlinia spp., and A. africana being the most cited substitutes. Conclusion Basic data was provided here to inform decision and guide efficient management of woody resources. There was evidence that immediate conservation measures are required for some high economic value woody taxa which were critically threatened. Ex-situ conservation of these species while promoting their integration into agroforestry-based systems were recommended. Besides, community-based management programs and community-led initiatives involving knowledgeable people from different horizons will lead to a long-lasting conservation of these threatened resources

Traditional ecological knowledge-based assessment of threatened woody species and their potential substitutes in the Atakora mountain chain, a threatened hotspot of biodiversity in Northwestern Benin, West Africa

Abstract Background Atakora mountains in Benin are a unique but fragile ecosystem, harboring many endemic plant species. The ecosystem is undergoing degradation, and the woody vegetation is dramatically declining due to high anthropogenic actions and recurrent drought. This study aimed to (i) assess the diversity of threatened woody species and (ii) identify their potential substitutes in the three regions of the Atakora mountains namely East Atakora, Central Atakora, and West Atakora. Methods The data were collected during expeditions on surveyed localities through semi-structured individual interviews. Free-listing was used to record threatened woody species and which were important and why. Alpha-diversity indices were used to assess diversity of threatened and important threatened woody species. A correspondence analysis was used to determine the reason supporting their importance. Differences in species composition were assessed using analysis of similarities. A number of potential substitutes were compared among species using generalized linear models. Results A total of 117 woody species (37 families and 92 genera) were identified. The most prominent families were Fabaceae (19.66%), Combretaceae (12.82%), and Moraceae (10.26%), and the richest genera were Ficus (10 species), Combretum (6), and Terminalia (5). Most threatened species differed across regions (East Atakora, Central Atakora, and West Atakora) and included Afzelia africana, Anogeissus leiocarpa, Borassus aethiopum, Diospyros mespiliformis, Khaya senegalensis, Milicia excelsa, and Pterocarpus erinaceus. Most socio-economically important species (K. senegalensis, Parkia biglobosa, Vitellaria paradoxa, and V. doniana) were used mainly for food, timber, and fuelwood purposes. Old and adult people, and Dendi and Fulfulde sociolinguistic groups had greater knowledge of threatened woody plant species. High intercultural differentiations in species composition were detected between Bariba-Berba and Bariba-Natimba. Knowledge of substitutes also differed across regions with P. erinaceus, Isoberlinia spp., and A. africana being the most cited substitutes. Conclusion Basic data was provided here to inform decision and guide efficient management of woody resources. There was evidence that immediate conservation measures are required for some high economic value woody taxa which were critically threatened. Ex-situ conservation of these species while promoting their integration into agroforestry-based systems were recommended. Besides, community-based management programs and community-led initiatives involving knowledgeable people from different horizons will lead to a long-lasting conservation of these threatened resources

Densitometric HPTLC quantification of asiaticoside isolated from Centella asiatica (L.) Urb (Apiaceae) of Benin

Asiaticoside isolated from Centella asiatica has been found through in vitro test to serve as an active agent of healing on wounds. To quantify this compound in Centella asiatica cultivated in Benin, a new, simple and rapid High-Performance Thin-Layer Chromatography (HPTLC) method was developed and validated for its selectivity, its recovery, and its repeatability. Compounds have been separated on silica gel 60F254 plates with ethyl acetate/methanol/water (100/25/10, v/v/v), as mobile phase. The detection was done by densitometry scanning at λ = 600 nm and the calibration plots showed that the graphical response was linear and dependent on the quantity in the range of 2.50- 12.50 μg, with good values of R² = 0.998. This method is repeatable and precise with relative standard deviations between1.42 and 5.92% for the intra-day tests and between 1.27 and 6.57% for the inter-day tests for the quantities belonging to an interval of 2.50 and 12.50 μg. The limits of detection and quantification were 0.317 and 1.05 μg respectively. The quantity of asiaticoside found was 0.24% in the alcoholic extract