BackgroundExtracts 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 α-glucosidase inhibition, antioxidant and antibacterial activities of those plants extract: Polygonum senegalensis leaves, and Pseudocedrela kotschyi root.MethodsHydro-alcoholic (50%) extracts were analyzed for their phytochemical content and tested for their inhibition potency on α-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.ResultsEach extract presented significant α-glucosidase inhibition and antioxidant activities. Polygonum senegalensis leaf extracts were the most active in each in vitro assay with an IC50 = 1.5 μg/ml for α-glucosidase inhibition and an IC50 = 6.8 μg/ml for DPPH scavenging, - 4.5 μmol Fe II/g of dry matter - 9366 μmol Trolox / g DW - for FRAP and ORAC values, respectively. IC50 = 2.3 μg 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.ConclusionThe results showed that the semi alcoholic extract of the two studied plants possess α-glucosidase inhibitory activity, antioxidant potency, and low antibacterial effect.

To reduce fossil fuel dependence and greenhouse gases, biomass energy is in high demand. Hura crepitans (HC) is a widely distributed plant species in Benin. But its seed oils are reputed to be purgative and unfit for consumption. So, we collected the seeds of HC in Agame (South of Benin). They were extracted and the seed oils have been converted into biodiesel. First, the quality indices (acid, peroxide, iodine and saponification) were determined. Then, elementary physicochemical parameters and fuel properties of the extracted oil have been highlighted according to standardised methods. Transesterification parameters of the seed oils (alcohol/oil and catalyst/oil ratios, temperature and yield) were also studied. The fatty acids of vegetable oil and the characteristics of its obtained biodiesel were finally identified. It appears that HC seeds have a lipid potential of 52.54%. Its oil is unsaturated and dominated by linoleic acid (54.13%). The yield of the transesterification reaction is 81.47%. The fuel parameters of the obtained biodiesel are: acidity (0.41%); density at 26°C (0.887); cetane number (54.44) compared to those of HC seed oils: acidity (4.81%), density at 26°C (0.929) and cetane number (44.53). The biodiesel obtained by transesterification with potash has much better parameters that comply with biodiesel standards. These results suggest that biodiesel of HC could be proposed to power Diesel engines without a preheating system.

The results brought back at the end of this work concerned various chemical constituents of P. butyracea materials collected in seven forest galleries in northern of Benin. The phytochemical analysis showed mucilage, coumarins, gallic tannins, flavones, sterols, and saponins, in its leaves. The cyclohexanic fractions realized from petroleum ether extracts and analysed by GC/MS were marked by important rates of 9, 19-cyclolanost-24-en-3 -3-ol (49.3-72.6%), taraxasterol (18.4-30.1%), and friedooleanan-3-one (10.0%). Essential oils extracted by hydrodistillation from P. butyracea and analyzed by GC/MS contained 11 to 38 compounds representing 85.2 to 99.5% of the weight of this volatile extracts essentially rich in sesquiterpene constituents. The essential oils predominant compounds (>10%) identified and recorded independently of the organ studied were -caryophyllene (14.9-77.9%), aromadendrene (43