Several studies revealed that oxidative stress was involved in a great number of diseases as a triggering factor or associated with evolutionary complications. Due to the side effects of synthetic molecules, medicinal plants always remained the reliable source of active substances for their therapeutic properties. In effect, this study of antioxidant activity and chemical composition was carried on Hydrocotyle bonariensis, a species frequently used for medical applications in Ivory Coast, but still very under researched. Different extracts obtained with solvents of increasing polarity were tested by the ABTS radical scavenging method and compared to a reference antioxidant, namely vitamin C. Qualitative phytochemical screening was performed according to standard procedures. The results revealed that all extracts significantly and dose-dependently inhibited the ABTS- radical. Ethylacetate and methanolic extracts were most active with IC50 values of 58.8±0.30 and 86.4±0.51 µg/mL, respectively, relative to vitamin C (IC50 = 15.7±0.06 µg/mL). Antioxidant-associated phytocompounds such as flavonoids and coumarins were detected in ethylacetate and methanolic extracts. These compounds were responsible for the ABTS radical reduction reported. This study indicated the presence of substances in Hydrocotyle bonariensis’s leaves, which, in generally are excellent antioxidants and can contribute to prevent various diseases as cardiovascular diseases among others.

The aim of this work is to study phytochemicals and evaluate the antibacterial activity of aqueous and ethanolic extracts of Myrianthus holstii bark on three reference and five clinical strains derived from biological products. The results obtained show that the gives the best extraction yield. Chemical screening revealed the presence of polyphenols, alkaloids, flavonoids, saponosides, quinones, anthocyanins, tannins, terpenoids and sterols in both extracts. The results obtained show that the strains tested have a variable sensitivity for the two extracts and their concentrations. Diffusion and dilution methods on Muller-Hinton were used to evaluate the antibacterial activity of the extracts. The diameters of the inhibition zones are between 8 and 16 mm for the ethanolic extract starting from 25 mg/mL and between 8 and 12 mm for the aqueous extract at 50 mg/mL. The results revealed that these extracts have a dose-dependent antibacterial activity on the bacterial strains used. However, the 70% ethanolic extract has a better antibacterial potential on the strains compared with the aqueous extract, namely on S. aureus (CMI=3.12 mg/mL), E. coli ATCC (CMI=12.5 mg/mL) and S. aureus Meti-R (CMI=12.5 mg/mL). Also, this extract is bactericidal on all strains studied and its MIC ranges from 3.12 to 100 mg/mL after 24 and 48 hours of incubation. This study showed that extracts of Myrianthus holstii could be used in the treatment of infectious diseases.

The objective of this study was to perform the determination of polyphenol and antioxidant activity evaluation of aqueous and methanolic extracts of Tetrapleura tetraptera (Fabaceae) leaves, a plant that is used in the traditional treatment of diabetes in Western Côte d’Ivoire. The quantitative estimation of total phenol contents by the colorimetric method showed that Methanolic Extract (ME) of leaves at 170 ± 0.88 mg GAE/g of extracts while Aqueous Extract (AqE) contains 140 ± 6.9 mg GAE/g of extracts. For flavonoids, the amount determined for ME is 87.33 ± 0.45 mg EQ/g of extracts, while AqE of leaves gave 54.66 ± 5.9 mg EQ/g. The results obtained indicate that ME of leaves from T. tetraptera contains more polyphenol compounds than AqE of leaves. The evaluation of the antioxidant activity of the various extracts was carried out according to two methods: the trapping of free radicals by the DPPH and the measurement of reducing power (FRAP). The antiradicalar power of ME of leaves gave an CI50 = 03.80 ± 0.97 μg/mL close to vitamin C (CI50 = 01.25 0.02 μg/mL) and higher than that of AqE of leaves with an CI50 = 08.60 ± 0.5 μg/mL. Similarly, for reducing power, ME of leaves with an CI50 = 04.24 ± 0.27 μg/mL, is similarly close to vitamin C (CI50 = 04.08 ± 0.01 μg/mL) and more effective than AqE of leaves (CI50 = 24.80 ± 0.37). So, this antioxidant activity could be an additional asset for the use of this plant in the traditional treatment of diabetes and other pathologies related to oxidative stress.