Volume 8 Number 3 September 2023

Phytochemical Screening and Assessment of the Antioxidant Activity of the Mucilage Contained in Baobab Leaves and Bark (Adansonia Digitata L) of Senegal

Authors: Babacar Sadikh Yatte ; Diégane Sarr ; Khémesse Kital.
Pages: 56-65
The present work involved determining the chemical composition and assessing the antioxidant activity of the mucilage contained in baobab leaves and bark. The mucilage from each organ was obtained separately in two beakers by extraction with ethanol and acetone. Phytochemical tests revealed the presence of various families of compounds such as alkaloids, flavonoids and tannins in the organic extracts. Antioxidant power was assessedusing the 2,2-diphenyl-1-picrylhydrazyl (DPPH-) radical scavenging method, based on determination of the 50% inhibitory concentration (IC50).This study shows that the solvent and the plant organ affect antioxidant activity. In fact, for ethanolic and acetonic extracts of leaves, the IC50 value varied respectively between 3.58 and 3.98 mg/mL then between 3.83 and 5.32 mg/mL; while for ethanolic and acetonic extracts of bark, the values found varied respectively between 6.49 and 8.12 mg/mL then between 5.51 and 9.11 mg/mL. These results therefore show that organic leaf extracts have a greater DPPH- radical scavenging capacity than organic bark extracts. However, the most powerful antioxidant power is observed in the ethanolic leaf extracts, where the values found are relatively lower and remain below those of ascorbic acid, the reference reducing compound (IC50 = 4.12 mg/mL).A statistical analysis showed that only the leaves had an influence on antioxidant activity, so baobab leaves could be used as a food additive.

Experimental (NMR) and Theoretical (DFT Method) Studies of the Nucleophilic Substitution Reaction of 1-Methyl-4-, 6- and 7-NitroIndazoles by 2-(p-Tolyl) Acetonitrile

Authors: Assoman Kouakou ; Mougo André Tigori ; Cissé M’Bouillé.
Pages: 45-55
Theoretical and experimental study of the reactivity between alkyl nitroindazole molecules and aryl acetonitrile molecules was evaluated by Density Functional Theory (DFT) using a basis set of B3LYP/6-311G (d, p) level and experimental Nuclear Magnetic Resonance (NMR) data. Global quantum chemical parameters derived from DFT showed that these compounds are reactive while NMR data indicated the influence of nitro group on ortho, meta and para positions. The distinction atoms capable of undergoing nucleophilic and electrophilic attacks at the level of each molecule were spread by Fukui functions and dual descriptor. This distinction has helped to explain the mechanism of some nitro derivatives formation. Experimental and theoretical results are convergent and consistent.