Chemical Characterization and Evaluation of the Antioxidant and Antibacterial Activities of Methanolic Extracts of the Root Bark of <i>Terminalia</i><i> </i><i>Avicennioides</i> (Combretaceae)

Terminalia avicennioides is a plant widely used in the Central African Republic for the treatment of numerous pathologies with anti-inflammatory components. The main objective of this study was to identify the chemical constituents and evaluate the antioxidant and antibacterial activities of Terminalia avicennioides root bark extracts. The phytochemical study showed that the methanolic extract was the best extraction solvent with a yield of 21.78%. Qualitative analysis revealed the presence of flavonoids, tannins, saponins, sterols and triterpenes. Quantitative analysis showed that the methanolic extract had a high total phenolic content, i.e. 2149 ± 1391,10 mg EqAG/g Ms. Evaluation of the free radical scavenging capacity of methanolic extracts of Terminala. avicennioides using the DPPH method gave a moderate IC50 value with an R2 = 0,75. The antimicrobial activity against Staphylococcus aureus and Escherichia coli was studied using the diffusion method. The zone of inhibition, inhibitory concentration and minimum bactericidal concentration of the extracts on the organisms were evaluated. The methanolic extract inhibited the growth of E. coli and S. aureus with MICs between 0,45-4,00 µg/mL and MBCs between 4,50-22,2 µg/mL. The root bark of T. avicennioides showed significant antibacterial activity due to its high content of polyphenolic compounds.