Phytochemical investigation and antibacterial activities of Cordia africana roots extracts

Cordia africana is one of the traditional medicinal plants that is used for the treatment of malaria, liver diseases, stomachaches, and diarrhea. Despite its ethnomedicinal application, the phytochemical composition of its root and its antibacterial activities have not been reported. Therefore, the aim of this study was to investigate the phytochemicals of C. africana root and evaluate its antibacterial activity. The air-dried root of C .africana was sequentially extracted by dichloromethane and methanol (1:1 v/v), and methanol. Phytochemical screening of crude extracts showed the presence of flavonoids, steroids, triterpenoids, phenols, and tannins, while alkaloids were absent. The column chromatographic isolation of the dichloromethane: methanol (1:1 v/v) crude extracts yielded two compounds, compound-GT1 (trilinolein) and compound-GT2 (β-sitosterol). The structure elucidation of the isolated compounds was performed based on data from ¹H-NMR, ¹³C-NMR and DEPT-135 and comparison with reported literature. The isolated compounds and crude extracts were evaluated for their antibacterial activities on four bacterial strains (S. pyogenes ATCC 19,615, S. aureus ATCC 25,923, P. aeruginosa ATCC 2785, and E. coli ATCC 25,922) using the disc diffusion method. Compound-GT2 and methanol extract demonstrated significant growth inhibition compared to ampicillin (12 mm), with a growth inhibition of 11 mm and 11.5 mm at a concentration of 300 μg/ml, observed in P. aeruginosa bacteria. Compound-GT1 (9 mm) and dichloromethane/methanol (1:1 v/v) extract (9 mm) showed moderate activities against S. pyogenes at a concentration of 300 μg/ml. The antibacterial properties of the crude extracts and isolated compounds validate the traditional applications of these plants in curing microbial infections.