Résumé:
This study aims to evaluate the phytochemical composition as well as the antibacterial
and gastroprotective activities of the aqueous extract of Senna alexandrina leaves. An in silico
assessment of the natural compounds, conducted through molecular docking simulations, was
used to analyze their inhibitory potential on ATPase and polymerase. LC-MS QTOF and FTIR
analyses revealed a richness in bioactive compounds, notably polyphenols (28.42 ± 0.4 mg
GAE/g), flavonoids (9.05 ± 0.84 mg QE/g), tannins (0.43 ± 0.026 mg CE/g), and the
characteristic presence of sennosides, anthraquinone compounds typical of the species. The
antibacterial activity was tested against E. coli (ATCC 25922), S. aureus (ATCC 25923), and P.
aeruginosa (ATCC 27853) at various concentrations (0.3125–200 mg/ml). A dose-dependent
effect was observed, with maximum inhibition zones at 200 mg/ml (12 mm for E. coli, 10 mm
for S. aureus, and 9 mm for P. aeruginosa). MIC values were 10 mg/ml for E. coli and S. aureus,
and 200 mg/ml for P. aeruginosa, with no bactericidal effect, indicating a bacteriostatic action,
confirmed by the time-kill assay. The gastroprotective effect was evaluated in mice using
ethanol-induced gastric ulcer model (96%, 0.1 ml/mouse). Two doses of the extract (100 and
200 mg/kg) were administered orally (by gavage), and compared to a positive control group
treated with omeprazole. The results showed a dose-dependent reduction of gastric lesions,
confirmed by a significant decrease in the ulcer index. Histological analysis revealed preserved
mucosal integrity and reduced inflammation in treated groups. Molecular docking studies
supported these experimental results by confirming potential interactions between the plants
major bioactive compounds and various target proteins, notably the bacterial RNA polymerase
enzyme and the gastric receptor (ATPASE proton pump). These findings support the results of
the study, showing a strong correlation with the experimental data.
