Evaluation of the Antibacterial Activity of Ethanolic Leaf Extract of Capparis spinosa Against a Clinical Escherichia coli Isolate

Abstract

This study aimed to evaluate the inhibitory effect of ethanolic leaf extract of Capparis spinosa against a clinical Escherichia coli isolate using concentrations of 100, 300, 360, and 700 mg/ml. Preliminary chemical screening indicated the presence of a significant amount of saponins, alongside low levels of flavonoids and tannins. The antibacterial activity was assessed using the agar diffusion method. The results demonstrated that the ethanolic leaf extract of C. spinosa exhibited no antibacterial activity against the clinical E. coli isolate, as no inhibition zones were observed at any tested concentration. This lack of activity may be attributed to factors such as low concentrations of active compounds, limited permeability through the Gram-negative bacterial outer membrane, and potential degradation of heat-sensitive components during the extraction process. In contrast, the positive control antibiotics Cefotaxime (40 mm), Amikacin (16 mm), and Amoxicillin (28 mm) showed activity, while Penicillin showed no inhibition. The study concludes that the effectiveness of plant extracts is highly dependent on the solvent, extraction method, chemical composition, and the specific bacterial strain.