ASSESSMENT OF PHYTOCHEMICALS AND ANTIMICROBIAL ACTIVITIES OF OLIVE (OLEA EUROPAEA L.) LEAVES EXTRACTS AGAINST FOODBORNE BACTERIAL PATHOGENS

Abstract

D.Olive (Olea europaea) leaves are a potential source of bioactive phytochemicals that may have applications against foodborne bacteria. The present study evaluated the phytochemical profile and antibacterial activity of olive leaf methanolic, ethanolic, and aqueous decoction extracts against selected Gram-positive and Gram-negative foodborne bacteria. Phytochemical screening revealed the presence of glycosides, saponins, flavonoids, tannins, alkaloids, and phenols in the tested extracts, with the methanolic extract showing the highest qualitative detection levels, particularly for flavonoids and phenols. Antibacterial activity was evaluated by determining the zone of inhibition (ZI), minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC). All three extracts exhibited inhibitory activity against the tested bacteria. The methanolic extract produced inhibition zones of 9–18 mm, with MIC and MBC values ranging from 50–100 and 100–200 mg/mL, respectively. The ethanolic extract produced inhibition zones of 8–17 mm, with MIC and MBC values of 100–150 and 150–300 mg/mL, respectively. The aqueous decoction produced inhibition zones of 7–16 mm, with MIC and MBC values of 200–250 and 400–500 mg/mL, respectively. Among the tested bacteria, Staphylococcus aureus showed the largest inhibition zones, whereas Pseudomonas aeruginosa showed the smallest. The findings demonstrate that olive leaves contain diverse phytochemicals and possess antibacterial activity against foodborne bacteria, with the methanolic extract showing the lowest MIC and MBC values among the tested extracts.