Antioxidant, Antibacterial and Antifungal Effects of Phenolic Extracts of Extra Virgin Olive Oil from Two Western Regions of Algeria: A Comparative Study

Abstract

The aim of the study was to evaluate the antioxidant, antibacterial and antifungal activities of phenolic extracts of extra virgin olive oil obtained from two distinct regions in Northwest Algeria. The first extra virgin oil (CHIALI) was produced industrially according to the international standards, whereas the second (TRAD) was produced by traditional methods. Antioxidant activity was evaluated using the DPPH (diphenylpicrylhydrazine) method. The antimicrobial activity of the two phenolic extracts was assessed against Escherichia coli (ATCC25922), Pseudomonas aeruginosa (ATCC27853), Staphylococcus aureus (ATCC25923), Alternaria sp., Candida albicans by using microdilution and disk diffusion methods. The extraction yield was found to be 26.7% and 20.5% for the industrial (CHIALI) and traditional methods (TRAD), respectively. The phenolic extract of the industrial extra virgin oil exhibited better antioxidant activity (IC50 = 1.56 μg/ml) when compared to those of the traditional oil (IC50 = 6.27 μg/ml). Both phenolic extracts exerted bactericidal and antifungal activities. These activities were more important with the phenolic extract of the industrial oil. Taken together, our results showed that the phenolic extract of the industrial extra virgin oil had better antioxidant, antibacterial and antifungal activities, owing to the extraction methods used.