Antibacterial effect of phenolic extract of olive tree on some pathogenic bacteria

Abstract

There is a growing problem of antibiotic resistance that requires new approaches and an urgent research on novel therapeutic strategies and antibacterial drugs. Olive fruit is one of the most popular mediterranian food. Phenolic metabolites (polyphenols) exhibit a series of biological properties that promotes human health. Olive tree (Olea europaea) can confer significant benefits to the human health, which motivated us to undertake the present study on its main benefits molecules (polyphenols) especially of other olive parts that are less used in humain therapy, since there are numerous findings about olive oil. The main objectiv of the present study was to valorize some parts of olive to evaluate their antibacterial effect in order to contribute to the development of an understanding of nutritional and clinical use. For this, total polyphenols were extracted from two algerian olive varieties (O. europaea); Chemlal and Sigoise using methanol. The polyphenol content was 0.17 ± 0.0006 and 0.05 ± 0.0031 μg / ml for the pulp and 0.0015 ± 0.12 and 0.08 ± 0,001μg / ml for the core respectively for the two varieties. Olive leaves had 0.08 ± 0.001 mg / ml of polyphenols. Leaves ethyl acetate extracts have shown high phenolic content (0.139 ± 0.011 μg / ml). Higher amounts (0.10 ± 0.001and 0.11 ± 0.0032 μg / ml) were registred for pulp and core respectively of the variety Sigoise. Antibacterial tests showed significant results represented by inhibition areas of 22 mm ± 1.41 for Staphylococcus aureus and Salmonella enteritidis and only 8.5 mm ± 0.71 for Listeria monocytogenes. No effect was observed for Escherichia coli. According to the results of this study, olive parts, especially leaves can be considered as a good source of antimicrobial agents that can be provided with a very low price and then can be used in medicine. For that, it is very interesting to continue valorizing other varieties of olive as described in the present study or for other uses.