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Evaluation of antioxidant activity of olive leaf extract obtained by ultrasound-assisted extraction and their antimicrobial activity against bacterial pathogens from food |
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| Authors: | Jasminka Giacometti Sanja Milovanovi? Diana Jurc\?i? Momc\?ilovi? Marina Bubonja-S\?onje |
| Affiliation: | 1. Department of Biotechnology, University of Rijeka, Radmile Matejc\?i? 2, Rijeka, HR-51000 Croatia;2. Department of Biotechnology, University of Rijeka, Radmile Matejc\?i? 2, Rijeka, HR-51000 Croatia
Contribution: ?Investigation (equal), Methodology (equal), Visualization (equal);3. Clinical Department for Clinical Microbiology, Clinical Hospital Center Rijeka, Kres\?imirova 42, Rijeka, HR-51000 Croatia Contribution: ?Investigation (equal), Methodology (equal), Visualization (equal);4. Clinical Department for Clinical Microbiology, Clinical Hospital Center Rijeka, Kres\?imirova 42, Rijeka, HR-51000 Croatia Department of Microbiology and Parasitology, Faculty of Medicine, University of Rijeka, Rijeka, HR-51000 Croatia Contribution: Conceptualization (equal), Data curation (equal), Methodology (equal), Supervision (equal), Visualization (equal) |
| Abstract: | The aim of the present study was to evaluate and compare the phenolic content and antioxidant and antimicrobial properties of olive leaf extracts obtained by ultrasound-assisted extraction (UAE) and conventional extraction (CSE). UAE of olive leaf extracts yielded a higher total phenolic content (TPC) and total flavonoid content (TFC) of 14.31% and 19.50%, respectively. Higher antioxidant activities were found from the extracts prepared with UAE (for 18.5%, 12.5%, 10.9% and 17.6% higher determined by DPPH, ABTS, FRAP and CUPRAC methods, respectively). Good antibacterial inhibitory activity (as MIC and MBC) was observed against both Y. enterocolitica and S. aureus (1.40 ± 0.40 mg mL?1 and 4.00 ± 1.60 mg mL?1, respectively) with the extract prepared with UAE. In conclusion, olive leaf extracts prepared with UAE exhibited higher antioxidant and antimicrobial activities against common food-borne pathogens than CSE extracts and thus could be beneficial in ensuring food quality and food safety. |
| Keywords: | Antimicrobial activity antioxidant activity food quality and safety olive leaf polyphenols total flavonoids total phenolics ultrasound-assisted extraction |