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Comparative Extraction of Phenolic Compounds from Olive Leaves Using a Sonotrode and an Ultrasonic Bath and the Evaluation of Both Antioxidant and Antimicrobial Activity
Ist Teil von
Antioxidants, 2022-03, Vol.11 (3), p.558
Ort / Verlag
Switzerland: MDPI AG
Erscheinungsjahr
2022
Quelle
EZB Electronic Journals Library
Beschreibungen/Notizen
A sonotrode ultrasound-assisted extraction of phenolic compounds from olive leaves has been developed using a Box-Behnken design to optimize the effects of solvent composition and ultrasound parameters. The determination of single phenolic compounds was performed by HPLC-MS and the highest recovery in total compounds, oleuropein and hydroxytyrosol was achieved using EtOH/H
O (55:45,
/
), 8 min and 100% of amplitude. The optimal conditions were applied on leaves from seven olive cultivars grown under the same conditions and the results were compared with those found by using a conventional ultrasonic bath, obtaining no statistical differences. Moreover, antioxidant activity by FRAP, DPPH and ABTS in these olive leaf extracts was evaluated and they exhibited a significant correlation with oleuropein and total phenolic content. All cultivars of olive leaf extracts were found to be active against
and methicillin-resistant
with minimum bactericidal concentration (MBC) values) that ranged from 5.5 to 22.5 mg mL
. No extracts showed antimicrobial activity against
. The percentages of mycelium reduction in
ranged from 2.2 and 18.1%. Therefore, sonotrode could be considered as an efficient and fast extraction technique that could be easily scaled-up at industrial level, thus allowing for olive leaves to be revalorized.