Phenolic profile (HPLC-UV) of olive leaves according to extraction procedure and assessment of antibacterial activity

Abstract

Highlights High recovery of olive leaves phenolics via maceration in ethanol-distilled water. Oleuropein is the major compound of extraction with ethanol-distilled water. Phenolics and flavonoids were better recovered from dried than fresh leaves. Caffeic and ferulic acids weren’t detected in fresh leaves compared to dried ones. Ethanol-distilled water extract has antibacterial effect against bacteria tested.

Eco-Friendly Extraction and Characterisation of Nutraceuticals from Olive Leaves

“…The authors, contrarily to us, finally established that water was not a good solvent to extract Olp from olive leaves. The Olp concentration in MF, O, and U water resulted also much higher than that reported by Ghomariet al [48] when cold distilled water was used for the extraction (about 100 mg/kg). On the other hand, higher Olp concentrations were detected by using distilled water at 60 °C (19.3 ± 0.99 mg/g) and distilled water at 60 °C and pH 3 (23.36 ± 0.91 mg/g) [48].…”

“…The Olp concentration in MF, O, and U water resulted also much higher than that reported by Ghomariet al [48] when cold distilled water was used for the extraction (about 100 mg/kg). On the other hand, higher Olp concentrations were detected by using distilled water at 60 °C (19.3 ± 0.99 mg/g) and distilled water at 60 °C and pH 3 (23.36 ± 0.91 mg/g) [48]. Similarly, Ansari et al [40] reported that distilled water at 60 °C and pH 3 for 4 h could allow the extraction of a large amount of Olp.…”

Evaluation of phenolic compounds and protective effects of olive (Olea europaea L.) leaf extracts on endothelial cells against hydrogen peroxide-induced toxicity

“…The amounts of hydroxytyrosol, luteolin and rutin were found less than 2.0 mg/g. In another report, they analyzed the olive leaf samples extracted with different solvents (80% ethanol, 20% acetonitrile, and distilled water) by using an HPLC-UV method [18]. For the sample extracted with 80% ethanol, oleuropein (29.5 mg/g) was found the major compound.…”

“…In another report, the usage of olive leaves was emphasized as an antioxidant source in pharmaceuticals [23]. Ghomari and co-workers worked on antibacterial activities of phenolic compounds against pathogenic bacteria and demonstrated that oleuropein showed a strong antibacterial activity [18]. It has been demonstrated that olive phenolic compounds, especially oleuropein or hydroxytyrosol exhibit L-type Ca 2+ channel antagonistic effects [24] and protect against vascular risk through the down-regulation of adhesion molecules [25,26].…”

Antioxidant and antimicrobial activity of olive trees cultivated in the Campanha Gaúcha region

“…Antimicrobial activity is another very important property of the compounds present in olive leaves. Some authors have reported activity against bacteria, such as Escherichia coli, Staphylococcus aureus, Campylobacter jejuni, Listeria monocytogenes e Salmonella spp., among others (Sudjana et al, 2009;Rafiei et al, 2012;Ghomari et al, 2019 ;Bayram et al, 2020).…”