Optimization of Ultrasound-Assisted Extraction of Flavonoids from Olive (Olea europaea) Leaves, and Evaluation of Their Antioxidant and Anticancer Activities

Olea europaea leaves are the major byproduct of olive farming. In this study, ultrasound-assisted extraction of flavonoids from olive leaves was optimized using response surface methodology, and the flavonoid compounds and their antioxidant and anticancer activities were investigated by high performance liquid chromatography. The results showed that the optimized conditions for achieving the maximum yield of flavonoids (74.95 mg RE/g dm) were 50 °C temperature, 270 W power, 50 min time, and 41 mL/g liquid-solid ratio. There was a significant difference in the total flavonoid content between the aged and young leaves harvested in April and July, and six main components were quantified. Among them, luteolin-4’-O-glucoside was the most predominant flavonoid compound, followed by apigenin-7-O-glucoside and rutin. Olive leaves also contained small amounts of luteolin, apigenin, and quercetin. Additionally, excellent antioxidant activity was exhibited when tested with the DPPH assay; superoxide radical-scavenging ability and reducing power was also tested. The anticancer activity of the flavonoids was assessed using HeLa cervical cancer cells, and it was observed that increasing concentrations of olive leaf flavonoids resulted in decreased cancer cell viability. These results suggest that the flavonoids from olive leaves could be used as a potential source of natural antioxidants for the pharmaceutical and food industries.

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Ultrasound-Assisted Extraction of Polyphenolic Antioxidants from Olive (Olea europaea) Leaves Using a Novel Glycerol/Sodium-Potassium Tartrate Low-Transition Temperature Mixture (LTTM)

Environments ◽

10.3390/environments4020031 ◽

2017 ◽

Vol 4 (2) ◽

pp. 31 ◽

Cited By ~ 17

Author(s):

Marianna Dedousi ◽

Valentina Mamoudaki ◽

Spyros Grigorakis ◽

Dimitris Makris

Keyword(s):

Transition Temperature ◽

Olea Europaea ◽

Ultrasound Assisted Extraction ◽

Sodium Potassium ◽

Sodium Potassium Tartrate ◽

Potassium Tartrate ◽

Assisted Extraction ◽

Polyphenolic Antioxidants ◽

Ultrasound Assisted ◽

Olea Europaéa

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Experimental and modeling study of polyphenols in Olea europaea leaves through ultrasound-assisted extraction

Journal of the Turkish Chemical Society Section A Chemistry ◽

10.18596/jotcsa.508113 ◽

2019 ◽

pp. 383-394

Author(s):

Selin Şahin Sevgili

Keyword(s):

Olea Europaea ◽

Ultrasound Assisted Extraction ◽

Assisted Extraction ◽

Ultrasound Assisted ◽

Olea Europaéa ◽

Modeling Study

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Optimization of Ultrasound-Assisted Extraction of Phloretin and Other Phenolic Compounds from Apple Tree Leaves (Malus domestica Borkh.) and Comparison of Different Cultivars from Estonia

Antioxidants ◽

10.3390/antiox10020189 ◽

2021 ◽

Vol 10 (2) ◽

pp. 189

Author(s):

Sana Ben-Othman ◽

Hedi Kaldmäe ◽

Reelika Rätsep ◽

Uko Bleive ◽

Alar Aluvee ◽

...

Keyword(s):

Antioxidant Activity ◽

Apple Tree ◽

Maximum Yield ◽

Plant Secondary Metabolites ◽

Polyphenolic Compounds ◽

Tree Leaves ◽

Ultrasound Assisted Extraction ◽

Assisted Extraction ◽

Ultrasound Assisted ◽

Promising Source

Polyphenolic compounds, plant secondary metabolites essential for plant survival, are known for their high antioxidant and anti-inflammatory activity. In addition, several polyphenols, such as phloretin, also have potential antiviral effects, making these compounds potential ingredients of biofunctional foods. A promising source for the extraction of phloretin is a by-product of apple production—apple tree leaves. Focusing on green technologies, the first aim of the present study was to optimize the direct ultrasound-assisted extraction conditions to gain the maximum yield of phloretin from air-dried apple leaves. For the optimization of process parameters, we applied the response surface method with Box–Behnken design. The optimal extraction conditions were extraction time 14.4 min, sonication amplitude 10% and 10 g of sample per 100 mL solvent (70% ethanol, w/w). Using these conditions, we assessed the content of individual and total polyphenolic compounds along with antioxidant activity in the leaves of different autumn and winter apple cultivars grown in Estonia. The analyses were carried out with chromatographic (HPLC-DAD-MS/MS) and spectrophotometric methods. The phloretin concentration ranged from 292 to 726 µg/g and antioxidant activity from 6.06 to 11.42 mg GA eq./g, these being the highest in the local winter cultivars ‘Paide taliõun’ and ‘Tellissaare’, respectively.

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Optimization of ultrasound-assisted extraction of phenolic compounds: Oleuropein, phenolic acids, phenolic alcohols and flavonoids from olive leaves and evaluation of its antioxidant activities

Industrial Crops and Products ◽

10.1016/j.indcrop.2018.07.070 ◽

2018 ◽

Vol 124 ◽

pp. 382-388 ◽

Cited By ~ 43

Author(s):

Maria Irakli ◽

Paschalina Chatzopoulou ◽

Loukia Ekateriniadou

Keyword(s):

Phenolic Compounds ◽

Phenolic Acids ◽

Antioxidant Activities ◽

Olive Leaves ◽

Ultrasound Assisted Extraction ◽

Assisted Extraction ◽

Ultrasound Assisted ◽

Phenolic Alcohols

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Effects of Ultrasound-Assisted Extraction and Solvent on the Phenolic Profile, Bacterial Growth, and Anti-Inflammatory/Antioxidant Activities of Mediterranean Olive and Fig Leaves Extracts

Molecules ◽

10.3390/molecules25071718 ◽

2020 ◽

Vol 25 (7) ◽

pp. 1718 ◽

Cited By ~ 5

Author(s):

Cristina Alcántara ◽

Tihana Žugčić ◽

Radhia Abdelkebir ◽

Jose V. García-Pérez ◽

Anet Režek Jambrak ◽

...

Keyword(s):

Bioactive Compounds ◽

Bacterial Growth ◽

Extraction Methods ◽

Olive Leaves ◽

Ultrasound Assisted Extraction ◽

Phenolic Profile ◽

Assisted Extraction ◽

Ultrasound Assisted ◽

Conventional Extraction ◽

Anti Inflammatory

Mediterranean plants, such as fig and olive leaves, are well-known to exert beneficial effects in humans because of the presence of a wide range of bioactive compounds. However, scarce information regarding the impact of extraction methods, such as ultrasound and types of solvents, on their profile of antioxidant and anti-inflammatory compounds is provided. In addition, no information is available on the effects of extraction methods and solvents on the inhibition of pathogenic bacteria or promoting probiotic growth. In this scenario, this study was aimed to study the effects of ultrasound-assisted extraction (UAE) and solvent on the phenolic profile (Triple TOF-LC-MS/MS), antioxidant and anti-inflammatory compounds of olive and fig leaves. Results showed that UAE extracted more carotenoids compared to conventional extraction, while the conventional extraction impacted on higher flavonoids (olive leaves) and total phenolics (fig leaves). The antioxidant capacity of aqueous extract of fig leaves was three times higher than the extract obtained with ethanol for conventional extraction and four times higher for UAE. In general terms, hydroethanolic extracts presented the highest bacterial growth inhibition, and showed the highest anti-inflammatory activity. In conclusion, these side streams can be used as sources of bioactive compounds for further development of high-added-value products.

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Ultrasound-Assisted Extraction, Antioxidant and Anticancer Activities of the Polysaccharides from Rhynchosia minima Root

Molecules ◽

10.3390/molecules201119734 ◽

2015 ◽

Vol 20 (11) ◽

pp. 20901-20911 ◽

Cited By ~ 11

Author(s):

Xuejing Jia ◽

Chao Zhang ◽

Jie Hu ◽

Muxue He ◽

Jiaolin Bao ◽

...

Keyword(s):

Anticancer Activities ◽

Ultrasound Assisted Extraction ◽

Assisted Extraction ◽

Ultrasound Assisted

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Multivariate optimization of an ultrasound-assisted extraction procedure for Cu, Mn, Ni and Zn determination in ration to chickens

Anais da Academia Brasileira de Ciências ◽

10.1590/s0001-37652013000300005 ◽

2013 ◽

Vol 85 (3) ◽

pp. 891-902 ◽

Cited By ~ 7

Author(s):

JOELIA M. BARROS ◽

MARCOS A. BEZERRA ◽

GISSELI S. VALASQUES ◽

BARAQUIZIO B. DO NASCIMENTO JUNIOR ◽

ANDERSON S. SOUZA ◽

...

Keyword(s):

Optimization Techniques ◽

Multivariate Optimization ◽

Ultrasound Assisted Extraction ◽

Flame Atomic Absorption ◽

Assisted Extraction ◽

Relative Standard ◽

Significant Difference ◽

Copper Manganese ◽

Ultrasound Assisted ◽

Zinc Determination

In this work, multivariate optimization techniques were used to develop a method based on the ultrasound-assisted extraction for copper, manganese, nickel and zinc determination from rations for chicken nutrition using flame atomic absorption spectrometry. The proportions of extracting components (2.0 mol.L–1 nitric, hydrochloric and acetic acid solutions) were optimized using centroid-simplex mixture design. The optimum proportions of this mixture taken as percentage of each component were respectively 20%, 37% and 43%. Variables of method (sample mass, sonication time and final acid concentration) were optimized using Doehlert design. The optimum values found for these variables were respectively 0.24 g, 18s and 3.6 mol.L–1. The developed method allows copper, manganese, nickel and zinc determination with quantification limits of 2.82; 4.52; 10.7; e 9.69 µg.g–1, and precision expressed as relative standard deviation (%RSD, 25 µg.g–1, N = 5) of 5.30; 2.13; 0.88; and 0.83%, respectively. This method was applied in the analytes determination from chicken rations collected from specialized commerce in Jequié city (Bahia State/Brazil). Application of paired t-test at the obtained results, in a confidence level of 95%, does not show significant difference between the proposed method and the microwave-assisted digestion.

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