Olive leaf is a rich source of phenolic compounds with numerous activities related to skin health and appearance. In this study, a green extraction method was developed using eco-friendly solvents: ...polypropylene glycol (PPG), lactic acid (LA), and water. The optimal extraction conditions were established, including solvent, extraction time, technique (magnetic stirrer vs. ultrasound-assisted extraction), and herbal material/solvent ratio. The composition of the solvent mixture was optimized using a mixture design. The content of phenolic compounds, including oleuropein and verbascoside, was determined using high-performance liquid chromatography (HPLC) and spectrophotometric methods. Using different extraction conditions, three extracts were prepared and their phytochemical compositions and antioxidant and skin-related bioactivities were investigated. The extracts were excellent inhibitors of elastase, collagenase, tyrosinase, and lipoxygenase. The best activity was shown by the extract richest in phenolics and prepared using magnetic-stirrer-assisted extraction for 20 min, with 0.8 g of herbal material extracted in 10 mL of PPG/LA/water mixture (28.6/63.6/7.8,
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), closely followed by the extract prepared using the same extraction conditions but with 0.42 g of herbal material. The investigated PPG/LA/water mixtures contributed to the overall enzyme-inhibitory activity of the extracts. The prepared extracts were appropriate for direct use in cosmetic products, thus saving the time and energy consumption necessary for the evaporation of conventional solvents.
Polifenolni spojevi, zaostali u komini koja je nusproizvod u proizvodnji maslinova ulja, antioksidansi su koji imaju pozitivan učinak na ljudsko zdravlje. Za izdvajanje polifenola sve češće se ...primjenjuju prirodna eutektička otapala koje karakterizira netoksičnost, biorazgradljivost, nezapaljivost te niska cijena. U ovom radu upotrijebljeno je prirodno niskotemperaturno eutektičko otapalo (NADES) pripravljeno od triju komponenti: DL-jabučne kiseline, D-fruktoze i glicerola (MaFruGly) s različitim udjelima vode koji omogućavaju uspješnu ekstrakciju polifenola. Određena je optimalna metoda ekstrakcije, a nakon provedene ekstrakcije, ekstrakti su podvrgnuti mikrobiološkoj analizi te je praćena stabilnost izdvojenih polifenola. Istraživanje je pokazalo da su najuspješnije metode za ekstrakciju polifenola mikrovalno ultrazvučna te ekstrakcija ultrazvučnom sondom, a NADES s 30 % vode optimalno otapalo za održavanje stabilnosti polifenola.
Polyphenols, left in olive pomace, which is a by-product in the production of olive oil, are antioxidants that have a positive effect on human health. For the extraction of polyphenols, the use of natural deep eutectic solvents is increasingly encountered, characterised by non-toxicity, biodegradability, nonflammability, and low price. In this work, a natural deep eutectic solvent (NADES) was prepared from three components: malic acid, D-fructose, and glycerol (MaFruGly) with different water contents that allow successful extraction of polyphenols. The optimal extraction method was determined. Following extraction, the microbial activity was tested and stability of the isolated polyphenols monitored. Research has shown that the most successful methods for polyphenol extraction are microwave ultrasound and ultrasonic probe extraction, and NADES with 30 % water has proven to be the optimal solvent for maintaining the stability of polyphenols.
The phytotoxic residues after olive oil production and residue leaves after pruning contain valuable bioactive compounds. A natural deep eutectic solvent (NADES) and an ethanol‐water mixture were ...used for polyphenol extraction from olive pomace and leaves. Type of solvent, extraction temperature, and particle size of the leaves were optimized. NADES demonstrated better efficiency in the extraction process than conventional solvents; with higher temperature and smaller fraction of olive leaves, a higher yield of polyphenols was obtained from leaves. Extraction with a nanofluid as solvent was carried out. A stable nanofluid was prepared from NADES by adding Al2O3 nanoparticles. A higher yield was obtained with nanofluid from leaves, while an improvement of polyphenol extraction was achieved after the removal of oil from olive pomace.
The suitability of the designed green solvent, i.e., natural deep eutectic solvent (NADES), for extraction of bioactive components like polyphenols is demonstrated. The relatively new idea of using a nanofluid prepared in NADES to enhance the extraction process is explored. The application of a nanofluid changes the conditions of the phase boundary and contributes to an improvement in mass transfer.
Natural deep eutectic solvents (NADES) may be considered ‘designer solvents’ due to their numerous structural variations and the possibility of tailoring their physicochemical properties. Prior to ...their industrial application, characterization of NADES is essential, including determination of their physicochemical properties, cytotoxicity, and antioxidative activity. The most important physicochemical properties of eight prepared NADES (choline chloride:malic acid, proline:malic acid, choline chloride:proline:malic acid, betaine:malic acid, malic acid:glucose, malic acid:glucose:glycerol, choline chloride:citric acid, and betaine:citric acid) were measured as functions of temperature and water content. In general, the structure of prepared NADES greatly influences their physical properties, which could be successfully modified and adjusted by addition of water. All tested NADES were absolutely benign and noncorrosive for investigated steel X6CrNiTi18-10. Furthermore, cytotoxicity of prepared solvents was assessed toward three human cell lines (HEK-293T, HeLa, and MCF-7 cells), and antioxidative activity was measured by the Oxygen Radical Absorbance Capacity (ORAC) method. With regard to cell viability, all tested NADES containing carboxylic acid could be classified as practically harmless and considered environmentally safe. The ORAC values indicated that the tested NADES displayed antioxidative activity.
Polifenolni spojevi, zaostali u komini koja je nusproizvod u proizvodnji maslinova ulja, antioksidansi su koji imaju pozitivan učinak na ljudsko zdravlje. Za izdvajanje polifenola sve češće se ...primjenjuju prirodna eutektička otapala koje karakterizira netoksičnost, biorazgradljivost, nezapaljivost te niska cijena. U ovom radu upotrijebljeno je prirodno niskotemperaturno eutektičko otapalo (NADES) pripravljeno od triju komponenti: DL-jabučne kiseline, D-fruktoze i glicerola (MaFruGly) s različitim udjelima vode koji omogućavaju uspješnu ekstrakciju polifenola. Određena je optimalna metoda ekstrakcije, a nakon provedene ekstrakcije, ekstrakti su podvrgnuti mikrobiološkoj analizi te je praćena stabilnost izdvojenih polifenola. Istraživanje je pokazalo da su najuspješnije metode za ekstrakciju polifenola mikrovalno ultrazvučna te ekstrakcija ultrazvučnom sondom, a NADES s 30 % vode optimalno otapalo za održavanje stabilnosti polifenola.
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