scholarly journals Comparison of Phenolic Compounds in Olive Leaves by Different Drying and Storage Methods

Separations ◽  
2021 ◽  
Vol 8 (9) ◽  
pp. 156
Author(s):  
Shiling Feng ◽  
Chunyan Zhang ◽  
Li Liu ◽  
Zhou Xu ◽  
Tao Chen ◽  
...  

Oleuropein, a bitter substance that exists in olive leaves, can be hydrolyzed to hydroxytyrosol. These are the main phenolic compounds, and they have beneficial properties to human bodies. In this study, we established a simple and new method to determine oleuropein and hydroxytyrosol quickly by HPLC. HPLC conditions were set as follows: water (A) acetonitrile (B) as mobile phase, gradient elution orders: 90%A–10%B for 0–10 min, 80%A–20%B for 14–30 min, and then change to 90%A–10%B for 30–33 min; detection wavelength: 280 nm. Compared with other detection methods, the method simplified the elution procedure and shortened the time. Additionally, we provided a better drying method and preservation of olive leaves in tea drinking production that were air-dried at room temperature of 25 °C.

Nutrients ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1653 ◽  
Author(s):  
Aurélia Malapert ◽  
Valérie Tomao ◽  
Marielle Margier ◽  
Marion Nowicki ◽  
Béatrice Gleize ◽  
...  

Alperujo—a two-phase olive mill waste that is composed of olive vegetation water and solid skin, pulp, and seed fragments - is a highly valuable olive by-product due to its high content in phenolic compounds. In this study, we assessed whether β-cyclodextrin (β-CD), which is used to extract and protect alpejuro phenolic compounds (hydroxytyrosol-O-glucoside, tyrosol, caffeic, and p-coumaric acids) could impact on their bioaccessibility (i.e., the percentage of molecule found in the aqueous phase of the digesta) and uptake by intestinal cells, by using an in vitro digestion model and Caco-2 TC7 cells in culture, respectively. Our results showed that β-CD did not change the bioaccessibility of the selected phenols. Hydroxytyrosol-O-glucoside and caffeic did not cross Caco-2 cell monolayers. Conversely ferulic acid, identified as the main caffeic acid intestinal metabolite, was absorbed through intestinal cell monolayers (~20%). Interestingly, β-CD moderately but significantly improved the local absorption of tyrosol and p-coumaric acid (2.3 + 1.4% and 8.5 ± 4.2%, respectively, p < 0.05), even if their final bioavailability (expressed as bioaccessibility × absorption by Caco-2 cells) was not modified (16.2 ± 0.6% vs. 16.8 ± 0.5% for tyrosol and 32.0 ± 3.2% vs. 37.2 ± 3.2% for p-coumaric acid, from pure alperujo and alperujo complexed with β-CD, respectively). Overall, our results show that β-CD is an interesting extraction and storage agent for phenolic compounds that does not alter their in vitro bioavailability.


2016 ◽  
Vol 8 (5) ◽  
pp. 635-645 ◽  
Author(s):  
Johan Spens ◽  
Alice R. Evans ◽  
David Halfmaerten ◽  
Steen W. Knudsen ◽  
Mita E. Sengupta ◽  
...  

2021 ◽  
Vol 11 (22) ◽  
pp. 10519
Author(s):  
Nguyễn Hoàng Ly ◽  
Sang Jun Son ◽  
Ho Hyun Kim ◽  
Sang-Woo Joo

Many scientists are increasingly interested in on-site detection methods of phenol and its derivatives because these substances have been universally used as a significant raw material in the industrial manufacturing of various chemicals of antimicrobials, anti-inflammatory drugs, antioxidants, and so on. The contamination of phenolic compounds in the natural environment is a toxic response that induces harsh impacts on plants, animals, and human health. This mini-review updates recent developments and trends of novel plasmonic resonance nanomaterials, which are assisted by various optical sensors, including colorimetric, fluorescence, localized surface plasmon resonance (LSPR), and plasmon-enhanced Raman spectroscopy. These advanced and powerful analytical tools exhibit potential application for ultrahigh sensitivity, selectivity, and rapid detection of phenol and its derivatives. In this report, we mainly emphasize the recent progress and novel trends in the optical sensors of phenolic compounds. The applications of Raman technologies based on pure noble metals, hybrid nanomaterials, and metal–organic frameworks (MOFs) are presented, in which the remaining establishments and challenges are discussed and summarized to inspire the future improvement of scientific optical sensors into easy-to-operate effective platforms for the rapid and trace detection of phenol and its derivatives.


2002 ◽  
Vol 34 (3) ◽  
pp. 247-259
Author(s):  
Dragica Minic-Popovic ◽  
M.V. Susic

Once hydrogen is generated, the question asked: How do we store hydrogen? Hydrogen can be stored in a variety of ways, each with specific advantages and disadvantages. The overall criteria for choosing a storage method should be safety and ease of use. Described in this paper and listed below are different storage methods available today (compressed hydrogen, liquid carrier storage, glass microsphere, chemically stored hydrogen) in addition to some techniques that are still in the research and development stage: power balls, metal hydride tanks and carbon clusters.


Botanica ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 76-87
Author(s):  
Aziza Lfitat ◽  
Hind Zejli ◽  
Abdelkamel Bousselham ◽  
Yassine El Atki ◽  
Badiaa Lyoussi ◽  
...  

AbstractWe conducted this study to determine and compare the content of phenolic compounds and flavonoids in the argan and olive leaves as well as their antioxidant capacity in aqueous, methanolic, and ethyl acetate extracted fractions. In vitro antioxidant activity was evaluated in comparison with synthetic antioxidants by assessing DPPH• radical scavenging capacity, ferric reducing antioxidant power, scavenging ability by inhibiting the β-carotene/linoleic acid emulsion oxidation, and by the ABTS radical scavenging activity assay. Total phenolic content in argan samples ranged from 221.69 ± 2.07 to 1.32 ± 0.01 mg GAE/g DW and in olive samples from 144.61 ± 0.82 to 1.21 ± 0.02 mg GAE/g DW. Total flavonoids content in argan samples varied from 267.37 ± 1.12 to 25.48 ± 0.02 mg QE/g DW, while in olives from 96.06 ± 0.78 to 10.63 ± 0.05 mg QE/g DW. In vitro antioxidant studies strongly confirmed the antioxidant potency of argan and olive leaves and their richness in secondary metabolites that are effective in free radicals scavenging and metal chelating capacities, indicating their antioxidant power.


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