Antioxidant Properties and Polyphenol Screening of the Leaves of Native Hungarian Oak (Quercus) Species

2021 ◽  
Vol 17 ◽  
Author(s):  
Tamás Hofmann ◽  
Eszter Visi-Rajczi ◽  
Levente Albert
Keyword(s):  
Antioxidant Capacity ◽  
State Of The Art ◽  
Antioxidant Properties ◽  
Antibacterial Properties ◽  
Flavonoid Glycosides ◽  
Waste Biomass ◽  
Quercus Species ◽  
Tandem Mass Spectrometric ◽  
Liquid Chromatographic ◽  
Phenolic Acid Derivatives

Background: Due to their ecological significance and timber value, Quercus species are especially important in Hungary. Nevertheless, the leaves of these species lack a dedicated utilization field and are considered a waste biomass. Materials and Methods: The present study comprehensively analyses three selected oak species (Q. petraea, Q. pubescens, Q. cerris) native to Hungary to assess their antioxidant capacity (FRAP, ABTS, DPPH) and provide information on their polyphenol pool using state-of-the-art liquid chromatographic/tandem mass spectrometric technique. To the best of our knowledge, no such investigation has yet been conducted for the assigned species. Results: According to the results, the antioxidant capacity of the three species’ leaves are roughly equal. Altogether, 109 compounds have been tentatively identified and described, including phenolic acid derivatives, tannins, flavonoid glycosides, and catechins. Compared to other oak leaf samples and other types of plant tissues, the investigated samples contained a large number (24) of acylated polyphenols. Conclusion: The recent findings on the excellent antioxidant and antibacterial properties of acylated polyphenols suggest that the investigated samples could also be beneficial to human health, requiring further analysis.

HPLC Screening of Bioactives Compounds and Antioxidant Capacity of Different Hypericum Species

2018 ◽  
Vol 69 (2) ◽  
pp. 305-309 ◽  
Author(s):  
Daniela Gitea ◽  
Simona Vicas ◽  
Manuel Alexandru Gitea ◽  
Sebastian Nemeth ◽  
Delia Mirela Tit ◽  
...  
Keyword(s):  
Antioxidant Capacity ◽  
Methanol Extract ◽  
Antioxidant Properties ◽  
Polyphenolic Compounds ◽  
The Other ◽  
The North ◽  
Western Area ◽  
North Western ◽  
Hypericum Species ◽  
Biological Actions

Our study compares the content in polyphenolic compounds and hypericin, in four species of Hypericum - H. perforatum L., H. maculatum Cr., H. hirsutum L., H. tetrapterum Fr. (syn. Hypericumacutum Mnch.) harvested from spontaneous flora in the north-western area of Transylvania, Romania. These species represent an important source of such compounds with different biological actions. After making the extracts, they were subjected to HPLC-SM analysis. The presence of rutoside in the largest amount (462.82 mg %) in the H. perforatum extract was observed, this containing most of the flavonoid heterosides. For the species H. maculatum, the presence in a much higher amount of the hyperoside (976.36 mg %) is characteristic compared to the other species. Quercetol is the best represented of the flavonoid aglycons, its concentration being the highest in H. hirsutum (659.66 mg %). The hypericin content ranges from 0.2171 g % in the H. tetrapterum extract, to 0.0314 g % in the methanol extract of H. maculatum.The highest antioxidant properties measured by FRAP method were recorded in the case of H. perforatum and H. maculatum.

scholarly journals Variation of the Polyphenolic Composition and Antioxidant Capacity of Freshly Prepared Pomegranate Leaf Infusions over One-Day Storage

Antioxidants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1187
Author(s):  
Manyou Yu ◽  
Irene Gouvinhas ◽  
Ana Barros
Keyword(s):  
Antioxidant Capacity ◽  
Gallic Acid ◽  
Antioxidant Properties ◽  
Punica Granatum ◽  
Added Value ◽  
Plant Materials ◽  
Polyphenolic Composition ◽  
Punica Granatum L ◽  
Intensive Search ◽  
By Products

In recent decades, an intensive search for natural and novel types of antioxidant polyphenolics has been carried out on numerous plant materials. However, the current literature has very little information on their storage stability in the form of freshly prepared infusions. This study aims to characterize the polyphenolic composition and the antioxidant capacity of pomegranate (Punica granatum L.) leaf infusions over one-day storage (analyzed at 0, 2, 4, 6, 8, and 24 h). Spectrophotometric evaluation demonstrated that the infusion presented no significant changes in the content of total phenols (131.40–133.47 mg gallic acid g−1) and ortho-diphenols (239.91–244.25 mg gallic acid g−1). The infusion also maintained high stability (over 98% and 82%, respectively) for flavonoids (53.30–55.84 mg rutin g−1) and condensed tannins (102.15–124.20 mg epicatechin g−1), with stable (>90%) potent antioxidant capacity (1.5–2.2 mmol Trolox g−1) throughout 0–24 h storage. The main decrease was observed during 0–2 h storage of flavonoids, 8–24 h storage of tannins, and 0–4 h storage of antioxidant capacity. Chromatographic analysis further revealed that 7 decreased and 11 increased compounds were found within 0–24 h storage. The good stability of the total polyphenolics and antioxidant properties might be related to the complex conversion and activity compensation among these compounds. The findings suggest that pomegranate leaf infusion could be of great interest in the valorization of high added-value by-products and in the application of green and functional alternatives in the food-pharma and nutraceutical industries.

scholarly journals Isolation and structural elucidation of dimeric epigallocatechin-3-gallate autoxidation products and their antioxidant capacity

2021 ◽  
Author(s):  
Julian Alfke ◽  
Uta Kampermann ◽  
Svetlana Kalinina ◽  
Melanie Esselen
Keyword(s):  
Antioxidant Capacity ◽  
Antioxidant Properties ◽  
Cd Spectroscopy ◽  
Trolox Equivalent Antioxidant Capacity ◽  
Published Data ◽  
Dietary Polyphenols ◽  
Cellular Effects ◽  
The Impact

AbstractDietary polyphenols like epigallocatechin-3-gallate (EGCG)—which represents the most abundant flavan-3-ol in green tea—are subject of several studies regarding their bioactivity and health-related properties. On many occasions, cell culture or in vitro experiments form the basis of published data. Although the stability of these compounds is observed to be low, many reported effects are directly related to the parent compounds whereas the impact of EGCG degradation and autoxidation products is not yet understood and merely studied. EGCG autoxidation products like its dimers theasinensin A and D, “P2” and oolongtheanin are yet to be characterized in the same extent as their parental polyphenol. However, to investigate the bioactivity of autoxidation products—which would minimize the discrepancy between in vitro and in vivo data—isolation and structure elucidation techniques are urgently needed. In this study, a new protocol to acquire the dimers theasinensin A and D as well as oolongtheanin is depicted, including a variety of spectroscopic and quadrupole time-of-flight high-resolution mass spectrometric (qTOF-HRMS) data to characterize and assign these isolates. Through nuclear magnetic resonance (NMR) spectroscopy, polarimetry, and especially circular dichroism (CD) spectroscopy after enzymatic hydrolysis the complementary atropisomeric stereochemistry of the isolated theasinensins is illuminated and elucidated. Lastly, a direct comparison between the isolated EGCG autoxidation products and the monomer itself is carried out regarding their antioxidant properties featuring Trolox equivalent antioxidant capacity (TEAC) values. These findings help to characterize these products regarding their cellular effects and—which is of special interest in the flavonoid group—their redox properties.

scholarly journals Studies on the Catalytic Properties of Crude Freeze-Dried Preparations of Yarrowia lipolytica Extracellular Lipases for Geranyl Ester Derivative Synthesis

Biomolecules ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 839
Author(s):  
Karina Jasińska ◽  
Bartłomiej Zieniuk ◽  
Dorota Nowak ◽  
Agata Fabiszewska
Keyword(s):  
Freeze Drying ◽  
Antioxidant Properties ◽  
Antibacterial Properties ◽  
Synthetic Activity ◽  
Drying Process ◽  
Enzyme Preparations ◽  
Ester Derivative ◽  
Freeze Dried ◽  
The Impact ◽  
Geranyl Ester

The study aimed to evaluate the impact of selected factors of the freeze-drying process on the hydrolytic and synthetic activity of the extracellular lipases of Y. lipolytica KKP 379 and to attempt the use of the crude enzyme preparation as a biocatalyst in the synthesis of geranyl 4-hydroxyphenylpropanoate. Antioxidant and antibacterial properties of the geranyl ester derivative were also investigated in order to evaluate their usefulness as a novel food additive. The studies confirmed that freeze-drying was an effective method of dehydrating yeast supernatant and allowed for obtaining lyophilizates with low water activity from 0.055 to 0.160. The type and concentration of the additive (2–6% whey protein hydrolyzate, 0.5% and 1% ammonium sulphate) had a significant effect on the hydrolytic activity of enzyme preparations, while the selected variants of drying temperature during the freeze-drying process were not significant (10 °C and 50 °C). Low yield of geranyl 4-hydroxyphenylopropionate was shown when the lyophilized supernatant was used (5.3%), but the yield of ester synthesis increased when the freeze-dried Y. lipolytica yeast biomass was applied (47.9%). The study confirmed the antioxidant properties of the synthesized ester by the DPPH• and CUPRAC methods, as well as higher antibacterial activity against tested bacteria than its precursor with 0.125 mM MIC (minimal inhibitory concentration) against L. monocytogenes.

scholarly journals Green Synthesis, Characterization, and Antibacterial Properties of Silver Nanoparticles Obtained by Using Diverse Varieties of Cannabis sativa Leaf Extracts

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4041
Author(s):  
Adriana Cecilia Csakvari ◽  
Cristian Moisa ◽  
Dana G. Radu ◽  
Leonard M. Olariu ◽  
Andreea I. Lupitu ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Green Synthesis ◽  
Antioxidant Capacity ◽  
Cannabis Sativa ◽  
Antibacterial Properties ◽  
Green Building ◽  
Human Pathogens ◽  
Leaf Extracts ◽  
Vis Spectroscopy ◽  
Ft Ir

Cannabis sativa L. (hemp) is a plant used in the textile industry and green building material industry, as well as for the phytoremediation of soil, medical treatments, and supplementary food products. The synergistic effect of terpenes, flavonoids, and cannabinoids in hemp extracts may mediate the biogenic synthesis of metal nanoparticles. In this study, the chemical composition of aqueous leaf extracts of three varieties of Romanian hemp (two monoecious, and one dioecious) have been determined by Fourier-Transformed Infrared spectroscopy (FT-IR), high-performance liquid chromatography, and mass spectrometry (UHPLC-DAD-MS). Then, their capability to mediate the green synthesis of silver nanoparticles (AgNPs) and their pottential antibacterial applications were evaluated. The average antioxidant capacity of the extracts had 18.4 ± 3.9% inhibition determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH•) and 78.2 ± 4.1% determined by 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS™) assays. The total polyphenolic content of the extracts was 1642 ± 32 mg gallic acid equivalent (GAE) L−1. After this, these extracts were reacted with an aqueous solution of AgNO3 resulting in AgNPs, which were characterized by UV−VIS spectroscopy, FT-IR, scanning electron microscopy (SEM-EDX), and dynamic light scattering (DLS). The results demonstrated obtaining spherical, stable AgNPs with a diameter of less than 69 nm and an absorbance peak at 435 nm. The mixture of extracts and AgNPs showed a superior antioxidant capacity of 2.3 ± 0.4% inhibition determined by the DPPH• assay, 88.5 ± 0.9% inhibition as determined by the ABTS•+ assay, and a good antibacterial activity against several human pathogens: Escherichia coli, Klebsiella pneumoniae, Pseudomonas fluorescens, and Staphylococcus aureus.

scholarly journals Novel Antioxidant Properties of Doxycycline

2018 ◽  
Vol 19 (12) ◽  
pp. 4078 ◽  
Author(s):  
Dahn Clemens ◽  
Michael Duryee ◽  
Cleofes Sarmiento ◽  
Andrew Chiou ◽  
Jacob McGowan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Hydrogen Peroxide ◽  
Chronic Inflammation ◽  
Antioxidant Properties ◽  
Antibacterial Properties ◽  
Reactive Oxygen ◽  
Protein Adducts ◽  
Oxygen Species ◽  
Free System

Doxycycline (DOX), a derivative of tetracycline, is a broad-spectrum antibiotic that exhibits a number of therapeutic activities in addition to its antibacterial properties. For example, DOX has been used in the management of a number of diseases characterized by chronic inflammation. One potential mechanism by which DOX inhibits the progression of these diseases is by reducing oxidative stress, thereby inhibiting subsequent lipid peroxidation and inflammatory responses. Herein, we tested the hypothesis that DOX directly scavenges reactive oxygen species (ROS) and inhibits the formation of redox-mediated malondialdehyde-acetaldehyde (MAA) protein adducts. Using a cell-free system, we demonstrated that DOX scavenged reactive oxygen species (ROS) produced during the formation of MAA-adducts and inhibits the formation of MAA-protein adducts. To determine whether DOX scavenges specific ROS, we examined the ability of DOX to directly scavenge superoxide and hydrogen peroxide. Using electron paramagnetic resonance (EPR) spectroscopy, we found that DOX directly scavenged superoxide, but not hydrogen peroxide. Additionally, we found that DOX inhibits MAA-induced activation of Nrf2, a redox-sensitive transcription factor. Together, these findings demonstrate the under-recognized direct antioxidant property of DOX that may help to explain its therapeutic potential in the treatment of conditions characterized by chronic inflammation and increased oxidative stress.

scholarly journals Qualities of Native Apple Cultivar Juices Characteristic of Central Europe

2012 ◽  
Vol 40 (1) ◽  
pp. 222 ◽  
Author(s):  
Otakar ROP ◽  
Martin POSOLDA ◽  
Jiri MLCEK ◽  
Vojtech REZNICEK ◽  
Jiri SOCHOR ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Ascorbic Acid ◽  
Hydroxyl Radical ◽  
Antioxidant Capacity ◽  
Antioxidant Properties ◽  
Landscape Management ◽  
Ascorbic Acid Content ◽  
Fruit Trees ◽  
Apple Fruit ◽  
Scavenging Effect

During the last century due to the changes in landscape management, in country people’s lives and with intensive fruit-growing the native cultivars of apple fruit trees have been gradually disappearing. The aim of the study was to compare the juices made of native apple cider cultivars. The cultivars-‘Boikovo’, ‘Jadernicka moravska’, ‘Kardinal zihany’, ‘Panenske ceske’, ‘Parmena zlata zimni’, ‘Strymka’ growing in the locality of the Litencicke Hills in the eastern part of the Czech Republic were selected. For comparison, the fruits of commercial ‘Idared’ cultivar were also included. The chemical composition, antioxidant capacity, phenols, flavonoids and ascorbic acid content and the influence of juices on scavenging activity of nitric oxide and hydroxyl radical were measured. The mutual ratio of examined properties which were found, provide information about qualities and possibilities of use of native cultivars. High antioxidant properties characterize the juice of native apple cultivars. In particular, the ‘Strymka’ cultivar contained 2,637.34 mg of AAE (ascorbic acid equivalent) per litre in case of antioxidant capacity. In the juice of this cultivar the value of 144.05 mg of ascorbic acid per litre was recorded. As regards the ‘Panenske ceske’ cultivar, antioxidant capacity was 2,548.38 mg of AAE l-1 and in relation to ascorbic acid, the value was 145.35 mg l-1. Similarly, high values were observed in both cultivars concerning the scavenging effect of apple juices on hydroxyl radical and nitric oxide (the ‘Strymka’ cultivar 16.38% and 19.26%, the ‘Panenske ceske’ cultivar 16.31% and 18.60%).

scholarly journals Physicochemical and Bioactive Characteristics of Wild Grown Bilberry (Vaccinium myrtillus L.) Genotypes from Northeastern Turkey

2018 ◽  
Vol 46 (1) ◽  
pp. 128-133 ◽  
Author(s):  
Ferit CELIK ◽  
Mehmet Ramazan BOZHUYUK ◽  
Sezai ERCISLI ◽  
Muttalip GUNDOGDU
Keyword(s):  
Vitamin C ◽  
Antioxidant Capacity ◽  
Gallic Acid ◽  
Antioxidant Properties ◽  
Fruit Weight ◽  
Total Phenolic ◽  
Soluble Solid Content ◽  
Anthocyanin Content ◽  
Total Anthocyanin ◽  
Antioxidant Power

In present study, fruit weight, fruit firmness, external fruit color, soluble solid content, pH, titratable acidity, vitamin C, total phenolics, total anthocyanins, and antioxidant capacity of eight wild bilberry grown in Coruh valley in northeastern Turkey were determined. The blueberry cv. ‘Bluecrop’ is also included study to make comparison with bilberry genotypes. Antioxidant activity of bilberry and blueberry fruits were comparatively assessed by FRAP (Ferric reducing antioxidant power) assay. Significantly higher content of phenolics and anthocyanins was found in bilberry fruits than in blueberry fruits. However blueberry cv. ‘Bluecrop’ exhibited higher fruit weight and vitamin C content than bilberry fruits. Total phenolic and total anthocyanin content was 327 mg gallic acid equivalent and 142 mg of cyanidin-3-glucoside equivalent in 100 g fresh fruit in cv. ‘Bluecrop’ while it was between 492-563 mg gallic acid equaivalent and 307-342 mg of cyanidin-3-glucoside equivalent in 100 g fresh fruits of  bilberry accessions. Moreover, wild accessions approximately had 2-3 folds higher antioxidant capacity than cv. ‘Bluecrop’. Results suggest the possibility of improving the bioactive and antioxidant properties of bilberry cultivars based food products by using wild ones in cross breeding. It was also concluded that genotypes significantly affect their bioactive content and consequently the possibility of using wild bilberry fruits as a potential source of natural antioxidants in food industry.

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