scholarly journals Monoalkylated Epigallocatechin-3-gallate (C18-EGCG) as Novel Lipophilic EGCG Derivative: Characterization and Antioxidant Evaluation

Antioxidants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 208 ◽  
Author(s):  
Cristina Minnelli ◽  
Roberta Galeazzi ◽  
Emiliano Laudadio ◽  
Adolfo Amici ◽  
Dario Rusciano ◽  
...  

Epigallocatechin-3-gallate (EGCG) has the highest antioxidant activity compared to the others catechins of green tea. However, the beneficial effects are mainly limited by its poor membrane permeability. A derivatization strategy to increase the EGCG interaction with lipid membranes is considered as one feasible approach to expand its application in lipophilic media, in particular the cellular absorption. At this purpose the hydrophilic EGCG was modified by inserting an aliphatic C18 chain linked to the gallate ring by an ethereal bond, the structure determined by NMR (Nuclear Magnetic Resonance) and confirmed by Density Functional Theory (DFT) calculations. The in vitro antioxidant activity of the mono-alkylated EGCG (C18-EGCG) was studied by the DPPH and Thiobarbituric Acid Reactive Substances (TBARS) assays, and its ability to protect cells towards oxidative stress was evaluated in Adult Retinal Pigmented Epithelium (ARPE-19) cells. Molecular Dynamics (MD) simulation and liposomal/buffer partition were used to study the interaction of the modified and unmodified antioxidants with a cell membrane model: the combined experimental-in silico approach shed light on the higher affinity of C18-EGCG toward lipid bilayer. Although the DPPH assay stated that the functionalization decreases the EGCG activity against free radicals, from cellular experiments it resulted that the lipid moiety increases the antioxidant protection of the new lipophilic derivative.

2021 ◽  
Vol 9 (5) ◽  
pp. 367-376
Author(s):  
S. S. Shatokhin ◽  
V. A. Tuskaev ◽  
S. Ch. Gagieva ◽  
D. I. Pozdnyakov ◽  
E. T. Oganesyan

The aim is based on the results of the in silico prediction, to obtain and characterize a number of (E)-3-(3-(4-oxo-4H-chromen-3-yl)acryloyl)-2H-chromen-2-one derivatives, and also to study their antioxidant activity.Materials and methods. The synthesis of the target compounds was carried out by condensation of substituted 3-formylchromones and 3-acetylcoumarins under the acid catalysis conditions. 1H NMR spectra were recorded on the instruments of Bruker Avance-400 (400 MHz) and Bruker Avance-300 (300 MHz) in the solutions of CDCl3 or DMSO-d6. Mass spectra (ESI) were obtained on a Finnigan LCQ Advantage mass spectrometer (USA). The melting points of the compounds were determined on a PTP (M) instrument. Quantum-chemical calculations were carried out on the basis of a density functional theory using the Gaussian 09 program using the B3LYP/6-311G (d, p) method, as well as using the Way2Drug (PASS Online) online service. The antiradical activity of the compounds was studied by the DPPH test, and the chelating properties were assessed by the o-phenanthroline method.Results. 15 derivatives of (E)-3-(3-(4-oxo-4H-chromen-3-yl)acryloyl)-2H-chromen-2-one have been obtained and characterized. The calculations based on the density functional theory showed that the highest occupied molecular orbital exhibiting electron-donating properties is localized on the propenone fragment, which confirms the likelihood of the manifestation of antiradical properties. According to the prediction of the probable spectrum of the biological activity, the obtained compounds are more likely to exhibit their direct antioxidant activity. According to the results of the in vitro study of the antioxidant activity, it was found out that compounds 1-15 are the most active in relation to the DPPH radical, which confirms the obtained prognostic data.Conclusion. Thus, based on the in silico prediction data, 15 derivatives of (E)-3-(3-(4-oxo-4H-chromen-3-yl)acryloyl)-2H-chromen-2-one have been obtained and characterized, for which the method antioxidant activity has been studied in vitro. It was found out that compounds 1-15 exhibit the antiradical activity to a large extent.


Antioxidants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 860
Author(s):  
Wu-Sheng Sun ◽  
Hoon Jang ◽  
Mi-Ryung Park ◽  
Keon Bong Oh ◽  
Haesun Lee ◽  
...  

Oxidative stress has been suggested to negatively affect oocyte and embryo quality and developmental competence, resulting in failure to reach full term. In this study, we investigated the effect of N-acetyl-L-cysteine (NAC), a cell-permeating antioxidant, on developmental competence and the quality of oocytes and embryos upon supplementation (0.1–10 mM) in maturation and culture medium in vitro using slaughterhouse-derived oocytes and embryos. The results show that treating oocytes with 1.0 mM NAC for 8 h during in vitro maturation attenuated the intracellular reactive oxygen species (ROS) (p < 0.05) and upregulated intracellular glutathione levels (p < 0.01) in oocytes. Interestingly, we found that NAC affects early embryonic development, not only in a dose-dependent, but also in a stage-specific, manner. Significantly (p < 0.05) decreased cleavage rates (90.25% vs. 81.46%) were observed during the early stage (days 0–2), while significantly (p < 0.05) increased developmental rates (38.20% vs. 44.46%) were observed during the later stage (from day 3) of embryonic development. In particular, NAC supplementation decreased the proportion of apoptotic blastomeres significantly (p < 0.05), resulting in enhanced hatching capability and developmental rates during the in vitro culture of embryos. Taken together, our results suggest that NAC supplementation has beneficial effects on bovine oocytes and embryos through the prevention of apoptosis and the elimination of oxygen free radicals during maturation and culture in vitro.


Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1409
Author(s):  
Yiqi Zhang ◽  
Ye Dong ◽  
Zhiyuan Dai

Bone hydrolysates from bighead carp (Aristichthys nobilis) were prepared using Protamex and Alcalase with degrees of hydrolysis (DH) of 5%, 10% and 15%. The antioxidant activity of bone hydrolysates was evaluated in vitro and then the hydrolysates with better antioxidant activity were used to immerse bighead carp fillets through a vacuum impregnation process at concentrations of 1% and 2%. Among the six hydrolysates, fish bone hydrolyzed with Protamex at DH 10% exhibited the highest ability to scavenge 1, 1-diphenyl-2-picrylhydrazyl (DPPH) (88.79%), 2, 2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) (57.76%) and hydroxyl radicals (62.72%), as well as to chelate ferrous ions (91.46%). The hydrolysates effectively postponed freezing- and thawing-induced protein/lipid oxidation. Compared with the fillets without treatment, the impregnated fillets had higher sulfhydryl contents, greater Ca2+-ATPase activity, lower carbonyls and lower thiobarbituric acid-reactive substances (TBARS). Bone hydrolysates also have a positive effect on the texture and water-holding ability of freeze-thawed fish fillets. Fish bone hydrolysates of Protamex could serve as potential antioxidants to preserve fish fillets.


Antioxidants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 541
Author(s):  
Giulia Graziani ◽  
Anna Gaspari ◽  
Claudio Di Vaio ◽  
Aurora Cirillo ◽  
Carolina Liana Ronca ◽  
...  

Four different varieties of apples have been considered (Limoncella, Annurca, Red Delicious, and Golden Delicious) to estimate the extent of colon polyphenolics release after in vitro sequential enzyme digestion. Since several studies report a positive effect of apple polyphenols in colonic damage, we found of interest to investigate the colon release of polyphenols in different varieties of apples in order to assess their prevention of colonic damage. UHPLC-HRMS analysis and antioxidant activity (ABTS, DPPH, and FRAP assays) were carried out on the apple extracts (peel, flesh, and whole fruit) obtained from not digested samples and on bioaccessible fractions (duodenal and colon bioaccessible fractions) after in vitro digestion. Polyphenolic content and antioxidant activities were found to vary significantly among the tested cultivars with Limoncella showing the highest polyphenol content accompanied by an excellent antioxidant activity in both flesh and whole fruit. The overall trend of soluble antioxidant capacity from the soluble duodenal phase (SDP) and soluble colonic phase (SCP) followed the concentrations of flavanols, procyandinis, and hydroxycinnamic acids under the same digestive steps. Our results highlighted that on average 64.2% of the total soluble antioxidant activity was released in the SCP with Limoncella exhibiting the highest values (82.31, 70.05, and 65.5%, respectively for whole fruit, flesh, and peel). This result suggested that enzymatic treatment with pronase E and viscozyme L, to reproduce biochemical conditions occurring in the colon, is effective for breaking the dietary fiber-polyphenols interactions and for the release of polyphenols which can exercise their beneficial effects in the colon. The beneficial effects related to the Limoncella consumption could thus be of potential great relevance to counteract the adverse effects of pro-oxidant and inflammatory processes on intestinal cells.


Antioxidants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1106
Author(s):  
Marko R. Antonijević ◽  
Dušica M. Simijonović ◽  
Edina H. Avdović ◽  
Andrija Ćirić ◽  
Zorica D. Petrović ◽  
...  

Compounds from the plant world that possess antioxidant abilities are of special importance for the food and pharmaceutical industry. Coumarins are a large, widely distributed group of natural compounds, usually found in plants, often with good antioxidant capacity. The coumarin-hydroxybenzohydrazide derivatives were synthesized using a green, one-pot protocol. This procedure includes the use of an environmentally benign mixture (vinegar and ethanol) as a catalyst and solvent, as well as very easy isolation of the desired products. The obtained compounds were structurally characterized by IR and NMR spectroscopy. The purity of all compounds was determined by HPLC and by elemental microanalysis. In addition, these compounds were evaluated for their in vitro antioxidant activity. Mechanisms of antioxidative activity were theoretically investigated by the density functional theory approach and the calculated values of various thermodynamic parameters, such as bond dissociation enthalpy, proton affinity, frontier molecular orbitals, and ionization potential. In silico calculations indicated that hydrogen atom transfer and sequential proton loss–electron transfer reaction mechanisms are probable, in non-polar and polar solvents respectively. Additionally, it was found that the single-electron transfer followed by proton transfer was not an operative mechanism in either solvent. The conducted tests indicate the excellent antioxidant activity, as well as the low potential toxicity, of the investigated compounds, which makes them good candidates for potential use in food chemistry.


2019 ◽  
Vol 123 (3) ◽  
pp. 241-254 ◽  
Author(s):  
T. Ruskovska ◽  
V. Maksimova ◽  
D. Milenkovic

AbstractOxidative damage of cells and tissues is broadly implicated in human pathophysiology, including cardiometabolic diseases. Polyphenols, as important constituents of the human diet and potent in vitro free radical scavengers, have been extensively studied for their beneficial effects on cardiometabolic health. However, it has been demonstrated that the in vivo antioxidant activity of polyphenols is distinct from their in vitro free radical-scavenging capacity. Indeed, bioavailability of nutritional polyphenols is low and conditioned by complex mechanisms of absorption, distribution, metabolism and excretion. Nowadays, it is commonly accepted that the cellular antioxidant activity of polyphenols is mainly carried out via modification of transcription of genes involved in antioxidant defence. Importantly, polyphenols also contribute to cardiometabolic health by modulation of a plethora of cellular processes that are not directly associated with antioxidant enzymes, through nutri(epi)genomic mechanisms. Numerous human intervention studies have demonstrated beneficial effects of polyphenols on the key cardiometabolic risk factors. However, inconsistency of the results of some studies led to identification of the inter-individual variability in response to consumption of polyphenols. In perspective, a detailed investigation of the determinants of this inter-individual variability will potentially lead us towards personalised dietary recommendations. The phenomenon of inter-individual variability is also of relevance for supplementation with antioxidant (pro)vitamins.


2014 ◽  
Vol 513-517 ◽  
pp. 359-362
Author(s):  
Ming Xun Yan ◽  
Jin Dong Gong ◽  
Ping Shen ◽  
Chang Ying Yang

Density functional theory (DFT) calculations, based on B3LYP/6-311G (d, p) basis set, were performed to evaluate the OH bond dissociation energies (BDEs) for phloretin, compared with naringenin, in order to assess the contribution of hydroxyl groups at different position to the radical-scavenging properties. It is indicated clearly that A6 OH is determined as the weakest O-H bond, give rise to the smallest BDE, 73.98 kcal/mol. BDE of B4 OH decreases 2.5 kcal/mol in benzene, very close to that of A6OH, indicated that B4 OH group is also mainly contributed to the reaction with free radicals, especially in non-polar environments.


2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Weerakoon Achchige Selvi Saroja Weerakoon ◽  
Pathirage Kamal Perera ◽  
Dulani Gunasekera ◽  
Thusharie Sugandhika Suresh

Sudarshanapowder (SP) is one of the most effective Ayurveda powder preparations for paediatric febrile conditions. The objective of the present study was to evaluate thein vitroandin vivoantioxidant potentials of SP. Thein vitroantioxidant effects were evaluated using ABTS radical cation decolourization assay where the TROLOX equivalent antioxidant capacity (TEAC) was determined. Thein vivoantioxidant activity of SP was determined in Wistar rats using the Lipid Peroxidation (LPO) assay in serum. Thein vitroassay was referred to as the TROLOX equivalent antioxidant capacity (TEAC) assay. For thein vivoassay, animals were dosed for 21 consecutive days and blood was drawn to evaluate the MDA level. Thein vitroantioxidant activity of 0.5 μg of SP was equivalent to 14.45 μg of standard TROLOX. The percentage inhibition against the radical formation was50.93±0.53%. The SP showed a statistically significant (p<0.01) decrease in the serum level of thiobarbituric acid-reactive substance in the test rats when compared with the control group. These findings suggest that the SP possesses potent antioxidant activity which may be responsible for some of its reported bioactivities.


2019 ◽  
Vol 20 (6) ◽  
pp. 1450 ◽  
Author(s):  
Yan-Zhen Zheng ◽  
Geng Deng ◽  
Rui Guo ◽  
Da-Fu Chen ◽  
Zhong-Min Fu

The radical scavenging activity of a flavonoid is largely influenced by its structure. The effects of the substituents at C3 position on the antioxidant activity of naringenin were carried out using the density functional theory (DFT) method. The reaction enthalpies related with the three well-established mechanisms were analyzed. Excellent correlations were found between the reaction enthalpies and Hammett sigma constants. Equations obtained from the linear regression can be helpful in the selection of suitable candidates for the synthesis of novel naringenin derivatives with enhanced antioxidant properties. In the gas and benzene phases, the antioxidant activity of naringenin was enhanced by the electron-donating substituents via weakening the bond dissociation enthalpy (BDE). In the water phase, it was strengthened by electron-withdrawing groups—via lowering the proton affinity (PA). The electronic effect of the substituent on the BDE of naringenin is mainly governed by the resonance effect, while that on the ionization potential (IP) and PA of naringenin is mainly controlled by the field/inductive effect.


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