Condensed tannins as antioxidants that protect poplar against oxidative stress from drought and UV‐B

2021 ◽  
Author(s):  
Gerry Gourlay ◽  
Barbara Hawkins ◽  
Andreas Albert ◽  
Jörg‐Peter Schnitzler ◽  
C. Peter Constabel
Keyword(s):  
Oxidative Stress ◽  
Condensed Tannins

scholarly journals Increasing the Oxidative Stress Response Allows Escherichia coli To Overcome Inhibitory Effects of Condensed Tannins

2003 ◽  
Vol 69 (6) ◽  
pp. 3406-3411 ◽  
Author(s):  
Alexandra H. Smith ◽  
James A. Imlay ◽  
Roderick I. Mackie
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Stress Response ◽  
Condensed Tannins ◽  
Resistant Mutant ◽  
Inhibitory Effect ◽  
Oxidative Stress Response ◽  
Inhibitory Effects ◽  
Acacia Mearnsii ◽  
E Coli

ABSTRACT Tannins are plant-derived polyphenols with antimicrobial effects. The mechanism of tannin toxicity towards Escherichia coli was determined by using an extract from Acacia mearnsii (Black wattle) as a source of condensed tannins (proanthocyanidins). E. coli growth was inhibited by tannins only when tannins were exposed to oxygen. Tannins auto-oxidize, and substantial hydrogen peroxide was generated when they were added to aerobic media. The addition of exogenous catalase permitted growth in tannin medium. E. coli mutants that lacked HPI, the major catalase, were especially sensitive to tannins, while oxyR mutants that constitutively overexpress antioxidant enzymes were resistant. A tannin-resistant mutant was isolated in which a promoter-region point mutation increased the level of HPI by 10-fold. Our results indicate that wattle condensed tannins are toxic to E. coli in aerobic medium primarily because they generate H2O2. The oxidative stress response helps E. coli strains to overcome their inhibitory effect.

scholarly journals Effect of Chitosan on the Removal of Different Types of Tannins from Red Wines

2021 ◽  
Vol 11 (24) ◽  
pp. 11743
Author(s):  
Luigi Picariello ◽  
Francesco Errichiello ◽  
Francesca Coppola ◽  
Alessandra Rinaldi ◽  
Luigi Moio ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Phenolic Compounds ◽  
Condensed Tannins ◽  
Precipitation Index ◽  
Salivary Proteins ◽  
Red Wines ◽  
Different Types ◽  
Colour Parameters ◽  
Previously Treated

(1) Background: most premium red wines are rich in tannins but the effect of chitosan on these macromolecules is unknown. In this work, the effect of a treatment with 0.5 g/L of chitosan on red wines, W, enriched with condensed tannins, CT, ellagitannins, ET, and gallotannins, GT, was evaluated. In addition, to understand if the effect of C was stable during wine evolution, treated wines underwent an oxidative stress simulating an exposure to 18 mg/L of oxygen. (2) Methods: parameters describing the reactivity of phenolic compounds were determined: iron reactive phenolics, BSA reactive tannins, vanillin reactive tannins, and the saliva precipitation index. Individual anthocyanins, total and polymeric pigments and chromatic characteristics were evaluated to determine the influence of each treatment on colour parameters. (3) Results: a decrease in BSA reactive tannins after the addition of C was detected for all wines and the effect persisted after oxidation. W and CT wines previously treated with C and oxidized showed a significant decrease in the reactivity towards salivary proteins. C caused a lower formation of polymeric pigments in all wines. (4) Conclusion: these results suggest a possible use of C to treat wines very rich in condensed tannins and excessively astringent.

scholarly journals Chemical Composition of Essential Oil, Phenolic Compounds Content, and Antioxidant Activity of Cistus monspeliensis from Northern Morocco

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Sara Haida ◽  
Kaltoum Bakkouche ◽  
Abdelaziz Ramadane Kribii ◽  
Abderahim Kribii
Keyword(s):  
Oxidative Stress ◽  
Antioxidant Activity ◽  
Phenolic Compounds ◽  
Condensed Tannins ◽  
Natural Antioxidants ◽  
Health It ◽  
Total Polyphenols ◽  
Antioxidant Power ◽  
Liquid Liquid Extraction ◽  
Ferric Reducing Antioxidant Power

Currently, oxidative stress is one of the major problems that threatens human health. It is at the root of many diseases such as cancer. Despite the enormous efforts provided to combat this scourge, oxidative stress is still relevant and hence comes the need for research of new remedies especially from natural origin. For this purpose, the study of the antioxidant activity of extracts of Cistus monspeliensis from Morocco is a principal research objective. The phenolic extracts were obtained by maceration of the plant in a water/acetone mixture and then separated by liquid/liquid extraction with solvents of increasing polarity. The first phytochemical tests carried out on these extracts showed the existence of different families of phenolic compounds, such as flavonoids, tannins, and others. Assays for total polyphenols, flavonoids, hydrolysable, and condensed tannins were carried out by known colorimetric methods. The results of these assays have shown that the studied extracts are rich in phenolic compounds present in the plant in the form of flavonoids (69.81 ± 0.22 mg EQ/g DM), hydrolysable tannins (61.86 ± 0.89 mg ETA/g DM), and condensed tannins (70.05 ± 1.61 mg EC/g DM). The evaluation of the antioxidant activity is carried out by two different methods: the DPPH test (2,2-DiPhenyl-1-Picryl-Hydrazyl) and the FRAP test (Ferric Reducing Antioxidant Power). The results obtained show that the extracts of Cistus monspeliensis are active and have interesting antioxidant powers. In particular, the water/acetone (WAE) (IC50 = 0.079 mg/mL) and butanolic (BUE) (IC0.5 = 0.099 mg/mL) extracts are the most active with values comparable to that of ascorbic acid. The interesting results obtained in this study clearly show that Cistus monspeliensis originating from Morocco can be considered as a source of natural antioxidants. Therefore, the extracts of this plant deserve to be tested in the medicinal field, against cancer and cardiovascular diseases, and in food field as an additive and preservative.

Antioxidant and intestinal recovery function of condensed tannins in Lateolabrax maculatus responded to in vivo and in vitro oxidative stress

Aquaculture ◽  
2022 ◽  
Vol 547 ◽  
pp. 737399
Author(s):  
Kai Peng ◽  
Xiaohui Lv ◽  
Hongxia Zhao ◽  
Bing Chen ◽  
Xiaoying Chen ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Condensed Tannins ◽  
Recovery Function ◽  
Lateolabrax Maculatus

Lycopene alleviates sulfamethoxazole-induced hepatotoxicity in grass carp (Ctenopharyngodon idellus) via suppression of oxidative stress, inflammation and apoptosis

2020 ◽  
Vol 11 (10) ◽  
pp. 8547-8559
Author(s):  
Hongjing Zhao ◽  
Yu Wang ◽  
Mengyao Mu ◽  
Menghao Guo ◽  
Hongxian Yu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Secondary Metabolites ◽  
Human Health ◽  
Grass Carp ◽  
Aquatic Environment ◽  
Ctenopharyngodon Idellus

Antibiotics are used worldwide to treat diseases in humans and other animals; most of them and their secondary metabolites are discharged into the aquatic environment, posing a serious threat to human health.

Copper-dependent ATP7B up-regulation drives the resistance of TMEM16A-overexpressing head-and-neck cancer models to platinum toxicity

2019 ◽  
Vol 476 (24) ◽  
pp. 3705-3719 ◽  
Author(s):  
Avani Vyas ◽  
Umamaheswar Duvvuri ◽  
Kirill Kiselyov
Keyword(s):  
Oxidative Stress ◽  
Head And Neck ◽  
Transcriptional Activation ◽  
Platinum Resistance ◽  
Mrna Levels ◽  
Strong Positive Correlation ◽  
Platinum Compounds ◽  
Copper Chelation ◽  
Novel Approach ◽  
Cancer Models

Platinum-containing drugs such as cisplatin and carboplatin are routinely used for the treatment of many solid tumors including squamous cell carcinoma of the head and neck (SCCHN). However, SCCHN resistance to platinum compounds is well documented. The resistance to platinum has been linked to the activity of divalent transporter ATP7B, which pumps platinum from the cytoplasm into lysosomes, decreasing its concentration in the cytoplasm. Several cancer models show increased expression of ATP7B; however, the reason for such an increase is not known. Here we show a strong positive correlation between mRNA levels of TMEM16A and ATP7B in human SCCHN tumors. TMEM16A overexpression and depletion in SCCHN cell lines caused parallel changes in the ATP7B mRNA levels. The ATP7B increase in TMEM16A-overexpressing cells was reversed by suppression of NADPH oxidase 2 (NOX2), by the antioxidant N-Acetyl-Cysteine (NAC) and by copper chelation using cuprizone and bathocuproine sulphonate (BCS). Pretreatment with either chelator significantly increased cisplatin's sensitivity, particularly in the context of TMEM16A overexpression. We propose that increased oxidative stress in TMEM16A-overexpressing cells liberates the chelated copper in the cytoplasm, leading to the transcriptional activation of ATP7B expression. This, in turn, decreases the efficacy of platinum compounds by promoting their vesicular sequestration. We think that such a new explanation of the mechanism of SCCHN tumors’ platinum resistance identifies novel approach to treating these tumors.

Clinical aspects of reactive oxygen and nitrogen species

2004 ◽  
Vol 71 ◽  
pp. 121-133 ◽  
Author(s):  
Ascan Warnholtz ◽  
Maria Wendt ◽  
Michael August ◽  
Thomas Münzel
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Risk Factor ◽  
Endothelial Dysfunction ◽  
Vascular Tissue ◽  
Rapid Development ◽  
Reactive Oxygen ◽  
Clinical Aspects ◽  
No Production ◽  
Oxygen Species

Endothelial dysfunction in the setting of cardiovascular risk factors, such as hypercholesterolaemia, hypertension, diabetes mellitus and chronic smoking, as well as in the setting of heart failure, has been shown to be at least partly dependent on the production of reactive oxygen species in endothelial and/or smooth muscle cells and the adventitia, and the subsequent decrease in vascular bioavailability of NO. Superoxide-producing enzymes involved in increased oxidative stress within vascular tissue include NAD(P)H-oxidase, xanthine oxidase and endothelial nitric oxide synthase in an uncoupled state. Recent studies indicate that endothelial dysfunction of peripheral and coronary resistance and conductance vessels represents a strong and independent risk factor for future cardiovascular events. Ways to reduce endothelial dysfunction include risk-factor modification and treatment with substances that have been shown to reduce oxidative stress and, simultaneously, to stimulate endothelial NO production, such as inhibitors of angiotensin-converting enzyme or the statins. In contrast, in conditions where increased production of reactive oxygen species, such as superoxide, in vascular tissue is established, treatment with NO, e.g. via administration of nitroglycerin, results in a rapid development of endothelial dysfunction, which may worsen the prognosis in patients with established coronary artery disease.

Pancreatic stones shockwave lithotripsy induces oxidative stress. A study of lipoperoxidation products in pure pancreatic juice

2001 ◽  
Vol 120 (5) ◽  
pp. A217-A217
Author(s):  
C SPADA ◽  
S SANTINI ◽  
F FOSCHIA ◽  
M PANDOLFI ◽  
V PERRI ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Pancreatic Juice ◽  
Shockwave Lithotripsy ◽  
Pure Pancreatic Juice ◽  
Pancreatic Stones

Dilinoleoylphosphatidylcholine (DLPC) protects against alcohol-induced oxidative stress in rats

2001 ◽  
Vol 120 (5) ◽  
pp. A116-A116
Author(s):  
S ALEYNIK ◽  
M ALEYNIK ◽  
C LIEBER
Keyword(s):  
Oxidative Stress
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