scholarly journals Vasodilation of Tea Polyphenols Ex Vivo Is Mediated by Hydrogen Peroxide under Rapid Compound Decay

Antioxidants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 390
Author(s):  
Mario Lorenz ◽  
Stephanie Lehmann ◽  
Ilija Djordjevic ◽  
Thomas Düsterhöft ◽  
Benno F. Zimmermann ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Ex Vivo ◽  
Health Effect ◽  
Black Tea ◽  
Tea Polyphenols ◽  
Time Range ◽  
Tea Polyphenol ◽  
Apparent Lack ◽  
Green And Black Tea

Improvement of endothelial function represents a major health effect of tea in humans. Ex vivo, tea and tea polyphenols stimulate nitric oxide (NO)-dependent vasodilation in isolated blood vessels. However, it was reported that polyphenols can generate reactive oxygen species (ROS) in vitro. We therefore aimed to elucidate the role of ROS production in tea polyphenol-induced vasodilation in explanted aortic rings. Vasorelaxation of rat aortic rings was assessed in an organ chamber model with low concentrations of epigallocatechin-3-gallate (EGCG), theaflavin-3,3’-digallate (TF3), and with green and black tea, with or without pretreatment with catalase or superoxide dismutase (SOD). The stability of EGCG and TF3 was measured by HPLC, and the levels of hydrogen peroxide (H2O2) were determined. EGCG and green tea-induced vasorelaxation was completely prevented by catalase and slightly increased by SOD. TF3 and black tea yielded similar results. Both EGCG and TF3 were rapidly degraded. This was associated with increasing H2O2 levels over time. Hydrogen peroxide concentrations produced in a time range compatible with tea polyphenol decay induced NO-dependent vasodilation in aortic rings. In conclusion, tea polyphenol-induced vasodilation in vitro is mediated by low levels of H2O2 generated during compound decay. The results could explain the apparent lack of vasodilatory effects of isolated tea polyphenols in humans.

Microarray reveals positive effects of green and black tea polyphenols on TNF[alpha]-induced changes of gene expression

2013 ◽  
Author(s):  
Husna Zulkipli ◽  
Norita Salim ◽  
Gabriele Anisah Froemming ◽  
Aletza Mohd Ismail ◽  
Hapizah Nawawi
Keyword(s):  
Gene Expression ◽  
Black Tea ◽  
Tea Polyphenols ◽  
Tnf Alpha ◽  
Positive Effects ◽  
Black Tea Polyphenols ◽  
Green And Black Tea ◽  
Induced Changes

scholarly journals Epigallocatechin Gallate (EGCG), a Green Tea Polyphenol, Reduces Coronavirus Replication in a Mouse Model

Viruses ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2533
Author(s):  
Rackhyun Park ◽  
Minsu Jang ◽  
Yea-In Park ◽  
Yeonjeong Park ◽  
Woochul Jung ◽  
...  
Keyword(s):  
Mouse Model ◽  
Green Tea ◽  
Particle Production ◽  
Epigallocatechin Gallate ◽  
Tea Polyphenols ◽  
Green Tea Polyphenols ◽  
Tea Polyphenol ◽  
Green Tea Polyphenol

The COVID-19 pandemic has resulted in a huge number of deaths from 2020 to 2021; however, effective antiviral drugs against SARS-CoV-2 are currently under development. Recent studies have demonstrated that green tea polyphenols, particularly EGCG, inhibit coronavirus enzymes as well as coronavirus replication in vitro. Herein, we examined the inhibitory effect of green tea polyphenols on coronavirus replication in a mouse model. We used epigallocatechin gallate (EGCG) and green tea polyphenols containing more than 60% catechin (GTP60) and human coronavirus OC43 (HCoV-OC43) as a surrogate for SARS-CoV-2. Scanning electron microscopy analysis results showed that HCoV-OC43 infection resulted in virion particle production in infected cells. EGCG and GTP60 treatment reduced coronavirus protein and virus production in the cells. Finally, EGCG- and GTP60-fed mice exhibited reduced levels of coronavirus RNA in mouse lungs. These results demonstrate that green tea polyphenol treatment is effective in decreasing the level of coronavirus in vivo.

scholarly journals Colon Bioaccessibility and Antioxidant Activity of White, Green and Black Tea Polyphenols Extract after In Vitro Simulated Gastrointestinal Digestion

Nutrients ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1711 ◽  
Author(s):  
Giuseppe Annunziata ◽  
Maria Maisto ◽  
Connie Schisano ◽  
Roberto Ciampaglia ◽  
Patricia Daliu ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Inflammatory Diseases ◽  
Black Tea ◽  
Tea Polyphenols ◽  
Array Detector ◽  
Total Phenol Content ◽  
Beneficial Effects ◽  
Polyphenolic Extract

The beneficial effects of the tea beverage are well-known and mainly attributed to polyphenols which, however, have poor bioaccessibility and bioavailability. The purpose of the present study was the evaluation of colon bioaccessibility and antioxidant activity of tea polyphenolic extract. An 80% methanolic extract (v/v) of tea polyphenols was obtained from green (GT), white (WT) and black tea (BT). Simulated gastrointestinal (GI) digestion was performed on acid-resistant capsules containing tea polyphenolic extract. The main tea polyphenols were monitored by HPLC-diode-array detector (DAD) method; in addition, Total Phenol Content (TPC) and antioxidant activity were evaluated. After GI digestion, the bioaccessibility in the colon stage was significantly increased compared to the duodenal stage for both tea polyphenols and TPC. Similarly, the antioxidant activity in the colon stage was significantly higher than that in the duodenal stage. Reasonably, these results could be attributable in vivo to the activity of gut microbiota, which is able to metabolize these compounds, generating metabolites with a greater antioxidant activity. Our results may guide the comprehension of the colon digestion of polyphenols, suggesting that, although poorly absorbed in the duodenum, they can exert their antioxidant and anti-inflammatory activities in the lower gut, resulting in a novel strategy for the management of gut-related inflammatory diseases.

scholarly journals Serial Passage of Cryptococcus neoformans in Galleria mellonella Results in Increased Capsule and Intracellular Replication in Hemocytes, but Not Increased Resistance to Hydrogen Peroxide

Pathogens ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 732 ◽  
Author(s):  
Muhammad Fariz Ali ◽  
Stephen M. Tansie ◽  
John R. Shahan ◽  
Rebecca L. Seipelt-Thiemann ◽  
Erin E. McClelland
Keyword(s):  
Hydrogen Peroxide ◽  
Cryptococcus Neoformans ◽  
Galleria Mellonella ◽  
Ex Vivo ◽  
Histopathological Examination ◽  
Serial Passage ◽  
Infection Model ◽  
Hydrogen Peroxide Production ◽  
Species Response

To gain insight into how pathogens adapt to new hosts, Cryptococcus neoformans (H99W) was serially passaged in Galleria mellonella. The phenotypic characteristics of the passaged strain (P15) and H99W were evaluated. P15 grew faster in hemolymph than H99W, in vitro and in vivo, suggesting that adaptation had occurred. However, P15 was more susceptible to hydrogen peroxide in vitro, killed fewer mouse macrophages, and had less fungal burden in human ex vivo macrophages than H99W. Analysis of gene expression changes during Galleria infection showed only a few different genes involved in the reactive oxygen species response. As P15 sheds more GXM than H99W, P15 may have adapted by downregulating hemocyte hydrogen peroxide production, possibly through increased capsular glucuronoxylomannan (GXM) shedding. Hemocytes infected with P15 produced less hydrogen peroxide, and hydrogen peroxide production in response to GXM-shedding mutants was correlated with shed GXM. Histopathological examination of infected larvae showed increased numbers and sizes of immune nodules for P15 compared to H99W, suggesting an enhanced, but functionally defective, response to P15. These results could explain why this infection model does not always correlate with murine models. Overall, C. neoformans’ serial passage in G. mellonella resulted in a better understanding of how this yeast evolves under selection.

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