Mechanisms of Nrf2/HO-1 pathway up-regulation induced by pu-erh black tea extract supplementation for quinocetone-treated Sprague-Dawley rats

Dark Tea Wine Protects Against Metabolic Dysfunction-Associated Steatotic Liver Disease In Vivo Through Activating the Nrf2/HO-1 Antioxidant Signaling Pathway

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a complex and multifactorial disease. Dark tea exhibits great potential for various bioactivities for metabolic health. In this study, we aimed to evaluate therapeutic effects and the underlying mechanisms of dark tea wine (DTW) on MASLD with obesity. A rat model of MASLD was established by high-fat diet and administered with different doses of DTW as an intervention. The biomarkers of lipid metabolism and oxidative stress in rats were tested. The weight of organs and adipose tissues and the expressions of nuclear factor erythroid 2-like 2 (Nrf2) and heme oxygenase-1 (HO-1) were investigated based on the pathology and western blot analysis. We found that DTW enhanced antioxidant capacity via activating the Nrf2/HO-1 signaling pathway, further markedly triggering inhibition of weight gain, reduction of lipid dysfunction, and improvement of pathological characteristics to ameliorate MASLD induced by high-fat diet. These results suggest that DTW is a promising functional supplement for prevention and treatment of MASLD and obesity.

The effect of theabrownins on the amino acid composition and antioxidant properties of hen eggs

Pu-erh tea theabrownins (TBs) exert beneficial effect on egg quality and antioxidant properties of eggs, but the underlying mechanisms behind this response are unclear. In this study, we investigate the effect of TBs on egg antioxidative activity, amino acid and fatty acid profiles, and the underlying relationship between the TBs and oxidant-sensitive Nrf2 signaling pathway in laying hens. Eighty layers were fed a basal diet (control) and 400 mg/kg of TBs supplemented diet for 12 wk. TBs led to an increase in albumen height and Haugh unit (P < 0.05). The albumen lysine, valine, and tryptophan were higher in layers fed TBs, whereas yolk tryptophan, methionine, vitamin A, and α-tocopherol content were enhanced by TBs (P < 0.05). Eggs albumen and yolk showed higher total antioxidant capacity (T-AOC), reducing power (RP), and the scavenging rate of 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH), and lower MDA content than those of eggs from the control group (P < 0.05). Also, magnum Nrf2, hemeoxygenase 1 (HO-1), NAD(P)H quinone dehydrogenase 1 (NQO1), and Bcl2 expression were up-regulated by TBs, whereas magnum proapoptotic gene (Bax, caspase 3, Cyt C) were down-regulated by TBs (P < 0.05). Our findings suggest that TBs improved egg albumen quality and antioxidant activity, and the Nrf2-ARE pathway were found to be involved in this process.

Possible Mechanisms of Dark Tea in Cancer Prevention and Management: A Comprehensive Review

Tea is one of the most popular drinks in the world. Dark tea is a kind of post-fermented tea with unique sensory characteristics that is produced by the special fermentation of microorganisms. It contains many bioactive substances, such as tea polyphenols, theabrownin, tea polysaccharides, etc., which have been reported to be beneficial to human health. This paper reviewed the latest research on dark tea's potential in preventing and managing cancer, and the mechanisms mainly involved anti-oxidation, anti-inflammation, inhibiting cancer cell proliferation, inducing cancer cell apoptosis, inhibiting tumor metastasis, and regulating intestinal flora. The purpose of this review is to accumulate evidence on the anti-cancer effects of dark tea, the corresponding mechanisms and limitations of dark tea for cancer prevention and management, the future prospects, and demanding questions about dark tea's possible contributions as an anti-cancer adjuvant.

Protective effects of phenolics rich extract of ginger against Aflatoxin B1-induced oxidative stress and hepatotoxicity

Aflatoxin B1 (AFB1) is one of the predominant mycotoxin contaminant in food and feed, causing oxidative stress and hepatotoxicity. Ginger phenolics have been reported for its antioxidant potential and hepatoprotective activity. The present study investigated the protective effects of phenolics rich ginger extract (GE) against AFB1 induced oxidative stress and hepatotoxicity, in vitro and in vivo. The phenolic acid profiles of GE showed 6-gingerol and 6-shogaol as predominant components. Pretreatment of HepG2 cells with GE significantly inhibited the production of intracellular reactive oxygen species (ROS), DNA strand break, and cytotoxicity induced by AFB1. A comparable effect was observed in in vivo. Male Wistar rats were orally treated with GE (100 and 250mg/kg) daily, with the administration of AFB 1 (200μg/kg) every alternative day for 28days. Treatment with GE significantly reduced AFB1 induced toxicity on the serum markers of liver damage. In addition, GE also showed significant hepatoprotective effect by reducing the lipid peroxidation and by enhancing the antioxidant enzymes activities. These results combined with liver histopathological observations indicated that GE has potential protective effect against AFB1 induced hepatotoxicity. Additionally, administration of GE up-regulated Nrf2/HO-1 pathway, which further proved the efficiency of GE to inhibit AFB1 induced hepatotoxicity.