Green Production of Zero-Valent Iron (ZVI) Using Tea-Leaf Extracts for Fenton Degradation of Mixed Rhodamine B and Methyl Orange Dyes

The danger from the content of dyes produced by textile-industry waste can cause environmental degradation when not appropriately treated. However, existing waste-treatment methods have not been effective in degrading dyes in textile waste. Zero-valent iron (ZVI), which has been widely used for wastewater treatment, needs to be developed to acquire effective green production. Tea (Camellia sinensis) leaves contain many polyphenolic compounds used as natural reducing agents. Therefore, this study aims to synthesize ZVI using biological reducing agents from tea-leaf extract and apply the Fenton method to degrade the color mixture of rhodamine B and methyl orange. The results show that the highest polyphenols were obtained from tea extract by heating to 90 °C for 80 min. Furthermore, PSA results show that ZVI had a homogeneous size of iron and tea extract at a volume ratio of 1:3. The SEM-EDS results show that all samples had agglomerated particles. The ZVI 1:1 showed the best results, with a 100% decrease in the color intensity of the dye mixture for 60 min of reaction and a degradation percentage of 100% and 66.47% for rhodamine B and methyl orange from LC-MS analysis, respectively. Finally, the decrease in COD value by ZVI was 92.11%, higher than the 47.36% decrease obtained using Fe(II).

Correction: Potential role of tea extract in oocyte development

Correction for ‘Potential role of tea extract in oocyte development’ by Lei Zhao et al., Food Funct., 2021, 12, 10311–10323, DOI: 10.1039/D1FO01725J.

Characteristics Evaluation of Commercial Fruit Tea Extracts in Korea

Purpose: We evaluated the physicochemical characteristics and antioxidant activity of 21 types of fruit tea extract that are consumed in Korea. The data were analyzed and curated for the development of processed products using tea in the future.Methods: After extraction using hot water at 70℃, we analyzed the physicochemical properties including color and pH, as well as the antioxidant activity (total flavonoid content, DPPH scavenging activity, and α-glucosidase inhibitory activity).Results: Calamansi tea exhibited the lowest brightness with a beet-red appearance, and a yellowness that was significantly higher in jujube and radish. The pH ranged from 3.04 to 7.18 and most samples were in an acidic state. Of these, the pH of schizandra fruit tea was the lowest at 3.04±0.01. The total flavonoid content was the highest in calamansi at 217.87±1.45 QE/g, whereas that of cacao nibs was the lowest at 29.04±0.70 QE/g. The α-glucosidase inhibitory activity of Chinese quince was the highest at 59.96%±0.22%.Conclusion: We obtained basic data for several fruit tea extracts by analyzing the physicochemical properties and antioxidant activities. We anticipate that these results will represent useful data for blending fruits for tea product development.

Senescence-Mediated Redox Imbalance in Liver and Kidney: Antioxidant Rejuvenating Potential of Green Tea Extract

This study investigates the catechin composition and protective effect of green tea extract on senescence-mediated redox imbalance in the livers and kidneys of aged mice. The results showed that the seven catechins in the green tea extract analyzed in this study could be completely separated within 30 min and the main components of catechins in green tea extract were EGCG, EGC and ECG. In terms of the anti-senescence effects of green tea extract, green tea extract supplementation at doses of 125, 625 and 1250 mg/kg for 4 weeks significantly alleviated the senescence-mediated redox imbalance, as exhibited from significantly (p < 0.05) reduced thiobarbituric acid-reactive substances (TBARS) and protein carbonyls levels in the serum, and increased glutathione (GSH) and total thiols contents in the plasma. Additionally, hepatic and renal protein carbonyls levels were significantly diminished (p < 0.05) and the activities of superoxide dismutase (SOD), catalase, glucose-6-phosphate dehydrogenase (G6PD), glutathione peroxidase (GSH-Px) and glutathione reductase (GSH-Rd) in the liver and kidney were remarkably elevated (p < 0.05). Overall, these results clearly show that green tea extract exhibits extremely potent protective effects against senescence-mediated redox imbalance in the livers and kidneys of mice by inhibiting oxidative damage of lipids and proteins and increasing the activities of antioxidant enzymes in organs.