Upregulation of erythrocyte ascorbate free radical reductase by tea catechins: Correlation with their antioxidant properties

Effect of shaking and piling processing on improving the aroma quality of green tea

Aroma plays a crucial role in the quality of pure green tea beverage. However, there are limited methods to improve their aroma. In this study, green tea produced using shaking and piling process (SPGT) demonstrated a notable improvement in aromatic intensity, particularly in floral, fruity, and sweet notes. A total of 58 volatile compounds were detected, with SPGT exhibiting the highest concentration of aroma compounds among the tested green teas. Eight key aroma compounds were selected based on a relative odor activity value (ROAV) greater than 1 in SPGT: dimethyl sulfide (71.14, cooked corn-like), 2-methylbutanal (3.17, cereal), octanal (1.31, fruity), linalool (5.25, floral), nonanal (5.00, floral), (E)-2-nonenal (2.81, cucumber), decanal (22.90, fruity), and β-ionone (60.51, floral). The concentration of aroma compounds, especially for floral and fruity key volatile compounds significantly increased during the shaking and piling process (p < 0.05), and their formation pathways help explained these changes. Our results provided a new theoretical foundation and practical guidelines for producing the high-aroma green tea.

Resveratrol up-regulates the erythrocyte plasma membrane redox system and mitigates oxidation-induced alterations in erythrocytes during aging in humans

Reactive oxygen/nitrogen species (ROS/RNS)-mediated oxidative damage followed by disturbed cellular homeostasis is involved in aging and related consequences. Lipid peroxidation, post-translational modifications of proteins, and an impaired defense system due to increased oxidative stress jeopardize cell fate and functions, resulting in cell senescence. Resveratrol, a natural stilbene, has extensively been reported to elicit a plethora of health-promoting effects. The present study carried out on 97 healthy human subjects (62 males and 35 females) of both sexes provides experimental evidence that resveratrol confers ability to up-regulate the plasma membrane redox system (PMRS) along with ascorbate free radical reductase, a compensatory system operating in the cell to maintain cellular redox state. Furthermore, resveratrol provided significant protection against lipid peroxidation and protein carbonylation and restored the cellular redox homeostasis measured in terms of glutathione (GSH) and sulfhydryl (-SH) group levels during oxidation injury in erythrocytes of different age groups in humans. Findings suggest a possible role of resveratrol in retardation of age-dependent oxidative stress.