Abstract
This study aims at investigating the antioxidant activity and repair effect of green tea polysaccharide (TPS) with different molecular weights (Mw) on damaged human kidney proximal tubular epithelial cells (HK-2). Scavenging activities on hydroxyl radical (·OH) and ABTS radical and reducing power of four kinds of TPS with Mw of 10.88 (TPS0), 8.16 (TPS1), 4.82 (TPS2), and 2.31 kDa (TPS3) were detected. A damaged cell model was established using 2.6 mmol/L oxalate to injure HK-2 cells. Then, different concentrations of TPSs were used to repair the damaged cells. Index changes of subcellular organelles of HK-2 cells were detected before and after repair. The four kinds of TPSs possessed radical scavenging activity and reducing power, wherein TPS2 with moderate Mw presented the strongest antioxidant activity. After repair by TPSs, cell morphology of damaged HK-2 cells was gradually restored to normal conditions. Reactive oxygen species production decreased, and mitochondrial membrane potential (Δψm) of repaired cells increased. Cells of G1 phase arrest were inhibited, and cell proportion in the S phase increased. Lysosome integrity improved, and cell apoptotic rates significantly reduced in the repaired group. The four kinds of TPSs with varying Mw displayed antioxidant activity and repair effect on the mitochondria, lysosomes, and intracellular DNA. TPS2, with moderate Mw, showed the strongest antioxidant activity and repair effect; it may become a potential drug for prevention and treatment of kidney stones.
Highlights
Tea originated from China features a long history of over 4000 years; it is the most popular nonalcoholic beverage and common food ingredient in Asia [1]
Chen et al [4] have confirmed that Tea polysaccharide (TPS) isolated from green tea manifests the scavenging activity of superoxide radicals, hydroxyl radicals (⋅OH), and lipid radicals in vitro
The four TPSs showed repair effects on HK-2 cells with damage induced by 2.6 mmol/L oxalate
Summary
Tea originated from China features a long history of over 4000 years; it is the most popular nonalcoholic beverage and common food ingredient in Asia [1]. Chen et al [4] have confirmed that TPS isolated from green tea manifests the scavenging activity of superoxide radicals, hydroxyl radicals (⋅OH), and lipid radicals in vitro. Many studies have shown that tea polyphenol has inhibitory effects on calcium oxalate urolithiasis due to its antioxidative effects [5, 6]. Tea polyphenol decreases osteopontin expression and cell apoptosis and increases superoxide dismutase activity in rat kidney tissues, inhibits the formation of calcium oxalate stones [5]. The binding ability of carboxyl groups to calcium ions is obviously higher than that of hydroxyl groups [7], so it has a better potential to inhibit the formation of stones. Research has shown that semisynthetic polysaccharides are more effective in preventing crystal-cell interactions than are GAGs [9]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
