The In Vitro Antioxidant Activity and Inhibition of Intracellular Reactive Oxygen Species of Sweet Potato Leaf Polyphenols

Figure 2

Protective effect of total polyphenols from sweet potato leaves on human hepatocyte LO2 oxidative stress. (a) The effect of total polyphenols from sweet potato leaves on the cell viability of oxidative stress LO2 cells. (b) The effect of total polyphenols from sweet potato leaves on the level of intracellular reactive oxygen species. Control was LO2 cells without H₂O₂ and antioxidant treatment; H₂O₂ control was the LO2 oxidative stress model group which was treated by H₂O₂ of 100 μM; Trolox, ascorbic acid, TPP, and GPP were LO2 cells pretreated by 100 μg/mL Trolox, ascorbic acid, tea polyphenols, and grape seed polyphenols, respectively, and then treated by 100 μM H₂O₂; SPLP1, SPLP2, SPLP3, SPLP4, SPLP5, and SPLP6 were LO2 cells pretreated by sweet potato leaf polyphenols of 25, 50, 100, 200, 400, and 800 μg/mL, respectively, and then treated by 100 μM H₂O₂; the dashed lines represented the values of the blank control group, while the solid lines represented the values of the LO2 oxidative stress model group. Values were means ± SD of five determinations. The different letters above the different bars mean that the cell viability or the level of intracellular reactive oxygen species was significantly different ().

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