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. Author manuscript; available in PMC: 2020 Feb 1.
Published in final edited form as: Toxicol In Vitro. 2018 Sep 6;54:1–9. doi: 10.1016/j.tiv.2018.09.001

Figure 1.

Figure 1.

Effect of catechin on superoxide anion generation rate. A) EPR determination of superoxide anion generation by insect cell microsomes (supersomes) after 10 min of incubation. EPR spectra were recorded using the parameters specified under Materials and Methods, a) Complete system: the complete system consisted of air-saturated 100 mM potassium phosphate buffer pH 7.0, 5 mM DTPA, 1 mM NADPH, 50 mM DEPMPO, and 1 mg protein/mL of CYP2E1-expressing supersomes co-expressing NADPH cytochrome P450 reductase (CPR) and cytochrome b5 (b5); b) Simulation: a simulated DEPMPO-OOH spectrum was generated using the parameters described under Materials and Methods; c) + SOD: superoxide dismutase at 1000 U/mL was added to the complete system; d) -NADPH: NADPH was omitted from the complete system; e) - supersomes: supersomes were omitted from the complete system; f) - CYP2E1: supersomes expressing only CPR and b5 replaced CYP2E1-expressing supersomes in the complete system; g) -CYP2E1, -CPR, -b5: supersomes devoid of CYP2E1, CPR and b5 replaced CYP2E1-expressing supersomes in the complete system; h) + catalase: catalase at 1000 U/mLwas added to the complete system; i) + catechin: catechin at 0.1 mM was added to the complete system; j) + catechin, -NADPH, - supersomes: NADPH and supersomes were omitted from, and catechin at 0.1 mM was added to the complete system; k) + catechin, -supersomes: supersomes were omitted from, and catechin at 0.1 mM was added to the complete system; 1) + catechin, - CYP2E1: catechin was added to the complete system, and supersomes expressing NADPH cytochrome P450 reductase and cytochrome b5 replaced CYP2E1-expressing supersomes in the complete system. B) EPR determination of superoxide anion generation by xanthine and xanthine oxidase after 10 min of incubation, a) Complete system: the complete system 0 of air-saturated 100 mM potassium phosphate buffer pH 7.0, 5 mM DTP A, 50 mM DEPMPO, 200 μΜ xanthine, and 20 mU/mL xanthine oxidase; b) + SOD: superoxide dismutase at 1000 U/mL was added to the complete system; c) + catechin: catechin at 0.1 mM was added to the complete system.