Fig. 4. Effects of propofol medium chain triglyceride/long chain triglyceride (MCT/LCT) or propofol LCT (Diprivan) on the generation of hydroxyl radical (HO^·) from ultraviolet irradiation of H²O². (  A ) Electron spin resonance spin trapping measurement of HO^·generation from ultraviolet irradiation (365 nm, 40 mW) of H²O²(20 mm) in 0.1 m phosphate-buffered saline (pH 7.2) as spin trap 5,5-dimethyl-1-pyrroline-  N -oxide (DMPO; 50 mm) in the absence of propofol MCT/LCT (control) with propofol MCT/LCT pretreatment at 56.09 μm, 112.18 μm, 224.36 μm, 560.9 μm, and original liquid (5,609 μm), respectively. (  B ) Electron spin resonance spin trapping measurement of HO^·generation  via ultraviolet irradiation of H²O²in 0.1 m phosphate-buffered saline (pH 7.2) as spin trap DMPO (50 mm) in the absence of vehicle (MCT/LCT) (control) with equivalent vehicle (MCT/LCT) pretreatment of propofol MCT/LCT. Signals appearing at either side of the electron spin resonance spectra correspond to manganese oxide installed in the cavity as a reference. In  C , we present the dose–response of propofol MCT/LCT (56.09–5,609 μm;  closed column ) or propofol LCT (56.09–5,609 μm;  open column ) on HO^·generation  via ultraviolet irradiation of H²O². The signal intensity of the second peak of the spectrum was normalized as the relative height against the standard's signal intensity of the manganese oxide marker. Data are presented as mean ± SD of quadruplicate experiments. * Significantly different (  P < 0.05) from the corresponding control value.