FIG. 7.

(A) α-Tocopherol inhibits the reduction of Cyt C during the XAO-catalyzed oxidation of nonenal. Nonenal (5 mM) was incubated with the XAO assay system in the presence of 200–800 μM α-tocopherol for up to 15 min. Wavelength scan was performed between 500 and 600 nm. Lines 1 to 5 represent control without enzyme (1), with XAO alone (2), and with 200, 400, and 800 μM α-tocopherol (3–5) at the end of 15 min. The figure is a representation from six separate trials. Insert represents optical-density difference at 549 nm in the absence and presence of α-tocopherol. (B) α-Tocopherol inhibits the conversion of nonenal to nonanoic acid. Experiments were set as described for Fig. 6A, but in the absence of cytochrome c. Reactions were scaled down and performed in 96-well microtiter plates with a final volume of 175 μl. At the end of incubations at 37°C for 30 min, 25 μl of Purpald solution (20 mg in 0.5 ml of 1N NaOH) was added, and the color was read at 540 nm. Appropriate controls (without enzyme or aldehyde) were performed. The figure represents average ± SD of three separate trials done in triplicate. *Statistically significant values (p < 0.05).