Antioxidative activity of 4-oxy- and 4-hydroxy-nitroxides in tissues and erythrocytes from rats
Abstract
AIM: To compare the activities of antioxidation of 4-oxy- and
4-hydroxy-nitroxides in tissues and RBC from rats.
METHODS: The homogenates of liver, heart, and kidneys of rats were used to
determine malondialdehyde (MDA) formation using TBA colorimetric method.
H2O2-caused hemolysis was measured spectrometrically. Superoxide anion from
zymosan-stimulated neutrophils of rats was assayed by NBT reduction method.
RESULTS: Nitroxide free radicals OTMPO and HTMPO inhibited MDA generation caused
by .OH generation system (MIC 10.5 and 21 mumol.L-1, respectively), antagonized
hemolysis induced by H2O2 (MIC: 338 and 168 mumol.L-1, respectively), but did not
affect O2- formation from activated neutrophils. 1-Hydroxyl compounds OTMPOH and
HTMPOH possessed similarly potent antilipoperoxidative activities. But nonfree
radical OTMP and HTMP had no effect on peroxidation of tissues.
CONCLUSION: Nitroxides exert their antilipoperoxidative effect by specifically
scavenging .OH free radicals in biological system. Trapping of .OH free radicals
by nitroxides is not by reduction of NO. group in nitroxides. Both NO. group and
NOH group are essential active groups.
Keywords:
4-hydroxy-nitroxides in tissues and RBC from rats.
METHODS: The homogenates of liver, heart, and kidneys of rats were used to
determine malondialdehyde (MDA) formation using TBA colorimetric method.
H2O2-caused hemolysis was measured spectrometrically. Superoxide anion from
zymosan-stimulated neutrophils of rats was assayed by NBT reduction method.
RESULTS: Nitroxide free radicals OTMPO and HTMPO inhibited MDA generation caused
by .OH generation system (MIC 10.5 and 21 mumol.L-1, respectively), antagonized
hemolysis induced by H2O2 (MIC: 338 and 168 mumol.L-1, respectively), but did not
affect O2- formation from activated neutrophils. 1-Hydroxyl compounds OTMPOH and
HTMPOH possessed similarly potent antilipoperoxidative activities. But nonfree
radical OTMP and HTMP had no effect on peroxidation of tissues.
CONCLUSION: Nitroxides exert their antilipoperoxidative effect by specifically
scavenging .OH free radicals in biological system. Trapping of .OH free radicals
by nitroxides is not by reduction of NO. group in nitroxides. Both NO. group and
NOH group are essential active groups.