Effect of nitric oxide and plant antioxidants on microsomal content of lipid radicals.
The antioxidant ability of nitric oxide (NO) generated by a chemical donor and of commercially available antioxidant preparations was assayed. SNAP (S-Nitroso-N-acetylpenicilamine) was used as the NO donor, and Ginkgo biloba, wheat and alfalfa preparations were tested. Lipid peroxidation was assayed by EPR employing a reaction system consisting of rat liver microsomes, ADP, FeCl3, NADPH and POBN in phosphate buffer, pH=7.4. In vitro NO exposure decreased microsomal lipid peroxidation in a dose-dependent manner. The dose responsible for inhibiting the microsomal content of lipid radical adducts by 50% (LD50) for SNAP was 550 microM (NO generation rate 0.1 microM/min). The addition of 50 microM hemoglobin to the incubation media prevented NO effect on lipid peroxidation. The addition of an amount of the antioxidant preparations equivalent to the LD50 doses inhibited lipid peroxidation by 21, 15, and 33% for wheat, alfalfa, ginkgo biloba preparations respectively in the presence of 550 microM SNAP. We detected a decrease in the content of lipid radical adducts after simultaneous supplementation, although it was less than 50%, even when LD50 doses of the products were added. This suggests that NO and the natural antioxidants inhibit lipid peroxidation by a mechanism that has both common and non-shared features.
Boveris
A D
AD
Physical Chemistry, School of Pharmacy and Biochemistry, University of Buenos Aires, Argentina.
Galatro
A
A
Puntarulo
S
S
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D020441:Ginkgo biloba; D007928:Lethal Dose 50; D015227:Lipid Peroxidation / Q000187:drug effects*; D008297:Male; D000455:Medicago sativa; D008862:Microsomes, Liver / Q000187:drug effects* / Q000378:metabolism; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D010936:Plant Extracts / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D026423:S-Nitroso-N-Acetylpenicillamine / Q000494:pharmacology*; D019097:Spin Trapping; D014908:Triticum
D000975:Antioxidants; D020030:Nitric Oxide Donors; D010936:Plant Extracts; D026423:S-Nitroso-N-Acetylpenicillamine