Three model systems measure oxidation/nitration damage caused by peroxynitrite

Diseases activate the innate immune response which causes ancillary damage to the human body. Peroxynitrite (OONO-) or its carbon dioxide derivatives cause oxidation/nitration and hence mutation to various body polymers e.g. DNA, RNA, protein, lipids and sugars. The control of the ancillary damage can come from antioxidants which inhibit control the amount of peroxynitrite available for damage. In this paper we have developed three different levels of antioxidant screening: (i) Peroxynitrite or SIN-1 reaction with luminol to produce light, and the inhibition of light by substances therefore represents antioxidation. (ii) Nicking of plasmid DNA occurs via oxidants: and is prevented by antioxidants. (iii) Detection of plasmid luciferase activity post-oxidation and infection indicates either prevention or repair of damage: via antioxidants. We found green tea and a number of its polyphenolic constituents effective only at the first level of antioxidation, while extracts of various fruit help at all levels antioxidation. In the final analysis, a combination of green tea extracts and fruits is suggested to produce more complete antioxidant protection.