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1 Peroxynitrite (ONOO 7 ) the highly reactive coupling product of nitric oxide and superoxide, has been implicated in the pathogenesis of an increasing number of (in¯ammatory) diseases. At present, however, selective peroxynitrite antagonizing agents with therapeutic potential are not available. Therefore, the NADPH-oxidase inhibitor apocynin (4-hydroxy-3-methoxy-acetophenone) was tested for its ability to inhibit peroxynitrite formation in vitro 2 The murine macrophage cell-line J774A.1, stimulated with IFNg/LPS, was used as a model. Conversion of 123-dihydrorhodamine (123-DHR) to its oxidation product 123-rhodamine was used to measure peroxynitrite production. 3 Stimulated peroxynitrite formation could be completely inhibited by apocynin, by the superoxide scavenger TEMPO as well as by the nitric oxide synthase inhibitor aminoguanidine. Apocynin and aminoguanidine speci®cally inhibited superoxide and nitric oxide formation respectively as con®rmed by measuring lucigenin enhanced chemiluminescence and nitrite accumulation. 4 It is concluded that J774A.1 macrophages produce signi®cant amounts of peroxynitrite, which is associated with nitric oxide production and NADPH-oxidase dependent superoxide formation. The NADPH-oxidase inhibitor apocynin proved to be a potent inhibitor of both superoxide and peroxynitrite formation by macrophages, which may be of future therapeutic signi®cance in a wide range of in¯ammatory disorders.

As buckwheat honey was most effective in reducing ROS levels, it was selected for use in wound-healing products. The major antioxidant properties in buckwheat honey derive from its phenolic constituents, which are present in relatively large amounts. Its phenolic compounds may also exert antibacterial activity, whereas its low pH and high free acid content may assist wound healing.

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Apocynin in vitro inhibits inflammation-mediated cartilage destruction without having adverse effects on cartilage. The latter may be an advantage of apocynin over many other non-steroidal anti-inflammatory drugs. Therefore, apocynin might have an added beneficial effect in protecting RA patients from joint destruction.