Coumarins represent a large group of 1,2-benzopyrone derivatives which have been identified in many natural sources and synthetized as well. Several studies have shown that their antioxidant capacity is not based only on direct scavenging of reactive oxygen and nitrogen species (RONS) but other mechanisms are also involved. These include: a) the chelation of transient metals iron and copper, which are known to catalyse the Fenton reaction; and b) the inhibition of RONS-producing enzymes (e.g. xanthine oxidase, myeloperoxidase and lipoxygenase), suggesting that mechanism(s) involved on cellular level are complex and synergistic. Moreover, many factors must be taken into account when analysing structure-antioxidant capacity relationships of coumarins due to different in vitro/in vivo methodological approaches. The structural features necessary for the direct RONS scavenging and metal chelation are apparently similar and the ideal structures are 6,7-dihydroxy- or 7,8-dihydroxycoumarins. However, the clinical outcome is unknown, because these coumarins are able to reduce copper and iron, and may thus paradoxically potentiate the Fenton chemistry. The similar structural features appear to be associated with inhibition of lipoxygenase, probably due to interference with iron in its active site. Contrarily, 6,7-dihydroxycoumarin seems to be the most active coumarin in the inhibition of xanthine oxidase while its derivative bearing the 4-methyl group or 7,8-dihydroxycoumarin are less active or inactive. In addition, coumarins may hinder the induction of inducible NO-synthase and cyclooxygenase- 2. Sparse data on inhibition of myeloperoxidase do not enable any clear conclusion, but some coumarins may block it.

• MeSH
• chelátory chemie   metabolismus   farmakologie   MeSH
• cyklooxygenasa 2 metabolismus   MeSH
• inhibitory enzymů chemie   metabolismus   farmakologie   MeSH
• kumariny chemie   metabolismus   farmakologie   MeSH
• lidé MeSH
• lipoxygenasa metabolismus   MeSH
• měď chemie   metabolismus   MeSH
• oxidační stres účinky léků   MeSH
• peroxidasa antagonisté a inhibitory   metabolismus   MeSH
• reaktivní formy kyslíku antagonisté a inhibitory   metabolismus   MeSH
• scavengery volných radikálů chemie   metabolismus   farmakologie   MeSH
• synthasa oxidu dusnatého, typ II antagonisté a inhibitory   metabolismus   MeSH
• vztahy mezi strukturou a aktivitou MeSH
• xanthinoxidasa antagonisté a inhibitory   metabolismus   MeSH
• železo chemie   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH