EPR evidence for the involvement of free radicals in the iron-catalysed decomposition of qinghaosu (artemisinin) and some derivatives; antimalarial action of some polycyclic endoperoxides.
EPR experiments confirm that reaction of qinghaosu and some related endoperoxides with Fe2+ in aqueous acetonitrile leads to the production of carbon-centred radicals derived by rapid rearrangement of first-formed cyclic alkoxyl radicals. Signals obtained from qinghaosu itself with spin-traps DMPO and DBNBS are assigned to the adducts (15) and (16), a finding which accounts for the formation of the major products (11) and (14).
Butler
A R
AR
School of Chemistry, University of St. Andrews, Fife, Scotland.
Gilbert
B C
BC
Hulme
P
P
Irvine
L R
LR
Renton
L
L
Whitwood
A C
AC
D000962:Antimalarials / Q000378:metabolism* / Q000494:pharmacology; D019306:Artemisia / Q000737:chemistry; D037621:Artemisinins; D002384:Catalysis; D004365:Drugs, Chinese Herbal / Q000378:metabolism* / Q000494:pharmacology; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D004579:Electron Transport; D005290:Ferric Compounds / Q000737:chemistry*; D005609:Free Radicals / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D010946:Plants, Medicinal; D011083:Polycyclic Compounds / Q000494:pharmacology; D019163:Reducing Agents / Q000737:chemistry; D012717:Sesquiterpenes / Q000378:metabolism* / Q000494:pharmacology
D000962:Antimalarials; D037621:Artemisinins; D004365:Drugs, Chinese Herbal; D005290:Ferric Compounds; D005609:Free Radicals; D011083:Polycyclic Compounds; D019163:Reducing Agents; D012717:Sesquiterpenes; C031327:artemisinin; D007501:Iron