649551-93-9Relevant articles and documents
Potential therapeutic antioxidants that combine the radical scavenging ability of myricetin and the lipophilic chain of vitamin E to effectively inhibit microsomal lipid peroxidation
Bennett, Christopher J.,Caldwell, Stuart T.,McPhail, Donald B.,Morrice, Philip C.,Duthie, Garry G.,Hartley, Richard C.
, p. 2079 - 2098 (2007/10/03)
The flavonol myricetin, reacts with oxygen-centred galvinoxyl radicals 28 times faster than d-α-tocopherol (vitamin E), the main lipid-soluble antioxidant in biological membranes. Moreover, each myricetin molecule reduces twice as many such radicals as vitamin E. However, myricetin fails to protect vitamin E-deficient microsomes from lipid peroxidation as assessed by the formation of thiobarbituric acid reactive substances (TBARS). Novel and potentially therapeutic antioxidants have been prepared that combine the radical-scavenging ability of a myricetin-like head group with a lipophilic chain similar to that of vitamin E. C6-C12 alkyl chains are attached to the A-ring of either a 3,3′,4 ′,5′-tetrahydroxyflavone or a 3,2 ′,4′,5′-tetrahydroxyflavone head group to give lipophilic flavonoids (ClogP=4 to 10) that markedly inhibit iron-ADP catalysed oxidation of microsomal preparations. Orientation of the head group as well as total lipophilicity are important determinants of antioxidant efficacy. MM2 models indicate that our best straight chain 7-alkylflavonoids embed to the same depth in the membrane as vitamin E. The flavonoid head groups are prepared by aldol condensation followed by Algar-Flynn-Oyamada (AFO) oxidation or by Baker-Venkataraman rearrangement. The alkyl tails are introduced by Suzuki or Negishi palladium-catalysed cross-coupling or by cross-metathesis catalysed by first generation Grubbs catalyst, which tolerate phenolic hydroxyl and ketone groups.
