CHEMISTRY OF TOXIC RANGE PLANTS. HIGHLY OXYGENATED FLAVONOL METHYL ETHERS FROM GUTIERREZIA MICROCEPHALA

Article abstract of DOI:10.1016/S0031-9422(00)84904-3

Gutierrezia microcephala; Broomweed; Compositae; Astereae; flavonol; oxygenated kaempferol; quercetin and myricetin derivatives; 13C NMR.The perennial American desert shrub, Gutierrezia microcephala, contains 20 flavonol methyl ethers displaying nine different oxygenation patterns.These include 11 new flavonols: 5,7-dihydroxy-3,6,8,3',4',5'-hexamethoxyflavone, 5,7,4'-trihydroxy-3,6,8,3',5'-pentamethoxyflavone, 5,7,3'-trihydroxy-3,6,8,4',5'-pentamethoxyflavone, 5,7,2',4'-tetrahydroxy-3,6,8,5'-tetramethoxyflavone, 5,7,3',4'-tetrahydroxy-3,6,8-trimethoxyflavone, 5,7,8,3',4'-pentahydroxy-3,6-dimethoxyflavone, 3,5,7,3',4'-pentahydroxy-6,8-dimethoxyflavone, 5,7,4'-trihydroxy-3,6,8-trimethoxyflavone, 5,7,8,4'-tetrahydroxy-3,3'-dimethoxyflavone, 5,7,8,3',4'-pentahydroxy-3-methoxyflavone and 5,7,8,4'-tetrahydroxy-3-methoxyflavone.In addition, the following known flavonols were isolated: 5,7-dihydroxy-3,8,3',4',5'-pentamethoxyflavone, 5,7,4'-trihydroxy-3,8-dimethoxyflavone, 5,7,4'-trihydroxy-3,8,3'-trimethoxyflavone, 5,7,3',4'-tetrahydroxy-3,8-dimethoxyflavone, 5,7,4'-trihydroxy-3,6,3'-trimethoxyflavone, 5,7,3',4'-tetrahydroxy-3-methoxyflavone, 5,4'-dihydroxy-3,6,7,8,3'-pentamethoxyflavone, 5,7,4'-trihydroxy-3,6,8,3'-tetramethoxyflavone and 3,5,7,4'-tetrahydroxy-6,8,3'-trimethoxyflavone.