Syntnesis and fungitoxicity of some natural and synthetic flavones

Abstract EN

Two natural flavones (flavone and 4'-methoxyflavone) and two artificial ones (3'-methylflavone and 4'-bromoflavone) were synthesized using Baker-Venkatarman rearrangement then characterized by spectroscopic techniques.

The prepared flavones along with the natural flavones quercetin and chrysin were used to examine the effect of structural variations on the fungitoxicity of flavones.

Results indicated correlation between the hydrophobicity and the fungitoxicity of flavones against Alternaria alternatae (R = 0.915) and Fusarium oxisporum (R = 0.562).

The conclusion is also applicable on the natural flavones, quercetin and chrysin, with five and two hydroxyl groups respectively since their activities against both organisms increased with increasing their hydrophobicity i.e.

chrysin > quercetin.

Key words: Flavones, fungitoxicity, structure-activity relationships, Alternaria alternatae, Fusarium oxisporum.