Abstract

Leaf essential oils of Callistemon rigidus and Callistemon citrinus obtained by steam-distillation were assigned for their antifungal activity against Phaeoramularia angolensis. The oils of C. rigidus and C. citrinus were dominated by the presence of 1,8-cineole (79.1% and 73.8% respectively). Fractions 6 and 5 isolated from C. rigidus and C. citrinus respectively were rich in1,8-cineole (100% and 91.4% respectively). The determination of the antifungal activity of the essential oils was done by the agar medium assay. Total inhibition was obtained with the concentrations of 6500 ppm and 6000 ppm for C. rigidus and C. citrinus essential oils respectively. Fraction 12 of C. citrinus rich in α-terpineol and terpinen-4-ol (88.7% and 10% respectively) was the most active showing total inhibition againstPhaeoramularia angolensis at 1500 ppm. The two essential oils used showed fungicidal properties against P. angolensis and could constitute an alternative to synthetic fungicides usually used for citrus fruit crops.

Key words: Essential oil, Callistemon citrinus, Callistemon rigidus, essential oil composition, Phaeoramularia angolensis, antifungal activity.