Abstract

Inula viscosa, Inula graveolens and Inula crithmoïdes (Asteraceae) leaf and flower organic extracts (hexane, chloroform and methanol) were assessed for their antifungal activity against two Trichoderma species (Trichoderma harzianum and Trichoderma viride) and three formae speciales of Fusarium oxysporum. I. viscosa organic extracts showed an important inhibitory activity against all target fungal isolates. Growth inhibition percentage ranged between 17-61, 77-100, and 55-100% in presence of hexane, chloroform and methanol I. viscosa leaf extracts, respectively. Flower organic extracts reduced mycelial growth of all fungi by 32-66, 30-75, and 8-70%, respectively. For I. graveolens, Stem + leaf organic extracts showed more or less important inhibition depending on solvent nature, though, flower organic extracts were found to be the most effective against tested fungi: a total inhibition of growth was recorded with methanol fraction against all target fungi and with hexane fraction against F. oxysporum f. sp. melonis (FOM) and T. viride. In presence of I. crithmoïdes leaf organic extracts, a total growth inhibition was noted with the three extracts against T. harzianum, with hexane and methanol fraction against T. viride and with chloroform fraction against FOM. I. crithmoïdes flower extracts caused a highly significant growth inhibition of about 57-100, 66-100, and 100-100% with hexane, chloroform and methanol extracts, respectively. Therefore, I. viscosa, I. graveolens and I. crithmoïdes could be an important source of biologically active compounds useful for developing environmentally safe antifungal products.

Key words: Antifungal activity, organic extracts, Inula, radial growth.