[Antifungal activity of peppermint [mentha piperita L.] on phytopathogenic fungi]

ABSTRACT

Using plant crude extracts on the control of microbial agents is increasing, because of medicinal, antifungal, antibacterial and antioxidant properties of plant-based secondary metabolites. The present work was conducted to find out antifungal activity of peppermint and access to the best solvent to elicit antifungal metabolites from peppermint. Aerial parts of peppermint were dried and crude extracts were obtained using water, methanol, ethanol, acetone and chloroform. The antifungal activity of this plant was evaluated on mycellial growth of phytopathogenic fungi, Rhizoctonia solani, Fusarium oxysporum, Phytophthora dershleri and Bipolaris sorkiniana using two different methods, paper disc and agar diffusion. The results of the tested solvents demonstrated that water is the best to elicit the inhibitory compounds from peppermint. Methanol and acetone extracts had little inhibitory effects on B. sorkiniana while ethanol and chloroform extracts could not elicit inhibitory compounds against all of tested fungi. The mycellial growth of F. oxysporum and B. sorkiniana was inhibited at the concentration of 2mg/paper disc while the other two fungi was affected at the concentration of 4 mg/paper disc. In agar diffusion method, aqueous extract completely supperesed the growth of P.dershleri and B. sorkiniana at 500 and 1000 ppm of the crude xtract, respectively. However, the mycellial growth R. solani, F. Oxysporum was not completely supperesed even at 2000 ppm. From these results it was concluded that peppermint possesses sufficient in vitro activity on the control of tested phytopathogenic fungi. Besides, it can be stated that water is the best solvent among the tested solvents for extracting the antifungal compounds from peppermint