In-Vitro Screening of Selected Medicinal Plant Extracts for the Antifungal Activity Against Fusarium oxysporum

Abstract

Economically feasible and eco- friendly management methods for Fusarium oxysporum is required, as this pathogen and its many special forms affect a wide variety of hosts of economic value. The study was carried out to evaluate the antifungal activity of some plant species used in folkloric medicine in Sri Lannka against an isolate of F. oxysporum. Methanol extracts of four plant species, Oxalis corniculata (creeping woodsorrel red and green), Ocimum gratissimum (wild basil) and bulbs of Kaempferia galangal (aromatic ginger), Zingiber officinale (ginger) were screened for their activity against F. oxysporum by agar dilution method. The extract of the different plant species at 10% concentration reduced colony growth of F. oxysporum from 25% to 88% (P<0.05) compared with the control. The most active extracts, aromatic ginger and wild basil inhibited more than 90 % growth of F. oxysporum at 20% concentration. Other than the reduction of radial growth, wrinkled mycelium was also observed in treated samples. The results showed that minimal inhibitory concentrations (MIC) were 5% (w/v) for aromatic ginger and for wild basil, while 20% (v/v) MIC was shown for all other plant crude extracts. Out of four plants extract screened, wild basil and aromatic ginger showed more than 75% fungal inhibition after 6 hour immersion and other extracts could not exceed 60% inhibition at any exposure time. The study revealed that methanol extract of aromatic ginger and wild basil exhibit strong fungicidal activities against F. oxysporum and therefore, Methanol extract of these two plants can be used as effective antifungal agents.