Plant Pathogenic Fungi as a Source of Anticandidal Drugs

Abstract

All higher plants are host to one or more microbes. Only a few these plants have been completely studied relative to their microbial biology. However fungi, which infect plant have mechanism to overcome the plant defense mechanism by the way of production of some secondary metabolites. These metabolites however have not been screened for their ability to be used as new antimycotics. So plant pathogenic fungi are a poorly investigated group of microorganisms that represent an abundant and dependable source of bioactive and chemically novel compounds with potential for exploitation in a wide variety of medical, agricultural, and industrial arenas. In the present study, screening of pathogenic phyllosphere fungi of plants likes Lantana camara, Hibiscus rosa-sinensis & Cannabis sativa was done by production of secondary metabolites by the process of fermentation. Antifungal activity of chloroform, dichloromethane, ethyl acetate, acetone, and methanol extracts of spent broth of pathogenic phyllosphere fungi was evaluated against test microorganisms by using agar well diffusion assay (prescreen). Studies revealed the activity of the different extracts produced by pathogenic phyllosphere fungi against multidrug resistant yeast. Among the extracts tested, chloroform extract was the most active. It exhibited prominent antifungal activity against Candida albicans (G1-isolate), Candida albicans (G2-isolate) and Candida albicans (G4-isolate). Chloroform extract evaluated was validated against standard antifungal antibiotics e.g., Griseofulvin to know the efficacy of the extract. MIC of the chloroform extract was determined using broth macrodilution assay. Chloroform extract exhibited similar trend of MIC against the test organisms. The MIC of the chloroform extract was ranging between 40 µg/ml to 128 µg/ml for all the test microorganisms. Death pattern of the test organisms in presence of the extracts was determined using macrobroth test tubes and plate count method. t was found that 90- 100% reduction in the microorganism count occurred between 8-16 hours after the growth. Partial purification of the extracts was done using Thin Layer Chromatography (TLC). TLC purified fractions 4,6,7,8,9 exhibited antifungal activity against test organisms. So the present study establishes the role of pathogenic phyllosphere fungi as a potential source of natural products for exploitation in medicine, agriculture & industry. These could be helpful in overcoming resistant of fungal pathogens.