Antimicrobial Activity of the Endophytic Fungi Isolated from the Medicinal Plants

Abstract

Medicinal plants are used since ancient times to cure various ailments, a lot of therapeutically important drugs have been obtained from plants with medicinal value. A great interest is shown in isolating fungal endophytes from these plants of medicinal value. Endophytic fungi present in these medicinal plants produce numerous novel compounds that have antibacterial, antifungal, anti cancerous, anti inflammatory, antioxidant and antidiabetic properties. Discovery of an important compound taxol, from endophytic fungi of plant Taxus brevifolia, encouraged scientists over the globe to explore more about endophytic fungi. The aim of the current research work was to isolate endophytic fungi from medicinal plant, screening of extracts for antimicrobial activity from isolated endophytic fungi and antimicrobial activity study of the fractions. In disc diffusion preliminary assay EL showed zone of inhibition of 21mm and 11mm against Staphylococcus aureus and Bacillus megaterium respectively. In MTT assay, EL showed maximum inhibition of 60% against Staphylococcus aureus and 41% against Bacillus megaterium. EL also had maximum phenolic content (126.8 mg GAE/ g of dried extract). Thus, EL was selected for further analysis. IC 50 value for EL was found out to be between a concentration 512µg/ml and 1024µg/ml by performing MTT assay. Finally TLC of crude extract EL was run to find out the actual fraction responsible for antimicrobial activity against Staphylococcus aureus. Each fraction was tested by disc diffusion assay, in which fraction 1 gave a zone of inhibition of 10mm. EL was viewed morphologically under microscope for fungal identification purpose. When viewed under microscope it consisted of sac like structures containing spores and had septate hyphae. Thus the results from above studies show that the microorganisms present within the plant could be a source of new bioactive compounds. Identifying and characterizing metabolites produced by endophytes is a promising and current area of research with wide applications in pharmaceutical industry.