Abstract:
Fungi are a very diverse group of organisms that can produce a vast number of pharmacologically
active secondary metabolites. Fungi also have the ability to produce numerous secondary metabolites
from a single strain. In this study, the One Strain Many Compounds (OSMAC) approach was used
to observe the biosynthetic potential of endolichenic fungus, Curvularia trifolii isolated from Usnea
sp. in Sri Lanka. Under the OSMAC approach, the variation of the metabolic profile of the fungus
when cultured in different culture media was investigated. Culturing in Potato Dextrose Broth (PDB)
medium resulted in the elution of two peaks in High- Performance Liquid Chromatographic (HPLC)
study while four major peaks resulted from Yeast Potato Dextrose Broth (YPDB) medium cultures.
Five major peaks eluted from Oatmeal extract broth (OEB) medium cultures and two major peaks
from Rice-Yeast Broth (RYB) medium cultures. The bioactivities of crude extracts from each culture
media were investigated using antioxidant, antibacterial, and anti-inflammatory assays and analyzed
using Graph Pad Prism software. The crude extract of OEB showed a comparatively high antioxidant
activity with ABTS radical scavenging assay with an IC50 value of 0.501 ± 0.036 mg mL-1 while the
crude extract of YPDB showed a comparatively high anti-inflammatory activity with human red
blood cell stabilization assay with an IC50 value of 0.151 ± 0.026 mg mL-1. The crude extract of RYB
showed the highest antibacterial activity against Escherichia coli, Staphylococcus aureus, and Bacillus
subtilis bacterial strains upon analysis using agar-well diffusion method. The study confirms the
variation of metabolic products and associated bioactivities of Curvularia trifolii with the variation
of its culture medium.
