Abstract:
Endolichenic fungi (ELF), which live in healthy tissues of lichens, are one of the promising
producers of structurally diverse novel bioactive secondary metabolites. It has been reported
that endolichenic fungi are rich sources for the discovery of new compounds with significant
medicinal values and this was demonstrated by isolation and identification of new anticancer,
antifungal, antibacterial and antioxidant agents from endolichenic fungal extracts. In Sri
Lanka, research group of University of Kelaniya initiated a research program on ELF and
have isolated few interesting bioactive poliketides from ELF of three lichen species available
in Sri Lanka. They have shown great potential to be a source for novel bioactive natural
products.
The objectives of this study were isolation and identification of bioactive compounds of the
endolichenic fungus, Curvularia trifolii isolated from the lichen Usnea species. In a
continuation of our chemical investigations in search of secondary metabolites of
endolichenic fungi with medicinal value led to the isolation of few bioactive compounds. In
this present study, C. trifolii was grown in large scale and incubated at room temperature for
10 days. The metabolites were extracted into ethyl acetate (EtOAc). Antibacterial, anticancer
and insecticidal activities of the EtOAc extract were evaluated using in-vitro bioassays. The
EtOAc extract was subjected to a silica gel column chromatography resulting, one major
compound with high bioactivities. The isolated pure white crystalline compound was
identified as 1,14-dihydroxy-6-methyl-6,7,8,9,10,10,14,14 -octahydro-1H-benzo[f][1]
oxacyclododecin-4(13H)-one using 1H, 13C NMR, 2D NMR and MS data. The compound
was found to possess antibacterial activity against three test pathogens, anticancer activity at
(NCIH-460), (MCF-7), (SF-268), (PC3M), and (MDA-MB-231) cell lines and insecticidal
activity.
