International Postgraduate Research Conference (IPRC)
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Item New Bioactive poliketide from endolichenic fungus, Curvularia trifolii, inhabiting the lichen, Usnea sp. collected from Haggala Botanical Garden(Faculty of Graduate Studies, University of Kelaniya, 2015) Samanthi, K.A.U.; Wickramaarachchi, S.; Wijerathne, E.M.K.; Paranagama, P.A.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.Item Investigating the bioactive compounds of endolichenic fungus Hypoxylon anthochroum isolated from the lichen, Pseudocyphellaria sp.(Faculty of Graduate Studies, University of Kelaniya, 2015) Antony, K.N.L.; Samanthi, K.A.U.; Paranagama, P.A.It has been reported that 11 endolichenic fungal strains were isolated from lichen, Pseudocyphellaria sp. Endolichenic fungi live asymptomatically within the lichen thallus and known as a new source useful of bioactive secondary metabolites. Secondary metabolites in endolichenic fungi show distinct bioactivities including antimicrobial, anti-inflammatory, analgesic, antioxidant and cytotoxic activities. These bioactive compounds have potential importance in development of pharmaceutical drugs, nutraceuticals and agrochemicals. The present study was carried out to investigate antioxidant activities of secondary metabolites produced from Hypoxylon anthochroum inhabiting the lichen, Pseudocyphellaria sp. In this research, H. anthochroum was cultured in 50 large petridishes containing potato dextrose agar (PDA) medium and incubated at room temperature for seven days. After the incubation period, secondary metabolites were extracted into ethyl acetate in order to obtain crude extract. The crude extract was partitioned using solvents hexane, chloroform and 60% aqueous methanol. Antioxidant activities of three fractions were evaluated using micro plate DPPH assay. Since chloroform fraction showed the highest antioxidant activity (81.96 % Inhibition at 800 μg/mL) it was further subjected to silica gel column chromatography and preparative thin layer chromatography to isolate bioactive compounds. One UV active pure compound which has antioxidant activity (43.21 % Inhibition at 800 μg/mL) was isolated from chloroform fraction and its structure elucidation will be carried out using 1H NMR, 13C NMR, and 2D NMR spectral data.Item Antioxidant active novel secondary metabolite from endolichenic fungus, Penicillium citrinum, inhabiting the lichen, Pamotrema sp. available in Sri Lanka(Faculty of Graduate Studies, University of Kelaniya, 2015) Samanthi, K.A.U.; Wickramarachchi, S.; Wijerathne, E.M.K.; Paranagama, P.A.