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Biomedical potential of marine organisms from Singapore
Author
Yogeswari Selvaraja
Supervisor
Tan, Lik Tong
Abstract
The research project was undertaken to study the biomedical potential of marine organisms in Singapore. Marine organisms belonging to the genus Dysidea and Lyngbya were collected from St John’s Island and Pulau Hantu Besar in Singapore. Both organisms bioactive potential were evaluated using in-house bioassays. The brine shrimp lethality assay was used to determine toxicity of the organic extracts of both the Dysidea (SJ/004) and Lyngbya majuscula (PHB/002). Fractions SJ/004-3 and SJ/004-5 obtained from the chromatographic analysis of the organic extract from Dysidea species showed toxic properties at 10ppm and 1ppm. Bioactivity of organic extract SJ/004-3 was observed at 10ppm with 100% mortality and at 1ppm with 86% mortality. Bioactivity of organic extract SJ/004-5 was observed at 10ppm with 67% mortality and at 1ppm with 46% mortality.
Fractions PHB/002-5 and PHB/002-6 collected from the chromatographic analysis of the Lyngbya majuscula showed toxic properties at 100ppm and 10ppm. Bioactivity of organic extract PHB/002-5 was observed at 100ppm with 100% mortality and 10ppm with 87% mortality. Bioactivity of organic extract PHB/002-6 was observed at 100ppm with 100% mortality.
Further fractionated extracts from these two fractions, PHB/002-5(3) and PHB/002- 6(3) showed cytotoxic results at 10ppm with 58% and 91% mortality respectively. The organic extract and fractions from the Lyngbya majuscula was further analyzed for quorum sensing inhibitors using the mutant strain, Chromobacterium violaceum (CV026). Only fraction PHB/002-3 showed positive quorum sensing inhibition activity. The bioactive fractions of the Dysidea and Lyngbya species collected from chromatographic analysis were analyzed using the nuclear magnetic resonance to predict their structural characteristics. All the compounds have 1 H-NMR spectra resembling those of peptides.
Fractions PHB/002-5 and PHB/002-6 collected from the chromatographic analysis of the Lyngbya majuscula showed toxic properties at 100ppm and 10ppm. Bioactivity of organic extract PHB/002-5 was observed at 100ppm with 100% mortality and 10ppm with 87% mortality. Bioactivity of organic extract PHB/002-6 was observed at 100ppm with 100% mortality.
Further fractionated extracts from these two fractions, PHB/002-5(3) and PHB/002- 6(3) showed cytotoxic results at 10ppm with 58% and 91% mortality respectively. The organic extract and fractions from the Lyngbya majuscula was further analyzed for quorum sensing inhibitors using the mutant strain, Chromobacterium violaceum (CV026). Only fraction PHB/002-3 showed positive quorum sensing inhibition activity. The bioactive fractions of the Dysidea and Lyngbya species collected from chromatographic analysis were analyzed using the nuclear magnetic resonance to predict their structural characteristics. All the compounds have 1 H-NMR spectra resembling those of peptides.
Date Issued
2006
Call Number
RS160.7 Yog
Date Submitted
2006