Thesis (M.Sc.)--Chulalongkorn University, 2004

The purpose of this research was to isolate bioactive compounds from endophytic fungi isolate LRUB 20 from Leea rubra Blume Ex Spreng. and isolate USIA 5 from Urobotrya siamensis Hiepko. Crude extract of endophytic fungus isolate LRUB 20 was purified by chromatographic techniques to afford three compounds, which were identified as asterric acid, 2-hydroxymethyl-3-methyl-cyclopent-2-enone, and 2-hydroxymethyl-3-methyl-cyclopentanone. The crude extract of endophytic fungus isolate USIA 5 provided 3-nitropropionic acid. The chemical structures of the isolated compounds were elucidated through extensive analyses of UV, IR, MS, and NMR and by comparison with literature. Asterric acid, 2-hydroxymethyl-3-methyl-cyclopent-2-enone, and 3-nitropropionic acid were found to exhibit activity against Mycobacterium tuberculosis H37Rv with the MIC values of 200, 200, and 0.39 g/ml, respectively. Based on morphology and nucleotide sequences of ITS1-5.8S-ITS2 regions of rDNA, endophytic fungus isolate USIA 5 was identified as Phomopsis sp. in the family Diaporthaceae. While based on morphology, the fungus isolate LRUB 20 limited in spore formation. Nucleotide sequences of ITS1-5.8S-ITS2 regions of rDNA were applied to classify endophytic fungus isolate LRUB 20, which was found to be in the family Magnaporthaceae