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

The purpose of this research was to isolate bioactive compounds from endophytic fungi isolated from Lagerstroemia speciosa Linn. leaves. Fungal isolate K_BK5 was selected for bioactive compounds due to this isolate produced active compounds against Bacillus subtilis ATCC 6633. Based on morphology, the fungal isolate K_BK5 was identified as Mycelia sterilia. Based on nucleotide sequencing of ITS region, it was closely related to Fungal endophyte MS6 IS133. In this study we investigated for secondary metabotites of fungal isolate K_BK5. Chromatographic techniques and crystallization method were used to purify bioactive compounds from sabourauds dextrose culture broth and mycelia. Two compounds and two mixtures were isolated and identified. The structures of these compounds were elucidated using their physical and chemical properties, spectral data and x-ray crystallographic analysis and comparison with literatures. Three compounds were triglyceride (mixture 1), deoaustrocortirubin (mixture 2), austrocortinin (compound 1) and 1,4,6,7,9-Pentahydroxy-2-methoxy-7-methy-5,6,7,8,8a,9-hexahydroanthracene-10(10aH)-one (compound 2). The pure compound and mixture were tested for antioxidant activity. Deoxyaustrocortirubin and austrocortinin showed high potentially of antioxidant activity with EC[subscript 50] 30.17 and 23.91 respectively. Deoaustrocortirubin inhibits B. subtilis with the MIC value of 250 microgram/ml.