Author : Bimo Budi Santoso

Summary : Antimicrobial-guided fractionation and isolation of the bioactive compounds from the stem bark of D. arfakensis were carried out. Four antimicrobial compounds were isolated. The structures of the antimicrobial compounds were elucidated by spectroscopic methods. The dried powdered stem bark from D. arfakensis was sequential fractionated with series solvents. Finely ground bark was initially extracted with hexane. The marc was allowed to dry and the process of fractionation was repeated with DCM, acetone, and finally methanol. The same dried powdered stem bark was directly extracted with methanol called whole extract. Bioautography, cylinder cup and minimum inhibitory concentration (MIC) assay were applied to determine antimicrobial activity of all the extracts. MIC and cylinder cup assay indicated that the acetone extract was the most active fraction against S. aureus and the hexane extract was the most active fraction against C. albicans . Therefore, the two extracts were further fractionated and characterized. The hexane extract was subjected to a series of vacuum liquid chromatography leading to the isolation of an active compound called compound-1. The fractionations and isolations of the acetone extract through series of vacuum liquid chromatography and radial chromatography yielded three antimicrobial compounds namely: compound-2, compound-3 and compound-4. On the basis of the spectral data from experiments and comparison with spectral data of known compounds, compound-1 is polygodial, compound-2 is 11-hydroxydrim-8-en-7-one, compound-3 is velutin and compound-4 is 4-(hydroxy (oxyran-2-yl) methyl)-2-methoxyphenol.