Antibacterial Activity of Bioactive Compound Produces by Endophtic Fungi Isolated from Mangifera casturi Kosterm Endemic Plant from South Kalimantan, Indonesia

One of promising bio-prospect as producer of an antibacterial compound is endophytic fungi that live in endemic plants. This research is aimed to evaluate the endophytic fungi antibacterial compound from Mangifera casturi, an South Kalimantan endemic plant that has ethnobotanical utilisation in the pharmaceutical field. The bioactive compounds of 13 endophytic fungi were extracted using ethyl acetate and evaluated for antibacterial activity using disc diffusion assay. The minimum inhibitory concentration (MIC) was measured by the serial broth dilution method. Scanning Electron Microscopy (SEM) was used to examine cell damage due to the effect of the extract. The antibacterial compounds then were detected using GC-MS analysis. The endophytic fungi were identified morphologically and molecularly based on ITS rDNA sequence. Among 13 isolates, endophytic fungi identified as Botryosphaeria rhodina AK32 able to produce antibacterial compounds that exhibited the highest activity and have a broad spectrum, moreover capable against resistant bacteria (MRSA) with 1.56% of MIC value for all of the test bacteria. AK32 ethyl acetate extract was inhibiting the cell wall synthesis and penetrate the outer membrane of bacteria. Based on GC-MS, antibacterial compounds of AK32 ethyl acetate extract were di-n-octylphthalate, phenol, 2-methyl-, 4-pentadecyne, 15-chloro-, benzeneacetonitrile, and benztriazole.