SECONDARY METABOLITES OF ENDOPHYTIC FUNGI Colletotrichum ti FROM Kaempferia pandurata LEAVES, ANTIBACTERIAL ASSAY AND EVALUATION OF USNIC ACID ADDITION EFFECT

• Main Author: MARIYATUL ULFAH - NIM: 20516027, SITI
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/30994
• Institution: Institut Teknologi Bandung

<p align="justify">Endophytic fungi are microbes that live in the internal tissue of healthy host plant without adversely affecting their host plant. Endophytic fungi can produce interesting bioactive compounds, especially which derived from medicinal plants. One of the medicinal plants that is widely known among Indonesia is Kaempferia pandurata (Temu Kunci) (Zingiberaceae). The study of endophytic fungi from K. pandurata that has been done previously successfully identified some isolates from the rhizome, but there is no study of secondary metabolites. Therefore, this study aims to isolate and identify the endophytic fungi of K. pandurata leaves, isolate and characterize the secondary metabolites of endophytic fungi and determine their antibacterial activities, and evaluate the effect of usnic acid addition in the culture medium. The isolation of endophytic fungi was performed by culture method through sterilization stage, inoculation on potato dextrose agar (PDA) medium and subculture until single isolate was obtained. The molecular species identification indicates that the isolate is Colletotrichum ti. The isolation of secondary metabolites was performed by various chromatographic methods. The structure of the isolated compounds was determined based on spectroscopic data including 1D and 2D-NMR. The antibacterial test was performed in-vitro using microdilution method against two Gram-(+) bacteria namely Bacillus cereus and Staphylococcus aureus and two Gram-(-) bacteria namely Citrobacter freundii and Salmonella enterica. The effect of usnic acid addition in the culture medium was evaluated based on the chromatogram comparison data of the mycelia MeOH extract and the medium EtOAc extract without usnic acid with the mycelia MeOH extract and the medium EtOAc extract which added usnic acid. Based on this methodology, there has been isolated six pure compounds of C. ti, namely ergosterol (1), ergosterol peroxide (2) and 2-hydroxyethylnicotinate (3) (from the mycelia MeOH extract), 1H-indene-2-carboxylic acid (4) (from the mycelia MeOH extract and medium EtOAc extract), 2-(4'-hydroxyphenyl)acetate acid (5) and 2-(2'hydroxyphenyl)acetate acid (6) (from medium EtOAc extract). The antibacterial test shows the six isolated compounds are inactive against four test bacteria because the MIC values are more than 100 &#956;g/mL. This is in line with the test of mycelia MeOH extract and medium EtOAc extract which are also inactive against four test bacteria because the MIC values are more than 500 &#956;g/mL. The addition of usnic acid in the culture medium is suspected to affect the formation of secondary metabolites in C. ti. <br /> <br /> The chromatogram comparison data of both mycelia MeOH extracts and both medium EtOAc extracts show the stain intensity of compound (1) and (2) were visibly reduced, while the stain intensity of some other components unsuccessfully isolated were visibly increased. Based on these results, it can be concluded that it has been isolated successfully six pure compounds of C. ti that are inactive as antibacterial. The addition of usnic acid in the culture medium is suspected to affect the formation of secondary metabolites in C. ti.<p align="justify"> <br /> <br />