PHENOLIC DERIVATIVES FROM THREE MEDICINE PLANTS, ANTIBACTERIAL PROPERTIES AND OBSERVATION OF PHOR PROTEIN

• Main Author: Bachtiar, Eri
• Format: Dissertations
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/36043
• Institution: Institut Teknologi Bandung

Disease due to bacterial infection is a common phenomenon that can infect humans or animals. One animal that is often infected with bacteria is shrimp, which is an important economic value commodity. Common bacteria infect shrimp especially species from Vibrio, so this disease is known as 'vibriosis'. There are two approaches to tackling bacterial infections, namely by developing antibiotic drugs that work directly on bacterial metabolism. This approach has proven problematic because it turns out that bacteria have succeeded in developing resistance to antibiotic drugs. In addition, it is difficult to get strong antibiotic agents with low toxicity. Another approach is to target the bacterial defense system (the interaction of bacteria with its environment), one of which is a two-component system (TCS) commonly found in bacteria. Based on this background, this study aims is to conduct a phytochemical study of three traditional Indonesian plants, namely Usnea sp. (wood wind), Nigella sativa (black cumin) and Tephrosia vogelii (seed of pork), determination of antibacterial properties of isolated compounds from shrimp pathogenic bacteria, and determination of inhibitory properties of protein dimer formation based on dimer-based screening system (DBSS) screening. The selection of the three plants were based on the initial screening of antibacterial evaluated on ten traditional plant extracts. Phytochemical studies were carried out through extraction, fractionation and purification stages of the extracts of the three traditional plants mentioned above. Extraction was carried out at room temperature using acetone solvent. Fractionation of the extract took place using silica gel adsorbent and vacuum liquid chromatography technique, while purification was carried out by radial chromatography technique on silica gel plate. The molecular structure of the isolated compounds was determined based on NMR spectrum data (1H, 13C, HSQC and HMBC) and high resolution mass (HR-ESI-MS-TOF). Antibacterial activity of isolated compounds and extracts was evaluated based on the method developed by CLSI, namely the diffusion method in disc cultures and microdilution. DBSS screening was carried out in vitro using transformers Escherichia coli BL21 (DE3) -EmGFP-araC-sitophoRMtb, which was developed by researchers from the School of Biological Sciences and Technology (SITH) -ITB, under the supervisor of Dr. Ernawati Arifin Giri-Rachman. This research has successfully isolated eight compounds, including one new compound, namely nigesativol (1). Seven known compounds include usnic acid (2), deguelin (3), tephrosine (4), isoloncocarpin (5), 7-hydroxy-8-prenylflavanone (6), pongacin (7), and candidone (8). The new compound nigesativol (1) is a glyceryl diester compound and caffeoyl of long chain carboxylic acid, so that in one molecular structure there are hydrophilic and hydrophobic groups at once. For the first time carried out in this research, it has been successfully revealed that the active compound, namely nigesativol (1), is an inhibitor of phoR protein dimer formation, based on DBSS screening system, which is associated with the virulence of Mycobacterium tuberculosis bacteria. This discovery opens new opportunities for the development of active compounds with a target for bacterial attenuation, by disrupting the two-component system's defense system (two-component system, TCS) in bacteria.