The Simargaolgaol (Aglaonema modestum Schott ex Engl) plant is a plant that grows wild in Barus District, Central Tapanuli, North Sumatra which is used by the community as a medicinal plant. This study aims to determine the antibacterial activity of n-hexane, ethyl acetate and ethanol extracts from Simargaolgaol leaves against Escherichia coli and Salmonella typhi bacteria. The antibacterial activity test of Simargaolgaol leaves was carried out using the disc diffusion method. The results of antibacterial activity showed that the highest inhibitory power of Simargaolgaol leaf extract was ethanol extract (polar), ethyl acetate extract (semi polar) and n-hexane extract (non polar). The inhibitory power of ethanol extract, ethyl acetate, and n-hexane against Escherichia coli bacteria was 13.1 mm (strong); 9.7 mm (medium); 8.0 mm (medium) and for Salmonella typhi bacteria respectively 11.2 mm (strong); 10.7 mm (strong) and 9.3 mm (medium). With the concentration of the extract in the diameter is 10%. Based on this, it can be concluded that Simargaolgaol leaf extract has potential as an antibacterial. Keywords: Aglaonema modestum Schott ex Engl, Antibacterial activity, Escherichia coli, Salmonella typhi

The research-based on empirical information from the community that used the leaves of Simargaolgaol (Aglaonema modestum Schott ex Engl.) as traditional treatments. This study aims to determine the class of phytochemical compounds contained in the extracted leaves samples based on the polarity of the solvent. Screening of phytochemical compounds was carried out using standard methods. Toxicity testing was carried out using the Brine Shrimp Lethality Test (BSLT) method for observing the mortality of A. salina Leach larvae and testing for biological activity as antibacterial conducted using the paper disc diffusion method. The study showed that the n-hexane extract had a class of steroid compounds; ethyl acetate extract contains alkaloids, flavonoids, saponins, and steroids while the ethanol extract contains alkaloids, flavonoids, saponins, and tannins. LC50 for n-hexane, ethyl acetate, and ethanol extract was 780.297, 33.083, and 20.548 respectively. The n-hexane and ethyl acetate extract had the moderate inhibitory ability on S. aureus, S. mutans, B. cereus, and S. viridans. The ethanol extract had strong activity as an antibacterial against S. mutans and B. cereus, and showed potential toxicity (LC50) to be developed as natural antibacterial drugs.