Antibacterial Activity of Ethanol Extract of Gotu Kola (Centella asiatica L.) Leaves against Pseudomonas solanacearum: Phytochemical Study and Bioactivity Testing

Pseudomonas solanacearum bacteria can cause wilt disease in tomatoes, chilies, tobacco, potatoes, and Solanaceae plants in general. The use of synthetic pesticides to treat wilt disease can cause negative impacts on plants, humans, and the environment, so it is necessary to find environmentally friendly pesticides. This research aims to determine the compounds contained in gotu kola (Centella asiatica L.) leaf extract, and the antibacterial effect of gotu kola leaf extract against the bacteria Pseudomonas solanacearum. The research was carried out at the Wood Properties and Product Analysis Laboratory, Department of Agricultural Agrotechnology, Samarinda State Agricultural Polytechnic, Keledang River, Samarinda Seberang District, Samarinda City, East Kalimantan from January to March 2023. Phytochemical test of gotu kola leaf extract to determine the content of secondary metabolite compounds. Consists of tannins, flavonoids, saponins, alkaloids, and steroids. To test the antimicrobial (anti-bacterial) activity, several concentrations of gotu kola leaf extract were carried out, namely 2.5% (25 ml/l); 5% (50 ml/l), 10% (100 ml/l); 15% (150 ml/l) and 20% (200 ml/l). The research results showed that the crude ethanol extract of gotu kola leaves contains secondary metabolites such as tannins, flavonoids, saponins, alkaloids, steroids. The ethanol extract of gotu kola leaves with a concentration of 50 ml/l (5%) showed more effective antibiotic activity compared to higher concentrations, namely 10% (100 ml/l), 15% (150 ml/l), and 20% (200 ml/l).