Antibacterial activity of fermented katuk leaves (Sauropus androgynus (L.) Merr.) against gram positive bacteria and its free radical inhibitory.

Katuk leaves (Sauropus androgynus (L.) Merr.) contain bioactive that protects cell structures, increases vitamin C's effectiveness, prevents bone loss, and acts as an anti-inflammatory. Another function is to work directly as an antibiotic by interfering with bacteria or viruses and increasing the body's immunity. Kombucha contains organic compounds beneficial for the body, such as antioxidants, polyphenols, organic acids produced and antibiotics. Based on the above background, this study aims to evaluate the antibacterial activity of fermented beverages from katuk leaves against gram-positive bacteria. The diameter of the inhibition zone (DZH) using the agar diffusion method with positive control of streptomycin sulfate was calculated. In addition, the inhibition of free radicals was evaluated. In this study, katuk leaves were fermented with SCOBY (a symbiotic yeast colony) with a ratio of sucrose: culture (15:10; 15:15; 15:20) and fermentation time of 0 and 12 days. The results showed that fermented katuk leaves with a ratio of sucrose: culture (15:20) fermented for 12 days showed optimum antibacterial activity against Staphylococcus aureus with an inhibition zone of 20 mm and free radical inhibition of 96.98%. There was an increase in polyphenols 1.85 mg GAE/mL, acetic acid 124864 ppm, gluconic acid 80525 ppm. while there was a decrease in glucose, fructose, maltose, lactic acid, and pH respectively: 471127, 184628, 5726, 48220 ppm and 3.75first, second, and third level headings (first level heading) [ABSTRACT FROM AUTHOR]