Staphylococcus aureus is one of the Gram-positive bacteria that can cause acne. Binahong (Anredera Cordifolia) with its extract can be used to slow down the growth of Staphylococcus aureus bacteria. Binahong contains alkaloids, flavonoids, triterpenoids, saponins and tannins which have antibacterial properties. The purpose of this study was to determine the effect of varying concentrations of Binahong leaf extract (Anredera Cordifolia) on the evaluation of serum preparations, and to determine the presence of antibacterial activity in binahong leaf extract serum preparations on S.aureus ATCC 25923 bacteria. Experimental research methods was conducted. Maceration of binahong leaf extract using 70% ethanol solvent. Antibacterial activity test was carried out using the disc diffusion method with Vancomycin® as a positive control and serum base without extract as a negative control. Serum is made with variations of binahong extract 5%, 10% and 15% w/v. Data is processed using SPSS 25 for windows. The results showed that the addition of binahong extract concentration resulted in a more concentrated color and a thicker consistency, increased the pH of the preparation, increased viscosity of the preparation, and decreased spreadability. The addition of binahong extract concentration increased antibacterial activity against S.aureus bacteria. The serum in the three formulations had an effect on the inhibition activity of Staphylococcus aureus bacteria. Serum in formula 3 with a concentration of 15% binahong extract showed the highest antibacterial activity against S.aureus bacteria with an inhibition zone of 7.8 mm.
