Diseases that are currently a problem in the health sector are infectious diseases is caused by various microorganisms such as bacteria, viruses, fungi and protozoa. Efforts to overcome these diseases usually use antibiotics, however, the use of antibiotics in uncontrolled treatment can lead to resistance. Therefore, there is a need for new alternative treatments that are safer and cheaper in terms of cost, for example by utilizing natural ingredients, one of which is rosella (Hibiscus sabdarifa L). The purpose of this study was to determine the antibacterial activity of rosella flower extract and nanoparticles of rosella flower extract against Eschericia coli, Staphylococcus aureus and staphylococcus epidermidis. Rosella flower research was carried out by extraction steps with maceration method using ethanol as solvent. The extracts obtained were tested for phytochemical and antibacterial tests using the diffusion method, then the extracts were made into nanoparticles by the ionic gelation method and the nanoparticles were characterized by PSA, Zeta Potential and FTIR and then tested for antibacterial using the diffusion method. The ethanolic extract of rosella flower contains secondary metabolites of tannins, saponins, flavonoids, phenolics, terpenoids, and triterpenoids and provides antibacterial activity against E coli bacteria with strong potential, S aureus, and S epidermidis. The resulting nanoparticles with a particle size of 499.03 nm and have weak potential as antibacterial against E coli, S aureus, and S epidermidis bacteria, so it can be seen that the extract has a higher antibacterial potential than nanoparticles.
