Antibiofilm and antimicrobial activities of papaya (Carica papaya L.) and stevia (Stevia rebaudiana Bertoni) leaf extracts against three biofilm-forming bacteria

Biofilm is a structural form of a microbial group that is protected by the Extracellular Polymeric Substance (EPS) matrix. The biofilm is considered as the main mediator of infection, and plays a major role in the occurrence of drug resistance. This study was aimed at determining the antimicrobial and antibiofilm activities of papaya ( Carica papaya L.) and stevia ( Stevia rebaudiana Bertoni) leaf extracts against three biofilm-forming bacteria. The antimicrobial assay showed that papaya leaf extract exhibits higher activity compared to stevia leaf extract in inhibiting the growth of the biofilm-forming bacteria. The optimum condition of papaya leaf extract to inhibit biofilm-forming bacterial growth occurred at 45% and 75% concentrations of the extract (pH 7). A 100% biofilm degradation by papaya leaf extract occurred at pH 6 and pH 9.