Inhibition and degradation activity of (Sapindus rarak seeds) ethanol extract against polymicrobial biofilm

Lerak (Sapindus rarak DC) is one of the native plants of Indonesia with saponin content in the seeds which has antibacterial activity, but the activity of antibiofilm has never been reported. Biofilms are one of the leading causes of chronic infection in humans, which results in a higher number of deaths. The diversity of microbes in polymicrobial biofilms causes chronic infections so that treatment is more complicated than monomicrobial biofilms. The discovery of candidates for anti-biofilm polymicrobial drugs is needed to overcome infections associated with biofilms. This study aims to determine the effectiveness of ethanol extracts of Lerak Lerak (Sapindus rarak DC) seeds in inhibiting the formation and degradation of Staphylococcus aureus polymicrobial biofilms, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans. Biofilm growth inhibition and degradation tests were determined using the microtiter broth method. The antibiofilm efficacy of ethanol extracts of lerak seeds towards polymicrobial biofilms was analyzed by calculating minimum biofilm inhibitory concentration (MBIC₅₀) and minimum biofilm eradication concentration (MBEC₅₀) values. The mechanism of action of Lerak (Sapindus rarak DC) against polymicrobial biofilm was observed using scanning electron microscopy (SEM). Lerak seed (Sapindus rarak DC) ethanol extract provides 50% accommodation activity against polymicrobial biofilms in the 24 and 48-hour phases with a concentration of 0.5% b/v. Lerak seed ethanol extract is known to degrade 50% polymicrobial biofilms at a level of 0.5% b/v. Based on the results of scanning electron microscopy (SEM) ethanol extracts of lerak seeds can damage extracellular polymeric substances (EPS) polymicrobial biofilms. Therefore, lerak seed ethanol extract has the potential to be developed as a candidate for new antibiofilm drugs against polymicrobial biofilms.