Determination of Potential Anti Quorum Sensing Activity of Eleusine indica Ethanolic Crude Extract against Escherichia coli and Staphylococcus aureus

Aim/Background: The study assesses the potential anti-quorum sensing ability of the ethanolic crude extract of the plant Eleusine indica and its ability to inhibit biofilm formations in two clinically significant bacteria, Escherichia coli and Staphylococcus aureus. Materials and Methods: To prove its anti-quorum sensing capability, antimicrobial susceptibility testing was done by placing filter paper disks loaded with Eleusine indica with varying concentrations (25%, 50%, 75% and 100%) on a MH agar inoculated with the two bacteria. Subsequently, biofilm inhibition testing was conducted to evaluate the extract’s effect on the bacteria’s biofilm formation by combining the Eleusine indica crude extract with overnight cultures of the bacteria in a 96-well plate then measuring its optical density. Descriptive statistics were employed to analyze the optical density data, with values higher than the positive control indicating increased biofilm formation. Results: Antimicrobial susceptibility testing showed that no antimicrobial activity was present in the extract for the two bacteria. Moreover, results revealed that Eleusine indica crude extract did not inhibit biofilm formation in gram-positive Staphylococcus aureus, while all concentrations (25%, 50%, 75% and 100%) successfully inhibited biofilm formation in gram-negative Escherichia coli. Conclusion: These findings suggest that Eleusine indica may possess anti-quorum sensing properties against certain bacteria. Further research on the overall mechanism of Eleusine indica and its differential response on different clinically significant bacteria is warranted..