Evaluation of minimum inhibitory concentrations of plants extracts against several bacterial pathogens

In the context of COVID-19, the use of face masks has been recommended as a preventive measure against the spread of SARS-CoV-2. Despite their health benefits, usage of single-use masks represents a threat to the environment as they are manufactured from long-lasting plastic materials. Reusable fabric masks are an alternative to reduce the risk of pollution and the amount of plastic wastage. The application of antimicrobial agents in the tissues used to produce masks would be an additional hurdle on the prevention of other respiratory infections and secondary bacterial infections that occur from touching contaminated masks. In this context, impregnation of the fabrics with plant extracts is an atractive approach since they are potentially safe and free of adverse side effects and powerful antimicrobials. The objective of this work was to study twelve plant extracts to select the most efficient against pathogenic microorganisms. The minimum inhibitory concentration (MIC) of each extract was determined by broth microdilution in 96-wells microtiter plates (tested concentrations between 50.00 and 0.78% V/V) against different pathogenic bacteria. According to the results obtained, it was possible to selecte two plant extracts, both extracted with 1:1 ethanol:water, as the more effective against most of the pathogens tested, with MICs between 50.00 and 1.56%. It is important to highlight that Gram-positive bacteria were eliminated more easily than Gram-negative bacteria. Although being a preliminary work and more tests are needed, the two plant extracts could be good candidates to be impregnated into tissues in order to eliminate pathogens and avoid health problems associated with them.