HERBAL PRODUCTS AS AN ALTERNATIVE TO ANTIBIOTICS: APPLICATION POSSIBILITIES AND LIMITATIONS

Abstract

Antimicrobial resistance (AMR) has developed as one of the top 10 global public health threats facing humanity. As the nosocomial bacterial strains are being increasingly resistant to most clinically available antibiotics, there is a constant need for exploration of new substances that could kill them or inhibit their growth, or alternatively inhibit some of their essential virulence factors to counteract the lack of new antibacterials and the rise of antibiotic resistance, plants could represent a potential solution. Plants produce a variety of bioactive secondary metabolites that could be used to fuel the future discovery pipeline. Aim of the present study was to examine inhibitory activity of the supercritical extract of J. communis L. green pseudofructus (7SCO2) against the growth, biofilm production and several virulence factors of significant nosocomial bacterial pathogens. The extract was obtained by fractional extraction with supercritical CO2, and the qualitative and quantitative analysis was performed using the GC-FID/MS method. Clinical isolates of Pseudomonas aeruginosa,Acinetobacter baumannii, Staphylococcus aureus (methicillin-sensitive-MSSA and methicillin- resistant - MRSA), Enterococcus faecalis, and Klebsiella pneumoniae, as well as their antibiotic resistance profiles, were obtained from the Clinical Hospital Centre “Dr Dragiša Mišović Dedinje”. Minimum inhibitory concentrations (MICs) of the 7SCO2 were determined by broth-microdilution method. Examination of the anti-adhesive effect of the extract was carried out using the spectrophotometric method. The pyocyanin production of Pseudomonas aeruginosa was determined by the method described by Rampioni et al. Most significant findings of this study are potent antivirulence activity of the 7SCO2 against P. aeruginosa through the inhibition of pyocyanin production. In addition, the biofilm production of A. baumannii was inhibited by the 7SCO2 in concentration 50 μg/mL. Finally, notable antivirulence activity of the 7SCO2 against E. faecalis and S. aureus was detected, since it significantly inhibited collagen and laminin adhesion of these pathogens.