Screening of antimicrobial, anti-quorum sensing activity and cytotoxicity of origanumoil against Gram-positive and Gram-negative bacteria

Abstract

Introduction and Aim: Essential oils have been used from ancient times to treat different gram-positive and gram-negative bacterial-related infections. The study aims to screen the antibacterial, anti-quorum sensing activity of origanum oil against the common infection causing gram-negative and gram-positive bacteria.
 
 Material andMethods: The MIC (minimum inhibitory concentration) and antibacterial activity of origanum oil against the eight bacterial species, namely, Pseudomonas aeruginosa, Shigella flexneri, Salmonella enterica, Klebsiella pneumoniae, Streptococcus pneumonia, Streptococcus pyogenes, Staphylococcus aureus, and Enterococcus faecalis, was assessed by broth-dilution method and well diffusion method. The anti-quorum sensing activity was analyzed using bioreporter strain CV026 at sub-MIC concentrations, while the cytotoxicity of the origanum oil was analyzed using the SW480 cell line.
 
 Results: The oil's antibacterial activity was analyzed by measuring the clear inhibitory zone diameter, and maximum inhibitory zone of 36.66 mm zone against Staphylococcus aureus (Gram-positive) and 33.33 mm against Salmonella enterica (Gram-negative) of origanum oil was measured. And the minimum inhibitory zone of 16.66 mm zone of Enterococcus faecalis (Gram-positive) and 19.66 mm against Klebsiella pneumoniae (Gram-negative) of oil was noted. And the lowest MIC (0.1 mg/ml) of oilwas found against Streptococcus pneumonia. The oil significantly inhibited the violacein pigment production (30.29 %) at 0.02 mg/ml concentration (this oil concentration did not significantly affect the growth curve). The in vitro cytotoxicity assay shows that the oil inhibited the SW480 cells growth with increasing concentration.
 
 Conclusion: The origanum oil possesses antibacterial and anti-quorum sensing activity and can be used as an alternative for treating tested bacterial infection.

The Potential Impact of Probiotics on Human Health: An Update on Their Health-Promoting Properties

“…According to data in the literature, the advancement of the epithelial barrier, increased adhesion to the intestinal mucosa, production of antibacterial substances, competitive exclusion of pathogens, simultaneous suppression of bacterial adhesion, and modulation of the immune system are some of the main mechanisms of action of probiotics [ 87 , 88 , 89 , 90 , 91 ] ( Figure 1 ).…”

“…According to data in the literature, the advancement of the epithelial barrier, in creased adhesion to the intestinal mucosa, production of antibacterial substances, com petitive exclusion of pathogens, simultaneous suppression of bacterial adhesion, and modulation of the immune system are some of the main mechanisms of action of probiot ics [87][88][89][90][91] (Figure 1). Probiotics interact with the gastrointestinal ecosystem by inhibiting the growth o pathogenic microorganisms (e.g., accelerating gastrointestinal transit and reducing th ability of disease-causing bacteria to colonize and adhere to the gastrointestinal mucosa) Probiotics also increase the production of bioactive metabolites (e.g., short-chain fatty Probiotics interact with the gastrointestinal ecosystem by inhibiting the growth of pathogenic microorganisms (e.g., accelerating gastrointestinal transit and reducing the ability of disease-causing bacteria to colonize and adhere to the gastrointestinal mucosa).…”