Abstract
Pseudomonas aeruginosa is an opportunistic pathogen, and it can produce cell-associated and extracellular virulence factors. Several of these virulence factors have been demonstrated to be regulated by quorum sensing (QS). Disabling QS system with anti-infective agent is considered as a potential strategy to prevent bacterial infection. Rabdosia rubescens has been used as antibacterial agents for many centuries in China. In this study, Oridonin, the major active components of Rabdosia rubescens, was tested for QS inhibition in Pseudomonas aeruginosa. QS inhibitory activity is demonstrated by reduction in pyocyanin (58.4%), rhamnolipids (64.3%), elastase (58.6%), and protease (49.1%) in Pseudomonas aeruginosa PAO1 at 125 µg/ml (MIC) concentration. Biofilm formation by Pseudomonas aeruginosa PAO1 was reduced considerably (40.3-57.7%) over control. These findings suggest that Oridonin might be a potent Quorum Sensing Inhibitor (QSI) and anti-biofilm agent in the treatment of Pseudomonas aeruginosa infections.
Highlights
Bacterial infection has been a major problem on the medical treatment
Serial two-fold dilutions method was used in this assay, 100μl of Oridonin(Sigma) solution and 100 μl of Luria– Bertani (LB) broth were placed into the first well of a microtiter plate and mixed evenly, extra 10μl PAO1 cultures was added in every well and incubated at 37°C
The results showed that oridonin inhibited PAO1 growth at the concentration of 250μg/ml (Table 1), while there was little effect on the growth of bacteria below 125μ g/ml
Summary
Bacterial infection has been a major problem on the medical treatment. With the introduction of natural antibiotics such as penicillin, antibiotic derivatives and synthetic antibiotics, they have opened a new era in the treatment of bacterial infections[1]. Quorum Sensing (QS) found in Gram-negative and Gram-positive bacteria. Bacteria could produce some signaling molecules, called autoinducers (AI), that can coordinate the physiological activities as well as the expression of virulence factors in the pathogenesis[3]. The attenuation of virulence factors and pathogenicity of bacteria through interfering QS is a possible alternative to killing or inhibiting growth of pathogenic bacteria. Many researchers have indicated that phytochemicals inhibit virulence factor production and biofilm formation by interfering auto-induce signaling molecules in quorum sensing system
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
