Effect of Traditional Chinese Herbal Medicine with Antiquorum Sensing Activity onPseudomonas aeruginosa

Abstract

Traditional Chinese herbal medicines (TCHMs) were tested for their ability of antiquorum sensing. Water extracts of Rhubarb, Fructus gardeniae, and Andrographis paniculata show antiquorumsensing activity when using Chromobacterium violaceum CV12472 as reporter; the sub-MIC concentrations of these TCHMs were tested against AHL-dependent phenotypic expressions of PAO1. Results showed significant reduction in pyocyanin pigment, protease, elastase production, and biofilm formation in PAO1 without inhibiting the bacterial growth, revealing that the QSI by the extracts is not related to static or killing effects on the bacteria. The results indicate a potential modulation of bacterial cell-cell communication, P. aeruginosa biofilm, and virulence factors by traditional Chinese herbal medicine. This study introduces not only a new mode of action for traditional Chinese herbal medicines, but also a potential new therapeutic direction for the treatment of bacterial infections, which have QSI activity and might be important in reducing virulence and pathogenicity of pathogenic bacteria.

Developing natural products as potential anti-biofilm agents

“…Quercetin, which exists in many fruits, vegetables and grains, is a plant polyphenol. It was reported to significantly inhibit biofilm formation and production of virulence factors including pyocyanin, protease and elastase at a lower concentration compared with that for most previously reported plant extracts and substances [44][45][46][47]. Further investigation of the transcriptional changes associated with QS found that the expression levels of LasI, LasR, RhlI and RhlR involved in QS signaling were significantly reduced [48].…”

In Search of Alternative Antibiotic Drugs: Quorum-Quenching Activity in Sponges and their Bacterial Isolates

“…DMSO and penicillic acid were used as negative and positive controls, respectively. After 18 h of incubation at 37°C, the protease activity was determined by a skim milk plate assay (Chu et al, 2013 ). Briefly, 100 μL of cell free supernatant of treated (extracts and penicillic acid) and untreated (negative control) PAO1 was loaded in each well containing Muller Hinton Agar with 2% skim milk and was incubated at 37°C for 24 h. Protease activity was evidenced by the presence of a zone of casein hydrolysis surrounding the well.…”

“…The majority of modern drugs either belongs to natural products or originate from them (Li and Vederas, 2009 ), with marine sponges being one of the most prolific sources of chemical diverse bioactive natural products (Blunt et al, 2015 ). These compounds have been studied in respect to chemical ecology and provide the sponge with defense against predation, fouling, and pathogen attack (e.g., Chu et al, 2013 ; Rohde et al, 2015 ). From a biotechnology perspective, these compounds can have a broad spectrum of action comprising anti-inflammatory, anticancer, and immune-modulating activities (e.g., Costantino et al, 2008 , 2009 ; Mayer et al, 2010 ; Teta et al, 2013 ; Blunt et al, 2015 ; Kaufman et al, 2015 ).…”

Quercetin is an effective inhibitor of quorum sensing, biofilm formation and virulence factors in Pseudomonas aeruginosa

“…In recent years, traditional Chinese drugs and food have attracted considerable attention because of their unique antibacterial properties (Chu et al . ; Li et al . ).…”