title: Influence of Huang Lian Jie Du Decoction on Quorum Sensing System of Pseudomonas aeruginosa.
abstract: Context • Pseudomonas aeruginosa (P aeruginosa) is an opportunistic and nosocomial, Gram-negative pathogen that is characteristic of quorum sensing (QS) modulation. QS inhibition (QSI) is considered to be a new approach to antimicrobial treatment that may reduce issues of antibiotic resistance. Traditional Chinese herbs have been recognized as a source of QSI. Objective • This study was intended to investigate whether the Huang Lian Jie Du decoction (HLJJD) possesses the ability to produce anti-QS activity. Design • P aeruginosa PAO1 was cultivated in the presence and absence of HLJDD or of the aqueous extracts of each of its 4 constituent herbs: Rhizoma coptidis (RC), Radix scutellariae (RS), Cortex phellodendri (CP), and Fructus gardeniae jasminoidis (FGJ). The minimum inhibitory concentrations (MICs) were found for the HLJDD or its 4 constituents through testing each for evidence of antibacterial activity at 3.13, 6.25, 2.5, 25, 50, 100, 200, and 400 mg/mL. Outcome Measures • QS-dependent virulence factors were analyzed at subminimum MICs (sub-MICs) for the HLJDD and its constituent herbs. The mRNA of the QS genes was also assessed by a quantitative real-time polymerase chain reaction. Results • The HLJDD exhibited the lowest MIC of 100 mg/mL, compared with MICs of 200 mg/mL for the RC and RS, 400 mg/mL for the CP, and more than 400 mg/mL for the FGJ. At the sub-MIC of 50 mg/mL for HLJDD, the results showed a significant reduction in pyocyanin pigment, elastolytic activity, proteolytic activity, biofilm formation, and bacterial motilities in the PAO1, without inhibiting the bacterial growth. The mRNA level of the P aeruginosa elastase gene (lasB) was also significantly reduced. The mRNA analysis also showed an increasing tendency for overexpressed QS genes when observed at sub-MICs. That inhibitory tendency was also observed in the sub-MICs of the constituent herbs in different degrees. Conclusions • The HLJDD showed the synergism of its 4 constituents against the growth of P aeruginosa and the QS-dependent virulence factors. Its anti-QS activity may interrupt the QS domination of the virulence factors of P aeruginosa downstream, leading to the overexpressed QS genes.
authors.forename: Fei
authors.initials: F
authors.lastname: Xia
authors.forename: Lihua
authors.initials: L
authors.lastname: Ye
authors.forename: Ping
authors.initials: P
authors.lastname: Wang
authors.forename: Mingwei
authors.initials: M
authors.lastname: Zhang
mesh_terms: D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D020869:Gene Expression Profiling; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity; D053038:Quorum Sensing / Q000187:drug effects*; D059467:Transcriptome / Q000187:drug effects; D037521:Virulence Factors / Q000378:metabolism
chemical_list: D004365:Drugs, Chinese Herbal; D037521:Virulence Factors; C061676:oren gedoku to