中药厚朴中群体感应抑制剂的分离与活性评价.

Objective: To find quorum sensing inhibitors (QSIs) from Chinese herbal medicine Magnolia officinalis and to evaluate its inhibitory activity. Method: Pseudomonas aeruginous QSIS-lasI biosensor was used to monitor quorumsensing inhibitory activity. The bioactive compound in M. officinalis with anti-QS activity was separated by a bioautographic TLC assay, preparative TLC, and HPLC analysis. Its structure was identified by spectroscopic analysis. The pyocyanin and rhamnolipid production were determined by spectrophotometric method and orcinol method, respectively. And the swarming motility was assayed on semisolid agar plates. The effect of mRNA of QS-regulated gene was measured by RT-PCR. Results: M. officinalis extract was found to inhibit QS-controlled gene expression in P. aeruginous QSIS-lasI Biosensor. The active compound was purified and identified as honokiol. Honokiol at sub-inhibitory concentrations inhibited the production of virulence factors, including pyocyanin, rhamnolipid and swarming motility. It significantly reduced the level of mRNA of QS-related genes (P<0.05). Conclusion: Honokiol is a new QS inhibitor, which could be a potential agent for the treatment of bacterial infections. [ABSTRACT FROM AUTHOR]