摘要：The Quorum Sensing (QS) inhibition and other antimicrobial activities of algae collected from the Gulf of Aqaba, The Red Sea were examined. Methanolic extracts of twenty-one different algae (green, red and brown) were screened for the QS inhibitory effect using the reporter strain Chromobacterium violaceum CV026 that was induced with acyl-homoserine lactone. Of these 21 extracts, only six exhibited QS inhibitory activity: three brown algae (Turbinaria decurrens, Sargassum asperifoli- um, Colpomenia sinusa), two green algae (Clado- phora prolifera, Ulva intestinalis) and one red alga (Gracilaria arcouata). The six extracts also reduced biofilm formation of Pseudomonas aeruginosa at varying degrees when grown on microtitre plates, and C. prolifera and G. arcouata caused statistically significant reductions. In addition, extracts of C. sinusa, U. intestinalis, S. asperifolium and T. decurrens were tested for their antimicrobial potentiating activity when combined with some antibiotics against Escherichia coli. The results showed variable effects depending on the extract and the antibiotic used in combination. In conclusion, we were able to identify some algae in the Gulf of Aqaba, with QS and biofilm inhibitory activities that could have potential therapeutic uses.
