Effect of Quercetin Rich Onion Extracts on Bacterial Quorum Sensing

Conclusion The effect of organic extracts of red and white onion and their major constituents on QS controlled phenotypes has been evaluated. Different glycosylated quercetins were found in both onion varieties. The onion organic extracts showed inhibition of violacein production and swarming motility. Violacein production was significantly inhibited by quercetin aglycone, while glycosylated and quercetin aglycone inhibited motility of P. aeruginosa PAO1 and S. marcescens MG1. In silico studies suggested a better interaction and accommodation of quercetin aglycone in the structures of the CviR protein of C. violaceum ATCC 12472 than the glycosylated compound. On the other hand, the two quercetins were able to bind and accommodate in the pocket of LasR protein of P. aeruginosa PAO1. Surprisingly, biofilm formation was not affected by any extracts or the quercetins tested in this study. These results suggest that the extracts and isolated compounds of onions could interfere in the antimicrobial and anti-QS activity, but interference on QS was limited to violacein production and swarming motility. Author Contributions All authors listed have made a substantial, direct and intellectual contribution to the work, and approved it for publication. Funding This research was funded by a grant from CNPq-Brazil (457794/2014-3) and supported by the Food Research Center – FoRC (2013/07914-8). Conflict of Interest Statement The authors declare that the research was conducted i...
Source: Frontiers in Microbiology - Category: Microbiology Source Type: research