Inhibition of biofilms by extracts from Vernonia adoensis in Pseudomonas aeruginosa and Staphylococcus aureus

Background: Bacteria that form biofilms have become a leading cause of increased morbidity and motility in healthcare settings, as they are responsible for over ۶۵% of nosocomial infections.  Biofilms are a major cause of drug resistance in bacteria.  Pseudomonas aeruginosa and Staphylococcus aureus are opportunist pathogens that cause numerous infections and are known for their ability to produce biofilms.  Vernonia adoensis is an African ethnomedicinal plant commonly used for the treatment of various disease conditions and has been shown to have antibacterial activity.  Objectives: The aim of this study was to investigate the effect of extracts from V. adoensis on the biofilms formed by P. aeruginosa and S. aureus and determine the phytochemicals present in the extract.  Methods: The effect of the extract on the biofilms of P. aeruginosa and S. aureus was determined on ۹۶-microwell plates using crystal violet.  Phytochemical constituents of the extract were determined using Ultra-performance liquid chromatography coupled to mass spectroscopy (UPLC-MS). Results: The extract disrupted the biofilms of the bacteria.  At ۱۰۰ µg/ml, the extract inhibited the formation of biofilms of P. aeruginosa and S. aureus by ۹۳% and ۱۷%, respectively.  V. adoensis was more potent in decreasing the attachment efficiency of the biofilm of P. aeruginosa as it caused the detachment of ۸۴% of the biofilm in the presence of SDS but only ۱۷% of the biofilm of S. aureus. Five compounds (kaempferol, quinic acid, caffeic acid, rhamnetin I, and luteolin were identified by UPLC-MS analysis.  Some of these compounds have been shown to have some antimicrobial activity.  Conclusions: It can be concluded that V. adoensis contains bioactive components that may be exploited as sources of lead compounds for the development of new antimicrobial agents that have antibiofilm activity.

کلیدواژه ها:

Biofilm ، Vernonia adoensis ، Crystal violet ، Phytochemicals ، Spectrometry