بررسی اثربخشی عصاره‌های الکلی گیاه Centaurea cyanus بر فرم منفرد و بیوفیلمی شش باکتری پاتوژن

Introduction: Nowadays, the treatments of infectious disease are regarded difficult due to increasing antibiotic resistance among pathogenic bacteria, which the reason may be placing of microorganisms in a structure named biofilm. Biofilms are complex structures consisting of surface-attached bacteria. Therefore, it is essential to find new compounds in order to remove and inhibit biofilms. This study aimed to examine the antibacterial activities of alcoholic extracts of Centaurea cyanus on the biofilm structures and planktonic form of six pathogen bacteria(Staphylococcusaureus, Bacilluscereus, Streptococcuspneumoniae, Pseudomonasaeruginosa, Escherichiacoli and Klebsiellapneumonia). Methods: Antimicrobial activities of the alcoholic plant extracts against the planktonic form of bacteria were assessed via using the disc diffusion method. MIC and MBC values were determined by a macrobroth dilution technique and anti-biofilm effects were scrutinized by microtiter plate method. Results: The results of this study confirmed high ability of C.cyanus extracts against the biofilm of the tested bacteria as well as their free-living forms. To inhibit bacterial growth, ethanolic extracts proved to be more effective than methanolic extracts. Anti-biofilm effects of plant extracts were associated with the solvent type and extract concentration. C.cyanus extracts were reported to be most efficient to inhibit biofilm formation of E. coli (84/26%) and S. pneumoniae(83/14%). The greatest eradication of biofilm structures were observed on S. pneumonia biofilm (75.66%), and the highest decrease in metabolic activity was reported in S.aureus biofilms (71/85%). Conclusion: In this study the high capacity of C. cyanus extracts to encounter with whit biofilm was emphasized. Moreover, it was demonstrated that these extracts possess an appropriate potential to become active principles of new drugs.