The Study of Synergistic Effects of n.butanolic Cyclamen coum Extract and Ciprofloxacin on inhibition of Pseudomonas aeruginosa biofilm formation

Introduction: Infections caused by Pseudomonas aeruginosa biofilm are the major causes of death in patients with cystic fibrosis (CF). Some studies revealed that biofilms are resistant to several antibiotics because of their impermeable structures. In order to resensitize bacteria to different antibiotics, biofilm formation should be inhibited. In this research, evaluation of antibiofilm activity of n-butanolic Cyclamen coum extract as a medicinal plant from Myrsinaceae family, in combination with ciprofloxacin was carried out. Materials and methods: The biofilm formation ability by P. aeruginosa PAO1 and one clinically isolated P. aeruginosa (PA214) was confirmed by microtiter plate method. Extraction of the tubers of Cyclamen coum was done by fractionation method. The antibiofilm and antibacterial properties of n-butanolic C. coum extract (which includes saponin compounds) alone and in combination with ciprofloxacin by using microdilution and crystal violet methods were examined. The cytotoxicity effect of the n-butanolic extract on HT-29 cells was assayed by MTT (3(4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide) test. Results: The biofilm formation ability by P. aeruginosa strains was quantitatively confirmed. Saponin content of the n-butanolic C.coum extract was 156 μg/mL. The extract revealed antibacterial activity against the growth of planktonic P. aeruginosa strains. The combination of n-butanolic C.coum extract and ciprofloxacin significantly inhibited P.aeruginosa biofilm formation (ΣFBIC = 0.5). The n-butanolic C.coum extract showed insignificant cytotoxic effect against HT-29 human cancer cell line after 48 hours and 72 hours incubation. Discussion and conclusion: It can be concluded that n-butanolic C.coum extract in combination with ciprofloxacin significantly revealed antibiofilm activity against P. aeruginosa biofilm however, further clinical investigations are required.