Arum italicum Miller tuber extracts: evaluation of synergistic activities with ciprofloxacin against some pathogens

Antibiotic misuse or overuse leads antibiotic resistance. Antibiotic resistant bacteria infections cause significant clinical problem. Recently, antibiotic resistant bacteria numbers have increased, this situation has become a global public health treat. To achieve these problems, development of new antibacterial compounds is still popular among researchers. The focus on natural compounds/plant extracts in combination with antibiotics increase their activities and decrease the doses of antibiotics and their side effects. Despite known as poisonous, Arum italicum Miller is used as food and/or is used for the treatment such ailments as furuncle, eczema, peptic ulcer, wounds, etc. This interesting species was found as anticancer, cytotoxic, apoptotic agent against some human cancers. In the present study, the fractions of A. italicum tuber extract against human pathogens (Pseudomonas aeruginosa ATCC 27853, Bacillus cereus NRRL B-3711, Staphylococcus aureus ATCC 6538) were evaluated for their antibacterial activities by microdilution method. Each fraction was combined with ciprofloxacin and their synergistic activities were tested by checkerboard method. The MIC (minimum inhibitory concentrations) and FICI (fractional inhibitory concentration indexes) values were calculated. Totally, seven synergic interactions, ten additive interactions, and four indifferent interactions of tested fractions with ciprofloxacin were found.