Antibacterial and antibiofilm activity of Ammi majus seed against Gram-positive bacteria

* Department of Pharmacognosy, College of Pharmacy, Hawler Medical University, Erbil, Iraq. Introduction Plants and their metabolites have a long history of use in folk medicine for the prevention and treatment of diseases and infection. Treatment of infectious diseases lead to development excessive use of antibacterial agents which resulted in the antibacterial resistant which increase the chance of treatment failure. Antibacterial resistance due to accepting of resistance genes by horizontal gene transfer, target alteration of drugs, low permeability systems and grow in a specific growth state like biofilm are important mechanisms involved in bacterial resistance. Bacterial biofilm is a sessile life form defined as community of microorganisms attached to a biotic or abiotic substrate surface and submerged into extracellular slimy matrix. Bacterial biofilms have been reported to have useful effects on food chains, sewage treatment plants, on other hand have harmful effects serves to encourage bacteria persistence by resisting antibacterial treatment and host immune responses. Biofilm causes numerous infections such as chronic otitis media, chronic prostatitis, chronic pneumonia in patients with cystic fibrosis, infections of orthopedic devices. The factors that are contributed to resistance in biofilm forming bacteria includes the slow growth rate, decreased diffusion of antimicrobials and accumulation of enzymes that are involved in the resistance. Approximately 60% of human infections are reported to be Background and objective: Ammi majus belongs to family Apiaceae is an important plant used in a different country traditionally for treatment bacterial infection. This study aimed to investigate in vitro antibacterial and antibiofilm activity of Ammi majus seed extracts against six isolated Gram-positive bacteria. Methods: The antibacterial activity of seed extracts were screened by disk diffusion and agar overlay bioautography method and their activities were further determined by minimum inhibitory and minimum bactericidal concentration. Biofilm formation was evaluated by the microtiter plate crystal violet assay. The quantity of bound bacteria was determined by measuring absorbance at (OD630 nm) using microtiter plate reader. Results: Ethanol 80% and ethyl acetate extracts showed variable activity against all isolated bacteria while petroleum ether extract revealed resistance against studied bacteria. Streptococcus mitis showed more pronounced sensitivity against both extracts by disk diffusion (12 mm and 10 mm) and bioautography method with minimum inhibitory concentration 7.8125 mg/ml of ethanol 80% and 15.625 mg/ml for ethyl acetate extracts. Ethanol 80% and ethyl acetate extract significantly reduced biofilm formation as compared to control, showed antibiofilm activity at 0.4883-62.5 mg/ml and exhibited strongest antibiofim activity against Staphylococcus aureus. Conclusion: Ammi majus seed extracts revealed highest antibacterial activity against Streptococcus species and strongest antibiofilm activity on Staphylococcus species.