Crude Extracts of Three Iris Species as Sources of MRSA Antimicrobial Compounds

Objective:Iris species are widely used in pharmaceutical and cosmetic applications owing to their high content of bioactive compounds with anti-inflammatory and antimicrobial properties. This study aimed to investigate the potential antibacterial effect of crude extracts (aqueous, 50% and 80% ethanol) of three Iris species (I. pumila, while I. reichenbachii and I. illyrica are endemic) from Bosnia and Herzegovina against the multiresistant bacterial strain methicillin-resistant Staphylococcus aureus subsp. aureus ATCC 33591 (MRSA strain).Materials and Methods: The antimicrobial compounds in the crude extracts were identified using High-performance liquid chromatography (HPLC), and their effects on the MRSA strain were tested using agar well diffusion and broth microdilution method. The binding affinities were analysed using molecular docking simulations.Results: We identified bioactive targeted compounds in these extracts, mainly flavonoids named isorhamnetin, hesperidin, quercetin, fisetin, genistein, and kaempferol. Antibacterial assays showed that extracts of all three Iris species inhibited MRSA. The binding affinity analysis showed that isorhamnetin and hesperidin had the highest affinity scores, stronger (isorhamnetin) or the same (hesperidin) as the positive control ceftobiprole.Conclusion: Thisin vitro and in silico study showed that Iris species represent a valuable source of bioactive compounds that can be used against multidrug-resistant strains such as MRSA. The potential use of these agents in multiple drugs is warranted, and further evaluation for human application is needed.