Bioassay Guided Fractionation of an Anti-Methicillin-Resistant Staphylococcus aureus Flavonoid From Bromus inermis Leyss Inflorescences.
BACKGROUND
Plants are considered as promising sources of new antibacterial agents as well as bioassay guided fractionation.


OBJECTIVE
In the present work, the antibacterial properties, especially against methicillin-resistant Staphylococcus aureus (MRSA), of Bromus inermis inflorescence was studied, using the bioassay guided fractionation as well as the bio-autographic method.


METHODS
The plant organic extract was prepared via maceration in methanol, followed by the fractionation using n-hexane. The extracts were subjected for minimum inhibitory concentrations (MICs) against some human pathogenic bacteria via standard broth micro-dilution assay. Thereafter, a bio-autographical method was applied using the high performance thin layer chromatography (HPTLC) coupled with agar overlay assays for the primary characterization and identification of bioactive substance (s).


RESULTS
Through the bioassay guided fractionation method, the greatest antibacterial activities were related to the n-hexane extract. It was also revealed that the effective anti-MRSA agent of the assessed plant was a relatively polar substance with an MIC value of about 8 μg/mL against the tested MRSA strain (in comparison with the MIC value of 32 μg/mL for chloramphenicol).


CONCLUSIONS
As a result of the full range UV-Vis scanning of the responsible band in the HPTLC experiments (200-700 nm), the flavonoid was the most imaginable natural compound.
Department of Biology, Medicinal Plants and Drug Research Institute, Shahid Beheshti University, Tehran, IR Iran.
Atousa
A
Aliahmadi
Department of Biotechnology, Faculty of Renewable Energies and New Technologies Engineering, Shahid Beheshti University, Tehran, IR Iran ; Department of Nanobiotechnology, Protein Research Institute, Shahid Beheshti University, Tehran, IR Iran.
Fateme
F
Mirzajani
Department of Phytochemistry, Medicinal Plants and Drug Research Institute, Shahid Beheshti University, Tehran, IR Iran.
Alireza
A
Ghassempour
Department of Biology, Medicinal Plants and Drug Research Institute, Shahid Beheshti University, Tehran, IR Iran.
Ali
A
Sonboli
Chemical Fractionation; Methicillin-Resistant Staphylococcus aureus, Flavonoid, Anti-bacterial Agents