Abstract
Onopordon acanthium L. is an important medicinal plant which has been used in
Iranian medicine. In the present study, total phenolic content
(TPC) was evaluated and antibacterial properties of n-hexane and methanol
extracts of O. acanthium L. seeds were screened. Methods:
TPC was determined by Folin–Ciocalteu reagent method. Antibacterial activities
of O. acanthium were investigated using disc diffusion method, minimum
inhibitory concentration (MIC) and resazurin microtiter assay against some
gram-positive bacteria including Staphylococcus aureus, Staphylococcus
epidermidis, Micrococcus loteus as well as gram-negative ones Escherichia
coli and Klebsiella pneumonia. Results: The TPC was
found to be 168.56 ± 4.89 mg of gallic acid/g of extract. Plant methanol
extract showed significant antibacterial activity against gram-positive
bacteria; Staphylococcus epidermidis and Micrococcus luteus (with
MIC= 0.612 mg/ml), while n-hexane extract demonstrated negligible to no inhibitory
activity against gram-negative and gram-positive bacteria. Conclusion:
The results of the present study suggested the effect of O. acanthium
methanol extract against the tested bacteria in vitro, may contribute to
the in vivo efficacy of this extract.