In vitro evaluation of antioxidant and antimicrobial activities of some Centaurea L. species

ABSTRACT: The purpose of this study was to investigate the antioxidant, antimicrobial activities and total phenolic contents of ten methanol extracts obtained by maceration from capitulums and aerial parts (except for capitulum) of five Centaurea species(C.stenolepis,C.kilaea, C.cuneifolia, C.iberica, C.solstitialissubsp.solstitialis). Free radical scavenging activities and total phenolic contents of the species were assayed by DPPH method andFolin–Ciocalteu method, respectively. The antimicrobial activity of the extracts were tested by the micro-broth dilution method against seven microbial species. In the DPPH radicalscavenging assay, the IC50 values of tested ten methanol extracts were in range 1.767-4.665 mg whilethe total phenol contents of four extracts were found to range between 4.825 and 12.460 mg GAE/g dry material. Four extract showed moderate activity against Pseudomonas aeruginosa(MIC: 312μg/ml), while six out of ten extracts exhibited moderate activity againstCandidaalbicans(MIC: 312μg/ml). The methanol extract prepared from the aerial parts of C.cuneifolia possessed weak activity against Staphylococcusaureusg/ml).