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The family Asteraceae include large number of Centaurea species which have been applied in folk medicine. One of the family Asteraceae members is the Centaurea damascena which authentically been tested for its antibacterial and antioxidant activity as well as its toxicity. The aims of the study were to determine the antimicrobial and antioxidant activities and toxicity of methanolic plant extracts of Centaurea damascene. The methanolic extracts were screened for their antibacterial activity against nine bacteria (Staphylococcus aureus ATCC 43300, Bacillus subtilis ATCC 6633, Micrococcus luteus ATCC 10240, and Staphylococcus epidermidis ATCC 12228, Escherichia coli ATCC 11293, Pseudomonas aerugino and Klebsiella pneumoniae, Enterobacter aerogenes ATCC 13048 and Salmonella typhi ATCC19430). The antibacterial activity was assessed by using the disc diffusion methods and the minimum inhibition concentrations (MIC) using microdilution method. The extracts from Centaurea damascene possessed antibacterial activity against several of the tested microorganisms. The MIC of methanol extract of C. damascene ranged from 60–1100 µg/mL. Free radical scavenging capacity of the C. damascena methanol extract was calculated by DPPH and FRAP test. DPPH radicals were scavenged with an IC50 value of 17.08 µg /ml. Antioxidant capacities obtained by the  FRAP was 51.9 and expressed in mg Trolox g-1 dry weight. The total phenolic compounds of the methanol extracts of aerial parts, as estimated by Folin–Ciocalteu reagent method, was about 460 mg GAE/ g. The phenolic contents in the extracts highly correlate with their antioxidant activity, (R2 = 0.976) confirming that the antioxidant activity of this plant extracts is considerably phenolic contents-dependent

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The family Asteraceae include large number of Centaurea species which have been applied in folk  medicine. One of the family Asteraceae members is the Centaurea damascena which authentically been tested for its antibacterial activity. The aim of the study was to discuss antibacterial activities of essential oil composition and methanolic extract of the same plant aerial part leaves.  Thirty-seven components were characterized with 86% of oxygenated terpenes. The composition was dominated by 11.45% Fokienol, 8.8% thymol, 8.21% Alpha Terpineol, 7.24% Chrysanthemumic acid, 7.13% Terpinen-4-ol and 6.59% Borneol with a high degree of polymorphism in the occurrence of these compounds as compared with the different species of centaurea.. Free radical scavenging capacity of the C. damascna methanol extract was calculated by DPPH and FRAP test. DPPH radicals were scavenged with an IC50 value of 17.08 µg /ml. Antioxidant capacities obtained by the FRAP was 51.9 and expressed in mg Trolox g-1 dry weight. The total phenolic compounds of the methanol extracts of aerial parts, as estimated by Folin–Ciocalteu reagent method, was about 460 mg GAE/ g. The phenolic contents in the extracts highly correlate with their antioxidant activity, (R2 = 0.976) confirming that the antioxidant activity of this plant extracts is considerably phenolic contents-dependent.

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