EN
The antibacterial and antifungal activity of Centaurea rupestris L. ethanolic and etheric leaf and inflorescence extracts and of quercetagetin 3’-methyl ether 7-O-β-D glucopyranoside isolated from inflorescences was investigated. Inflorescence extract in 45% ethanol showed significant antifungal activity against the dermatophytes Epidermophyton floccosum, Microsporum gypseum and Trichophyton mentagrophytes (fungicidal zones between 18 and 23 mm, minimum fungicidal concentration 5-7%). The same extract showed weak bactericidal activity against Bacillus anthracis (bactericidal zone 9 mm, minimum bactericidal concentration 90%). In contrast, leaf extract in 90% ethanol possessed significant antibacterial activity against Streptococcus faecalis (bactericidal zone 23 mm, minimum bactericidal concentration 9%). The antimicrobial spectrum of quercetagetin was broad but weak for G- bacteria and moderate for dermatophytes. Namely, it showed antibacterial activity against Klebsiella pneumoniae, Escherichia coli, Salmonella java and Serratia sp. (bactericidal zones 10 mm, minimum bactericidal concentrations 5-6 mg/ml). The fungicidal zones created by quercetagetin against the dermatophytes Epidermophyton floccosum, Trichophyton mentagrophytes and Microsporum gypseum ranged from 14 to 18 mm (minimum fungicidal concentrations 3 mg/ml).