In vitro assay for the anti-brucella activity of medicinal plants against tetracycline-resistant Brucella melitensis

• Published in: Journal of Zhejiang University. B. Science 2010-07, Vol.11 (7), p.506-511
• Main Authors: Motamedi, Hossein, Darabpour, Esmaeil, Gholipour, Mahnaz, Seyyed Nejad, Seyyed Mansour
• Format: Article
• Language: English
• Subjects: Animals; Anti-Bacterial Agents - isolation & purification; Anti-Bacterial Agents - pharmacology; Biomedical and Life Sciences; Biomedicine; Biotechnology; Brucella melitensis; Brucella melitensis - drug effects; Brucella melitensis - pathogenicity; Brucellosis - drug therapy; Cordia; Crocus; Humans; Microbial Sensitivity Tests; Phytotherapy; Plant Extracts - isolation & purification; Plant Extracts - pharmacology; Plantago; Plants, Medicinal - chemistry; Ruminantia; Salvia sclarea; Tetracycline Resistance; Teucrium; Vitex
• ISSN: 1673-1581; 1862-1783
• DOI: 10.1631/jzus.B0900365

Brucellosis, a zoonosis caused by four species of brucella, has a high morbidity. Brucella mefitensis is the main causative agent of brucellosis in both human and small ruminants. As an alternative to conventional antibiotics, medicinal plants are valuable resources for new agents against antibiotic-resistant strains. The aim of this study was to investigate the usage of native plants for brucellosis treatment. For this purpose, the anti-brucella activities of ethanolic and methanolic extracts of Salvia sclarea, Oliveria decumbens, Ferulago angulata, Vitex pseudo-negundo, Teucrium pofium, Plantago ovata, Cordia myxa, and Crocus safivus were assessed. The activity against a resistant Br. melit- ensis strain was determined by disc diffusion method at various concentrations from 50-400 mg/ml. Antibiotic discs were also used as a control. Among the evaluated herbs, six plant （Salvia sclarea, Ofiveria decumbens, Ferulago angulata, Vitex pseudo-negundo, Teucrium polium, and Crocus safivus） showed anti-brucella activity. Ofiveria decumbens was chosen as the most effective plant for further studies. A tested isolate exhibited resistance to tetracycline nafciltin, oxacillin, methicillin, and colistin. Minimal inhibitory concentration （MIC） and minimal bactericidal concentraion （MBC） values for Ofiveria decumbens against resistant Br. melitensis were the same （5 mg/ml）, and for gentamicin they were both 2 mg/ml. Time-kill kinetics for a methanolic extract of Ofiveria decumbens was 7 h whereas for an ethanolic extract it was 28 h. Also, Ofiveria decumbens extracts showed a synergistic effect in combination with doxycycline and tetracycline. In general, the similar values of MIC and MBC for Ofiveria decumbens suggest that these extracts could act as bactericidal agents against Br. melitensis. In addition to Ofiveria decumbens, Crocus safivus and Salvia sclarea also had good anti-brucella activity and these should be considered for further study.