Antibacterial activity of selected Dendrobium species against clinically isolated multiple drug resistant bacteria

Abstract

Dendrobium species are widely used in traditional medicine as remedies for tonic to nourish the stomach, promote the production of body fluids and decrease fever. In this study, the antibacterial activities of four traditionally used Dendrobium species were tested against clinically isolated multiple drug resistant (MDR) bacteria. Hexane, chloroform, acetone, ethanol and methanol extracts of Dendrobium amoenum, Dendrobium crepidatum, Dendrobium moniliforme and Dendrobium longicornu were tested for antibacterial activity against methicillin-resistant Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhi and Acinetobacter baumannii by using the well diffusion method. Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) were determined using the serial dilution method. For D. amoenum, hexane, chloroform and acetone extracts showed antibacterial activity against S. aureus (ZOI: 11.33, 12.00 and 11.00 mm respectively), acetone extract against A. baumannii (ZOI: 13.00 mm) and methanol extract against P. aeruginosa (ZOI: 12.00 mm). For D. crepidatum, hexane, chloroform, acetone, ethanol and methanol extracts showed antibacterial activity against S. typhi (ZOI: 10.00, 11.67, 12.00, 9.67 and 12.67 mm respectively), hexane, ethanol and methanol extracts against P. aeruginosa (ZOI: 10.00, 9.67 and 15.00 mm respectively), choloroform and acetone extracts against S. aureus (ZOI: 9.67 mm) and ethanol extract against E. coli (ZOI: 11.00 mm). For D. moniliforme, chloroform extract showed antibacterial activity against K. pneumoniae, P. aeruginosa, S. typhi, A. baumannii (ZOI: 12.67, 12.00, 11.67 and 13.00 mm respectively), acetone extract against S. aureus (ZOI: 11.00 mm) and A. baumannii (ZOI: 12.67 mm). For D. longicornu, chloroform extract showed antibacterial activity against A. baumannii (ZOI: 12.00 mm). MIC and MBC of these extracts of plants showed they have moderate antibacterial activity against the bacterial strains used. In conclusion, these Dendrobium species can be used as antibiotic agents.