New perspective of dendrobium crumenatum orchid for antimicrobial activity against selected pathogenic bacteria

The present study was undertaken to investigate the potential anti-microbial activity from different parts of dendrobium crumenatum (leaf,stem,root and pseudo-bulb) against 8 pathogenic bacteria. the antimicrobial activities were determined by using disc diffusion assay,microdilution test for determination of minimum inhibitory concentration (mic) and minimum bactericidal concentration (mbc). the methanolic extracts of stem,root and pseudo-bulb displayed antimicrobial activity comparable to that of the standard antibiotics. stem extract of d. crumenatum had the most potent antimicrobial activity against staphylococcus aureus,klebsiella pneumoniae and enterobacter aerogenes with mic values of 0.39,0.195 and 0.195mg/ml,respectively. root and stem extracts were found to be active against streptococcus pneumoniae,shigella dysentriae and saccharomyces cerevisiae with mic values of 0.78 mg/ml compared to 0.00312mg/ml,0.025mg/ml and 0.0125mg/ml of standard antibiotics of amoxcillin,chloramphenicol and kanamycin. stem and root extracts yield mbc values in the range of 0.78 mg/ml to 6.25 mg/ml against staphylococcus aureus,enterobacter aerogenes,klebsiella pneumoniae and saccharomyces cerevisiae. the present study showed that d. crumenatum exhibited potential antimicrobial activity which could be due to the presence of alkaloid and flavonoid compounds and this is a first report on south east asia region's wild orchid.