Chemical Composition and Antimicrobial Efficiency of Swietenia macrophylla Seed Extract on Clinical Wound Pathogens

Microbial wound infection prolonged the hospitalization and increase the cost for wound management. Silver is commonly used as antimicrobial wound dressing. However, it causes several adverse side effects. Hence, this study was aimed to evaluate the antimicrobial efficiency of Swietenia macrophylla seed extract on clinical wound pathogens. Besides, the bioactive constituents of the seed extract were also determined. S. macrophylla seeds were extracted with methanol by maceration method. The seed extract inhibited 5 test bacteria and 1 yeast on disc diffusion assay. The antibacterial activity was broad spectrum, as the extract inhibited both Gram positive and Gram negative bacteria. On kill curve analysis, the antibacterial activity of the seed extract was concentration-dependent, the increase of extract concentration resulted in more reduction of bacterial growth. The extract also caused 99.9% growth reduction of Bacillus subtilis relative to control. A total of 21 compounds were detected in gas chromatography-mass spectrometry analysis. The predominant compounds present in the extract were oleic acid (18.56%) and linoleic acid (17.72%). In conclusion, the methanolic extract of S. macrophylla seeds exhibited significant antimicrobial activity on clinical wound pathogens. Further investigations should be conducted to purify other bioactive compounds from the seeds of S. macrophylla.

Chemical compositions and in vitro antimicrobial activity of Cymbopogon nardus on food borne microorganisms

Aims@#Food borne infections are routinely observed and frequently reported. Cymbopogon nardus, or commonly known as citronella is a tropical plant widely used for aromatherapy and insect repellant. This study aimed to evaluate the phytochemical compositions of C. nardus ethanol extract and its antimicrobial activity on food borne microorganisms. @*Methodology and results@#The plant materials were extracted with ethanol using maceration technique. The ethanol extract obtained was analysed using GC-MS and the most abundant compounds were 6-methyloctahydrocoumarin (31.5%) and 2,4-di-tert-butylphenol (28.7%). On Kirby Bauer assay, the extract showed wide spectrum inhibitory effect on one Gram-positive bacteria (Bacillus coagulans), two Gram-negative bacteria (Proteus mirabilis and Escherichia coli), and one yeast (Candida albicans). All the test microorganisms showed different susceptibility to the extract, where the minimal inhibitory concentrations were ranged from 63 to 250 μg/mL. The inhibitory effect of the extract was bactericidal. In addition, the time kill analysis of the extract exhibited inhibitory effect on P. mirabilis which was concentration-dependent. The C. nardus extract exhibited rapid bactericidal effect on P. mirabilis and lower bacterial counts were obtained with increased extract concentration. Besides, the extract did not exert significant toxicity effect to Artemia salina on brine shrimp lethality assay. @*Conclusion, significance and impact of study@#Therefore C. nardus can be a potential source of safe and effective antimicrobial agent to combat food borne infections.