Determination of the Antimicrobial Activity of Plectranthus amboinicus and Plectranthus verticillatus extracts against Escherichia coli and Staphylococcus aureus By Katrina Grau Mentor Dr. Carolyn Mathur Department of Biology, York College of Pennsylvania P. amboinicus P. verticillatus Introduction Methods Results Results Results Results Introduction Methods Extraction Method Dried Leaves Approximately 2 weeks Pulverized Leaves Approximately 4g leaf matter 95% Ethanol Vortexed with glass beads Soaked for approximately 24 hours Evaporated for approximately 48 hours Resuspended in Sterile Water Plectranthus Genus Found in Tropical Africa, Asia, and Australia Includes over 300 species Many species have medicinal uses anti-inflammatory respiratory infections skin infections E. coli Frequently used in scientific research Lactose fermenting, anaerobic, gram negative rod Part of the human body’s natural microbiota A cause for multiple health issues Food poisoning Urinary tract infections Water contamination S. aureus Gram positive cocci Associated with nosocomial infections MRSA Toxic Shock Syndrome Pneumonia Relevance Provides possible grounds for future antibiotic research Possibly lead to an explanation for why this genus has such fantastic medicinal uses No zones of inhibition were observed for any of the agar diffusion plates Activity Assays Minimum Inhibitory Concentration (MIC) Method Conclusion P. amboinicus and P. verticillatus extracts inhibited S. aureus at titers of 2 and 16, respectively, using the Minimum Inhibitory Concentration (MIC) method Neither plant extracts inhibited E. coli using the MIC method The Agar Diffusion Plates method indicated no antimicrobial activity against either bacterium for both P. verticillatus and P. amboinicus MIC method was more sensitive than the Agar Diffusion Method for detecting inhibition in these experiments 2-fold Serial Dilution Plant Extract and Nutrient Inoculated Wells MacFarland Standard of 1 Objectives Incubated Approximately 24 hours Determine a Titer To determine if P. amboinicus and/or P. verticillatus extracts exhibit antimicrobial activity against E. coli and/or S. aureus To measure the degree of antimicrobial activity, if present, for each extract Agar Diffusion Method Plate Extract Drenched Disks Triplicate on each plate Incubated Approximately 24 hours Inoculate Plates Measure Zones of Inhibition Literature Acknowledgments Bauman, Robert. 2007. Microbiology: with diseases by Taxonomy. 2nd ed. Pearson Education Inc., San Francisco, CA. De Castro-Ontengco, Delia. 2004. Screening for the Antibacterial Activity of Medicinal Plants. MicrobeLibrary. Diniz Gurgel, Ana Pavla A., da Silva, Jackeline G., Grangeiro, Ana Ruth S., Oliveira, Danielli C., Lima, Cynthia M.P., da Silva, Aldo C.P., Oliveira, Rinalda A.G., Souza, Ivone A. 2009. In vivo study of the anti-inflammatory and antitumor activities of leaves from Plectranthus amboinicus (Lous.) Spreng (Lamiaceae). Journal of Ethnopharmacology. 125(361-363 Egwaikhide, P.A., and Gimba, C.E. 2007. Analysis of the Phytochemical Content and Anit-microbial Activity of Plectranthus glandulosis Whole Plant. Middle-East Journal of Scientific Research. 2(3-4):135-138 Murthy, Pushpa S., Ramalakshmi, K., and Srinivas, P. 2009. Fungitoxic activity of Indian borage (Plectranthus amboinicus volatiles. Food Chemistry. 114:1014-1018 Special thanks to Dr. Carolyn Mathur for all her advice and help in the idea, design, and execution of this experiment. Thanks to Professor Daly for supplying the plant materials used in this research. Great appreciation to Jen Woolfenden, Lauren Rebuck, and Kelli Braightmeyer who helped with the preparation for this research.