Determination of the Antimicrobial Activity of Plectranthus amboinicus and Plectranthus verticillatus extracts against Escherichia coli and

Staphylococcus aureusBy Katrina Grau

Mentor Dr. Carolyn MathurDepartment of Biology, York College of Pennsylvania

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•Frequently used in scientific research•Gram positive cocci•A cause for multiple health issues

•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

Introduction

Acknowledgments

Results Results

•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

•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.

•No zones of inhibition were observed for any of the agar diffusion plates

• 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

Extraction MethodDried Leaves

Approximately 2 weeks

Pulverized LeavesApproximately 4g leaf matter

95% EthanolVortexed with glass beads

Soaked for approximately 24 hoursEvaporated for approximately 48 hours

Resuspended in Sterile Water

Methods

P. verticillatusP. amboinicus

Objectives

Introduction Methods Results Results

Conclusion

Literature

Activity Assays

Minimum Inhibitory Concentration (MIC) Method

Determine a Titer

IncubatedApproximately 24 hours

2-fold Serial DilutionPlant Extract and Nutrient

Inoculated WellsMacFarland Standard of 1

Agar Diffusion Method

Plate Extract Drenched Disks

Triplicate on each plate

IncubatedApproximately 24 hours

Inoculate Plates

Measure Zones of Inhibition