1. 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 Microbiology: with diseases by Taxonomy. 2nd ed. Pearson Education Inc., San Francisco, CA.
De Castro-Ontengco, Delia 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 In vivo study of the anti-inflammatory and antitumor activities of leaves from Plectranthus amboinicus (Lous.) Spreng (Lamiaceae). Journal of Ethnopharmacology. 125(
Egwaikhide, P.A., and Gimba, C.E Analysis of the Phytochemical Content and Anit-microbial Activity of Plectranthus glandulosis Whole Plant. Middle-East Journal of Scientific Research. 2(3-4):
Murthy, Pushpa S., Ramalakshmi, K., and Srinivas, P Fungitoxic activity of Indian borage (Plectranthus amboinicus volatiles. Food Chemistry. 114:
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.