Graduation Year


Document Type

Campus Only Senior Thesis

Degree Name

Bachelor of Arts



Reader 1

Pete Chandrangsu

Reader 2

Sierra Williams

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Antibiotic resistance is a growing issue that threatens global health. Despite the gravity of this issue, few new therapies are being launched in clinical settings. Zinc (Zn) compounds, historically employed for their antibacterial properties, such as in the form of zinc oxide for wound healing, continue to be investigated for their potential role in addressing bacterial infections. Additionally, in recent years cannabidiol (CBD), a compound found in marijuana, has been shown to have antibacterial potential against Gram-positive, but not Gram-negative, bacteria. Improving the antibiotic activity of CBD through combination therapy with already existing, historically used, antibiotics such metallic elements has been a recent area of interest. This study aims to explore the antibiotic potential of CBD in combination therapy with the metallic element zinc. The Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus were employed as model organisms. A checkerboard assay was conducted to evaluate the potential synergistic effect between CBD and zinc against these bacteria. The average Fractional Inhibitory Concentration (FIC) of CBD and Zn against Staphylococcus aureus was determined to be 1.07 suggesting an indifferent or additive relationship while the average FIC of CBD and Zn against Escherichia coli could not be discerned. Furthermore, a time-kill assay was performed to learn more about the concentration-dependent and time-dependent effects of these compounds as a combination therapy. The results of the time-kill assay showed promising effects of the CBD and Zn combination therapy against Escherichia coli. However, indifferent results were observed against Staphylococcus aureus. It is imperative to note that these findings are preliminary in nature and highlight the need for future studies on these relationships. Drawing from the conclusion of this study, the effectiveness of CBD and Zn combination therapy exhibits potential and warrants further research.

This thesis is restricted to the Claremont Colleges current faculty, students, and staff.