Date of Award

Spring 5-2024

Degree Type


Degree Name

MS Microbiology




Tinchun Chu, PhD


Jane L. Ko, PhD

Committee Member

Daniel B. Nichols, PhD


EGCG, EGCG-palmitate, EC16, antibacterial agents, formulations, natural products


Polyphenols, key compounds in teas, have been associated with various health benefits across multiple studies. This study assessed the antibacterial properties of novel formulations containing a green tea polyphenol (GTP), Epigallocatechin-3-Gallate-Palmitate (EC16). EC16 is a modified compound derived from one of the major catechins found in green tea, epigallocatechin-3-gallate (EGCG), to increase overall stability and prevent oxidization. Microtiter plate assays were conducted using proprietary formulations F2-0, F2-0.1, F2-0.3, and F2-1 at concentrations of 0.85X, 0.50X, 0.25X, and 0.125X were conducted to assess antibacterial efficacy against six bacterial species: Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, Staphylococcus aureus, Bacillus cereus, and Bacillus megaterium. The minimum inhibitory concentration (MIC) and half-maximal inhibitory concentration (IC50) were determined for each bacterial strain. Fluorescent microscopy was performed with staining to image viable cells, in which the bacterial samples treated with EC16 formulations showed comparative results with the positive control. Differences in average cell size were observed and log reductions were calculated from average cell concentrations to conduct cell viability analysis. Most formulations were observed with a log reduction of 2 or more and differences in average cell sizes were apparent between treated and non-treated cells. Lastly, qPCR was conducted with genes katB, sodA, and soxR to determine if the F2-0 formulation was able to induce oxidative stress on E. coli. An increase in sodA and soxR expression were observed indicating oxidative stress. The results from the study show that the EC16 containing formulations were effective in inhibiting all six selected bacteria, thus, suggesting its potential broad-spectrum applications in antibacterial properties.

Available for download on Wednesday, May 03, 2034

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