Date of Award

8-2011

Document Type

Thesis

Degree Name

Master of Science (MS)

College/School

College of Science and Mathematics

Department/Program

Biology

Thesis Sponsor/Dissertation Chair/Project Chair

Lee H. Lee

Committee Member

Chunguang Du

Committee Member

Carlos Molina

Abstract

Green tea leaves contain many polyphenolic compounds such as (-)-epicatechin, (-)- epicatechin-3-gallate, (-)-epigallocatechin, and (-)-epigallocatechin-3-gallate(EGCG). Green tea polyphenols (GTPs) have been implicated to have distinct properties that combat the harmful effects of cell proliferation. These compounds contain certain anti-viral and antimicrobial mechanisms that inhibit growth and perhaps reverse the process in which replication occurs. In this study, varied concentrations of GTP, Lipophilic Tea Polyphenol (LTP), Curcumin, and Red Algae Polysaccharides were used separately and in synergism with the most commonly used antiseptics and antibiotics to study the effect on different species of gram positive and gram negative bacteria. The antiseptic study consisted of using the disk diffusion method. The antibiotic portion of the study utilized the Kirby-Bauer Method with an antibiotic disk dispenser consisting of twelve unique and commonly prescribed antibiotics. The zones of inhibition were measured in MDL and categorized as being resistant, intermediate, or susceptible to the chemical agent used.

The results suggested that synergistic effects of EGCG and LTP varied dependent upon microorganism, strain, classification, and antibiotic used against certain strains. The most studied organisms found to have had some form of impact when EGCG and LTP were combined with the antibiotic against the growth of the organism. It was found to work efficiently against Escherichia coli and Staphylococcus epidermidis. These organisms serve as an essential model for potentially pathogen strains that become pathogenic either due to plasmid exchange or developing other mechanisms to evade antibiotic resistance. It was also found that LTP had a greater synergistic effect with the antibiotics against the growth of the microorganism. The ampicillin-resistant strains of Escherichia coli were also focused upon to determine if strains that develop antibiotic resistance can still become susceptible to treatment of the antibiotic in conjunction with the polyphenol to inhibit the mechanism of antibiotic resistance. The red algae polysaccharides also shown promise to inhibit the growth of many of these potentially pathogenic microorganism models. The spore study indicated that there was a certain extent of inhibition—up to 64%. The CFU Time-Kill portion of the study also indicated that after a polyphenolic treatment, the ability to inhibit the growth of microorganism up to 2 hours became 99.99999% (almost 100%).

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