Individual, Family, and Community Education ETDs

Roger Vaughan

Publication Date

7-1-2011

Abstract

Obesity is one of the most prevalent maladies in the United States and is a major cause of preventable death. Weight loss supplements frequently claim uncoupling as a mechanism of action. Uncoupling agents could be used for weight loss because they disrupt mitochondrial metabolism thereby reducing adenosine triphosphate (ATP) yield. Consequently, metabolic efficiency diminishes increasing basal metabolic rate. 2,4-Dinitrophenol (DNP) successfully uncouples but was banned in 1938 because of a narrow window between efficacy and toxicity. PURPOSE: To measure the ability of a blend that reportedly contains 17-dihydroxy-delta-5-etiocholane-7-one and p-methylcarbonylethylphenol and other substances (A7E), a purported uncoupling agent, to interfere with oxidative phosphorylation in Saccharomyces cerevisiae as evidenced by lower ATP production. METHODS: Timed culture studies of S. cerevisiae were performed using two separate agents, A7E (a purported uncoupling agent) and DNP (a known uncoupling agent) at three doses (DNP: Low, Moderate, High; A7E: Low, Moderate, High ), and an ethanol-treated control to detect interference with mitochondrial coupling. Microbial staining was used to ascertain cell viability and any changes in cell densities. ATP production was estimated by measuring luminosity generated in culture supernatants using the ATP Bioluminescence Kit (Sigma St. Louis, MO.). RESULTS: Luminosity measurements estimating ATP production revealed statistically lower ATP in agent-treated supernatants than in control supernatants (p < 0.001) except for low dose A7E versus control (p > .05), suggesting that both A7E and DNP acted by a mechanism of uncoupling. Luminosity values were measured in relative luminosity units (RLU). Treatments with A7E at Low, Moderate, and High doses generated group mean luminosity values of 24,596, 16,038, and 6,969, respectively. Treatments with DNP at Low, Moderate, and High doses generated group mean luminosity values of 17,191, 11,901, 767 RLU respectively. The control group mean was 31,645 RLU. Culture studies had no statistical difference (p > 0.0167 adjusted) in total and viable cell densities between the control and A7E and DNP treatments. CONCLUSION: A7E is effective at reducing ATP levels in this assay, as is known uncoupling agent DNP, supporting the hypothesis that A7E may also uncouple oxidative phosphorylation. Because A7E requires a higher dosage than DNP to equivalently disrupt mitochondrial metabolism, it may have a wider range of therapeutic doses. This suggests that A7E should be studied further for safety and efficacy with respect to metabolic efficiency and weight loss.

Keywords

Phosphorylation., Adenosine triphosphate., Dinitrophenol., Mitochondria--Physiology., Saccharomyces cerevisiae--Metabolism., Obesity--Treatment.

Document Type

Thesis

Language

English

Degree Name

Nutrition

Level of Degree

Masters

Department Name

Individual, Family, and Community Education

First Committee Member (Chair)

Conn, Carole

Second Committee Member

Dichosa, Armand

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