Cherie Hacker

Date of Award


Degree Name

Master of Science


Biological Sciences

First Advisor

Dr. John Geiser

Second Advisor

Dr. Bruce Bejcek

Third Advisor

Dr. Haeri Roh-Schmidt

Access Setting

Masters Thesis-Open Access


Hydroxyl free radicals are biologically important molecules in that they attack proteins, lipids and DNA to obtain an electron to fill their outer valence shell. The consequences of such attacks include protein degradation, lipid peroxidation and DNA damage, which leads to many diseases and cancer. While there are many antioxidant assays available to predict anti-radical properties of compounds against different free radicals, the assessment of hydroxyl radical damage has been challenging. This is due to the extremely high reaction rate of hydroxyl radicals. The present study defines an in vitro assay that quantitatively detects antioxidant efficacy against hydroxyl free radicals, by measuring the production of ethylene created from the reaction of KMBA with hydroxyl radical formation. The method uses gas chromatography to detect the presence of ethylene using headspace aliquots from the sample vial. The assay will be used to analyze plant extracts for their use in nutritional supplements and personal care products, in order to market them as having antioxidant properties. Green tea extract was used to develop the method because it contains polyphenols, which are extremely efficient free radical scavengers. Results indicate that this assay can measure the amount of hydroxyl free radical generated and the antioxidant effects of hydroxyl free radical scavengers.

Included in

Biology Commons