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Cardiovascular and Metabolic Diseases

Vitamin C, Lipid Peroxidation, and Oxidative Stress


Principal Investigator: Fred Stevens, Ph.D.

The research mission of the Stevens lab is to determine the role of phytochemicals and vitamins in preventing or treating cardiovascular and metabolic diseases. We develop analytical methods for targeted and untargeted metabolomics experiments to determine the biological effects of phytochemicals and vitamins in supplementation/deficiency studies using cell culture, animal models, and humans. Our lab has developed novel biomarkers to examine the role of oxidative stress and the protective effects of dietary supplements in human health and disease.

Vitamin C and oxidative stress

This research project aims to determine how vitamin C interacts with lipid peroxidation products and how vitamin C prevents cellular damage to proteins caused by oxidized lipids. We are interested in these interactions because lipid peroxidation contributes to the development and progression of chronic inflammatory and age-related diseases, such as atherosclerosis. The tools that we use for our research include liquid chromatography coupled to mass spectrometry (LC-MS/MS) for analysis of lipid conjugates in complex biological matrices, synthesis of (labeled) lipids and their conjugates, cell culture for investigating the biological properties of oxidized lipids and their conjugates, and animal models for studying the in vivo formation, metabolism, and excretion of oxidized lipids. One of our main findings is that vitamin C, at physiologically relevant concentrations, prevents adduct formation of oxidized lipids with cellular proteins. The significance of this finding is that vitamin C may help maintain proper function of metabolizing and transporter proteins, thus mitigating the deleterious effects of oxidized lipids.

Structure elucidation and biological activity of phytochemicals

Our laboratory also has interests in the biological effects of phytochemicals. We have explored the chemistry and biology of prenylated flavonoids of the hop plant (Humulus lupulus) since 1995. We were the first to report that the principal prenylated flavonoid in hops, xanthohumol, exerts anti-inflammatory and cancer chemopreventive activities. Our current aim is to determine whether and how xanthohumol improves dysfunctional lipid and glucose metabolism in humans diagnosed with metabolic syndrome.

Another research project in our laboratory is focused on the chemistry and biology of phytochemicals from the oilseed crop, meadowfoam (Limnanthes alba). The Oregon oilseed industry produces a high-quality oil from meadowfoam seeds that is used in personal care products. Considered useless in the past, the seed waste may prove of value as a natural herbicide in organic farming. We have developed a fermentation procedure for enhancing the herbicidal activity of the seed waste by converting inactive seed-meal glucosinolates into degradation products with herbicidal activity.