Toxicity and Biological Reactivity of Naturally Occurring Polyphenols

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******The use of natural product-based remedies to maintain good health or treat disease has been known for centuries, and in recent years the use of natural health products has increased in Canada. Beneficial effects observed with natural health products are the result of the actions of the specific natural products present, unfortunately a great deal remains poorly understood regarding their safety and effectiveness. Our research is aimed at developing a better understanding of how some natural health products work.***Specifically, we are investigating the fundamental chemical properties of these natural products, and how they may help us to learn about their health benefits.***One research focus is on a group of compounds called lignans. A lignan in flaxseed, secoisolariciresinol (SECO), is associated with improved heart health and cancer treatment, whereas a lignan found in the creosote bush, nordihydroguaiaretic acid (NDGA), has both beneficial effects and also causes liver and kidney toxicity. We have determined that NDGA undergoes reactions to produce a toxic compound as well as a new compound, known as cNDGA, whose properties remain unknown. We are synthesizing new lignans that will allow us to determine what structural factors control the reactions of SECO, NDGA, and cNDGA and how this may influence their function as natural health products.***A second research focus is how natural plant products called flavonols protect against damage caused by excess exposure to sunlight. Our goal is to determine whether flavonols possess properties that would make them candidates for topical sunscreens. We have determined the stability of several flavonols when exposed to ultraviolet (UV) radiation and observed these compounds undergo unexpected reactions under these conditions. We are continuing to determine those structural features that help maintain flavonol stability to UV and pH. We have developed a method to measure DNA damage by UV and are using this to assess how the flavonols may provide protection against UV.***The information created through this research will be critical to better predict the properties of lignans, flavonols and other natural products and in evaluating the safety and efficacy of natural products.*****