2003 Annual Report 4.What were the most significant accomplishments this past year? D. Progress Report: This report serves to document research conducted under a cooperative agreement between the Agricultural Research Service (ARS) and the Center for Bioenvironmental Research, Tulane University. Additional details of research can be found in the report for the ARS parent research project 6435-42000-017-00D, "Identify Mechanisms of Isoflavonoid Induction in Legumes and Their Phytoestrogenic Effects." Hormonal changes in post-menopausal women can increase the risk of developing breast cancer, bone loss, and reduced cardiovascular health. Populations consuming a diet high in soybean phytoestrogens (compounds that mimic estrogen) have lower incidences of several diseases, including breast and prostate cancer. Recently, research has shown that isoflavones, a group of phytoestrogens found in soybean derived foods, are compounds that reduce the risk of certain potential health problems when consumed in the diet. Identifying the phytoestrogenic activity of soybean isoflavones would benefit the nutritional health of the population in general, particularly women. Techniques are being determined by ARS scientists to manipulate phytoestrogen levels in soybean seed and soy-based products to maximize health benefits by their consumption. Several biotic (living) and abiotic (non-living) elicitors have been evaluated for potential use in effectively inducing beneficial isoflavones. Collaborating scientists from Tulane University have performed a series of laboratory bioassays using various phytoestrogen compounds extracted from soybean seeds treated with elicitors that induce phytoestrogens. Inducible compounds in soybean seed known as glyceollins were purified and used in several animal cell assays, demonstrating that these compounds block the growth of hormone-dependent breast cancer cells and indicating their potentially useful phytoestrogenic activity. In vivo (animal) studies using the glyceollins are underway in order to determine their potential therapeutic value. Recent research has included method development and large scale production of an "induced" soybean seed to be used for animal studies to test for any toxic effects and anticancer activity. Also, research to identify and isolate active metabolites (breakdown products) of glyceollin and other phytoestrogens is ongoing. A new cooperative agreement is being entered into with University of Toledo as a result of the FY 2003 funding increase in phytoestrogen research. Researchers associated with this new cooperating group have unique capabilities in isolation of new potentially useful phytoestrogens as phytoestrogens from other (besides the seed) induced soybean plant parts (e.g. roots). The cooperative interaction begun with University of Toledo also provides expertise in organic synthesis (formation of a compound from simpler compounds or elements) of novel phytoestrogens and their analogues (structural derivatives) for testing in animal systems IMPACT: This research could lead to a better understanding of the effects of soybean-derived isoflavonoids (plant compounds) on human health and may lead to alternative or value-added uses of soybean (legume) isoflavonoids.