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United States Department of Agriculture

Agricultural Research Service

Research Project: PHYTOESTROGENIC EFFECTS OF FUNGALLY INDUCED ISOFLAVONOIDS IN LEGUMES Title: Effects of Soybean Glyceollins and Estradiol in Postmenopausal Female Monkeys

Authors
item Wood, Charles - WAKE FOREST UNIV SC MED
item Clarkson, Thomas - WAKE FOREST UNIV SC MED
item Appt, Susan - WAKE FOREST UNIV SC MED
item Franke, Adrian - CANCER RESERCH CTR, HI
item Boue, Stephen
item Burow, Matthew - TULANE SCHOOL OF MEDICINE
item Mccoy, Thomas - WAKE FOREST UNIV SC MED
item Cline, J - WAKE FOREST UNIV SC MED

Submitted to: Nutrition and Cancer
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 1, 2006
Publication Date: December 15, 2006
Citation: Wood, C.E., Clarkson, T.B., Appt, S.E., Franke, A.A., Boue, S.M., Burow, M.E., Mccoy, T., Cline, J.M. 2006. Effects of soybean glyceollins and estradiol in postmenopausal female monkeys. Nutrition and Cancer. 56(1):74-81.

Interpretive Summary: Glyceollins are a novel class of soybean phytoalexins with potential cancer-protective antiestrogenic effects. The purpose of this study was to evaluate the estrogen-antagonist effects of glyceollin-enriched soy protein on biomarkers for breast cancer risk. Thirty female postmenopausal cynomolgus macaques were randomized to one of three dietary treatments for 3weeks: (1) estradiol control; (2) estradiol + soy protein isolate (SPI); and (3) estradiol + glyceollin-enriched soy protein (GLY). Glyceollin concentrations were analyzed in the serum. Breast proliferation was significantly increased in the estradiol control group, but not in the SPI group or GLY group. Two markers of estrogen receptor activity in breast epithelium were also significantly higher in the control, but not in the GLY group. These preliminary findings suggest that soybean glyceollins are natural compounds with potential estrogen-modulating properties in the breast. The glyceollins have potential to benefit human health.

Technical Abstract: Glyceollins are a novel class of soybean phytoalexins with potential cancer-protective antiestrogenic effects. The purpose of this study was to evaluate the estrogen-antagonist effects of glyceollin-enriched soy protein on biomarkers for breast cancer risk. Thirty female postmenopausal cynomolgus macaques were randomized to one of three dietary treatments for 3weeks: (1) estradiol (E2, 1 mg/day) + casein / lactalbumin (control); (2) E2 + soy protein isolate (SPI) containing 194 mg/day isoflavonoids; and (3) E2 + glyceollin-enriched soy protein (GLY) containing 189 mg/day isoflavonoids + 134 mg/day glyceollins. Doses are expressed in calorically-scaled human equivalents. Mean serum glyceollin concentrations at 4 hours postfeeding were 134.2 ± 34.6 nmol/L in the GLY group and negligible in the SPI group (P =0.0007). Breast proliferation was significantly increased in the control group (+237%, P = 0.01) but not in the SPI group (+198%, P = 0.08) or GLY group (+36%, P = 0.18). Gene expression of TFF1 and PGR, two markers of estrogen receptor activity in breast epithelium, were alsosignificantly higher in the control (P < 0.05 for both) but not in the GLY group. These preliminary findings suggest that soybean glyceollins are natural compounds with potential estrogen-modulating properties in the breast. The glyceollins have potential to benefit human health.

Last Modified: 10/25/2014