Isoflavone, Glyphosate, and Aminomethylphosphonic Acid Levels in Seeds of Glyphosate-Treated, Glyphosate-Resistant Soybean

• Published in: Journal of agricultural and food chemistry Vol. 51; no. 1; pp. 340 - 344
• Main Authors: Duke, Stephen O, Rimando, Agnes M, Pace, Patrick F, Reddy, Krishna N, Smeda, Reid J
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.01.2003
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Chemical constitution; Drug Resistance; Economic plant physiology; Food industries; Food toxicology; Fundamental and applied biological sciences. Psychology; Genistein - analysis; Glycine - administration & dosage; Glycine - analogs & derivatives; Glycine - analysis; Glycine - pharmacology; Glycine max - chemistry; Glycine max - drug effects; Glyphosate; Herbicides - administration & dosage; Herbicides - pharmacology; Isoflavones - analysis; Isoxazoles; Organophosphonates - analysis; Seeds - chemistry; Shikimic Acid - analysis; Tetrazoles; Benzothiadiazine derivatives; Cyclohexane derivatives; Pesticides; herbicide-resistant crop; transgenic crop; Soybean; Glyphosate; Isoflavone derivatives; Herbicide; shikimic acid; Grain legume; isoflavone; Chemical treatment; Aminoacid; Quality; Sulfonylureas; Chemical composition; Food safety; Aminomethylphosphonic acid; Fluorine Organic compounds; Comparative study; Chemical contamination
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf025908i

The estrogenic isoflavones of soybeans and their glycosides are products of the shikimate pathway, the target pathway of glyphosate. This study tested the hypothesis that nonphytotoxic levels of glyphosate and other herbicides known to affect phenolic compound biosynthesis might influence levels of these nutraceutical compounds in glyphosate-resistant soybeans. The effects of glyphosate and other herbicides were determined on estrogenic isoflavones and shikimate in glyphosate-resistant soybeans from identical experiments conducted on different cultivars in Mississippi and Missouri. Four commonly used herbicide treatments were compared to a hand-weeded control. The herbicide treatments were (1) glyphosate at 1260 g/ha at 3 weeks after planting (WAP), followed by glyphosate at 840 g/ha at 6 WAP; (2) sulfentrazone at 168 g/ha plus chlorimuron at 34 g/ha applied preemergence (PRE), followed by glyphosate at 1260 g/ha at 6 WAP; (3) sulfentrazone at 168 g/ha plus chlorimuron at 34 g/ha applied PRE, followed by glyphosate at 1260 g/ha at full bloom; and (4) sulfentrazone at 168 g/ha plus chlorimuron at 34 g/ha applied PRE, followed by acifluorfen at 280 g/ha plus bentazon at 560 g/ha plus clethodim at 140 g/ha at 6 WAP. Soybeans were harvested at maturity, and seeds were analyzed for daidzein, daidzin, genistein, genistin, glycitin, glycitein, shikimate, glyphosate, and the glyphosate degradation product, aminomethylphosphonic acid (AMPA). There were no remarkable effects of any treatment on the contents of any of the biosynthetic compounds in soybean seed from either test site, indicating that early and later season applications of glyphosate have no effects on phytoestrogen levels in glyphosate-resistant soybeans. Glyphosate and AMPA residues were higher in seeds from treatment 3 than from the other two treatments in which glyphosate was used earlier. Intermediate levels were found in treatments 1 and 2. Low levels of glyphosate and AMPA were found in treatment 4 and a hand-weeded control, apparently due to herbicide drift. Keywords: Aminomethylphosphonic acid; glyphosate; herbicide-resistant crop; isoflavone; shikimic acid; transgenic crop