title: Colloidal gold-based indirect competitive immunochromatographic assay for rapid detection of bioactive isoflavone glycosides daidzin and genistin in soy products.
abstract: Daidzin (DZ) and genistin (GEN) are two major soy isoflavone glycosides isolated from soybeans. Soy products containing isoflavones have recently been widely accepted for commercial use. However, the Japanese Government has suggested that soy isoflavone intake should be limited because of their estrogenic effects due to their interactions with estrogen receptors. In this study, we established a one-step indirect competitive immunochromatographic assay (ICA) for rapid and sensitive detection of total isoflavone glycosides (DZ and GEN) using gold nanoparticles conjugated with a monoclonal antibody against DZ. This assay was able to be completed in 15min following the immersion of a test strip in an analyte solution. Furthermore, the limit of detection for the total amount of isoflavone glycosides was ∼125ngmL(-1). Considering that the major soy isoflavone glycosides found in soy products are DZ and GEN, this study demonstrates the potential use of ICA for the assessments of over consumption of isoflavones in soy supplements and foods, which would increase the safe dietary intake of soy products.
authors.affiliation: Department of Pharmacognosy, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
authors.forename: Seiichi
authors.initials: S
authors.lastname: Sakamoto
authors.affiliation: Department of Pharmacognosy, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
authors.forename: Gorawit
authors.initials: G
authors.lastname: Yusakul
authors.affiliation: Department of Pharmacognosy, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
authors.forename: Benyakan
authors.initials: B
authors.lastname: Pongkitwitoon
authors.affiliation: Department of Pharmacognosy, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan. Electronic address: htanaka@phar.kyushu-u.ac.jp.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tanaka
authors.affiliation: Department of Pharmacognosy, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Morimoto
mesh_terms: D000911:Antibodies, Monoclonal / Q000378:metabolism*; D002846:Chromatography, Affinity / Q000379:methods*; D006027:Glycosides / Q000737:chemistry*; D017979:Gold Colloid / Q000737:chemistry*; D007529:Isoflavones / Q000737:chemistry*; D013025:Glycine max / Q000737:chemistry*
chemical_list: D000911:Antibodies, Monoclonal; D006027:Glycosides; D017979:Gold Colloid; D007529:Isoflavones; C040641:genistin; C013908:daidzin
keywords: Colloidal gold; Daidzin; Genistin; Immunochromatographic assay; Monoclonal antibody