Quantitation of genistein and genistin in soy dry extracts by UV-Visible spectrophotometric method

Abstract

Recebido em 4/5/07; aceito em 1/7/08; publicado na web em 5/11/08 This paper describes the development and validation of an UV-Visible spectrophotometric method for quantitation of genistein and genistin in soy dry extracts, after reaction with aluminum chloride. The method showed to be linear (r 2 = 0.9999), precise (R.S.D. < 2%), accurate (recovery of 101.56%) and robust. Seven samples of soy dry extracts were analyzed by the spectrophotometric validated method and by RP-HPLC. Genistein concentrations determined by spectrophotometry (0.63% -16.05%) were slightly higher than values obtained by HPLC analysis (0.40% -12.79%); however, the results of both methods showed a strong correlation.

High-power ultrasonication-assisted extraction of soybean isoflavones and effect of toasting

“…Daidzin, genistin, their corresponding aglycons, daidzein and genistein, are the major component of soybean isoflavones (Cesar et al, 2008). The presences of soy isoflavones were reported to be the highest in the cotyledon and the lowest in the seed coat (Siviengkhek, Yeon-Shin, Yong-Hoon, & Young-Hyun, 2008).…”

Analytical chemistry in Brazil: healthy and growing

“…Mendes et al 48 have developed an electrochemical immunosensor based on impedance measurements to detect Asian rust on soybeans leaf extract at the early stages of the disease. César et al 49 also worked with soybeans focusing the determination of genistein and genistin in soy dry extracts after reaction with aluminum chloride and measurement by spectrophotometry. Genistein is one of the major isoflavones found in soy extracts and soy isoflavones are the most frequently used phytoestrogens.…”

Fast simultaneous determination of free and conjugated isoflavones in soy milk by UHPLC–UV

“…Analytical determination of isoflavones in soy products can be carried out through a variety of approaches, including spectrophotometry (César et al, 2008;Kotenko, Mamatkhanov, & Turakhozhaev, 1993), capillary electrophoresis (Mellenthin & Galensa, 1999;Micke, Fujiya, & Tonin, 2006), immuno-analysis (Dentith & Lockwood, 2008), liquid chromatography (Apers et al, 2004;Prabhakaran, Perera, & Valiyaveettil, 2005), gas chromatography (Ghosh & Fenner, 1999) and thin layer chromatography (César et al, 2007). Most of these methods have been developed to determine the release of aglycones after enzymatic hydrolysis (Liggins, Bluck, Coward, & Bringham, 1998), strong acid hydrolysis (Mazur et al, 1996) or saponification (Klump, Allred, Macdonald, & Ballam, 2001).…”