Analysis of compounds with phytoestrogenic activity in dietary supplements with use of HPTLC-densitometry method.

Soy (Glycine max L., Fabaceae) and soy products are becoming more popular because of their low toxicity and therapeutic effects. Soy possesses antioxidant, anti-inflammatory and anti-allergic properties, however, the most important is its estrogenic activity associated with occurrence of phytoestrogens. Isoflavones with phytoestrogenic effects were determined in four commercially available soya formulations. Analyses were performed with the use of high performance thin-layer chromatography (HPTLC) combined with densitometry. The compounds were extracted, hydrolyzed in order to obtain aglycone forms and separated on HPTLC silica gel 60 F254 plates with the use of mobile phase consisting of chloroform--ethyl acetate--formic acid 4:6:0.1 (v/v/v). After drying, the spots on the plates were determined in absorbance/reflectance mode at a wavelength of 260 nm using a computer-controlled densitometer Desaga CD 60.