Isoflavones introduction

Four pure isoflavones were obtained from a crude soybean extract after CPC with the solvent system CHCl3-Me0H-H20 (4 3 2) (Figure 1.2). The isoflavones were isolated in amounts of 5 to 10 mg after the introduction of 150 mg of sample. 

An alternative biosynthetic route for the introduction of the 4 -methoxyl has been suggested from studies of M. sativa. Initial studies of one of the four isoflavone OMTs (lOMTs) of M. sativa showed it had 7-0-methylation activity to the A-ring of daidzein, thus forming isoformononetin from daidzein. However, overexpression of this lOMT in transgenic... 

In the spectra of isoflavones (64) and flavanones (25), in which rings A and B are not conjugated, band I frequently appears only as a shoulder on band II. Not surprisingly, introduction of oxygen substituents in ring B has little effect on the spectra, whereas substitution in ring A shifts band II to the red. 

Soy foods are complex matrices (see Table 11.6.1). After initial aqueous extraction, the crude extract containing isoflavones is concentrated but may contain components that are immiscible with the HPLC mobile phase for direct injection. A clean-up step is necessary to prevent the introduction of particles and precipitates that may block the frit and foul the column. 

Isoflavones result from the arylation of 3-(allyloxycarbonyl) chroman-4-ones with aryllead (IV) triacetates. Of particular interest is the introduction of a 2-hydroxy function through incorporation of a protected phenolic unit into the aryllead reagent (95JCS(P1)1679). 

---