Isoflavones compounds extraction

One could argue that efficacy may be improved by extracting and concentrating in tablets the compound considered to be the active principal of soy. This should also, at least theoretically, improve compliance. Western women, in general, do not find the traditional Japanese diet easy to follow, hence, isolated isoflavones in tablet form have been used. 

Soy protein preparations contain a variety of biologically active compounds including saponins, fibers, trypsin inhibitors, and isoflavones (Potter, 2000). Hamsters and rats fed ethanol-extracted soy protein isolates had no ability to lower plasma cholesterol compared to intact soy protein isolates (Lucas et al., 2001 Ni et al., 1999). Extraction with ethanol is a treatment that would remove saponins, isoflavones, and other phytochemicals from the protein. Although one study showed that ethanol washing did not... 

Iwamura (1984) designed a process for isolating saponins and flavonoids from leguminous plants, including seed, leaf, root, stem, stalk, flower or the entire plant. Alkaline extract, which was clarified by acid precipitation to get rid of proteins, followed by filtration or centrifugation, was applied to a nonpolar resin (styrene-vinyl benzene) or a slightly polar resin (such as acrylic ester resin). Water was used to elute soluble sugars, then the column was eluted with methanol to obtain a mixture of saponins and flavonoids. These two compounds were separated by acetone extraction to yield isoflavones in the soluble fraction. 

A wide variety of flavonoid compounds have been isolated from hardwoods, including flavones, flavanols, flavanones, isoflavones, and chalcones, most of whieh are highly hydroxylated, and which vary in hydroxylation pattern. Two of the many compounds present are shown in Figure 2.17 robinetin is the 3-hydroxy-flavone extracted from Robinia and Intsia sp. while the chalcone, okanin, is found in Cyclodiscus sp. 

Processing of Coenzyme QIO was studied by Nunes et al. (47) using SC-C02. Some other studies were conducted on the extraction by SC-C02 of polar compounds such as phenols, with the addition of polar modifiers. Chepe et al. (48) demonstrated the possibility to obtain the concentration of the isoflavones biochanin A and formononetin continuously from a red clover EtOH/water extract by means of SC-C02-fractionation using a column. 

Although tomato was the matrix most studied with this technique, other matrices such as pepper, eggplant, apple, pear, beans, mango, orange, citrus fruit, onion, garlic, potato, chillies, and strawberries were also studied by UAE. The extracted phenolic compounds included phenolic acids, isoflavones, flavonols, flavonones, fla-vones, flavonones, cinnamic acids, dihydrochalcones, chalcones, flavanols, and pro-cyanidins (Table 16.3). 

One problem inherent in these earlier LC-NMR studies is that of analyte concentration. In on-flow mode, this may be too low for anything other than ID H spectra to be acquired. Use of the stopped-flow mode greatly increases the overall time of the LC-NMR experiment, especially where there are many components of interest. One solution is the so-called LC-SPE-NMR method, where the analytes of interest are concentrated by solid-phase extraction before transfer to the NMR flow-cell. Using this procedure, acquisition of 2D NMR datasets such as H— H COSY and inverse-detected H— C experiments (HSQC, HMBC) becomes more practicable. Lambert et al. (2005) have demonstrated the potential of this approach by using LC-SPE-NMR to identify 10 new and 7 known constituents present in extracts of Smimowia iranica. The new compounds comprised isoflavans, iso-flavanones, and isoflavones, many of which are prenylated. 

The distribution of the isoflavones in the plant kingdom is largely restricted to the family Leguminoseae. There are over 350 known isoflavones, making them the largest group of compounds in the class of isoflavonoids. The four most common isoflavones associated with phytoestrogenic herbs or extracts are daidzein,... 

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