495
from Science Direct, the Pubmed science web of Knowledge, Google. The
result of the search and study shows that 49 plant species belonging to 29 families were screened and evaluated for their anti-parasitic effects during this
period. The result obtained shows that family Fabaceae was the most screened
which consists of 10 species and exhibited an inhibitory effect against
Plasmodium falciparum.
22.5 Isoflavones: Extraction Procedure
Extraction of isoflavones can be performed using methanol, ethanol, acetonitrile, acetone or their mixtures with water as extraction solvents. Isoflavonoids
are present in plant material in free forms, called aglycones, but they are present mostly as glycosides. Due to the relative instability of the glycosides, the
extraction method must be carefully considered in order to preserve the original isoflavone profile. Several studies have shown that isolation at high temperatures causes changes in isoflavone composition due to glycoside
decomposition (Rostagno et al. 2009). Decarboxylation of malonylglucosides
to acetyl glucosides and ester hydrolysis of malonyl and acetyl glucosides to
underivatized glucosides are the two most common conversions of glycosides
occurring during the extraction process. It is also possible for any conjugated
isoflavone to generate the aglycone form by cleavage of the glucosidic bond.
Some glycosides, including malonyl and acetyl isoflavones, are particularly
unstable (Rostagno et al. 2009). Due to these potential chemical alterations,
the use of drastic temperature and pressure conditions and long extraction
times may cause degradation of isoflavonoids conjugates, changing the isoflavone profile of the samples and limiting the information obtained. In addition, chemical hydrolysis leads to a marked increase in the concentration of
aglycones present in the sample at the expense of the glucosides and hence
increase in the available amount of aglycones to be extracted. So, mild extraction techniques like maceration or negative pressure cavitation extraction are
often favoured in order to extract the conjugated forms of isoflavonoids intact.
For extraction of aglycones, however, more drastic methods, such as microwave-assisted extraction or accelerated solvent extraction, may be performed.
The principles of Green Chemistry, formulated in 1998 by Anastas and Warner,
involve friendly products and processes (Gałuszka et al. 2013; Perez and Escandar
2016). The most important areas of GAC associated with the extraction of plant
isoflavones are: automation and simplification of the process; increasing operator
safety; reduction of sample size, solvent volume and waste production; elimination
of toxic reagents and minimization of energy and time.
22 Health Benefits of Isoflavones Found Exclusively of Plants of the Fabaceae Family
from Science Direct, the Pubmed science web of Knowledge, Google. The
result of the search and study shows that 49 plant species belonging to 29 families were screened and evaluated for their anti-parasitic effects during this
period. The result obtained shows that family Fabaceae was the most screened
which consists of 10 species and exhibited an inhibitory effect against
Plasmodium falciparum.
22.5 Isoflavones: Extraction Procedure
Extraction of isoflavones can be performed using methanol, ethanol, acetonitrile, acetone or their mixtures with water as extraction solvents. Isoflavonoids
are present in plant material in free forms, called aglycones, but they are present mostly as glycosides. Due to the relative instability of the glycosides, the
extraction method must be carefully considered in order to preserve the original isoflavone profile. Several studies have shown that isolation at high temperatures causes changes in isoflavone composition due to glycoside
decomposition (Rostagno et al. 2009). Decarboxylation of malonylglucosides
to acetyl glucosides and ester hydrolysis of malonyl and acetyl glucosides to
underivatized glucosides are the two most common conversions of glycosides
occurring during the extraction process. It is also possible for any conjugated
isoflavone to generate the aglycone form by cleavage of the glucosidic bond.
Some glycosides, including malonyl and acetyl isoflavones, are particularly
unstable (Rostagno et al. 2009). Due to these potential chemical alterations,
the use of drastic temperature and pressure conditions and long extraction
times may cause degradation of isoflavonoids conjugates, changing the isoflavone profile of the samples and limiting the information obtained. In addition, chemical hydrolysis leads to a marked increase in the concentration of
aglycones present in the sample at the expense of the glucosides and hence
increase in the available amount of aglycones to be extracted. So, mild extraction techniques like maceration or negative pressure cavitation extraction are
often favoured in order to extract the conjugated forms of isoflavonoids intact.
For extraction of aglycones, however, more drastic methods, such as microwave-assisted extraction or accelerated solvent extraction, may be performed.
The principles of Green Chemistry, formulated in 1998 by Anastas and Warner,
involve friendly products and processes (Gałuszka et al. 2013; Perez and Escandar
2016). The most important areas of GAC associated with the extraction of plant
isoflavones are: automation and simplification of the process; increasing operator
safety; reduction of sample size, solvent volume and waste production; elimination
of toxic reagents and minimization of energy and time.
22 Health Benefits of Isoflavones Found Exclusively of Plants of the Fabaceae Family