New Tool for Mining Phytochemicals From Soy
Suszkiw March 28, 2007
Saponinsnatural compounds found in soybeans and a wide variety
of plantsare typically used as foaming agents in shampoos and cleaning
products. Now, a new method for extracting saponins could shed new light on
their health-promoting potential in both whole soybeans and processed soy
Agricultural Research Service (ARS) chemist
Berhow spearheaded the method's development as part of his collaboration
with other research labs to ascertain the anticancer potential of group-A and
-B saponins, isoflavones and other phytochemicals in soy. Berhow works in the
ARS National Center for Agricultural Utilization Research (NCAUR)
at Peoria, Ill.
For example, in a 2005 in-vitro study, Berhow and
University of Illinois professor Keith
Singletary showed that exposing cancerous human colon cells to group-B saponins
reduced the cells' growth by 27 to 68 percent. Through mode-of-action studies,
the scientists determined that the saponins acted as "chemoprotectants" that
prompted cancerous cells to self destruct.
Berhow also recently teamed with ARS colleagues and University of the
Incarnate Word (UIW) scientists to improve
the extraction of saponins and isoflavones from whole soybeans and processed
foods like soy flour. One problem that has plagued saponin studies in the past
has been the difficulty of purifying sufficient amounts of saponins for
analysis, notes Berhow.
To address the problem, Berhow, UIW scientist Suk Bin Kong, and NCAUR
Vermillion chose a combination of steps that other laboratories could
easily follow and adapt to their studies. The method involves grinding dried
beans, defatting them and using solvents to extract the saponins. The final
step uses high-pressure liquid chromatography to identify individual saponins
based on their molecular weights. Soy isoflavones can be similarly obtained
with the process, according to Berhow.
In another project, Berhow and Iowa
State University professor Ruth MacDonald are assessing the effects of
isolated soy protein, isoflavones and saponins on the development of cancerous
cells in the colons of mice used as animal models.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.