Glycine max: The Antioxidant
and Anti-Hyperlipidemic Nutraceutical.
Prin. K M Kundnani College of
Pharmacy, 23, Jote Joy Bldg., Rambhau Salgaonkar Marg, Cuffe Parade, Mumbai-
400005.
ABSTRACT:
The nutraceutical industry has seen a great boom in the
recent years as a result of the consumers seeking the convenient “healthful”
solution in their diet. Amongst the various candidates of the nutraceutical
world the everyday soybean has become a great nutraceutical today. In view of
the importance gained by soybeans (Glycine max Family: Leguminosae)
studies were carried out on the seeds of soybean. To evaluate its nutraceutical
claims, antioxidant and anti-hyperlipidemic evaluations were carried out on the
extracts obtained from the seeds of Glycine max. With an increase in the
health reports relating free radicals and high lipid levels to an array of
disease conditions, there has been a search for a safer solution from the
nutraceutical world as a support to the conventional therapy. In the current
study, the free radical scavenging activity was carried out using the DPPH
method whereas the diet induced hyperlipidemia model in hamsters was used to
evaluate the anti-hyperlipidemic activity. Both the studies yield results that
support the current position of soybeans in the nutraceutical world.
KEYWORDS: Glycine max, Soybean, antioxidant, anti-hyperlipidemic
INTRODUCTION
Since ages, soybean has been used in a variety of forms
in the diet of the people from China, Japan, Indonesia, the Philippines,
Vietnam, Thailand, Malaysia, Burma, Nepal and north India1. Soybean
is utilized in liquid, powder or curd forms to make soy sauce, tofu, soy milk
etc.2
Glycine max commonly known as soybean belonging to the family
Leguminosae3, is an annual upright bushy herb that can reach a
height of 1 meter. The plant is covered by fine rusty colored hair. It grows
well in subtropical climates. The current study is carried out on the seeds of
soybean. Seeds are 5 to 11mm in diameter. They range in shape from round and
spherical to elliptical and flattened.
Protein
and oil are two major components of high-quality and high-value soybeans.
Various other valuable nutrients present in soybean are carbohydrates,
vitamins, minerals, etc. Earlier experiments reveal the presence of
phytoconstituents like b-sitosterol, beta-conglycinin, one of the component
of soy protein, isoflavones such as daidzin, genistin and glycetin,
tocopherols, phospholipids, saponins comprising of Group A, B and E, folic acid
and the Protease Inhibitors namely Bowman-Birk inhibitor, Kunitz trypsin
inhibitor and the glycine-rich trypsin inhibitor.4, 5, 6
Numbers of biological activities have been associated
with the various components of soybean. Soybean has been indicated in diseases
like osteoporosis, certain types of cancers like prostate cancer, breast
cancer, colon cancer, in cardiovascular diseases, to reduce obesity, in
hyperglycemic
patients, as anti-hyperlipidemic agent, to reduce
menopausal symptoms, in neurodegenerative diseases, etc6-10. Studies
have been carried out on the different isolated components of soybean or on
various other extracts to ascertain these properties. The current experiment is
based on the studies carried out on the aqueous and the hydroalcoholic extracts
of seeds of soybeans.
With the large number of diseases prevalent amongst the
general population and the increasing urge to remain healthy has led to the
popularization of the nutraceuticals. Nutraceuticals are defined as a “food (or
part of food) that provides medical or health benefits, including the
prevention and/or treatment of a disease” 11.
The large variety of components and the numerous
biological effects shown by soybean has lead to the entry of soybeans in the
nutraceutical world. The current experimental plan was selected with a view to
ascertain the position of soybean in today’s nutraceutical world.
MATERIALS AND METHODS:
1) Authenticated MACS-450 variety of seeds of Glycine
max was obtained from Agharkar Research Institute, Pune.
2) DPPH (1,1-diphenyl 2-picryl hydrazyl) was procured from Fluka
chemicals (CAS 1898-66-4)
3) Male Golden Syrian Hamsters (weights range 140-170g)
were obtained from ACTREC, Mumbai
4) Clofibrate API, obtained from Smruthi Organics Ltd.
Solapur, Maharashtra
5) Edible coconut oil was purchased from the local
market (Parachute).
6) Cholesterol sample was obtained from Sigma Aldrich,
India.
Preparation of extracts:
Powdered Glycine max seeds were extracted with
water, Ethanol:Water (80:20) and Methanol:Water (80:20) as solvents by
maceration. The ratio of powder: solvent was maintained at 1:10 and maceration
with shaking was carried out at room temperature for 24 hours. Filtrate
obtained was evaporated at 60°C. Final drying was carried out in a vacuum oven at 60°C.The extracts were
stored at 4°C
The extracts obtained were further used for evaluating
the antioxidant property and the anti-hyperlipidemic activity.
Phytochemical evaluation was carried out for these
different soy extracts. The results reveal the presence of carbohydrates,
proteins and saponins in the aqueous extract. The ethanol: water extract and
the methanol: water extract show similar phytochemical profile. In addition to
carbohydrates, proteins and saponins, they show presence of isoflavones.
Antioxidant activity: The antioxidant activity was evaluated
using the DPPH method (1, 1-diphenyl 2-picryl hydrazyl). The activity was
expressed as the effective concentration at 50% (EC50) i.e. the
concentration of the test solution required to give 50% reduction in absorbance
of the test solution as compared to that of the blank solution. A graph of percent
reduction in absorbance v/s log concentration was plotted to obtain the EC50
value12.
Anti-hyperlipidemic activity: All the animal procedures were carried out
as per the norms and conditions of the Institutional Animal Ethics Committee of
Prin. K M Kundnani College of Pharmacy, Mumbai. Animal protocol number, 070808.
Golden Syrian Hamsters were
fed High Fat Diet (HFD) for 14 days prior to start of the study. The HFD was
prepared by addition of 0.5% cholesterol to the normal feed along with coconut oil.
All the animals were maintained on HFD throughout the study. The animals were
randomly divided into four groups,
I] Control Group: Maintained on the vehicle (water)
II] Standard Group: Fed 150mg/kg of clofibrate per
hamster once daily
III] Test Group 1: Fed 5g/kg of ethanol:water (80:20)
extract per hamster once daily
IV] Test Group 2: Fed a combination of 2.5g/kg of
ethanol:water (80:20) extract + 2.5g/kg of aqueous extract per hamster once
daily.
The cholesterol levels were
estimated at the beginning of the study (0 day). The study was carried out for
14 days. At the end of the study, blood samples were withdrawn from the retro
orbital plexus and samples analyzed for their cholesterol levels13.
RESULTS:
Antioxidant Activity: A set
of six readings each, was taken for the two different soy extracts and the
standard solution of ascorbic acid. EC50 values for the standard,
ethanol: water extract and the methanol: water extracts were 2.86μg/ml,
1.32mg/ml and 1.67mg/ml respectively. (Table 1) The present study shows that
both the soy extracts possess the free radical scavenging activity. Amongst the
ethanol: water extract and the methanol: water extract, the former possesses
better free radical scavenging power.
Table 1 Results of antioxidant
activity of Glycine max extracts.
|
Extract |
Mean* EC 50 |
r** |
|
Ascorbic Acid |
2.86mg/ml |
0.9618 |
|
Ethanol:Water
Extract (80:20) |
1.32mg/ml |
0.9246 |
|
Methanol:Water
Extract (80:20) |
1.67mg/ml |
0.9458 |
*Mean of three readings
**Correlation coefficient
Table 2 Descriptive statistics
of the treatment groups.
|
Group |
Median (0
day) |
Median (14
day) |
|
HFD |
158 |
149 |
|
Clofibrate |
133 |
104 |
|
EtOH: H2O
(80:20) extract |
150.5 |
143.5 |
|
Combination |
153 |
146 |
Anti-hyperlipidemic activity:
The cholesterol levels were monitored to evaluate the effect of the various
extracts on the lipid levels of hamsters. Levels were noted at the beginning
and at the end of the study. (Table 2)
In order to test the hypothesis that there is a
difference between the 0 day values and the 14 day values of cholesterol in
each of the above groups, the Wilcoxon Signed Ranks test for two related
samples was used. Table 3 shows the results of the Wilcoxon Signed Ranks test
and indicate that there is no significant difference between the 0 day values
and 14 day values of the HFD group, hence it can be concluded that the group
has reached a plateau level for cholesterol. There is a significant difference
between the 0 day and 14 day values for Clofibrate. Hence we can say that the
standard is working. The combination group shows p value of 0.08. Hence we can
conclude that the 0 day and 14 day values for the combination group differ
significantly. In order to compare the different treatments, the differences
between the 0 day and 14 day values were considered for each treatment. HFD v/s
Clofibrate and Clofibrate v/s Combination therapy were compared on the basis of
these differences using the Mann-Whiney U test for two independent samples. The
Clofibrate group was compared with the HFD group and the combination group. The
results indicate that there is a difference between the HFD and the Clofibrate
group trends, whereas the clofibrate and the combination group show similar
trends. Hence the combination therapy is comparable to the standard i.e.
clofibrate group. (Table 4)
Table 3 Statistical
significant values for Wilcoxon Signed Ranks test.
|
Group |
p value |
Interpretation |
|
HFD |
0.715 |
Non significant |
|
Clofibrate |
0.043* |
Significant |
|
EtOH:H2O (80:20) |
0.249 |
Non significant |
|
Combination |
0.08* |
Significant |
*p values significant
Table 4 Statistical
significance values for Mann-Whitney U Test.
|
Group |
p value |
Interpretation |
|
HFD v/s Clofibrate |
0.056* |
Significant |
|
Clofibrate v/s combination |
0.347 |
Non significant |
* p value significant
The levels reveal that the
combination of ethanol: water extract and the aqueous extract has significant
anti-hyperlipidemic activity. The ethanol: water extract alone does not show
significant results.
The anti-hyperlipidemic studies indicate that the
ethanol: water extract alone is not sufficient to bring about a significant
decrease in the cholesterol levels. But a combination of this extract with the
aqueous extract yields significant results. The reason behind the significant
activity shown by the combination therapy could be the relative increase in the
percentage of the various components in the combination as compared to the
ethanol: water extract alone. Also the study is based on the administration of
the drug once daily for a period of 14 days. An increase in the frequency of
administration along with an increase in the duration of the treatment period
may yield better results. The study shows that the administration of clofibrate
reduces serum cholesterol levels. Clofibrate is a lipoprotein lipase activator.
The combination group also shows a decrease in the serum cholesterol levels in
this animal model. Hence there is a possibility that the combination therapy
could be imparting its effect in a similar manner as clofibrate by activating
lipoprotein lipase.
The advancement in scientific research has lead to the
establishment of theories linking the free radicals to a number of diseases and
disorders of the human body15. Also increased lipid levels have now
been considered a health hazard. A combination of the presence of free radicals
along with elevated lipid level is surely a matter of great concern. Hence an
attempt was made to evaluate the antioxidant and anti-hyperlipidemic activities
of extracts of soybean. There is now a general trend, throughout the world,
toward herbal and natural medicines. Along with many other entities soybeans
are been considered to be an important part of this nutraceutical world. As
stated earlier nutraceutical is nothing but a “food (or part of food) that
provides medical or health benefits, including the prevention and/or treatment
of a disease”. In light of this situation the current study was taken up to
ascertain the position of soybeans in the nutraceutical world. The results of
the study have further strengthened the position of soybeans. Hence it can be
said that the daily consumption of the soy nutraceutical can prove to be
beneficial to the body.
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Received on 30.04.2010
Accepted on 13.07.2010
© A&V Publication all right reserved
Research J. Pharmacology and
Pharmacodynamics. 2(5): Sept.-Oct. 2010, 328-331