Vol.2, No.3, 175-183 (2010) Natural Science
http://dx.doi.org/10.4236/ns.2010.23027
Copyright © 2010 SciRes. OPEN ACCESS
The antioxidant activity and hypolipidemic activity of the
total flavonoids from the fruit of Rosa laevigata Michx
Yue-Tao Liu, Bi-Nan Lu, Li-Na Xu, Lian-Hong Yin, Xiao-Na Wang, Jin-Yong Peng*, Ke-Xin Liu
College of Pharmacy, Dalian Medical University, Dalian, China; jinyongpeng2005@163.com
Received 21 December 2009; revised 8 January 2010; accepted 30 January 2010.
ABSTRACT
In the present work, the antioxidant activity in
vitro and hypolipidemic activity of the total fla-
vonoids (TFs) from the Rosa laevigata Michx
fruit was evaluated, and the antioxidant effect in
vivo was also discussed. The TFs exhibited a
high scavenging effect on 2, 2-diphenyl-1-
picrylhydrazyl (·DPPH) with IC50 values 0.01 mg/mL,
and a stong reduce power in the test. Hyperli-
pemic mice were intragastric administrated with
TFs (25, 50 mg/kg/day) for 4 weeks, and fenofi-
brate was used as the positive reference sub-
stance. After the experiment, the levels of TC
(total cholesterol), TG (triglyceride), LDL- C (low
density lipoprotein-cholesterol) of the mice ad-
ministrated with high-dose of TFs were mark-
edly declined by 45.02%, 33.86% and 73.68%, re-
spectively, while HDL-C (high density lipopro-
tein-cholesterol) was significantly increased com-
pared with model group. To investigate the
hepatoprotective effect, histopathological assay,
ALT (alanine aminotransferase), AST (aspartate
aminotransefrase) and ALP (alkaline phosphatase)
were also studied, and the results showed that
TFs exhibited a favorable effect on liver protec-
tion, of which the levels of ALT, AST and ALP
were elevated by 55.85%, 29.15% and 25.68%,
respectively. Furthermore, the TFs could sig-
nificantly decrease the MDA (malondialdehyde)
level and improve the levels of CAT (Catalas),
SOD (superoxide dismutase), GSH (reduced
glutathione), and GPX (glutathione peroxidase)
compared with hyperlipemia mice. Our results
suggested that TFs has a high antioxidant ac-
tivity and hypolipidemic activity, which can be
used as a potential medicine for cardiovascular
diseases.
Keywords: Rosa laevigata Michx; Total Flavonoids;
Antioxidant Activity; Hypolipidemic Activity
1. INTRODUCTION
Many studies have proved that reactive oxygen species
(ROS) and free radicals play a vital role in maintaining
human health. When the balance between the generating
and scavenging of ROS and free radicals in vivo is de-
stroyed, an oxidative stress would happen, which might
lead to extensive oxidative damage to cellular bio-
molecules, such as DNA, proteins and lipids. Many
chronic-diseases, such as hyperlipemia, hyperpiesia and
cancer, have proved to be associated with the existence
of oxidative stress.
Hyperlipemia is considered as a risk factor involved in
the development of cardiovascular disease [1]. High
lipid levels can harden the arteries or speed up the proc-
ess of atherosclerosis. Nowadays, there are numerous
hypolipidemic drugs for clinical use, however, the
pharmacologists and chemists have been perplexing by
the characteristic profiles of toxic side effects including
numerous harmful syndromes [2,3], which can increase
the risk of heart disease, stroke, and other vascular dis-
eases. Thus, an investigation of hypolipidemic agents
with negligible side effect seems important. In recent
researches, there has been a growing interest in the in-
gredients of natural plants, vegetables and cereals, not
only for their radical-scavenging activities, but also due
to their neglectable physical side effects. There are nu-
merous herbal medicines exerting good hypolipidemic
actions with few side effects in Asian countries. Plant
materials have long been used as traditional medicines
for the treatment of a wide variety of ailments and dis-
eases, such as the polysaccharides from Lycium barba-
rum, Saponins in Ipomoea batatas tubers, total flavon-
oids of Litsea coreana leaf, the flavonoid-riched extract
from Eugenia jambolana seeds. Vast numbers of plants
have been shown to lower plasma lipid levels [4-7].
R. laevigata Michx is a famous medicinal plant in
China, and its fruit is widely used as the invigorator,
paregoric and astringent. Now chemical and pharmacol-
ogical researches have demonstrated that this medicinal
plant can cure hyperpiesia, chronic cough, and dermato-
gic disease, as well as inhibit experimental arterial scle-
rosis [8]. Flavonoids are primarily considered as the pig-
Y. T. Liu et al. / Natural Science 2 (2010) 175-183
Copyright © 2010 SciRes. OPEN ACCESS
176
ments responsible for the autumnal burst of hues and
many shades of yellow, orange and red in flowers and
food. The flavonoids have long been applied to possess
anti-inflammatory, antioxidant, antiallergic, hepatopro-
tective, antithrombotic, antiviral and anticarcinogenic
activities [9-11]. Up to now, the report about the antioxi-
dant activity and hypolipidemic activity of the flavonids
from this medicinal plant fruit was not discovered.
The major of the present work is to study the anti-
oxdant activity and hypolipidemic activity of the total
flavonoids (TFs) from the fruis of Rosa laevigata Michx
on hyperlipemic mouse. In the test, we measured the
diversity on biotical parameters on hyperlipidemic mice
and the antioxidant effect in vivo. This is the first cover
about it as far as we known.
2. MATERIALS AND METHODS
2.1. Plant Material
The dried fruit of R. laevigata Michx was purchased
from Yunnan Qiancaoyuan Pharmaceutical Company Co.
LTD (Yunnan, China), and authenticated by Dr. Yun-
peng Diao (School of Pharmacy, Dalian Medical Uni-
versity, Dalian, China). Voucher specimen was depos-
ited in College of Pharmacy, Dalian Medical University
(Dalian, China).
2.2. Chemicals
NaNO2, Al (NO3)3, NaOH, FeCl3, potassium ferricyanide,
cholesterol , sodium cholate (biochemical reagent), tri-
chloroacetic acid (TCA) and vitamin C (VitC) were pur-
chased from Shenlian Chemical Company (Shenyang,
China). Rutin was purchased from TCM institute of Chi-
nese Materia Medica (Nanjing, China). 2, 2-diphenyl-1-
picrylhydrazyl (·DPPH) was purchased from Sigma-
Aldrich (St. Louis, USA). Commercial kits used for de-
termination of TC (total cholesterol), TG (triglyceride),
HDL-C (high density lipoprotein-cholesterol), ALT
(alanine aminotransferase), ALP (alkaline phosphatase),
AST (aspartate aminotranse- frase), MDA (malondialde-
hyde), CAT (Catalase), SOD (superoxide dismutase),
GSH (reduced glutathione), and GPX (glutathione per-
oxidase) were all purchased from Jiancheng Institute of
Biotechnology (Nanjing, China). Fenofibrate was pur-
chased from Laboratoires Fournier S.A. (France). All the
chemicals were of analytical grade.
2.3. High-Fat Diet and Animals
High-fat diet was made according to the method de-
picted by Experimental methodology of pharmacology
[12], containing normal pulverized food (97.5%), cho-
lesterol (2%) and sodium cholate (0.2%). The cake was
cut into pieces and dried at room temperature for 3 days
before feeding to mouse.
Male Kunming mice were obtained from the Experi-
mental Animal Center of Dalian Medical University
(Dalian, China). The animals, weighted 20 ± 2g, were
group-housed and kept in a regulated environment at 25
± 1C and 60 ± 5% relatively humidity under 12 h
light/12 h dark conditions. The animals had free access
to water and normal or high-fat diet.
2.4. Preparation of TFs from the Medicinal
Plant
The fruit was ground into powder. Samples of 1.0 kg
were weighted and mixed with 60% aqueous ethanol
(solvent: sample= 8:1, v/w) for extraction. The process
was refluxed in haven for two times and 2 h for each.
The extracted solutions were filtered and evaporated to
1000 mL under reduced pressure at 60C. Then, 100 mL
of the residue was added into a glass column (4.0 cm×60
cm, contained 200.0 g D101 macroporous resin pur-
chased from the Chemical Plant of Nankai University,
Tianjin, China). The column was first washed by water
(600 mL) to remove the un-desired compounds, and then
the resin was eluted by 40% aqueous ethanol (800 mL)
to elute the targets. The 40% aqueous ethanol elution
was collected and evaporated under reduced pressure at
60C to dryness, and 5.44 g powder was produced,
which was stored in a refrigerator for subsequent ex-
periments.
2.5. Determination the Content of Tfs the
Medicinal Plant
The content of TFs was determined with a colorimetric
method described by China Pharmacopeia [13].
2.6. ·DPPH Radical Scavenging Activity
Assay
Different concentrations (0-1 mg/mL) of the TFs solu-
tions were produced by dissolving the samples in deion-
ised water. Each sample solution (2 mL) was mixed with
2 mL of ethanolic solution containing 2 × 10-4 mM ·DPPH.
The mixture was shaken vigorously and left to stand for
30 min in dark place, and then the absorbance was
measured at 517 nm against a blank [14]. VitC was used
as the positive control.
2.7. Reducing Power Assay
The reducing power was determined according to the
literature with some modifications [15]. VitC was used
as the reference compound.
2.8. Experimental Procedure
After 1 week of acclimatization to the home cage, the
mice were randomly divided into five groups with each
group containing 10 mice. Group I (controlled group):
animals were fed the normal laboratory diet daily for 4
weeks; Group II (model group): mice were fed the
Y. T. Liu et al. / Natural Science 2 (2010) 175-183
Copyright © 2010 SciRes. OPEN ACCESS
177
high-fat diet daily for 4 weeks; Group III (positive
group): mice were fed the high-fat diet plus fenofibrate
(50 mg/kg/day, i.g.) daily for 4 weeks; Group IV: mice
were fed the high-fat diet plus TFs (25 mg/kg/day, i.g.)
daily for 4 weeks; Group V: mice were fed the high-fat
diet plus TFs (50 mg/kg/day, i.g.) daily for 4 weeks.
During the experimental procedure, the treated animals
were given sufficient normal or high-fat diet.
2.9. Preparation of Biotical Samples and
Protein Assay
After the experiments, the mice were killed and then the
blood was collected, and the liver was quickly removed.
The collected blood was placed 30-40 min for clot for-
mation, and then the serum was separated by centrifuga-
tion at 3000 rpm for 15 min. Each liver tissue was imme-
diately rinsed with saline, blotted on filter paper, weighed
and finally stored at -70C pending biochemical analyses.
One part of liver was cut and put into a flasket containing
10% buffered formalin solution for the following histo-
pathology analysis. The other part of the liver tissues was
sampled quickly and washed with chilled normal saline
water. 10% (w/v) of tissue homogenate was prepared in
cold normal saline, and centrifuged at 3000 rpm at 4C
for 15 min, and the supernatants were preserved for the
next step assay. Lowry method [16] was employed to
measure the protein concentration in the homogenate
with bovine serum albumin as the standard.
2.10. Histopathological Assay
Liver tissues were fixed with 10% neutral formalin and
embedded in paraplast. Tissue sections (5 μm) were cut
and stained by hematoxylin and eosin.
2.11. Measurement of Biochemical
Parameters and Hepatic Enzymes in
Serum
The levels of TC, TG and HDL-C in serum were deter-
mined using enzymatic kits according to the manufac-
ture’s instructions. The LDL-C was estimated by the
method of Friedwald et al. [17]. ALT, AST and ALP
were all assayed using the corresponding commercial
kits.
2.12. Measurement of Hepatic Lipid
Peroxidation and Antioxidant
Enzymes
The assays of the levels of MDA, CAT, SOD, GSH and
GPX were measured following the kits’ instruction.
2.13. Statistical Analysis
All values were expressed as mean ± S.D. The signifi-
cance of differences between the means of the treated
and un-treated groups have been compared by one-way
analysis of variance (ANOVA), followed by Student’s
t-test and p-values less than 0.05 were considered sig-
nificant.
3. RESULTS
3.1. Tfs Purification Protocol
Before pharmacological investigation, the TFs from the
fruit of R. laevigata Michx were required to prepare. In
the present study, a kind of macroporous resin (MR)
named D101, which has been widely used to purify fla-
vonoids from medicinal plants as previously reported
[18,19], was selected to accomplish the work in this
study.
In MR column chromatography, 100 mL residue of
the extraction (1 g plant material/mL) was added into a
glass column (4.0 × 60 cm, containing 200 g D101 MR).
Water (600 mL) and different concentrations of aqueous
ethanol (10%, 20%, 30%, 40%, 50%, and 70%, each 600
mL) were used to elute the column in serials, and the
elution solutions were collected individually to produce
42 different fractions (100 mL for each fraction) (Figure
1(a)). All the fractions were evaporated to dryness under
reduced pressure at 50, and then the contents of the
Figure 1. (a) The elution curve of the TFs on D101 MR column using water and dif-
ferent concentrations of ethanol as the elution solvents; (b) The elution curve of the TFs
on D101 MR column using 40% aqueous ethanol as the elution solvent.
Y. T. Liu et al. / Natural Science 2 (2010) 175-183
Copyright © 2010 SciRes. OPEN ACCESS
178
TFs were determined. And then the recovery of every
concentrations of alcohol was calculated through sum-
ming every fraction in one concentration. It was obvious
that the flavonoids mainly existed in 10%, 20%, 30% and
40% aqueous ethanol elution solutions. There was nearly
nothing in water, 50%, and 75% aqueous ethanol solu-
tions. Thus, water was first used to elute the water solu-
ble chemicals, which were the undesired components and
not supposed to be retained on D101 MR. Then, 40%
aqueous ethanol was selected to elute the targets.
Secondly, the required amount of water to remove
undesired constituents and 40% aqueous ethanol to col-
lect the TFs were detrmined. When water was applied to
the column, each 100 mL was collected individually, and
then the contents of the TFs in each fraction were de-
tected. The results showed no flavonoid was eluted out
untill water volume increasing to 600 mL. However,
with more water was used, part of flavonoids appeared
in water. Therefore, 600 mL was set as the water quan-
tity to clean the column in our research. Then, 40%
aqueous ethanol was used to elute the flavonoids, and
each 100 mL of the ethanol solution was collected indi-
vidually and evaporated to dryness. The contents of the
TFs were determined. As shown in Figure 1(b), it was
apparently us that when 800 mL of 40% aqueous ethanol
was used to elute the column, almost all the TFs was
eluted out. Thus, it is reasonable to choose 800 mL as
the elution volume.
After optimization, the TFs purification was carried
out in triplicate as the mentioned protocol. The produc-
tion rate, purity and recovery of the TFs were obtained,
of which the production rate and the recovery were cal-
culated as the following formula.
1
2
Production rate%100%
W
W
() , where W1 repre-
sents the amount of the crude extract; W2 represents the
amount of plant material used for MR column chromatography.
Recovery (%)()100%
PW
CV

, where P is the pu-
rity of the TFs in crude extract; W represents the amount
of the crude extract; C is the TFs concentration in resi-
due before MR column chromatography, and V is the
volume of the residue added into the column for purifi-
cation. In the study, the production rate of the crude ex-
tract was 5.44 ± 0.07%, of which the content of the TFs
reach to 78.45 ± 2.41%.
3.2. ·DPPH Radical Scavenging Activity
DPPH, a stable free radical, has widely been used as a
substance to evaluate the antioxidant activity of various
samples. The method is based on the reduction of the
absorbance of ·DPPH solution at 517 nm in the presence
of proton-donating substance, due to the formation of the
diamagnetic molecule by accepting an en electron or
hydrogen radical [20]. The TFs exhibted good scaveng-
ing activities to scavenge the stable radical ·DPPH to
yellow-colored diphenyl picrylhydrazine in a dose de-
pendent. As shown in Figure 2(a), the TFs showed
strong scavenging activity on ·DPPH with no difference
compared with VitC, and the estimated IC50 value was
0.01 mg/mL. TFs can clear almost 90% of the radical at
0.15 mg/mL. From our test, the TFs can significantly
clear ·DPPH in vitro with a dose-depended manner from
0 to 0.15 mg/mL compatible with the positive drug.
3.3. Reducing Power Assay
The reducing power of a compound may serve as a sig-
nificant indicator of its potential antioxidant activity.
The absorbance at 700 nm was used to demonstrate the
reducing power. Increased absorbance of the reaction
mixture indicates increased reducing power of the sam-
ple. As shown in Figure 2(b), the reducing power of the
TFs increased slightly in a dose-depended manner when
Figure 2. (a) Scavenging effect of the TFs and VitC at different concentrations on DPPH. (b) Re-
ducing power of the TFs and VitC at different concentrations. Data was expressed as means ± S.D.
(n = 5).
a b
Y. T. Liu et al. / Natural Science 2 (2010) 175-183
Copyright © 2010 SciRes. OPEN ACCESS
179
then it reached a plateau. The reducing power of the TFs
was 0.812 at 0.025 mg/mL and 1.17 at 0.125 mg/mL.
However, VitC only showed slightly higher activity, with
the reducing power of 1.32 at 0.025 mg/mL and 1.45 at
0.125 mg/mL.
3.4. Histopathological Assay
As shown in Figure 3, histopathology of the liver in nor-
mal mouse (a) was that the central vein was surrounded
by hepatic cord of cells, while the liver of high-fat diet
treated mouse (b) showed patches of liver cell necrosis
with macrovesicular and microvesicular steatosis, and
massive fatty changes. Whereas, the livers of the animals
trested by fenofibrate (c) and TFs (E, 50 mg/kg/day)
showed the absence of vesicular steatosis to display good
hepatoprotective actions. The low-dose of TFs (d), 25
mg/kg/day) treated groups showed less vesicular steatosis.
Figure 3. Protective effect of TFs on liver injury induced by
high-fat diet in mice. (a) Group I; (b) Group II; (c) Group III;
(d) Group IV; (e) Group V. high-fat diet treatment induced
vesicular steatosis (black arrows). Hematoxylin and eosin
staining; Original magnification, ×100.
Table 1. Effect of TFs on serum lipid profile in experimental animals.
Group TC (mg/dL) TG (mg/dL) HDL-C (mg/dL) LDL-C (mg/dL)
I 72.63 ± 7.22 53.86 ± 9.19 48.44 ± 5.49 13.40 ± 4.27
II 143.33 ± 9.71b 100.1 ± 17.3 b 47.03 ± 4.84 83.55 ± 14.23 b
III 87.12 ± 7.31d 64.0 ± 8.41 d 63.09 ± 5.49 c 16.18 ± 7.06 d
IV 98.64 ± 15.74c 86.18 ± 4.15 c 64.11 ± 13.49 c 27.40 ± 16.53 d
V 78.8 ± 9.80 d 66.18 ± 4.75 d 63.84 ± 13.41 c 18.31 ± 3.40 d
Values are given as mean ± S.D. (n=10). a p<0.05 compared with Group I . b p < 0.01 compared with Group
I. c p < 0.05 compared with Group II. d p < 0.01 compared with Group II.
Table 2. Effect of TFs on serum liver enzymes in experimental animals.
Group ALT (IU/L) AST (IU/L) ALP (IU/L)
I 22.70 ± 3.40 27.70 ± 5.40 321.92 ± 130.33
II 102.60 ± 24.50b 76.50 ± 17.40 b 495.38 ± 126.02a
III 45.30 ± 18.0d 71.80 ± 14.86 336.77 ± 71.15 c
IV 91.00 ± 27.20c 60.29 ± 7.90 c 382.28 ± 83.69 c
V 45.8 ± 2.20 d 54.20 ± 17.5 c 368.16 ± 128.08 c
Values are given as mean ± S.D. (n=10). a p<0.05 compared with Group I . b p < 0.01 compared with Group
I. c p < 0.05 compared with Group II. d p < 0.01 compared with Group II.
Y. T. Liu et al. / Natural Science 2 (2010) 175-183
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180
3.5. Effects of TFs on Serum Lipid Profiles
As seen in Table 1, the serum levels of TC, TG, and
LDL-C were significantly increased in animals fed with
high-fat diet compared with those in Group I. The levels
of TC, TG and LDL-C of those animals given fenofi-
brate or TFs were significantly decreased compared with
hyperlipemic animals. High-dose of TFs (50 mg/kg/day)
was able to markedly eliminate TC, TG, and LDL-C by
45.02%, 33.86% and 73.68%, respectively, with no dif-
ference compared with the positive group. Although
there was no statistically significant difference in the
serum HDL-C levels between normal and hyperlipemia
mice, an increasing tendency was exhibited in the groups
administrated with TFs and fenofibrate.
3.6. Effect of TFs on Hepatic Enzymes
The levels of ALT, AST and ALP in serum were per-
formed to evaluate liver function. As can be observed in
Table 2, animals fed with high-fat diet exhibited a sig-
nificantly elevation in serum ALT, AST and ALP com-
pared with normal group, which suggested that the liver
was markedly damaged. Compared with hyperlipemic
mice, the activities of ALT, AST and ALP were reduced
to 55.85%, 29.15% and 25.68%, respectively, of the
animals treated by TFs at the dosage of 50 mg/kg/day,
which was no difference compared with fenofibate-treated
group. The results implied that the TFs executed a pro-
tective effect against liver damage induced by high-fat
diet.
3.7. Effect of TFs on Hepatic Lipid
Peroxidation
Figure 4 showed that the MDA levels of the liver in all
experimental groups. The hepatic MDA level of model
group was increased significantly compared with normal
group (p < 0.01). The decline extents of TFs-treated
Figure 4. Effect of TFs on hepatic level of MDA in mouse fed
with high-fat diet. Values are expressed as mean ± S.D. (n =
10). b p < 0.01 compared with Group I. c p < 0.05 compared
with Group II. d p < 0.01 compared with Group II.
groups (25 and 50 mg/kg/day) were 31.09% (p < 0.05)
and 53.65% (p < 0.01) compared with hyperlipemic mouse.
Meanwhile, there was no difference between fenofi-
brate- and TFs (50 mg/kg/day)-treated groups.
3.8. Effect of TFs on Hepatic Antioxidant
Enzymes
The variations of CAT, SOD, GSH and GPX in liver
among the experimental groups were shown in Figure 5.
Contrasting with normal animals, the levels of CAT,
SOD, GSH and GPX of the liver tissues were signifi-
cantly decreased after feeding high-fat diet for 4 weeks
(p < 0.05). Fenofibrate and TFs both could amend the
antioxidant status in vivo. The improvement capacity of
CAT and GPX was TFs (50 mg/kg/day) > fenofibate (50
mg/kg/day) > TFs (25 mg/kg/day). Furthermore, the
improvement capacities of SOD and GSH were fenofi-
bate (50 mg/kg/day) > TFs (50 mg/kg/day) > TFs (25
mg/kg/day).
4. DISCUSSIONS
Hyperlipemia is the largest endocrine disease in the
world, involving metabolic disorders of carbohydrate, fat
and protein. Therefore, it is necessary to search for new
drugs that can be used to amendment this metabolic dis-
order without any side effect. Oxidative stress is cur-
rently suggested as a mechanism underlying hyperli-
pemia, which is one of the major risk factors for coro-
nary artery diseases [21]. In our study, the TFs with high
flavonoids showed a good antioxidant activity in vitro,
which encouraged us to check the antioxidant activity in
vivo in hyperlipemic mice.
MDA, one of the lipid peroxidation products, could
make the deomosine between the cellulose molecular
relax or inhibit protein synthesis. The hepatic MDA level
significantly improved in hyperlipemia animals. In the
present experiment, the MDA level was significantly
decreased in mouse fed with TFs. These findings are in
accordance with those of other investigators [22].
Furthermore, Biological antioxidants are natural com-
pounds which can prevent the un-controlled formation of
free radicals and activated oxygen species, or inhibit their
reaction with biological structures. These compounds
include antioxidative enzymes exist in all oxy-
gen-metabolizing cells, such as superoxide dismutase
(SOD), catalase (CAT), glutathione peroxidase (GPX)
and non-enzymatic antioxidants, such as glutathione
(GSH), vitamin C and vitamin E [23]. The main role of
the CAT, mainly existing in some cells, is to catalytic the
decomposition of hydrogen peroxide [24]. It could pre-
vent hydrogen peroxide to form hydroxyl radical, which
is the most harmful radical in vivo [25]. SOD mutates the
superoxide radicals to form molecular oxygen and H2O2.
GPX, one of the most important hepatic detoxification
Y. T. Liu et al. / Natural Science 2 (2010) 175-183
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181
Figure 5. Effect of TFs on hepatic levels of CAT, SOD, GSH and GPX in mouse fed with high-fat
diet. Values are expressed as mean ± S.D. (n = 10). a p < 0.05 compared with Group I . b p < 0.01
compared with Group I. c p < 0.05 compared with Group II. d p < 0.01 compared with Group II.
elements [26], almost presents in the whole biological
tissues, especially the liver and RBC. It can scavenge
lipid peroxidation induced by hydroxyl radical, postpone
the aging of cells and clear the nucleic acid peroxide.
Moreover, GPX could remove hydrogen peroxide gener-
ating in the tissues. Meanwhile, GSH is the most impor-
tant biomolecule against chemically induced toxicity and
can participate in the elimination of reactive intermedi-
ates by reducing hydroperoxides in the presence of GPX
[27,28]. GSH also functions as a free radical scavenger
and in the repair of free radical-induced biological dam-
ages [28]. The decrease in the GSH level represents in-
creased utilization due to oxidative stress [29].
The efficiency of this defense system is apparently
weakened in hyperlipemia condition resulting in ineffec-
tive scavenging of free radicals and lipid peroxidantion
products, which can improve the levels of tissue lipid
profiles in vivo. The inhibition of CAT, SOD and GPX
activities are found to be involved in many degenerative
diseases. Likewise, in our study, high-fat diet caused a
markedly decrease in SOD, GPX, CAT activities and
nonenzymatic antioxidant (GSH) levels in test organs in
mice. These adaptive decreases in antioxidant enzyme
activities protect the organs against lipid peroxidation
mouse [30]. TFs significantly increased hepatic CAT,
SOD, GSH and GPX levels. Our data also showed that
TFs significantly reduced the hepatic MDA concentra-
tion in a dose-dependent manner. These results sug-
gested that, the antioxidative effect of TFs might reduce
oxidative stress, resulting in a lower lipid peroxidation in
liver. These results indicated that the antioxidative effect
of TFs in the liver may only be observed in the presence
of severe oxidative stress, suggesting that TFs may act as
a chemopreventive agent with inhibition activity on oxi-
dative-induced cell damage.
Elevated blood triglyceride and cholesterol, especially
low-density-lipoprotein cholesterol (LDL-C), is a major
risk factor in development of cardiovascular disease [31].
It is well-known that cholesterol is a fatty substance
which is important to the membrane of cells in the ani-
mal body. TC is a measure of the total amount of all
cholesterol in blood at a given time and is the sum of
HDL-C, LDL-C. TG composed of three fatty acids and
glycerol. Liking cholesterol, they circulate in blood, but
are stored in body fat and used when body needs extra
energy. HDL-C removes excess cholesterol from arteries
and moves it to liver for further processing or to be
eliminated from the body. The higher serum HDL-C is
the better. Therefore, the HDL-C is called ‘‘good’’ cho-
lesterol. It also plays a key role in the protection against
oxidative damage of membrane. LDL-C contributes to
buildup of fat deposits in the arteries (atherosclerosis),
which can cause decreased blood flow and head attack.
So it is always called ‘‘bad’’ cholesterol, and a less lev-
els are desirable. The value of AI indicates the deposi-
tion of foam cells or plaque or fatty infiltration or lipids
in heart, coronaries, aorta, liver and kidney. In this study,
TC, TG and LDL-C levels significantly increased in the
hyperlipemic animals fed a high-fat diet for 4 weeks, but
with no significantly decreased in HDL-C level (Table
1). All these results showed that the mouse hyperlipemic
model was established successfully by feeding a high-fat
Y. T. Liu et al. / Natural Science 2 (2010) 175-183
Copyright © 2010 SciRes. OPEN ACCESS
182
diet for 4 weeks. After the experiment, the animals ad-
ministration of fenofibrate and TFs were all exhibited a
decrease tendency (p < 0.05). As to the data of HDL-C
in the experiment, there was also a remarkable increase
of the serum HDL-C levels in the mouse fed a high-fat
diet for 4 weeks. The increase of ‘good’ cholesterol does
not mean high-fat diet is favorable to serum lipid profile
levels, because the increase of ‘good’ probably does not
surpass that of ‘bad’, which has negative effects on
lipid-lowering. In summary, the administration of TFs
could decrease the serum levels of TC, TG and LDL-C.
The liver is capable of removing cholesterol from the
blood circulation as well as manufacturing cholesterol
and secreting cholesterol into the blood circulation and
liver damages are generally induced in the condition of
hyperlipemia as dramatic increase of serum ALT and
AST levels. Furthermore, ALP, one of hepatic enzymes,
also reflects the damage induced by high-fat diet. In our
test, the damage to liver induced by high-fat diet was
also investigated, which included hepatic enzymes and
histopathological examination. These results indicated
that TFs was characterized by an ameliorating effect on
fatty liver.
5. CONCLUSIONS
The present study demonstrated TFs from R. laevigata
Michx has favorable potency to develop a hypolipidemic
and hepatoprotective activities, of which the levels may
be mediated, in part, by enhancing the system of anti-
oxidant defense. It can be used as a potential medicine
for cardiovascular diseases. The toxicity, clinical appli-
cation, and chemical constituents of TFs are not clear
and need further investigation.
6. ACKONWLEDGEMENT
This research was supported by funds of Liaoning BaiQianWan Talents
Program, Liaoning, China.
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