World Applied Sciences Journal 21 (10): 1445-1452, 2013
ISSN 1818-4952
© IDOSI Publications, 2013
DOI: 10.5829/idosi.wasj.2013.21.10.72160
Hepatoprotective Effect of Avocado Fruits Against Carbon
Tetrachloride-Induced Liver Damage in Male Rats
1
Mohamed Y. Mahmoed and 2Amr A. Rezq
Department of Home Economics,
Faculty of Education, Suez Canal University, Egypt
2
Department of Nutrition and Food Science,
Faculty of Home Economics, Helwan University, Cairo, Egypt
1
Abstract: Avocado is highly nutritious fruit, having curative effects for many human ailments, from diarrhea
to high blood pressure due to assortment of vitamins, high in monounsaturated fat and potassium. The present
study aimed to identify types and concentration of phenolic and flvonoid compounds in avocado fruits
andinvestigate itshepatoprotective effect in carbon tetrachloride-induced liver damaged in male rats. Serum
biochemical parameters as aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline
phosphatase (ALP),total protein (TP), total and direct bilirubin,malondialdehyde (MDA) and reduced
glutathione (GSH) levels as well as the activities of superoxide dismutase (SOD) glutathione peroxidase (GPx)
and catalase (CAT) enzymes were determined. The experiment was conducted for 4 weeks on forty male rats
weighing 200±5 g.Animal were divided into five groups, eight rats each. Group (1) was normal healthy rats fed
on basal diet and served as a negative control group. Groups (2), (3), (4) and (5) were given a single
subcutaneous injection of CCL4 (2 ml/kg). Group (2) was kept as a positive control group. Groups (3), (4) and
(5) were fed on supplemented diets with 5, 10 and 15% dried avocado fruits.Results indicated thatdetected
phenolicscompounds in avocado wereferulic, salycilic, syrengic, P–coumaric and cinnamic acids and
flavonoidscompounds werequerectin, luteolin, rutin, kamferol and hypersoid acid.Avocado caused significant
decrease in serum concentrations of AST, ALT, ALP, TP, total and direct bilirubin and MDA andsignificant
increase the activity of SOD, GPX and CAT enzymes compared with that of the positive control rats.
Histological study showed slight hydropic degeneration of hepatocytes in treated rats with 5 and 10% of
avocado andno pathological changes in some liver sections of treated rats with 10% as well as those treated
with 15%. The present study concluded that avocado fruit effectively improved liver functions and antioxidant
system due to its phenloic and flavonids compounds.
Key words: Liver Functions
Antioxidant Enzymes
INTRODUCTION
Liver is the largest internal organ in human body.
It processes and stores many of the nutrients absorbed
from the intestine that are necessary for body functions.
Some of these major functions include protein,
carbohydrate and fat metabolism. It also secretes bile into
the intestine to absorb nutrients [1]. The liver is the first
organ to encounter ingested nutrients,drugs and
environmental toxicants that enter the hepaticportal vein
Carbon Tetrachloride
from the digestive system and liver functioncan be
detrimentally altered by injury resulting fromacute or
chronic exposure to toxicants [2].
Avocado is the most commonly sold fruits in the
world [3] and its nutritional content depends on fruit
variety and theseason of the year [4]. Avocado contains
one to two times more proteinthan any other fruits.
It hashigher content of iron, phosphorous, manganeseand
potassium, while it is low in sodium.Avocado is loaded
with nutrients such as vitamins E, C, thiamin, riboflavin,
Corresponding Author: Amr Abd-Elmordy Rezq, 65 Elmatba Elahlia Street, Bolaq Abu Elaala, College of Home Economics,
Helwan University, Cairo, Egypt.
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nicotinic acid and folate as well as -carotene [3]. It is an
excellent source of monounsaturated fat and is a good
source of the essential linoleic acid [5]. It contains several
structuralpolysaccharides,
including cellulose and
lignin (insoluble fiber) andhemicelluloses and pectin
(soluble fiber) [6].
Previous study reported that avocado have effect on
blood serum cholesterol levels. Itdecreases total serum
cholesterol levels, LDL and triglycerides and increase
HDL in hypercholesterolemia patients [7]. It has also been
showed that anavocado extracts improved calcium
absorption and significantly improved lycopene,
lutein and carotenes absorption in healthy human
subjects [8]. Avocado has a positive influence
on short-term memory. It is rich in serotonin
5-hydroxytryptamine (5-HT) which is a monoamine
neurotransmitter [9]. Recently, Ali et al. [10] reported that
avocado fruits provide curative effects for a number of
human ailments, from diarrhea to high blood pressure due
to assortment of vitamins, highin monounsaturated fat
and potassium.
The present study aimed to identify types and
concentrations of phenolic and flavonoid compounds in
avocado fruits andinvestigatehepatoprotectiveactivitiesof
avocado fruit against carbon tetrachloride (CCl 4)-induced
liver damage, in rats.The hepatoprotective activity was
assessed using various serum biochemical parameters
AST, ALT, ALP, TP, direct and indirect bilirubin, MDA
and GSH level as well as the activities of SOD, GPX and
CAT were determined to explain the possible mechanism
of activity. The hepatoprotective activity was also
supported by histopathological studies of liver tissue.
MATERIALS AND METHODS
Materials
Avocado Fruit: Freshly avocado fruit (cv. Fuerte)
waspurchased from the local market, Cairo, Egypt.
Rats and Diet: Forty male Sprague-Dawley rats weighing
200±5 g were purchased from the Laboratory Animal
Colony, Ministry of Health and Population, Helwan,
Egypt. Basal diet constituents were obtained from
El- Gomhorya Company for Chemical and Pharmaceutical,
Cairo, Egypt.
Chemicals: Carbon tetrachloride(CCl4) was purchased
from El-Gomhorya Company for Chemical and
Pharmaceutical, Cairo, Egypt. Kits for biochemical
analysis of serum AST, ALT, ALP, total protein (TP), total
and direct bilirubin, MDA and GSH as well as the activity
of, GPX, SOD and CAT enzymes were purchased from the
Gamma Trade Company for Pharmaceutical and Chemicals,
Dokki, Egypt.
Methods
Preparation of Avocado Fruit: The fresh avocado fruit
were washed with tap water to remove possible potential
pathogenic microorganisms and dust. Afterwards, the
fruit was dried by cotton cloth to remove the excess
liquid prior. The clean fruitwas cut into thin slice,
removing the seed, skin and any blemished portions.
Then, fruitpulpwas soakedin a solution prepared with
added lemon juiceto prevent enzymatic browning action,
to drying. Dried pulps were achieved at 60°C for 1.30 hour
usingvacuum oven.
Identification Types and Concentrations of Phenolic and
Flavonoid Compounds: Separation and determination of
avocado fruit phenolic compounds were done using
HPLC as described by Goupy et al. [11]. Identification
types and concentration of flavonoidswere performed
using HPLC as described by Mattila et al. [12].
Preparation of Basal Diet: The basal diet (AIN-93M) was
prepared according to Reeves et al. [13]. Diet was
formulated to meet the recommended nutrients levels for
rats.
Study Design and Grouping of Rats: The experiment was
conducted on forty male rats weighing approximately
200±5 g for 4 weeks. The animals were housed in healthy
condition at room temperature (20-25°C), exposed to a
12:12-h light-dark cycle and fed on the basal diet and
water was provided ad libitum for one week before
starting the experiment for acclimatizationand then was
divided randomlyinto five groups of eight rats each.
Rats infirst group were healthy and fed on basal diet and
served as a negative control group (-ve). Animals of
groups (2), (3), (4) and (5) were given a single
subcutaneous injection of CCL4 (2 ml/kg) according to the
method described by Sundaresan and Subramanian [14].
The second group kept as a positive control group (+ve)
and fed only on the basal diet. The third, fourth and fifth
groups fed on supplemented diets with 5, 10 and 15%
dried avocado fruits.
At the end of the experimental period (4 weeks),
animals were fasted for 12 hr (except of water) and then
rats were sacrificed.Serum samples were collected for the
biochemical analysis. Liver samples were collected from all
rats, washed with saline solution, dried and kept in
formalin solution (10%) for histopathological examination.
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Biochemicalassay: Serum AST, ALT, ALP, TP and total
and direct bilirubin concentrations were determined using
colorimetric methods as described in the kits instruction
(Diamond Co, Hannover, Germany). The absorption of the
test samples were read at 505nm for AST and ALT, 510 nm
for ALP, 546 nm for TP, 578 nm for total bilirubin and 546
for direct bilirubin.
Serum MDA level was determined as described
byDraper and Hadley [15]. The principle of the methods
is spectrophotometric measurements of the color
produced by the reaction of thiobarbituric acid (TBA)
with MDA. The concentration of MDA was then
calculated as expressed as µmoles/dL.
Serum reduced glutathione concentration (GSH) was
measured by the method described by Beutler et al. [16].
This method depends on spectrophotometric estimation
at 412 nm. The concentration of GSH was calculated as
expressed as µmoles/dl.
Serum activity of SOD,GPX and CAT enzymes were
determined by Autoanalyzer (Roche-Hitachi, Japan) using
commercial kits according to the methods described by
Kakkor et al. [17], Hissin and Hiff [18] and Sinha [19],
respectively.
Histopathological Examination: The liver of the sacrificed
rats were taken and immersed in 10% formalin solution.
The fixed specimens were then trimmed, washed and
dehydrated in ascending grades of alcohol. Specimens
were then cleared in xylol, embedded in paraffin, sectioned
at 4-6 microns thickness, stained with Heamtoxylin and
Eosin stain for histopathological examination as described
by Carleton [20].
Statistical Analysis: The obtained results were expressed
as Mean±SD. Data were evaluated statistically with
computerized SPSS package program (SPSS 6.00
software for Windows). Phenolic and flavonoid
compounds were statistically analyzed using t-test
method, while data of biochemical analysis were
evaluated statistically using one-way analysis of variance
(ANOVA). Significant difference among means was
estimated at p<0.05.
RESULTS
Table 1 presents the findings upon types and
concentrations of phenolic compounds in avocado fruit.
Data revealed that avocado fruit has ferulic, salycilic,
syrengic, P-–coumaric and cinnamic acids, which were at
concentrations of 6.050±0.01, 8.010±0.01, 4.390±0.01,
Table 1: Types and concentrations of polyphenolic compounds
Phenolic compounds
Concentrations (ppm) as Mean±SD
Ferulic acid
6.050 ±0.01
Salycilic acid
8.010 ±0.01
Syrengic acid
4.390 ±0.01
P-coumaric acid
0.164 ±0.01
Cinnamic acid
0.983±0.01
Table 2: Types and concentrations of flavonoid compounds
Flavonoid compounds
Concentrations (ppm) as Mean ±SD
Querectin
9.447±0.001
Luteolin
5.626±0.001
Rutin
0.135±0.001
Kamferol
8.993±0.01
Hypersoid acid
0.987±0.02
Table 3: Serum concentrations of AST, ALT and ALP in normal and
hepatotoxicity rats
Serum levels as Mean±SD
-----------------------------------------------------------Animal groups
AST (mg/dL)
ALT (mg/dL)
ALP (mg/dL)
Negative group
27.27±0.24e
24.01±0.20e
49.41±0.31 e
45.41±0.49a
50.54±0.94a
81.24±0.97a
41.60±0.47b
43.35±0.67b
68.20±0.39b
with avocado fruit 10% 36.43±0.64c
37.50±0.76c
57.12±0.40c
15% 30.25±0.24d
32.29±0.74d
51.64±0.54d
Positive group
Treated groups
5%
Means with different superscripts letters are significant at p<0.05.
A uses harmonic mean sample size = 8 rats.
0.164±0.01 and 0.983±0.01 ppm, respectively. Ferulic and
salycilicacids were the most abundant phenolic
compounds, the moderate abundant was syrengic acid
and the lowest abundant was P–coumaric and cinnamic
acids.
Table 2 gives the types and concentrations of
flavonoid compounds in avocado fruit. It obvious that
querectin and kamferol were the abundant flavonoid
compounds, which were at concentration of 9.447±0.001
and
8.993±0.01
pmm,
respectively.
Luteolin
(5.626±0.001ppm) was the moderate abundant, while the
lowest abundant was rutin (0.135±0.001ppm) and
hypersoid acid (0.987±0.02 ppm).
Table 3 shows that serum levels of AST, ALT and
ALP (45.41±0.49, 50.54±0.94 and 81.24±0.97 mg/dl,
respectively) were significantly higher at p< 0.05 in
untreated rats (positive control rats), compared with the
normal control rats (27.27±0.24, 24.01±0.20, 49.41±0.31
mg/dl, respectively). Administration of avocado fruit at
the three testes levels induced significantly lower at p
<0.05 in serum AST, ALT and ALP concentrations,
compared with untreated rats. These decreases were more
detectable with increasing level of avocado fruit.
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Table 4: Serumconcentrations of total protein, total bilirubin and direct
bilirubinin hepatotoxicity rats
Serum levels as Mean±SD
-----------------------------------------------------------Total
Total bilirubin Direct bilirubin
Animal groups
protein (g/dl) (mg/dl)
(mg/dl)
Normal group
7.10±0.11e
0.36±0.02e
0.50±0.01e
Positive group
9.42±0.10a
0.76±0.01a
0.90±0.02 a
8.83±0.03
b
0.69±0.01
b
0.79±0.02b
with avocado fruit 10% 8.04±0.10
c
0.55±0.01
c
0.60±0.02 c
0.40±0.01d
0.54±0.02d
Treated groups
5%
15% 7.46±0.10d
Means with different superscripts are significant at p<0.05.
A uses harmonic mean sample size = 8 rats.
Table 5: Serum
concentrations
of
malondialdehyde
and
reduced
glutathionein normal and hepatotoxicity rats
Serum levels as Mean±SD
------------------------------------------MDA
GSH
Animal groups
(µmol/dl)
(µmol/dl)
Normal group
1.25±0.02e
41.27±0.02a
Positive group
2.28±0.01
a
27.44±0.01e
32.36±0.17d
Treated groups
5%
2.02±0.01
b
with avocado fruit
10%
1.92±0.01
c
37.25±0.10c
15%
1.64±0.01d
40.54±0.01b
Means with different superscripts letters are significant at p<0.05.
A uses harmonic mean sample size = 8 rats.
Table 6: Serum activity of superoxide dismutase, glutathione peroxidase
and catalaseenzymesin normal and hepatotoxicity rats
Serum levels as Mean±SD
------------------------------------------------------SOD
GPX
CAT
Animal groups
(mmol/dl)
(µmol/dl)
(mmol/dl)
Normal group
93.75±0.01a
17.78±0.04a
Positive group
65.54±0.01
7.29±0.04
Treated groups with
5%
feeding avocado fruit 10%
15%
e
73.75±0.01d
e
65.64± 0.26a
44.51± 0.10e
11.32±0.01d
50.45± 0.12d
84.70±0.004c 15.82± 0.02c
58.53±0.18 c
91.85±0.01b
61.89± 0.10b
17.76±0.1b
Means with different superscripts letters are significant at p<0.05.
A uses harmonic mean sample size = 8 rats.
Table 4 shows the effect of feeding diets
supplemented with different levels of avocado fruit
(5, 10 and 15%) on serum levels of totalprotein and total
and direct bilirubin. The present results indicated that
positive controlrats had significant higher level (p<0.05)
of serum totalprotein and total and direct bilirubin
(9.42±0.10 g/dl, 0.76±0.01mg/dl and 0.90±0.02 mg/dl,
respectively), compared with those of the normal rats
(7.10±0.11 g/dl, 0.36±0.02 mg/dl and 0.50±0.01mg/dl
respectively). Affected rats treated with supplemented
diets with avocado fruit ingroups 3,4 and 5 had significant
lower levels (p<0.05) of serum totalprotein and total and
direct bilirubin levels, compared with those of the positive
control group. The decreased in serum totalprotein and
total and direct bilirubin levels were increased with
increasing avocado fruit level.
The results of the effect of three different levels of
avocado fruit on serum MDA and GSH levels in
experimental rats is recorded in Table 5. Results showed
that untreated rats had significant increaseat p<0.05 in
serum MDA level (2.28±0.01µmol/dl), compared with
those ofthe normal rats (1.25±0.02µmol/dl). Affected rats
fed on supplemented diets with avocado fruit had
significant decrease at p<0.05 in serum levels of MDA,
compared with the untreated hepatotoxicity rats fed on
normal diet.
Values of serum GSH level in untreated hepatotoxicity
rats weresignificantly lower at p<0.05 (27.44±0.01 µmol/dl),
compared with those of the normal rats (41.27±0.02
µmol/dl). Supplemented diets with the three different
levels of avocado fruit caused significant reduce (p<0.05)
in serum GSH level in hepatotoxicity rats, compared with
those of untreated hepatotoxicity rats fed on normal diet
only. Results also indicated that the decreases in serum
MDA levels and the increases in serum GSH levels were
more detectable with increases avocado fruit level.
Concerning the effect of avocado fruit on antioxidant
system in affects rats (Table 6) results revealed that
untreated rats G2 had significantly p<0.05 lower values of
SOD, GPX and CAT enzymes (65.54±0.01 mmol/dl,
7.29±0.04 µmol/dl and 44.51±0.10mmol/dl, respectively),
compared with those of the normal healthy rats
(93.75±0.01 mmol/dl, 17.78±0.04 µmol/dl and 65.64±0.26
mmol/dl, respectively). Administration of avocado fruit at
the three different levels (5, 10 and 15%) induced
significantlyhigherin serum activity of SOD, GPX and
CAT enzymes, compared with those of untreated
hepatotoxicity rats. It obvious that, the increasesin serum
activity of antioxidant enzymes (SOD, GPX and CAT)
were more detectable with increases avocado fruit levels.
Histopathological examination showedno histological
change in the liver structure of normal control rats
(Figure 1). Hepatic degeneration of hepatocytes was
showed in the liver sections ofaffected hepatotoxicity rats
(Figures 2). Examined liver sections of hepatotoxicity rats
treated with 5 and 10% of avocado fruit revealed the
presence of slight hydropic degeneration of hepatocytes
as shown in Figure 3, whereas, other sections of treated
rats with 10% of avocado fruit were nearly normal
hepatocytes. Affectedrats treated with avocado fruit at
level of 15% had apparent normal hepatocytes.
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Fig. 1: Livers of negative rats showing the normal
histological structure of hepatic lobular (H and E
x 200).
Fig. 2: Livers of positive rats showing hepatic
degeneration of hepatocytes (H and E x 200).
Fig. 3: Livers of treated groups with 5 and 10% of
avocado fruits showing slight hydropic
degeneration of hepatocytes (H and E x 200).
DISCUSSION
The present study achieved to screening types and
concentration of phenolic and flavonoid compounds in
avocado fruit. In addition to investigate of
hepatoprotective activity of avocado fruit against carbon
tetrachloride (CCl4)-induced liver damage in rats.
The observed finding revealed that phenolic
compounds in avocado fruit wereferulic, salycilic,
syrengic, P–coumaric and cinnamic acids andflavonoid
compounds were querectin, luteolin, rutin, kamferol and
hypersoid acid. Rodriguez Carpena et al. [21] analyzed
and classified phenolic compounds in two avocado
varieties as catechins, (sum of catechin and epicatechin),
hydroxybenzoic acids (p-coumaric, caffeic, ferulic and
sinapic), hydroxycinnamic acids (p-hydroxybenzoic,
protocatechuic, vanillic, syringic and gallic), flavonols and
procyanidins (sum of dimers, oligomers and polymers).
Recently, Maria et al. [22] reported that protocatechuic
acid was the main phenolic compound identified, followed
by kaempferide and vanillic acid. In addition, clorogenic
acid, syringic acid, rutin and kaempferol were present in
small amounts.
Liver is one of the vital organs in the body and it is
responsible for detoxification of toxic chemicals
and drugs. Thus it is the target organ for all toxic
chemicals. Carbon tetrachloride is one of the most
commonly used hepatotoxins in the experimental
studyof liver disease [23]. It is widely used to induce
liver damage because it is metabolized in hepatocytes
by cytochrome P450, generating a highly reactive
carbon centeredtrichloromethy radical, leading to lipid
peroxidation and thereby causing liver fibrosis [24].
The hepatoprotective activity of avocado fruits was
assessed using various serum biochemical parameters as
AST, ALT, ALP, total proteins and total and direct
bilirubin. Malondialdehyde level as well as the activities
of GSH, SOD, GPX and CAT was determined to explain
the possible mechanism of activity. The hepatoprotective
activity was also supported by histopathological studies
of liver tissue.
The present study showed that positive rats havea
significant increase in serum concentration of AST, ALT,
ALP, total protein, total and direct bilirubin and MDA,
while serum concentration of GSH and activity of SOD,
GPX and CAT enzymes were significantlylowerthan that
in the normal control group.These results were in
accordance with Naik and Panda [25] who mentioned
that increased serum levels of AST, ALT and ALP in
CCl4-treated animals is an indicator of liver damage as
these enzymes leak out from liver into the blood at the
instance of tissue damage, which is always associated
with hepatonecrosis. Burtis [26] indicated that bilirubin
is a breakdown product of hemoglobin, which is
transported from the spleen to the liver and excreted
into bile. However, hyper-bilirubin a direct result of
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hepatocellular damage. Augustinian et al. [27] found that
CCl4 initiates lipid peroxidation and reduces tissue CAT
and SOD activities. These results were confirmed by
Ruidong et al. [28] who demonstrated that MDA levels in
the CCl4-treated group as indicators of lipid peroxidation
were significantly higher than that in the normal control
group. In addition to CCl 4 treatment resulted in the
depletion of antioxidant enzymes as indicated by the
depletion in the activities of SOD, CAT, GSH-Px in
heptotxic rats.
In the present study, histopathological investigation
was used to confirm the effect of the treatment on liver
tissues. It observed hepatic degeneration of hepatocytes
in the liver sections of positive control rats. These finding
was agreed with the previously reported which mentioned
that CCl4 causes liver cirrhosis [29], fibrosis
andmononuclear cell infiltration [30], necrosis and
apoptosis [31], steatosis, degeneration ofhepatocytes and
increase in mitotic activity [32].
The body counter the effectof free radicals by
endowed with antioxidants. These antioxidants are
produced either endogenously or received from
exogenous sources and include enzymes like superoxide
dismutase, catalase, glutathione peroxidase and
glutathione reductase and. Other compounds with
antioxidant activity include glutathione, flavonoids [33]
which protect cells against oxidative stress [34].
The present data demonstrated that feeding
supplemented diet withthe three different levels of
avocado fruit effectively improved liver functions and
protected against liver tissues damage as well as
protected against the loss of antioxidant activities
induced by Ccl4 injection. These results was confirmed by
the significantly lower in serum concentration of AST,
ALT, ALP, total protein, total and direct bilirubin and
MDA and significantlyhigher inthe activity of SOD, GPX
and CAT enzymes compared with that of the positive
control rats. In addition to the improvement in liver
tissues as indicated by slight hydropic degeneration of
hepatocytes in treated rats with 5 and 10% of avocado
fruit and apparent normal hepatocytes in some sections of
treated rats with 10% of avocado and treated rats with
15% of avocado.These improvements in the biochemical
parameters and liver tissues were dose dependent.
These results mean that rats feeding avocado fruits
have a protective mechanism against dangerous of
oxidative stress caused by Ccl4 injection due to its
phytochemicals compounds (phenloic and flavonids).
There have been extensive studies on the effect of
phytochemicals present in food on drug-metabolising
enzymes through which they offer protection against
carcinogens and toxins. Paradoxically, the phase I
drug-metabolising
enzymes
induced by these
phytochemicals can also activate some biologically
inactive compounds to become toxic derivatives
(namely CCl4) and they can also metabolise drugs rapidly
and reduce their effectiveness in the treatment of diseases
[35].
The mechanism by which avocado fruits improve
liver functions may be attributed
to
protective
antioxidant mechanismswhich employ both enzymatic
(such as catalase) and non-enzymatic substances
(such as phenolic and flavones) [3]. Moreover, Terpinc
et al. [36] reported that flavonoids, rutin, catechin and
quercetin are widespread in nature and may act as
powerful antioxidants. These findings and our results
provide evidence for the importance of phenolic and
flavonoids present in avocado.
Flavonoid and phenolic compounds possess
antioxidants which have free radical scavenging
mechanism and potential alteration of physiological
antioxidant status and imbalance in the free radical
defense enzymatic system [37]. They have been shown
tostimulate synthesis of antioxidant enzymes and
detoxification systemsat the transcriptional level, through
antioxidant response elements [38]. Phenolic compounds
are plant secondary metabolites, which play an important
role in a disease resistance [39]. Phenolic compounds
could be a major determinant of antioxidant potentials of
food items [40] and could therefore be a natural source of
antioxidants. Flavonoids contribute to different extents to
the beneficial health effects due to its antioxidant
potential and the modulation of multiple cellular
pathways that are crucial in the pathogenesis diseases
[41]. The biological activities of the flavonoids are related
to their antioxidant activity by various mechanisms, e.g.
by scavenging or quenching free radicals, by chelating
metal ions, or by inhibiting enzymatic systems responsible
for the generation of free radicals [42]. The flavonoid
luteolin has been shown to possess direct antioxidant
activity, it is useful in treatment of many chronic disease
associated with oxidative stress. Luteolin treatment
involved changes in SOD activity, MDA content and
expression of Heme Oxygenase-1 (HO-1) protein [43].
CONCLUSIONS
Avocado fruit effectively improved liver functions
and protected against liver tissues damage induced by
toxic substances. Avocado fruits have protective effect
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against the loss of antioxidant activities as result of
oxidative process caused by CCl4 injection due to its
phytochemicals compounds (phenloic and flavonids).
This protective activity of avocado fruit suggests that
regular consumption of it or food containing phenoilc and
flavonoids may protect against liver disease and
imbalanced antioxidant. Thus, the possibility that
avocado reduce the risk of liver disease and oxidation
process remains open and further longitudinal studies are
needed to confirm the importance of it in the prevention
of liver disease.
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