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Oil palm phenolics and vitamin E reduce atherosclerosis rabbits

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  • Malaysian Palm Oil Council (MPOC)

Abstract and Figures

The protective effects of oil palm vitamin E and phenolics against atherosclerosis, either singly or in combination, were studied in an atherogenic rabbit model. Rabbits were either fed atherogenic diet only (CTR), or atherogenic diet with vitamin E (VIT E), or atherogenic diet with oil palm phenolics (OPP), or atherogenic diet with both vitamin E and oil palm phenolics (VIT E + OPP). Results from lipid profile and antioxidant analyses were not signif-icantly different between groups (p > 0.05). However, fibrous plaques were associated with the CTR group (8.90 ± 5.41%) and these were significantly less (p < 0.05) in the VIT E (2.88 ± 2.01%) and OPP (1.48 ± 4.45%) groups. Fibrous plaques were not detected at all in the VIT E + OPP group. Our findings suggest that oil palm vitamin E and oil palm phenolics individually inhibited atherosclerotic lesion development. However, oil palm vitamin E in combination with oil palm phenolics provided the highest protective effect against devel-opment of atherosclerotic lesions. Ó 2014 Published by Elsevier Ltd.
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Oil palm phenolics and vitamin E reduce
atherosclerosis in rabbits
Che Anishas Che Idris
a,b
, Tilakavati Karupaiah
b
, Kalyana Sundram
c
,
Yew Ai Tan
a
, Nagendran Balasundram
a
, Soon-Sen Leow
a
,
Nurrul Shaqinah Nasruddin
d
, Ravigadevi Sambanthamurthi
a,*
a
Malaysian Palm Oil Board, 6, Persiaran Institusi, Bandar Baru Bangi, 43000 Kajang, Selangor, Malaysia
b
National University of Malaysia, Jalan Raja Muda Aziz, 50300 Kuala Lumpur, Malaysia
c
Malaysian Palm Oil Council, 2nd Floor, Wisma Sawit, Lot 6, SS6, Jalan Perbandaran, 47301 Kelana Jaya, Selangor, Malaysia
d
Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
ARTICLE INFO
Article history:
Received 1 April 2013
Received in revised form
24 December 2013
Accepted 3 January 2014
Available online xxxx
Keywords:
Atherosclerosis
Oil palm phenolics
Lipid profiles
Antioxidant activity
ABSTRACT
The protective effects of oil palm vitamin E and phenolics against atherosclerosis, either
singly or in combination, were studied in an atherogenic rabbit model. Rabbits were either
fed atherogenic diet only (CTR), or atherogenic diet with vitamin E (VIT E), or atherogenic
diet with oil palm phenolics (OPP), or atherogenic diet with both vitamin E and oil palm
phenolics (VIT E + OPP). Results from lipid profile and antioxidant analyses were not signif-
icantly different between groups (p> 0.05). However, fibrous plaques were associated with
the CTR group (8.90 ± 5.41%) and these were significantly less (p< 0.05) in the VIT E
(2.88 ± 2.01%) and OPP (1.48 ± 4.45%) groups. Fibrous plaques were not detected at all in
the VIT E + OPP group. Our findings suggest that oil palm vitamin E and oil palm phenolics
individually inhibited atherosclerotic lesion development. However, oil palm vitamin E in
combination with oil palm phenolics provided the highest protective effect against devel-
opment of atherosclerotic lesions.
Ó2014 Published by Elsevier Ltd.
1. Introduction
The terms nutraceuticals and functional foods have been
used to describe extracts and whole foods that have the char-
acteristics of providing protective, preventive and possibly
curative effects in the pathogenesis of cancer and other
chronic disease progression. Both nutraceuticals and func-
tional food groups provide benefits beyond what are rendered
by their nutrient components (Shahidi, 2005). The oil palm
(Elaeis guineensis) has various functional phytochemicals, thus
making it valuable as a source for the production of nutraceu-
ticals and functional foods (Tan, Sambanthamurthi,
Sundram, & Wahid, 2007).
The presence of several fat-soluble micronutrients in palm
oil such as vitamin E, carotenoids and phytosterols contrib-
utes to its pleiotropic nutritious profile. The oil palm fruit
1756-4646/$ - see front matter Ó2014 Published by Elsevier Ltd.
http://dx.doi.org/10.1016/j.jff.2014.01.002
*Corresponding author. Tel.: +603 8769 4498; fax: +603 8926 1995.
E-mail address: raviga@mpob.gov.my (R. Sambanthamurthi).
Abbreviations: ABTS
Æ+
, 2,20-azinobis (3-ethylbenzothiazoline) 6-sulphonic acid radical cation; ANOVA, analysis of variance; CTR,
control; E
o
, E-deficient; Fe
2+
-TPTZ, ferrous-2,4,6-tripyridyl-S-triazine; Fe
3+
-TPTZ, ferric-2,4,6-tripyridyl-S-triazine; FRAP, ferric reducing
ability of plasma; GAE, gallic acid equivalent; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol;
OPP, oil palm phenolics; RBD, refined, bleached, deodorised; TC, total cholesterol; TE, Trolox equivalent; TG, triglycerides; LSD, least
significant difference; VIT E, vitamin E.
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Please cite this article in press as: Che Idris, C.A. et al., Oil palm phenolics and vitamin E reduce atherosclerosis in rabbits, Journal of Functional
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has been identified as an excellent source of two major phy-
tochemicals, namely vitamin E (tocopherols and tocotrienols)
and carotenoids, both of which are fat-soluble. Oil palm vita-
min E has been reported to act as a potent biological antioxi-
dant, protecting against oxidative stress and the
atherosclerotic process (Mukherjee & Mitra, 2009; Sundram,
Sambanthamurthi, & Tan, 2003). Recently, oil palm fruits have
also been identified as a rich source of phenolic compounds
(Sambanthamurthi et al., 2011a). A water-soluble extract rich
in phenolic acids has been successfully recovered from the
vegetation liquor generated from the milling of oil palm fruits
(Sambanthamurthi et al., 2011a). These oil palm phenolics
(OPPs) have been found to have antioxidant properties with
potent protective effects against chronic diseases such as car-
diovascular disease, diabetes and cancer, based on studies
with animal models (Sambanthamurthi et al., 2011b).
Oxidation of low-density lipoproteins (LDL-C), the major
cholesterol carrying lipoproteins in plasma is commonly
implicated as an initiator of atherosclerosis. Increased LDL-
C concentration is a major risk factor for atherosclerosis in
humans (Carmena, Duriez, & Fruchart, 2004; Steinbrecher,
Zhang, & Lougheed, 1990). Oxidised LDL-C is engulfed by mac-
rophages, and this rapidly leads to the formation of athero-
sclerotic plaques. The sequential steps in the formation of
foam cells, their rupture into fatty streaks, maturation into
fatty plaques which accumulate in the arterial wall and grad-
ually become fibrous, and their enlargement contributing to
the narrowing of the blood vessel lumen or rupture to form
a thrombus, have been well described by Tedgui and Mallat
(2006). Disruption of blood flow to the heart causing a myocar-
dial infarction or to the brain causing a stroke are the ultimate
events initiated from atherogenic plaque formation (Ross,
1993; Tedgui & Mallat, 2006).
The possible association of atherosclerosis with oxidative
events has led to the hypothesis that dietary antioxidants
may inhibit the development of atherosclerosis and reduce
the incidence of coronary artery disease (Pandey & Rizvi,
2009; Xu et al., 1998). Water-soluble antioxidants (vitamin C,
phenolic compounds including flavonoids) and lipid-soluble
antioxidants (vitamin E, carotenoids) are natural antioxidants
that are hypothesised to have the potential to intervene in the
development of atherosclerosis and cardiovascular disease by
modulating redox sensitive steps in disease progression
(Kinsella, Frankel, German, & Kanner, 1993).
Vitamin E is a generic name for both tocopherols and
tocotrienols. They are structurally similar but tocotrienols dif-
fer from tocopherols in having an unsaturated phytyl side
chain (Colombo, 2010). Both tocopherols and tocotrienols
comprise a,b,cand dforms, depending on the number and
position of methyl groups on the chromanol ring. In total
there are thus eight forms of vitamin E. Both tocopherols
and tocotrienols are recognised for their antioxidative effects
and are suggested to reduce cardiovascular disease by arrest-
ing free radical damage (Stephens et al., 1996; Vasanthi,
Parameswari, & Das, 2012). In this study, we investigated the
effects of palm vitamin E that comprised tocotrienols (70%)
and tocopherols (30%). The nutritional and physiological
properties of vitamin E in palm oil, especially the tocotrienols
are well described by Sundram et al. (2003) and Vasanthi et al.
(2012).
In addition to oil palm vitamin E, water-soluble oil palm
phenolics have been shown to have cardioprotective effects.
Sambanthamurthi et al. (2011a) reported that oil palm phen-
olics inhibited copper-mediated oxidation of human LDL-C
in vitro and promoted vascular relaxation in both isolated aor-
tic rings and perfused mesenteric vascular beds pre-con-
tracted with noradrenaline ex vivo.In vivo, oil palm
phenolics reduced blood pressure in a NO-deficient rat model,
protected against ischaemia-induced cardiac arrhythmia in
rats and reduced plaque formation in rabbits fed an athero-
genic diet (Sambanthamurthi et al., 2011b). These findings
suggest that oil palm phenolics have significant biological
activities and may be used as a potential preventative or ther-
apeutic vehicle against atherosclerosis and cardiovascular
disease.
Given that both palm vitamin E (VIT E) and oil palm phen-
olics are individually protective against atherosclerosis devel-
opment in an atherogenic diet-fed rabbit animal model, our
interest therefore was to evaluate these oil palm antioxidants
in combination with each other in the same animal model of
atherosclerosis for potential synergism.
2. Materials and methods
2.1. Animals, diets and experimental design
The animal procedures carried out in this study were ap-
proved by the Animal Care and Use Committee of the Na-
tional University of Malaysia, Kuala Lumpur, Malaysia.
Thirty-two male New Zealand White rabbits aged five months
with approximately equal mean body weights were divided
into four different treatment groups of eight animals each.
The animals were housed individually in stainless steel cages
and maintained in a temperature-controlled room (18–23 °C)
with a 12-h daylight cycle. All animals were fed ad libitum
on an atherogenic diet for 100 days. Additionally, the animals
were provided with palm vitamin E, oil palm phenolics or a
combination thereof. The experimental groups were classi-
fied as follows:
1. High-Fat Atherogenic Diet Control (CTR)
2. High-Fat Atherogenic Diet + Palm Vitamin E (VIT E)
3. High-Fat Atherogenic Diet + Oil Palm Phenolics (OPP)
4. High-Fat Atherogenic Diet + Palm Vitamin E + Oil Palm
Phenolics (VIT E + OPP)
The high-fat atherogenic diet contained fat at approxi-
mately 35% energy (Tab le 1) and comprised 72.3% saturated
fatty acids (C12:0 + C14:0 = 54.9%), 15.7% monounsaturated
fatty acids (C18:1) and 12.0% polyunsaturated fatty acids
(C18:2 n6 = 11.88%; C18:3 n3 = 0.14%). The fatty acid com-
position of the dietary oil used was determined by gas chro-
matography (Sundram, Pathmanathan, Wong, & Baskaran,
1997a). Additionally, a dietary cholesterol of 0.15% was added
in the diet formulation. In rabbits, lesion morphology is al-
tered by the percentage of cholesterol added to the diet and
the feeding duration (Bocan et al., 1993; Kolodgie et al., 1996;
Finking & Hanke, 1997). Short feeding duration with high per-
centage of cholesterol of more than 2% may cause hypercho-
2JOURNAL OF FUNCTIONAL FOODS xxx (2014) xxxxxx
Please cite this article in press as: Che Idris, C.A. et al., Oil palm phenolics and vitamin E reduce atherosclerosis in rabbits, Journal of Functional
Foods (2014), http://dx.doi.org/10.1016/j.jff.2014.01.002
lesterolaemia and atherosclerotic lesions rich in foam cells
which originate from macrophages. In contrast, a diet supple-
mented with a high fat, low dietary cholesterol content and
long feeding duration may cause atherosclerotic lesions that
are rich in smooth muscle cells and contain cholesterol
deposits leading to atherosclerotic lesions more similar to
those of humans (Kolodgie et al., 1996). Kritchevsky and
Tepper (1965) stated that saturated fats were more athero-
genic in rabbits than unsaturated fats and the atherogenic effect
can be further enhanced by the presence of dietary choles-
terol. Besides that, Yanni (2004) and Kolodgie et al. (1996) also
justified the usage of low cholesterol to induce atherosclerosis
in rabbits. This is based on evidence that human lesions at
late stage are similar to those seen in rabbits given a diet high
in fat and low in cholesterol for extended periods (Adams,
Miller, Morgan, & Rao, 1982). Additionally, Yanni (2004)
reported high mortality rates in animals supplemented for long
periods with 1–2% cholesterol in their diets. Similar to our
study, Tijburg, Wiseman, Meijer, and Weststrate (1997) also
fed rabbits with a high fat diet containing 35% energy and
0.15% (w/w) of dietary cholesterol. Therefore, although the
standard rabbit model for atherosclerosis usually contains
higher level of added cholesterol (0.5–1%), the low level of
cholesterol used in our study is justified and plaque formation
in these animals was primarily driven by the saturated fat
content of the diet and not cholesterol. The diet was designed
to mimic the human diet where a higher fat content predom-
inates and is recognised as the contributing factor to athero-
sclerosis plaque formation (Sundram, Ismail, Hayes,
Jeyamalar, & Pathmanathan, 1997b).
Palm vitamin E rich in tocotrienols was supplied by Sime
Darby Bioganic Sdn. Bhd. (previously known as Golden Hope
Bioganic, Selangor, Malaysia). The tocol content of the palm
vitamin E used is shown in Table 2. The final vitamin E con-
tent in the VIT E pellet diet was 125 mg/kg, whereas the base
pellet diet (fed to CTR and OPP groups) contained 50 mg/kg
diet, primarily from the oil used in the diet formulation. Oil
palm phenolics were supplemented to the OPP and VIT
E + OPP groups as drinking fluid containing total phenolics
at 1500 mg GAE/L. The preparation and characterisation of
the composition of oil palm phenolics have been previously
described (Sambanthamurthi et al., 2011a), with the phenolic
content of oil palm phenolics shown in Tab le 3. On a dry
weight basis, the phenolic content in oil palm vegetation
liquor ranged from 1.38% to 2.43% and the remaining 98%
were fruit sugars, soluble fibers, organic acids and water-sol-
uble vitamins, etc. (Sambanthamurthi et al., 2011a). During
the feeding duration, animals were monitored for their food
and fluid intakes and weight changes. The consumption of
oil palm phenolics in the OPP and VIT E + OPP groups was
carefully measured over a continuous 11 day duration and
was found to be approximately 150 mg GAE/day/animal.
At the end of the feeding trial, all animals were exsangui-
nated via cardiac puncture. Prior to exsanguination, the ani-
mals were fasted overnight and then anaesthetised with a
mixture of ketamine (100 mg/ml) and xylazil (20 mg/ml) at
0.2 ml/kg body weight. Thirty millilitres of blood were drawn
by cardiac puncture. Plasma was prepared by centrifugation
at 3000gfor 20 min and stored at 80 °C until analysis. The
animals were then overdosed with sodium pentobarbital be-
fore autopsy. Various organs of interest such as liver, heart,
lungs and kidneys were harvested. The entire aorta system
was carefully traced, dissected and cleaned of adherent
adventitial tissues. The aorta was then cut open longitudi-
nally and preserved in 10% formalin.
2.2. Plasma lipid analysis
Plasma lipids (TC, TG, LDL-C, HDL-C) were analysed using
enzymatic assay kits (Roche Diagnostics GmbH, Mannheim,
Germany), as per manufacturer’s protocol on the clinical
chemistry autoanalyser, Roche/Hitachi 902.
2.3. Plasma antioxidant status
Plasma antioxidant status was measured by two methods, the
2,20-azinobis (3-ethylbenzothiazoline) 6-sulphonic acid radi-
cal cation (ABTS
Æ+
) decolorisation and ferric reducing ability
of plasma (FRAP) assays.
The ability of plasma from rabbits to scavenge the ABTS
Æ+
cation was measured using the method of Re et al. (1999),
as adapted by Balasundram (2006). The intensely coloured
ABTS
Æ+
is relatively stable, but in the presence of an antioxi-
dant, it is readily reduced to a colourless ABTS
Æ2
. The loss
of absorbance at 734 nm after 6 min is taken as a measure-
ment of the ABTS
Æ+
scavenging activity. Standard ABTS
Æ+
scav-
enging curve was constructed using 6-hydroxy-2,5,7,8-
tetramethylchroman-2-carboxylic acid (Trolox), and the
ABTS
Æ+
scavenging capacity of the plasma is reported in terms
of mg Trolox equivalents/mL (mg TE/mL).
The ferric reducing antioxidant power (FRAP) of plasma
was determined using the method of Firuzi, Lacanna,
Petrucci, Marrosu, and Saso (2005), as adapted by Balasundram
Table 1 – Composition of formulated rabbit atherogenic
diet.
Ingredients g/kg diet % en
Casein 250.0 25.51
Corn starch 200.0 20.41
Dextrose 193.0 19.64
Dietary fat 150.0 34.44
Cellulose 150.0
Mineral mix 40.0
Vitamin mix 10.0
Choline bitartrate 2.5
DL-Methionine 3.0
Cholesterol 1.5
Table 2 – Composition of palm vitamin E.
Vitamin E
isomer
Content
(mg/kg dietary fat)
Percentage (%)
a-Tocopherol 262.5 21
a-Tocotrienol 325.0 26
c-Tocotrienol 500.0 40
d-Tocotrienol 162.5 13
Total 1250.0 100
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Please cite this article in press as: Che Idris, C.A. et al., Oil palm phenolics and vitamin E reduce atherosclerosis in rabbits, Journal of Functional
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(2006). The FRAP assay measures the ferric reducing ability of
plasma, i.e. the ability to reduce a ferric-2,4,6-tripyridyl-S-tri-
azine (Fe
3+
-TPTZ) ion to a ferrous-2,4,6-tripyridyl-S-triazine
(Fe
2+
-TPTZ) ion via an electron transfer mechanism (Benzie
& Strain, 1996). This reduction results in the production of
an intensely blue coloured reduced complex, with a maxi-
mum absorption at 593 nm (Benzie & Strain, 1996).
2.4. Determination of lesion area
After removal of adventitial tissues and fat, aorta was stained
in a 1% (w/v) solution of oil red O in 60% (v/v) triethyl phos-
phate for 20 min and then destained with 60% (v/v) triethyl
phosphate for 30 min (Paigen, Morrow, Holmes, Mitchell, &
Williams, 1987). Plaque area was quantified by using a digital
image analysis software (i-SolutionDT, i-MTechnology, Dusan,
Daejeon, Korea) and expressed as percentage of the total aor-
tic surface. Lesions were categorised according to Kritchevsky,
Tepper, and Story (1978):
1. Fibrous plaques: Raised nodular lesions, continuous,
intense red, white hard and visible to naked eyes
2. Fatty plaques: Raised distinct lesions, intensely stained red
3. Fatty streaks: Lipid accumulation, stained light red
4. Lesion free: No plaques or streaks
2.5. Histological assessments
For histological assessments of the segments/plaques, the
aorta was fixed in formalin solution and paraffin-embedded.
The formalin-fixed paraffin-embedded blocks were sectioned
(5 lm per section) using a Jung Multicut 2045 rotary micro-
tome, transferred onto glass slides and stained with hema-
toxylin and eosin (H&E) (Kierman, 1990). The slides were
assessed blindly and independently by two experienced
pathologists using the Nikon Eclipse 50i photomicroscope.
2.6. Statistical analyses
All data were analysed using the one-way analysis of variance
(ANOVA) followed by LSD multiple comparisons (protected
LSD) to test differences between dietary treatments. Differ-
ences were considered statistically significant at p< 0.05. Sta-
tistical analysis was performed using the Statistical Package
for Social Science (SPSS).
3. Results
3.1. Body and organ weights
Mean body weights of the rabbits, prior to and at the end of
the study, were not significantly different (p> 0.05) between
dietary treatments after 100 days of dietary intervention (Ta-
ble 4). This indicates that the high-fat atherogenic diet used
in this study did not adversely impact the normal growth of
the animals. At sacrifice, organ weights namely liver, heart,
lungs and kidneys were not significantly different (p> 0.05)
between treatment groups (VIT E, OPP, VIT E + OPP) when
compared to the CTR group (Table 4 ).
3.2. Plasma lipid levels
The analysis of plasma lipid profiles (TC, TG, LDL-C and HDL-
C) showed that rabbits in the OPP and VIT E + OPP groups did
not exhibit significant differences compared to the CTR and
VIT E groups, although the HDL-C level was observed to be
slightly higher (but not statistically significant (p> 0.05).
3.3. Plasma antioxidant capacity
The antioxidant capacity of the rabbit plasma was deter-
mined by both the ABTS
Æ+
decolourisation assay and the FRAP
assay. Although the FRAP results for the OPP group
(12.32 ± 5.69 mg TE/mL) and the VIT E + OPP group
(10.53 ± 4.84 mg TE/mL) were comparatively higher than that
of the CTR group (7.18 ± 2.66 mg TE/mL), the differences were
not statistically significant (p> 0.05) (Tabl e 4). Similarly, the
plasma ABTS
Æ+
scavenging capacity among all the four treat-
ments was not significantly different (p> 0.05).
3.4. Atherosclerosis development
All the rabbits used in this study developed atherosclerotic le-
sions after being fed the atherogenic diet for 100 days (Ta -
ble 5). The CTR group had a significantly higher (p< 0.05)
fibrous plaque score (8.90 ± 5 .41) compared to the other three
groups (VIT E, OPP and VIT E + OPP) (Fig. 1A). In the VIT
E + OPP group, all animals did not show any development of
fibrous plaques compared to the CTR, VIT E and OPP groups
which developed these plaques. Fatty plaques were signifi-
cantly higher (p< 0.05) in both the CTR and VIT E groups com-
pared to the OPP and VIT E + OPP groups (Fig. 1B). In addition,
Table 3 – Composition of oil palm phenolics.
Phenolic compound (mg/kg)
Protocatechuic acid 900
p-Hydroxybenzoic acid 10 500
Caffeoylshikimic acid (total of three isomers) 16 200
Total phenolics (based on Folin Ciocalteau assay) 38 400
Figures are on a dry weight basis (mg of each major phenolic component for every kg of freeze-dried oil palm phenolics) and represent
triplicate analyses of oil palm phenolic samples processed from the aqueous by-products obtained from the Malaysian palm oil mills in Labu,
Negeri Sembilan, according to the methods described in Sambanthamurthi et al. (2011a). Total phenolics assessed based on the Folin Cio-
calteau assay comprise major and mostly unidentified minor phenolics. Only the major phenolics in oil palm phenolics are shown in this table.
4JOURNAL OF FUNCTIONAL FOODS xxx (2014) xxxxxx
Please cite this article in press as: Che Idris, C.A. et al., Oil palm phenolics and vitamin E reduce atherosclerosis in rabbits, Journal of Functional
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the lowest fatty plaque score (0.00 ± 0.00) was observed with
the VIT E + OPP treatment. Fatty streak incidence was highest
(23.02 ± 7.75) in the VIT E treated animals followed by the CTR
group (Fig. 1C).
OPP and VIT E + OPP groups had significantly lower
(p< 0.05) development of fatty streaks compared to the CTR
and VIT E groups. Lesion free area denoting the total area that
was not altered morphologically (i.e. free of fatty streaks, fatty
and fibrous plaques), was significantly higher (p< 0.05) follow-
ing the VIT E + OPP and OPP diets compared to the VIT E and
CTR diets (Fig. 1D). This observation suggests protective ef-
fects of the OPP and VIT E + OPP treatments against the occur-
rence of atherosclerosis.
The histological assessments generally agreed with the
above observations with regards to the extent of atheroma-
tous plaque formation. The main microscopic lesions ob-
served in the CTR group included formation of fibrous cap
and lipid core with disorganised layers of foamy macrophages
deposited in the tunica intima which directly increased its
thickness. The infiltration of inflammatory cells, mainly
mononuclear, was evident in this group. At certain areas,
the tunica intima was sloughed off leaving the tunica media
exposed. Invasion of foam cells was observed in the begin-
ning of the tunica media. The oil palm phenolics treated ani-
mals showed smooth muscle proliferation, intimal fibrosis
and extracellular lipid but there was no evidence of lipid core
or necrosis. There was lesser degree of foam cell formation.
The VIT E group generally exhibited well-formed lipid core fi-
brous cap atheroma distinguished by fibrous cap, free of
inflammatory cells. In contrast, pathological lesions were
far less discernible in the VIT E + OPP group where fewer foam
cells and mild thickening of the tunica intima were observed.
Table 4 – Animal body weights, organ weights, plasma lipid profiles and plasma antioxidant profiles after 100 days of
treatment.
Parameter CTR VIT E OPP VIT E + OPP
Mean SD Mean SD Mean SD Mean SD
Body weights (g)
Initial 1871.43 48.80 1857.14 78.68 1860.97 214.12 1822.27 146.90
Final 2229.43 369.30 2432.37 171.39 2185.87 752.94 2122.47 375.10
Organ weights (g)
Liver 72.63 11.34 61.83 8.71 67.90 12.63 64.46 11.54
Heart 4.11 0.83 4.45 0.60 4.30 0.71 4.15 0.94
Lungs 7.56 1.63 7.20 1.03 8.54 1.57 7.26 1.30
Kidneys 9.60 0.99 10.49 1.59 11.72 1.78 9.65 2.42
Plasma lipid profiles (mmol/L)
TC 19.78 3.14 17.91 4.67 18.01 4.18 19.11 1.76
TG 2.33 1.42 1.95 1.34 0.18 0.32 0.87 0.20
LDL-C 14.80 2.73 13.21 4.50 13.60 4.32 14.66 2.05
HDL-C 3.90 0.96 3.81 1.10 4.03 0.56 4.05 0.61
Plasma antioxidant capacity (TE/mL)
ABTS
Æ+
74.95 6.75 77.14 4.88 75.73 4.84 76.39 5.12
FRAP 7.18 2.66 6.17 1.15 12.32 5.69 10.53 4.84
(Mean values and standard deviations, n= 8).
Table 5 – Inhibition of the development of aortic lesions in rabbits fed an atherogenic diet.
*
Parameter CTR VIT E OPP VIT E + OPP
Mean SD Mean SD Mean SD Mean SD
Fibrous plaque
8.90 5.41
a,b,c
2.88 2.01
a
1.48 4.45
b
0.00
c
0.00
Fatty plaque
9.32 2.48
a,b
10.66 4.45
c,d
3.51 4.52
a,c
0.72 1.82
b,d
Fatty streak
§
14.41 5.25
a,b
23.02 7.75
a,c,d
8.45 2.55
c
6.21 4.36
b,d
Lesion free
||
67.20 7.67
a,b
63.35 8.04
c,d
86.38 8.12
a,c
92.93 5.13
b,d
Total lesion area 99.83 0.28 99.91 0.02 99.82 0.12 99.86 0.09
Total aorta area
**
(mm
2
) 1410.28 121.80 1515.84 148.62 1486.85 135.36 1281.05 127.13
*
Values are percentages of total aorta area (Mean values and standard deviations, n= 8).
Raised nodular lesions, continuous, intense red, white hard and visible to naked eyes.
Raised distinct lesions, intensely stained red.
§
Lipid accumulation, stained light red.
|| Healthy intima.
**
Percentage (%) of aortic area as fibrous plaques, fatty plaques and fatty streaks.
a,b,c
Mean values with the same superscript letters are significantly different from each other (p< 0.05).
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Please cite this article in press as: Che Idris, C.A. et al., Oil palm phenolics and vitamin E reduce atherosclerosis in rabbits, Journal of Functional
Foods (2014), http://dx.doi.org/10.1016/j.jff.2014.01.002
There was no evidence of lesions in the rest of the tunics.
These descriptions refer to the most characteristic lesions
in the various groups and are qualitative assessments.
4. Discussion
The protective effect of various plant products against chronic
diseases has been attributed to the various antioxidants con-
tained in them, especially their synergistic effects (Steinberg
et al., 1989; Steinberg, 1991). Zawistowski, Kopec, and Kitts
(2009), Kwok et al. (2010, 2013), Thilakarathnaa, Wang,
Vasantha Rupasinghea, and Ghanam (2012) and Asgary et al.
(2013) have reported the roles of black rice extract, hawthorn,
apple peel extracts and black cumin respectively as functional
foods in preventing hypercholesterolaemia and/or atheroscle-
rosis development in various animal models. In addition,
vitamin E (Williams, Motteram, Sharp, & Gallagher, 1992)
and phenolic compounds (Yamakoshi, Kataoka, Koga, &
Ariga, 1999) have been documented to inhibit the develop-
ment of aortic lesions in rabbits. Results obtained from the
present study are consistent with these previous findings. A
mixture containing both water-soluble and lipid-soluble anti-
oxidants is able to quench free radicals in both aqueous and
lipid phases (Chen & Tappel, 1996). Murakami, Yamaguchi,
Takamura, and Matoba (2003) showed that a combination of
quercetin or catechins plus a-tocopherol exhibited signifi-
cantly higher activity than the sum of the individual activities
using the liposome oxidation method. The cholesterol-rich
atherogenic diet that was fed to the rabbits in this study did
not result in any significant differences in their lipid profiles
(p> 0.05). This was not entirely surprising since the animals
were all subjected to the high cholesterol atherogenic diet
that rendered them all hypercholesterolaemic. The resulting
hypercholesterolaemia triggered atherogenic tendencies
within the 100 days of the feeding duration. Despite the in-
duced hypercholesterolaemia, the overall atherogenic out-
comes were significantly modulated by the type of
antioxidant added to the diet of these animals.
Frankel, Waterhouse, and Kinsella (1993), Vinson et al.
(1999) and Pietta (2000), reported that many flavonoids and re-
lated polyphenols are actually better antioxidants than vita-
mins. The oil palm is also rich in phenolic compounds, as
reported by Sambanthamurthi et al. (2011a). To our knowl-
edge, no studies have investigated the effects of oil palm
phenolics in combination with other compounds on the
development of atherosclerosis although a preliminary study
in rabbits on the effects of oil palm phenolics at low and high
doses was reported by Sambanthamurthi et al. (2011b).In
their study, all rabbits were fed a high-fat atherogenic diet
and provided either distilled water (control), oil palm pheno-
lics at 500 mg/L GAE, or oil palm phenolics at 1000 mg/L
GAE, as their drinking fluids. The results indicated a net pro-
tection against the development and progression of athero-
sclerosis in a dose-dependent manner.
Ross (1993) and Tedgui and Mallat (2006) stated that the
first step of atherogenesis is the progression of the accumula-
tion of foam cells resulting in the formation of fatty streaks,
which are the earliest observable abnormality of the vessel
wall. These fatty streaks will gradually progress to intermedi-
ate, fatty plaques and ultimately evolve into fibrous plaques.
Sambanthamurthi et al. (2011b) reported that control rabbits
developed extensive aortic fibrous and fatty plaques as well
as fatty streaks. On the other hand, animals given the same
atherogenic diet but supplemented with oil palm phenolics
had significantly reduced fatty plaques and fatty streaks.
However, not much is known about the synergistic effects of
Fig. 1 – Photographs of aortic lesions in rabbits fed an atherogenic diet in different groups (A) CTR, (B) VIT E, (C) OPP and (D)
VIT E + OPP.
6JOURNAL OF FUNCTIONAL FOODS xxx (2014) xxxxxx
Please cite this article in press as: Che Idris, C.A. et al., Oil palm phenolics and vitamin E reduce atherosclerosis in rabbits, Journal of Functional
Foods (2014), http://dx.doi.org/10.1016/j.jff.2014.01.002
oil palm phenolics in combination with other antioxidants.
Thus, in the present study, we examined the synergistic ef-
fects when palm vitamin E and oil palm phenolics were com-
bined and provided as a supplement to the rabbits. According
to Upaganlawar, Gandhi, and Balaraman (2009), several stud-
ies have shown that antioxidants are uniquely different from
one another and work synergistically and more effectively
when they are used in combination. Our current observations
are also in agreement with Stocker and O’Halloran (2004) who
reported that dealcoholised red or white wine which contains
polyphenolic compounds was capable of synergising with
vitamin E and decreasing atherosclerosis in apolipoprotein
E-deficient (E
o
) mice.
From the analysis of plasma lipid profiles (TC, TG, LDL-C
and HDL-C) in this present study, rabbits in the OPP group
did not exhibit significant differences although the HDL-C le-
vel was observed to be slightly higher (but not statistically sig-
nificant (p> 0.05)) compared to the CTR and VIT E groups.
However, these animals had significantly reduced incidence
of atherosclerosis (i.e. less fibrous and fatty plaques as well
as fatty streaks) (p< 0.05) when compared to the CTR and
VIT E groups. Similar observations were also made by Wang
et al. (2005), who reported that a 12 week supplementation
of dealcoholised red wine containing resveratrol suppressed
atherosclerosis in hypercholesterolaemic rabbits and con-
cluded that the phytochemicals present in red wine could
suppress atherosclerosis without affecting plasma lipid lev-
els. Fuhrman, Volkova, Coleman, and Aviram (2005) also re-
ported that fresh grape powder attenuated atherosclerotic
development in apolipoprotein E
o
mice without affecting
their lipid profiles. Similarly, although no changes were seen
in plasma LDL-C or HDL-C upon feeding of red wine to E
o
mice, reduced progression of lesions was reported by Hayek
et al. (1997).
In the present study, rabbits in the VIT E + OPP group also
did not exhibit significant changes (p> 0.05) in their plasma li-
pid profiles (TC, TG, LDL-C and HDL-C), although the HDL-C
level was observed to be slightly higher (not statistically sig-
nificant (p> 0.05)) compared to the CTR and VIT E groups. This
was similar to the rabbits in the OPP group, except that these
animals from the VIT E + OPP group had no fibrous plaques
and also significantly reduced incidence of atherosclerosis
(i.e. less fatty streaks and plaques) compared to the CTR
and VIT E groups (p< 0.05). This suggests that the atheropro-
tective effects of oil palm phenolics might be contributed by
other mechanisms instead of influencing lipid and antioxi-
dant profiles.
One possible mechanism by which oil palm phenolics
could reduce atherosclerotic lesions is through its anti-
inflammatory effects. Cytokines play a significant role in
mediating the inflammatory response in atherosclerosis. Ath-
erosclerosis is generally associated with cytokines that pro-
mote a Type 1 helper T-cell (Th1) cellular immune response
rather than a Type 2 helper T-cell (Th2) humoral immune re-
sponse. The modulation of the Th1/Th2 axis toward the latter
may thus be atheroprotective. Leow, Sekaran, Sundram, Tan,
and Sambanthamurthi (2013), showed that oil palm phenolics
were able to attenuate antigen presentation and processing in
the spleens of mice given an atherogenic diet. In addition, oil
palm phenolics also modulated the Th1/Th2 axis of the
immune system towards the latter, thus suggesting that oil
palm phenolics reduce atherosclerosis via its anti-inflamma-
tory actions. This mechanism may thus help explain the
changes observed in the current study. Leow et al. (2013) also
showed that in addition to its anti-inflammatory effects, oil
palm phenolics restored the antioxidant capacity of mice
fed the atherogenic diet. Further investigations to discover
other possible/probable mechanisms by which oil palm phen-
olics reduce atherosclerosis are warranted. Thus, VIT E + OPP
resulted in significant reduction (p< 0.05) in the development
of atherosclerotic lesions compared to animals given either
vitamin E alone or oil palm phenolics alone. In a similar study,
Xu et al. (1998) reported that reduction of oxidative stress
in vivo by catechin and vitamin E in their hamster study could
prevent fatty streak accumulation in the aorta. The effect of
oil palm phenolics in inhibiting the formation of fibrous pla-
ques in the present study was evident in both the OPP and
VIT E + OPP groups compared to the CTR and VIT E groups,
suggesting that oil palm phenolics may potentially inhibit
atherosclerosis. Similarly, other phenolic compounds demon-
strated this property as well. For example, pomegranate juice
(Kaplan et al., 2001), grape extract (Auger et al., 2004), as well
as red wine, dealcoholised wine and wine polyphenols
(Stocker & O’Halloran, 2004; Manach, Mazur, & Scalbert,
2005) were found to reduce atherosclerotic lesions when fed
to various animal models. Although the VIT E group had high-
er incidence of fatty plaques, this group showed a significant
reduction in fibrous plaque formation, indicating that VIT E
arrested the progression of fatty plaques to fibrous plaques.
Histopathological examination revealed massive destruc-
tion of the tunica intima in the CTR group indicating endothe-
lial activation (De Caterina, Liao, & Libby, 2000). These fibrous
caps were formed due to proliferation and migration of
smooth muscles and connective tissue deposition. The for-
mation of lipid core and form cells was reduced after admin-
istration of vitamin E and oil palm phenolics individually and
especially in combination. These results suggest the great po-
tential of these phytonutrients in mitigating atherosclerosis
even when on high fat diets.
In this study, plasma antioxidant capacity was also mea-
sured by two different methods, i.e. the ABTS
Æ+
and FRAP as-
says. The use of two methods for measurement of
antioxidant activity was based on the suggestions by Frankel
and Meyer (2000) as well as Verhagen et al. (2003), on the need
to evaluate antioxidant activity by using different methods.
Additionally, these two methods are recommended for
measuring antioxidant capacity due to their rapidity of
analysis, ease of use and high sensitivity (Maisuthisakul,
Pongsawatmanit, & Gordon, 2007).
Results obtained from the ABTS
Æ+
scavenging assay, showed
no significant differences in all the four groups tested (p> 0.05).
Results from the FRAP assay also appeared to be not signifi-
cantly different (p> 0.05), although the plasma antioxidant
capacity values of the OPP and VIT E + OPP groups appeared
higher than that of the CTR group. The different results ob-
tained from the ABTS
Æ+
and FRAP methods could be due to
the different mechanisms of reactions involved. The ABTS
Æ+
method is a diammonium salt radical cation scavenging assay,
whereas the FRAP method is a ferric reducing power assay. In
addition, the antioxidants in plasma consist of a complex cas-
JOURNAL OF FUNCTIONAL FOODS xxx (2014) xxxxxx 7
Please cite this article in press as: Che Idris, C.A. et al., Oil palm phenolics and vitamin E reduce atherosclerosis in rabbits, Journal of Functional
Foods (2014), http://dx.doi.org/10.1016/j.jff.2014.01.002
cade of enzymatic and non-enzymatic antioxidants which
may have evoked different responses to both the ABTS
Æ+
and
FRAP measurements (Jimenez-Escrig, Dragsted, Daneshvar,
Pulido, & Saura-Calixto, 2003). Although not significant, the
OPP and OPP + VIT E groups had higher plasma antioxidant
capacity based on the FRAP assay. Previous in vitro studies
had confirmed potent antioxidant potential of oil palm pheno-
lics (Sambanthamurthi et al., 2011a). It has also been reported
that phenolic compounds exert their positive impact in the gut
itself (Kemperman, Bolca, Roger, & Vaughan, 2010). The antiox-
idant activities of phenolic compounds increase with the de-
gree of hydroxylation (Rice-Evans, Miller, & Paganga, 1996).
Phenolics usually exist in the conjugated form with sugars
and other moieties. The conjugation reactions occur via the hy-
droxyl groups and hence reduce the degree of hydroxylation
and thus antioxidant potential of the phenolic compounds.
However oil palm phenolics exist mainly as free phenolic acids
as they are obtained from the oil palm milling process where
sterilisation of the fruits results in hydrolysis of conjugated
phenolics and the release of unconjugated phenolic acids. Oil
palm phenolics comprise three isomers of caffeoylshikimic
acid, followed by p-hydroxybenzoic and protocatechuic acids
as the major phenolic compounds. Caffeoylshikimic acid has
four hydroxyl groups, and this would account for the potent
in vitro antioxidant activity of oil palm phenolics. The other
phenolic acids would also be expected to contribute to the anti-
oxidant activity observed. Working together, these phenolic
acids may have a synergistic effect with each other as well as
with the vitamin E mixture comprising mainly tocotrienols (a,
band cforms) and a-tocopherol. It is also highly likely that
the phenolic acids and vitamin E in combination effect positive
outcomes via mechanisms other than antioxidative routes.
Thus, the anti-atherogenic effects conferred by oil palm
phenolics and vitamin E in the present study may be ex-
plained by the vast mixture of phenolic acids, together with
the tocotrienols and tocopherols present. These anti-athero-
genic mechanisms of oil palm phenolics should be investi-
gated in future studies.
5. Conclusion
The effects of oil palm phenolics (OPPs) either on their own or
in combination with vitamin E (VIT E + OPP) in inhibiting ath-
erosclerosis were investigated, and a superior inhibitory ef-
fect on the development of atherosclerotic lesions was
observed in both the OPP and VIT E + OPP groups compared
to the CTR and VIT E groups. These findings suggest a poten-
tial area for the application of oil palm vitamin E and oil palm
phenolics as antioxidants in modulating cardiovascular risk
factors, which merit further research attention. The effects
shown by this combination of bioactives present in the oil
palm also constitute an important factor in the formulation
of functional foods and in the choice of a diet which uses
the oil palm as a food source.
Acknowledgments
The authors thank the Director-General of the Malaysian
Palm Oil Board for her support and permission to publish this
paper. The present study was fully supported by the Malay-
sian Palm Oil Board. The authors gratefully acknowledge the
technical assistance of Dr Fuzina Nor Hussien (Universiti Pu-
tra Malaysia) in sacrificing the animals, as well as thank the
staff of the Nutrition Research Laboratories of the Malaysian
Palm Oil Board for various technical assistance. The authors
also thank Dr. Vaihsali Jain of MAHSA University for assis-
tance in assessing the aortic lesions.
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10 JOURNAL OF FUNCTIONAL FOODS xxx (2014) xxxxxx
Please cite this article in press as: Che Idris, C.A. et al., Oil palm phenolics and vitamin E reduce atherosclerosis in rabbits, Journal of Functional
Foods (2014), http://dx.doi.org/10.1016/j.jff.2014.01.002
... In these studies, OPP has demonstrated its effects in atherosclerosis, cardiac arrhythmia and hypertension. For instance, Che Idris et al. (2014) explored the effects of OPP against atherosclerosis in an atherogenic rabbit model. It was described that the OPP-treated rabbits had significantly less fibrous plaques compared to the atherogenic diet control rabbits, suggesting that OPP might inhibit atherosclerotic lesion development. ...
... Additionally, the formation of foam cell with lesser degree has been also reported. However, in this study, the plasma lipid profile of OPP-treated group was insignificant compared to the atherogenic diet control group [28]. OPP treatment showed no significant difference in plasma lipid profile, while slightly higher in the highdensity lipoprotein cholesterol (HDL-C) level compared to control. ...
... Moreover, natural antioxidants such as vitamins (vitamin C and E), carotenoids and flavonoids have been hypothesized to interfere with atherosclerosis and CVD development by modulating the oxidation and reduction in disease progression [77,78]. In a study by Che Idris et al., OPP supplementation to atherogenicdiet fed rabbits had a significant reduction of fatty streaks and plaques [28]. Nevertheless, in comparison to the control group, the plasma antioxidant status (ABTS+ and FRAP assays) showed no significant differences. ...
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Cardiovascular disease (CVD) is globally known as the number one cause of death with hyperlipidemia as a strong risk factor for CVD. The initiation of drug treatment will be recommended if lifestyle modification fails. However, medicines currently used for improving cholesterol and low-density lipoprotein cholesterols (LDL-C) levels have been associated with various side effects. Thus, alternative treatment with fewer or no side effects needs to be explored. A potential agent, oil palm phenolics (OPP) recovered from the aqueous waste of oil palm milling process contains numerous water-soluble phenolic compounds. It has been postulated that OPP has shown cardioprotective effects via several mechanisms such as cholesterol biosynthesis pathway, antioxidant and anti-inflammatory properties. This review aims to summarize the current evidence explicating the actions of OPP in cardiovascular health and the mechanisms that maybe involved for the cardioprotective effects.
... PFAD is a valuable source of bioactive compounds wherein the unsaponifiable fraction (USF) of PFAD contains vitamin E, phytosterols, and squalene, and USF is a potential candidate for dietary supplements and all bioactive compounds in USF are expected to act synergistically [7] . According to [8] , saponification of PFAD produces unsaponifiable matter (USM) which is rich in vitamin E, especially tocotrienols, phytosterols, and squalene. Total cholesterol and LDL cholesterol of rats fed USM-fortified diet were lower than controls, as well as better ratios of total cholesterol to HDL and LDL cholesterol to HDL. ...
... The tocotrienol-rich fraction of PFAD has antioxidant and cholesterol-lowering properties, and has hepatoprotector, immunomodulatory, antioxidant properties, and lactogenic effects in animal test experiments [7] . Tocotrienol compounds in PFAD are able to inhibit HMG Co-A reductase, the enzyme responsible for converting HMG to mevalonate in cholesterol biosynthesis [8] . Phytosterols have the ability to compete with cholesterol during the formation of micelles in the intestine. ...
... They found that the consumption of this phenolic-rich fruit juice was associated with a decreased triacylglycerides, LDL, and total cholesterol in serum while preventing the thickening of the blood vessel wall, deposition of lipid formation and foam cells in the tunica intima of the aorta and coronary arteries. Similarly, Che Idris et al. (2014) found that extracts of oil palm fruit, which are also sources of phenolic acids (protocatechuic, p-hydroxybenzoic, and caffeoyl shikimic acids), increased the plasma antioxidant capacity and reduced the development of fatty streaks, fatty plaque, and fibrous plaque in male New Zealand White rabbits fed a high-fat atherogenic diet. These two examples show the significant association between the consumption of phenolics and the decreased risk factors for atherosclerosis. ...
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Background Atherosclerosis is the primary cause of cardiovascular diseases (CVDs), contributing to more than 33% of the annual deaths globally. Westernized dietary patterns, a high prevalence (50%) of overweight and obesity, and an increased incidence of glucose intolerance and type-2 diabetes are related to atherosclerosis. However, increased demand for functional foods has boosted the production of different foods to improve people's life quality and decrease the CVDs' risk. Nonetheless, functional foods targeting CVDs are scarce in the marketplace. Scope and approach To perform a multidisciplinary and cross-sectoral approach by linking atherosclerosis biomarkers, potential bioactive compounds (e.g., phenolics), and food technology, besides scientific limitations, we propose a practical step-by-step guide to designing functional foods. First, a comprehensive and up-to-date overview of atherosclerosis is provided, focusing on the inflammation markers to counteract its onset and progression. Then, a structure-based–(SBDD) or ligand-based drug design (LBDD) approach is presented, and illustrated by the incorporation of vescalagin, a phenolic compound from jaboticaba seed, into a functional food to mitigate atherosclerosis. Key findings and conclusions Tailored functional foods added with phenolic compounds can be designed through computational approaches predicting their bioactivity. Together with chemical analyses, mathematical models can explore a vast array of molecular mechanisms, allowing the discovery of novel bioactive compound sources. Altogether, food science/technology, nutrition, and structure- and ligand-based approaches should be fused to support the design of tailor-made functional foods/nutraceuticals to contribute to public health interventions related to atherosclerosis and other cardiometabolic diseases.
... Working together with other phenolic acids in OPP, it might also contribute to the synergistic effect of the antioxidant activity observed. Due to its powerful antioxidant property, OPP was also noted to possess medicinal properties such as anti-tumor (Sekaran et al., 2010), anti-atherogenic (Idris et al., 2014), anti-diabetic (Bolsinger et al., 2014), anti-amyloidogenic (Monplaisir, 2016), and anti-hyperlipidemic properties (Fairus et al., 2018). In terms of toxicity, a 9-weeks acute and 90-days subchronic animal toxicity study of OPP showed no observable adverse effect in a human equivalent dose of up to 2,000 mg/kg body weight per day. ...
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Background and aim : Oil palm aqueous by-products rich in phenolic content are known as oil palm phenolics (OPP), and pre-clinical research has shown that OPP has great potential to be further developed as an anti-hyperlipidemic agent. Hence, in order to introduce OPP into market, its safety profile needs to be established by undergoing a phase I clinical trial on healthy humans. Methods : A parallel, placebo-controlled, randomized, and double-blinded clinical trial was conducted for 2 months on 100 healthy subjects aged 20–40 years old. This trial was registered at clinicaltrials.gov (NCT04164446). The subjects were randomly allocated to four treatment arms with 25 participants each: placebo, 250, 1,000, and 1,500 mg of OPP. During the trial, subjects were required to consume four capsules simultaneously per day. Withdrawal of fasting blood for hematology, liver and renal function analysis, and medical examination were conducted at baseline (day 1), day 30, and day 60. For monitoring, vital signs (blood pressure and pulse rate) and weight measurements were taken during each visit. Results : Minor adverse events (AEs) were reported in all groups especially at high dose (1,500 mg) but none were serious adverse events (SAEs). Fasting blood parameters between control and all OPP-treated groups demonstrated no statistically significant difference from baseline to day 60. Conclusion : With no major AEs and SAEs reported and no abnormal findings in biochemistry and hematology results, OPP supplementation in capsule form is safe to be taken up to 1,500 mg a day.
... The presence of flavonoids in the body has been found to block the enzyme aldose reductase, which prevents the activation of the sorbitol pathway, which has been linked to a range of diabetes problems.Their interaction with a broad variety of enzyme systems, such as the enzymes cyclooxygenase and lipoxygenase, results in a decrease of platelet activation and aggregation, as well as cardiovascular disease prevention, cancer chemoprevention, and anti-inflammatory properties.Additional biological effects of flavonoids and phenolic acids are known, including antiviral, antibacterial, and antihepatotoxic characteristics [43]. Flavonoids and phenolic acids have also been shown to exhibit antioxidant capabilities [44]. ...
... The higher oxidative stress in this part of the world that is caused by strong sun radiations, vehicle exhaust, lack of greenery etc. increases our requirements for these antioxidant phytonutrients. Consumption of foods rich in these antioxidant vitamins would, therefore, provide health benefits to the consumers (Idris et al., 2014;Gonzalez-Diaz et al., 2021). The presence of this natural vitamin E in palm oil ensures a longer shelf life for palm-oil-based food products (Meng et al., 2020). ...
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The objective of this research work was to produce acceptable quality functional foods, namely, extruded snacks, digestive biscuits and pan bread, on a pilot scale, using vitamin E and β-carotene-rich red palm olein (RPOL) and red palm shortening (RPS). These products were evaluated for their chemical composition and sensory quality along with the antioxidants and vitamin contents during the six months of storage at room temperature (22±1°C). Extruded snacks and digestive biscuits prepared with RPOL and RPS were found to be good sources of these antioxidant vitamins. The average β-carotene content of the control and test snacks at the end of six months of storage ranged from 26.8 to 56.1 mg/kg fat, and from 430.9 to 468.9 mg/kg fat, respectively. The total vitamin E content in control and test snacks made in Plant No. 1 decreased after six months of storage from 786.1 to 704.4 mg/kg fat, and from 765.1 to 695.4 mg/kg fat, respectively. As expected, the total tocotrienol content was four to five times higher than the total tocopherols in control biscuits. The RPOL containing 600-750 ppm of carotenes (mainly α- and β-carotenes), 710-774 ppm of vitamin E, was found to be suitable for industrial application in producing acceptable quality pan bread, digestive biscuits and snacks. These functional foods contained significant amounts of β-carotene and total vitamin E, indicating the possibility of producing such foods rich in these two of the important antioxidant vitamins coming from a natural source. The research findings strongly indicate that good-quality pan bread, extruded snacks and digestive biscuits can successfully be produced to offer healthier eating choices to the consumers of this region, thereby promoting better health and productivity among the population.
... The GRAS Panel was selected and convened in accordance with the United States (U.S.) Food and Drug Administration (FDA)'s guidance for industry on Best Practices for Convening a GRAS Panel [101]. PFBc has been shown to benefit several diseases in animal models with no evidence of toxicity [77,83,86,90,91,[102][103][104]. It has been demonstrated that PFBc was safe and well-tolerated in healthy human volunteers at doses up to 1000 mg/day for 30 days [97]. ...
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Cognitive function is a key aspect of healthy aging. Inflammation associated with normal aging, also called inflammaging is a primary risk factor for cognitive decline. A diet high in fruits and vegetable and lower in calories, particularly a Mediterranean Diet, may lower the risk of age-related cognitive decline due in part to the associated high intake of antioxidants and polyphenols. A phenolic, Palm Fruit Bioactive complex (PFBc) derived from the extraction process of palm oil from oil palm fruit (Elaeis guineensis), is reported to offset inflammation due to its high antioxidant, especially vitamin E, and polyphenol content. The benefit is thought to be achieved via the influence of antioxidants on gene expression. It is the purpose of this comprehensive review to discuss the etiology, including gene expression, of mild cognitive impairment (MCI) specific to dietary intake of antioxidants and polyphenols and to focus on the potential impact of nutritional interventions specifically PFBc has on MCI. Several in vitro, in vivo and animal studies support multiple benefits of PFBc especially for improving cognitive function via anti-inflammatory and antioxidant mechanisms. While more human studies are needed, those completed thus far support the benefit of consuming PFBc to enhance cognitive function via its anti-inflammatory antioxidant functions.
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