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Nutrigenomic effects of edible bird's nest on insulin signaling in ovariectomized rats


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Estrogen deficiency alters quality of life during menopause. Hormone replacement therapy has been used to improve quality of life and prevent complications, but side effects limit its use. In this study, we evaluated the use of edible bird's nest (EBN) for prevention of cardiometabolic problems in rats with ovariectomy-induced menopause. Ovariectomized female rats were fed for 12 weeks with normal rat chow, EBN, or estrogen and compared with normal non-ovariectomized rats. Metabolic indices (insulin, estrogen, superoxide dismutase, malondialdehyde, oral glucose tolerance test, and lipid profile) were measured at the end of the experiment from serum and liver tissue homogenate, and transcriptional levels of hepatic insulin signaling genes were measured. The results showed that ovariectomy worsened metabolic indices and disrupted the normal transcriptional pattern of hepatic insulin signaling genes. EBN improved the metabolic indices and also produced transcriptional changes in hepatic insulin signaling genes that tended toward enhanced insulin sensitivity, and glucose and lipid homeostasis, even better than estrogen. The data suggest that EBN could meliorate estrogen deficiency-associated increase in risk of cardiometabolic disease in rats, and may in fact be useful as a functional food for the prevention of such a problem in humans. The clinical validity of these findings is worth studying further.
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Nutrigenomic effects of edible bird’s nest
on insulin signaling in ovariectomized rats
Zhiping Hou1,2
Mustapha Umar Imam1
Maznah Ismail1,3
Der Jiun Ooi1
Aini Ideris4
Rozi Mahmud5
1Laboratory of Molecular Biomedicine,
Institute of Bioscience, Universiti
Putra Malaysia, Serdang, Malaysia;
2Department of Pathology, Chengde
Medical University, Chengde, People’s
Republic of China; 3Department of
Nutrition and Dietetics, Universiti
Putra Malaysia, Serdang, Malaysia;
4Department of Veterinary Clinical
Studies, Faculty of Veterinary
Medicine, Universiti Putra Malaysia,
Serdang, Malaysia; 5Department
of Imaging, Faculty of Medicine
and Health Sciences, Universiti
Putra Malaysia, Serdang, Malaysia
Abstract: Estrogen deficiency alters quality of life during menopause. Hormone replacement
therapy has been used to improve quality of life and prevent complications, but side effects
limit its use. In this study, we evaluated the use of edible bird’s nest (EBN) for prevention
of cardiometabolic problems in rats with ovariectomy-induced menopause. Ovariectomized
female rats were fed for 12 weeks with normal rat chow, EBN, or estrogen and compared with
normal non-ovariectomized rats. Metabolic indices (insulin, estrogen, superoxide dismutase,
malondialdehyde, oral glucose tolerance test, and lipid profile) were measured at the end of
the experiment from serum and liver tissue homogenate, and transcriptional levels of hepatic
insulin signaling genes were measured. The results showed that ovariectomy worsened meta-
bolic indices and disrupted the normal transcriptional pattern of hepatic insulin signaling genes.
EBN improved the metabolic indices and also produced transcriptional changes in hepatic
insulin signaling genes that tended toward enhanced insulin sensitivity, and glucose and lipid
homeostasis, even better than estrogen. The data suggest that EBN could meliorate estrogen
deficiency-associated increase in risk of cardiometabolic disease in rats, and may in fact be use-
ful as a functional food for the prevention of such a problem in humans. The clinical validity
of these findings is worth studying further.
Keywords: ovariectomy, lipid metabolism, insulin resistance, antioxidant, aging
Menopause is characterized by depletion of the ovarian follicles and decreasing levels
of estrogen and related hormones. As menopause sets in, the ovaries progressively fail
to produce estrogen, resulting in symptoms that may be severe and disabling and have
an impact on quality of life.1 Estrogen has modulatory effects on metabolic processes
including the maintenance of optimal glucose and lipid homeostasis, which it does
through regulation of key hormones and genes involved in cardiometabolic health.2
During menopause, fluctuations and/or relative or absolute deficiency of estrogen and
other sex hormones will result in loss of the balance maintained by these hormones,
thereby leading to a disturbed internal milieu and heightened risk of diseases including
insulin resistance and associated problems.3,4
The symptoms and diseases that are a consequence of menopause have received
considerable attention, due to their distressing nature and impact on quality of life. It is
increasingly becoming a concern for women because of increasing life expectancy. Hor-
mone replacement therapy has been used to restore premenopausal hormonal levels in
order to reverse menopausal problems, but associated side effects including cancers and
cardiovascular disease have necessitated the search for alternatives.5,6 Phytoestrogens from
plants have also been associated with side effects similar to those of hormone replacement
therapy.7 Alternatives like Remifemin® have not offered significant improvements in
Correspondence: Maznah Ismail
Laboratory of Molecular Biomedicine,
Institute of Bioscience, Universiti
Putra Malaysia, 43400, Serdang,
Selangor, Malaysia
Fax +60 3 8947 2116
Journal name: Drug Design, Development and Therapy
Article Designation: Original Research
Year: 2015
Volume: 9
Running head verso: Hou et al
Running head recto: Edible bird’s nest prevents insulin resistance
This article was published in the following Dove Press journal:
Drug Design, Development and Therapy
14 August 2015
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Hou et al
long-term sequelae of menopause like cancer and cardiometa-
bolic disease risk, and side effects further limit their use.8
The burden of cardiometabolic disease has grown consid-
erably over the years, and in women the risk of these diseases
increases significantly after menopause.3,4 Edible bird’s nest
(EBN) has been used as a traditional supplement mostly by
Asians to improve wellbeing.9 Recent evidence indicates
that EBN may have anti-inflammatory and antioxidative
properties,10–12 which can be beneficial in cardiometabolic
disease.13,14 In this study, we determined the effects of EBN on
cardiometabolic indices in ovariectomized rats, and a possible
mechanistic basis for such effects. We hypothesized that the
outcome of the study could provide the evidence needed for
use of EBN as a functional food in preventing cardiometabolic
disease in menopause, where the risk of such is increased due
to loss of protection from estrogen and related hormones.
Materials and methods
A rat insulin enzyme-linked immunosorbent assay kit was
purchased from Millipore (Billerica, MA, USA), while kits
for superoxide dismutase (SOD) and estrogen were from
Cell Biolabs (Cell Biolabs Inc, San Diego, CA, USA) and
Cusabio Biotech Co Ltd (Wuhan, People’s Republic of
China), respectively. The GenomeLab™ GeXP start kit
was from Beckman Coulter Inc (Miami, FL, USA) and the
RNA extraction kit was from RBC Bioscience Corp (Taipei,
Taiwan). MgCl2 and DNA Taq polymerase were purchased
from Thermo Fisher Scientific (Pittsburgh, PA, USA), while
RCL2 solution was purchased from Alphelys (Toulouse,
France). Glucometer strips were from Roche Diagnostics
(Indianapolis, IN, USA) and lipid profile kits (low-density
lipoprotein cholesterol, high-density lipoprotein cholesterol,
total cholesterol, and triglycerides) were purchased from
Randox Laboratories Ltd (Crumlin, County Antrim, UK). Rat
chow was obtained from Specialty Feeds (Glen Forrest, WA,
Australia). Ketamine/xylazine was from Sigma Chemical Co
(St Louis, MO, USA) and other solvents of analytical grade
were purchased from Merck (Darmstadt, Germany).
EBN samples
Ready-to-use EBN was supplied by Niah Bird’s Nest Trading
Company (Sarawak, Malaysia), and was incorporated into
standard rat chow for animal feeding. For determination of
nutritional composition, EBN was dried at 50°C for 3 days,
ground into powder, and used. Nutritional composition
(protein, carbohydrate, fat, ash, and moisture; Table 1) was
determined as reported previously.15
Animal handling and feeding
Approval for use of animals was granted by the Animal Care
and Use Committee of the Faculty of Medicine and Health
Sciences, Universiti Putra Malaysia (approval UPM/IACUC/
AUP-R012/2014), and the animals were handled as stipulated
by the guidelines for the use of animals. Thirty-six Sprague-
Dawley rats (3 months old, female, 160–180 g) were housed
under controlled conditions (12-hour light/12-hour dark
cycle, 20°C–22°C, 40%–50% humidity) with free access to
water and food for 2 weeks prior to the experiments. After
acclimatization, rats were ovariectomized under anesthesia
using 10 mg/60 mg/kg xylazine/ketamine (intraperitoneally),
except for the normal controls. The rats were then observed for
4 weeks and randomly assigned to one of five groups (n=6):
a sham group, maintained on standard rat chow; an ovariectomy
(OVX) control group maintained on standard rat chow; an OVX +
estrogen group maintained on standard rat chow and daily
estrogen (0.2 mg/kg body weight); an OVX + 3% EBN group
maintained on standard rat chow containing 3% EBN; and an
OVX + 1.5% EBN group maintained on standard rat chow con-
taining 1.5% EBN. The normal group was not ovariectomized
and was maintained on standard rat chow. Treatments lasted
for 12 weeks, and food intake in each group was adjusted to the
average intake each day according to observation of the OVX
group the day before. Weights were measured weekly, and the
total amount of feed (g) given was reviewed weekly based on
the weekly weights of the rats. At the end of the experiment, all
animals were exsanguinated after anesthesia (10 mg/60 mg/kg
xylazine/ketamine, intraperitoneally). The livers were collected
into RCL2 solution for gene expression studies.
OGTT and lipid prole
At the end of the intervention, an oral glucose tolerance
test (OGTT) was performed on each animal after 12 hours
of an overnight fast, and measurements were taken with a
glucometer. Serum samples from blood collected on the day
of euthanasia were used to analyze the rat lipid profiles (total
Table 1 Nutritional values for edible bird’s nest
Nutritional value*Crude protein Carbohydrate Fat Ash Moisture
Edible bird’s nest 67.72%±1.9% 31.07%±1.5% 1%±0.002% 0.06%±0.002% 0.15%±0.004%
Notes: *Nutritional values are expressed as percent dry weight. All the values are shown as the mean ± standard deviation (n=3).
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Edible bird’s nest prevents insulin resistance
cholesterol, high-density lipoprotein cholesterol, low-density
lipoprotein cholesterol, and triglycerides) using a Dimension
Xpand Plus Integrated chemistry system (Siemens, Germany)
with commercially available kits.
Determination of serum estrogen
and insulin
Serum samples were used for measurements of estrogen and
insulin using the respective enzyme-linked immunosorbent
assay kits according to the manufacturers’ instructions.
Absorbance was read on a microplate reader (BioTek
Synergy H1 Hybrid Reader, BioTek Instruments Inc,
Winooski, VT, USA) and results were calculated from the
respective standard curves: estrogen (y = -30.12x +113.73,
R2=1), insulin (y =0.762x -0.143, R2=0.966). Addition-
ally, homeostatic model assessment of insulin resistance
(HOMA-IR), a measure of insulin sensitivity, was com-
puted from the fasting plasma glucose and insulin levels
as reported previously.16
Hepatic antioxidative markers
Superoxide dismutase enzyme
Liver homogenates were used for SOD quantification using
the enzyme-linked immunosorbent assay kit according to
the manufacturer’s instructions. Absorbance were read on
a microplate reader (BioTek Synergy H1 Hybrid Reader)
and results were calculated from the standard curve
(y =0.143x -0.017, R²=1).
Thiobarbituric acid reactive substances assay
Thiobarbituric acid reactive substances were determined
using a modified method based on the protocol of Chan
et al.17 Briefly, homogenized liver tissues (50 mg/100 μL
phosphate-buffered saline) were added to 0.25 N HCl,
15% trichloroacetic acid, and 0.375% thiobarbituric acid
separately, then incubated at 100°C for 10 minutes, and
centrifuged at 3,000 rpm for 15 minutes. Finally, absorbance
of the supernatant were read at 540 nm using the Synergy
H1 Hybrid Multi-Mode microplate reader. Malondialdehyde
(MDA) was used as the standard (y =0.1982x -0.1898,
RNA extraction, reverse transcription,
and multiplex polymerase chain reaction
RNA was extracted from rat livers using the Total RNA
isolation kit according to the manufacturer’s instructions.
Primer sequences were designed on the National Center for
Biotechnology Information website, except for the internal
control (KanR), which was supplied by Beckman Coulter.
The primers (Table 2) were supplied by Integrated DNA
Technologies (Singapore), and reconstituted in 1× TE buffer
according to the protocol outlined in the GenomeLab GeXP
kit. Reverse transcription and polymerase chain reaction were
performed according to the GenomeLab GeXP kit protocol
in an XP Thermal Cycler (Bioer Technology, Germany). The
polymerase chain reaction products were finally analyzed
with a GeXP genetic analysis system, and the results were
normalized using eXpress Profiler software based on the
manufacturer’s instructions.
Statistical analysis
Statistical analyses were done using one-way analysis of
variance with Tukey’s honest significant difference test.
The data are expressed as the mean ± standard error of
the mean. P,0.05 indicates statistical significance. All
values were statistically evaluated using Statistical Package
for the Social Sciences version 20.0 (SPSS Inc, Chicago,
Results and discussion
Food intake and body weight
Menopause is characterized by a drop in estrogen levels,
which results in lipid and glucose metabolic perturbation.1,3,4
In this study, serum estrogen levels in the OVX group
were significantly lower than in the other groups (Table 3),
suggesting that removal of the ovaries produced a condition
similar to menopause in the rats. The higher levels in the
estrogen group could be attributed to exogenous estrogen
administration, while the high levels of the hormone in
the EBN group could have been due to increased extrago-
nadal synthesis of estrogen18 induced by EBN or possibly
estrogen-like compounds absorbed from EBN. Body weights
were similar for all groups at the start of the experiment
(Table 3), and calorie intake remained similar throughout
the intervention period. At the end, however, differences in
weight gain were observed. The OVX group had the highest
weight gain, indicating that loss of estrogen affected body fat
deposition and distribution. Moreover, estrogen is believed
to regulate weight in women, while menopause is associated
with increased weight gain, which is linked to increased
risk of cardiometabolic disease.2–4 Estrogen treatment and
EBN produced lower weight gains similar to the control
group, suggesting that both treatments had some weight-
modulating properties, possibly mediated through estrogen
and/or estrogen-mimetic effects.
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Hou et al
Serum lipid prole
Table 4 shows the lipid profiles for the different groups.
Total cholesterol for the OVX group was highest although
no significant differences were observed between the groups.
Low-density lipoprotein cholesterol was also highest in
the OVX group, while the others were significantly lower,
except for the 1.5% EBN group. Triglyceride levels were
significantly lower in the EBN groups in comparison with
the OVX group, while high-density lipoprotein cholesterol
levels were not significantly different between the groups.
As expected, estrogen improved the lipid profiles. Estrogen
modulates cholesterol metabolism, and in estrogen-deficient
states similar to OVX, there is dysregulation of cholesterol
metabolism in favor of higher cholesterol levels, with an
increased risk of cardiometabolic disease.4 EBN on the
other hand was able to ameliorate lipid profile and cho-
lesterol ratios (Table 4) similar to estrogen. This effect of
EBN on the lipid profile may have been secondary to the
enhanced estrogen concentration induced by EBN, but other
EBN constituents may also have played a role since EBN
is known to be bioactive-rich.9 The improved lipid profiles
observed in this study suggest that EBN could lower the risk
of cardiometabolic disease without the associated risks of
estrogen administration.
OGTT, serum insulin, and HOMA-IR
The OGTT results are shown in Figure 1. The glycemic
response in the OVX group was impaired in comparison
with the other groups, which showed similar and significantly
(P,0.05) lower responses (Figure 1A). Moreover, the area
under the curve for glucose over 120 minutes (Figure 1B)
was significantly lower (P,0.05) for the EBN and estrogen
treatments in comparison with the OVX group. Additionally,
the insulin level was highest in the OVX group, which could
have been a counter-response to the loss of estrogen-regulated
insulin action in the rats (Figure 2). The estrogen group, on
the other hand, showed significantly lower insulin levels
(P,0.05), while the EBN groups were not significantly dif-
ferent from the OVX group. HOMA-IR results showed that
the OVX group had the highest tendency for insulin resis-
tance, while estrogen therapy significantly improved insulin
sensitivity (P,0.05). These effects of OVX and estrogen
therapy mirror what has been reported previously;4 OVX
tends to increase the risk of insulin resistance, which can
be prevented by estrogen therapy. EBN treatments showed
dose-dependent effects on insulin sensitivity, but only the 3%
EBN treatment showed significantly better results than those
seen in the OVX group. Although estrogen may prevent the
Table 2 Names, accession numbers, and primer sequences used in the study
Gene name Accession number Left sequence Right sequence
Kan (r)**
Notes: *Housekeeping gene. #Normalization gene. Underlined sequences are left and right universal left and right sequences (tags). **Internal control supplied by Beckman Coulter Inc, as part of the GeXP kit. Reverse transcription
conditions were: 48°C for 1 minute; 37°C for 5 minutes; 42°C for 60 minutes; 95°C for 5 minutes, then hold at 4°C. Polymerase chain reaction conditions were initial denaturation at 95°C for 10 minutes, followed by two-step cycles of
94°C for 30 seconds and 55°C for 30 seconds, ending in a single extension cycle of 68°C for 1 minute.
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Edible bird’s nest prevents insulin resistance
OVX-induced risk of insulin resistance as demonstrated in
the present study (lower HOMA-IR in the estrogen group),
EBN may be preferred since its consumption is not associ-
ated with side effects as with estrogen therapy, except when
it is adulterated.9
Hepatic antioxidant capacity of EBN
Oxidative stress is increased while antioxidants are decreased
in estrogen-deficient states. This imbalance is thought to
underlie some problems related to menopause.19 Thus, in
this study, MDA levels, indicative of oxidative stress, were
potentiated in the OVX group while SOD, an antioxidant
enzyme, was suppressed (Figure 3), in keeping with a report
by Muthusami et al.20 Further, estrogen treatment reduced
MDA and improved SOD levels but not as well as EBN.
Moreover, the side effects of estrogen therapy may be asso-
ciated with the pro-oxidant effects of exogenous estrogen.21
EBN significantly ameliorated oxidative stress status and
improved antioxidant abilities, in agreement with reports on
its antioxidant properties.11,12 The results therefore suggest
that improved antioxidant enzymes may partly form the basis
for improved metabolic indices in ovariectomized rats fed
EBN, since improved antioxidant status has been linked with
better metabolic outcomes.22
mRNA levels of hepatic insulin signaling
The results thus far indicate that EBN could lower the risk
of estrogen deficiency-induced perturbations in glucose
and lipid homeostasis. In an effort to understand some
of the mechanistic bases for the observed effects, we
evaluated mRNA levels for hepatic insulin signaling genes
(Figures 4–6). Figure 4 shows the effects of the interven-
tions on mRNA levels of the hepatic insulin receptor, insulin
receptor substrate 2 (IRS2), and phosphoinositide-3-kinase
(PI3K). Insulin exerts its effects after binding to its receptor
and activating a cascade of events mediated by IRS2,23 in
which PI3K plays a prominent role through enhanced insulin
signaling in the cell.24 Disruption of this pathway promotes
insulin resistance. In this study, OVX downregulated IRS2
and PI3K, suggesting that estrogen deficiency-induced inter-
ruption of cellular insulin signaling contributed to worsening
of glucose and lipid homeostasis in the rats. Interestingly,
EBN increased expression of the insulin receptor, IRS2, and
PI3K even better than estrogen therapy, indicating that its
ability to prevent estrogen deficiency-induced worsening
of glucose and lipid homeostasis in ovariectomized rats
was partly through transcriptional upregulation of insulin
Furthermore, OVX upregulated mitogen-activated protein
kinase (MAPK) and inhibitor of kappa light polypeptide gene
enhancer in B-cells, kinase beta (IKBKB, Figure 5), which
have both been implicated in impaired insulin signaling.25,26
These genes have been reported to influence the activity of
IRS2, and the OVX-induced low transcriptional levels of
IRS2 observed in this study may have been due to upregula-
tion of MAPK1 and IKBKB.25,26 The EBN groups had lower
mRNA levels of these genes in comparison with other groups,
further suggesting that the effects of EBN on transcriptional
regulation of IRS2 may have been through MAPK1 and
IKBKB. Glucose transporter type 4 (GLUT4) transports
glucose into cells for metabolism and is downregulated in
insulin-resistant states.27 Although the exact contribution of
hepatic expression of GLUT4 to glucose transport remains
a matter of debate, there are indications that its dysregula-
tion is linked to insulin resistance.28 In this study, OVX
downregulated GLUT4, while EBN treatments upregulated
the gene in a dose-dependent manner. Moreover, lower lev-
els of MAPK, with consequently higher PI3K levels, have
been reported to enhance glucose uptake through increased
GLUT4 expression.27 In keeping with findings of decreased
MAPK and increased PI3K and GLUT4 in this study.
Table 3 Body weight, food intake, and serum estrogen levels in ovariectomized rats after 12 weeks of intervention
Rat groups Body weight
before intervention (g)
Body weight at end of
intervention (g)
Total food intake
Serum estrogen
Normal control 221.5±33.5a227.5±6.0a134±4.8a151.1±8a
Sham control 217.8±44.0a224.6±6.8a134±4.8a156.7±13a
OVX control 230±29.7a283.1±23.1b134±4.8a35.6±0.9b
Estrogen-treated 236±33.3a239±3.0a134±4.8a169.8±11.4a
3% EBN 228.1±53.9a242.8±14.6a134.97±4.99a147.8±8.7a
1.5% EBN 216±31.5a242.6±26.7a,b 134.81±4.45a143.3±13.4a
Notes: Values are shown as the mean ± standard deviation, n=6. All rat groups received standard rat chow for 12 weeks, and in addition, the estrogen-treated groups
received 0.2 mg/kg/day of estrogen, while EBN groups received 3% or 1.5% EBN in their rat chow. Columns with different letters signify statistical difference (P,0.05).
Abbreviations: OVX, ovariectomy; EBN, edible bird’s nest.
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Transcriptional levels of other genes that contribute
to enhanced cellular glucose sensing and homeostasis
(glucokinase, pyruvate kinase-liver isoform, and potas-
sium inwardly rectifying channel, subfamily J, member 11
[KCNJ11] genes) were downregulated in the OVX group
(Figure 6). Conversely, the EBN group showed increased
expression of these genes, except KCNJ11, even better
than estrogen therapy. The implications of these effects
could be increased hepatic glucose storage and utilization
(glucokinase and pyruvate kinase-liver isoform),29 which
may then enhance cellular adenosine triphosphate levels
and subsequent upregulation of KCNJ11 with improved
glucose homeostasis.30
Based on the effects of EBN observed in this study, we
propose that EBN transcriptionally regulates multiple targets
in the insulin signaling pathway (Figure 7) and that this is
the basis for the improved insulin signaling and glucose and
lipid homeostasis.
Overall, the data show that OVX worsened glucose
and lipid homeostasis and oxidative stress (low insulin
and SOD levels; high body weight, HOMA-IR, MDA, and
lipid profile levels; and impaired insulin signaling) in rats.
Estrogen therapy, on the other hand, was able to improve
the lipid profile and OGTT, SOD, and MDA levels, and
was even associated with some transcriptional changes in
hepatic insulin signaling genes that tended toward better
glucose and lipid homeostasis. However, EBN improved
glucose and lipid homeostasis, lowered weight and oxidative
stress, and enhanced estrogen deficiency-induced impaired
signaling of insulin better than estrogen. Simple linear
regression analyses indicate that estrogen levels significantly
correlated with changes in HOMA-IR (r= -0.82, P=0.046),
SOD (r=0.82, P=0.046), MDA (r= -0.87, P=0.023), and
PI3K-mediated insulin signaling (r=0.86, P=0.027). Addi-
tionally, SOD levels (r= -0.86, P=0.028) and PI3K-mediated
insulin signaling (r= -0.85, P=0.033), but not MDA levels
(r=0.53, P=0.28) correlated with HOMA-IR in this study.
Multiple linear regression analyses indicate further that
changes in estrogen were overall strong determinants of
changes in SOD, MDA, HOMA-IR, and PI3K expression
changes (R=1, R2=0.995), and that estrogen, SOD, MDA, and
PI3K expression was a significant predictor of HOMA-IR
(R=0.987, R2=0.873). The combined effects of EBN on these
markers of cardiometabolic disease, coupled with the known
side effects of estrogen therapy, suggest that EBN may be
better than hormone replacement therapy at preventing
menopause-associated cardiometabolic disease, especially
impaired glucose and lipid homeostasis.
Table 4 Serum lipid proles after 12 weeks of intervention
Rat groups TC (mg/dL) LDL (mg/dL) HDL (mg/dL) LDL/HDL (ratio) VLDL* (mg/dL) TC/HDL (ratio) TG (mg/dL)
Normal control 1.858±0.240a,b 0.194±0.035a1.268±0.127a,b 0.153±0.027a0.396±0.078a,d 1.465±0.189a,b 0.473±0.033a,c
Sham 1.690±0.234a0.198±0.035a1.092±0.120a0.181±0.032a0.400±0.079a,d 1.548±0.214a,b 0.587±0.090a,b,d
OVX control 2.220±0.248b0.374±0.046b1.360±0.157a,b 0.275±0.034b0.486±0.045a1.632±0.183a0.657±0.067b
Estrogen 1.885±0.105a,b 0.286±0.038c1.375±0.077b0.208±0.028c0.224±0.011b1.371±0.076b0.460±0.026c
3% EBN 1.683±0.301a,b 0.298±0.021c1.316±0.135a,b 0.226±0.016b,c 0.068±0.014c1.278±0.229a,b 0.455±0.021c
1.5% EBN 1.897±0.254a,b 0.320±0.020b,c 1.260±0.132a,b 0.254±0.016b,c 0.317±0.010d1.505±0.201a,b 0.527±0.006d
Notes: Values are shown as the mean ± standard deviation. Columns with different letters indicate statistical difference (P,0.05). *Total cholesterol – (HDL + LDL). All rat groups received standard rat chow for 12 weeks, and in addition,
the estrogen treated groups received 0.2 mg/kg/day of estrogen, while EBN groups received 3% or 1.5% EBN in their rat chow.
Abbreviations: TC, total cholesterol; TG, triglycerides; LDL, low-density lipoprotein; HDL, high-density lipoprotein; VLDL, very low-density lipoprotein; EBN, edible bird’s nest; OVX, ovariectomy.
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Edible bird’s nest prevents insulin resistance
  
Figure 1 Effects of 12 weeks of supplementation with EBN on (A) oral glucose tolerance test and (B) AUC for glucose in ovariectomized rats.
Notes: EBN high, 3% EBN; EBN low, 1.5% EBN. Different letters for bars in (B) indicate a statistically signicant difference (P,0.05). All rat groups received standard rat
chow for 12 weeks, and in addition, the estrogen treated groups received 0.2 mg/kg/day of estrogen, while EBN groups received 3% or 1.5% EBN in their rat chow.
Abbreviations: AUC, area under the curve; EBN, edible bird’s nest; OVX, ovariectomy.
a,b a,b
Rat groups
Insulin (ng/mL)HOMA-IR
Rat groups
OVX Estrogen
EBN high
EBN high
EBN low
Normal control
Normal control
Figure 2 Effects of 12 weeks of supplementation with EBN on (A) serum insulin and (B) HOMA-IR in ovariectomized rats.
Notes: EBN high, 3% EBN; EBN low, 1.5% EBN. Different letters for bars in each panel indicate a statistically signicant difference (P,0.05). All rat groups received standard
rat chow for 12 weeks, and in addition, the estrogen treated groups received 0.2 mg/kg/day of estrogen, while EBN groups received 3% or 1.5% EBN in their rat chow.
Abbreviations: EBN, edible bird’s nest; OVX, ovariectomy; HOMA-IR, homeostatic model assessment of insulin resistance.
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EBN high
EBN high
EBN low
EBN low
Rat groups
MDA content
(nmol/L) SOD (U/mg protein)
Rat groups
Figure 3 Effects of 12 weeks of supplementation with EBN on serum (A) SOD levels and (B) MDA levels in ovariectomized rats.
Notes: Different letters for bars in each panel indicate a statistically signicant difference (P,0.05). All rat groups received standard rat chow for 12 weeks, and in addition,
the estrogen treated groups received 0.2 mg/kg/day of estrogen, while EBN groups received 3% or 1.5% EBN in their rat chow.
Abbreviations: EBN, edible bird’s nest; MDA, malondialdehyde; SOD, superoxide dismutase; OVX, ovariectomy.
Normal Normal
Sham Sham
Estrogen Estrogen
Rat groupsRat groups
Relative expression
Relative expression
Relative expression
Insr IRS2
Rat groups
Figure 4 Hepatic mRNA levels of the (A) Insr, (B) IRS2, and (C) PI3K in ovariectomized rats fed with EBN for 12 weeks.
Notes: Different letters for bars in each panel indicate a statistically signicant difference (P,0.05). All rat groups received standard rat chow for 12 weeks, and in addition,
the estrogen treated groups received 0.2 mg/kg/day of estrogen, while EBN groups received 3% or 1.5% EBN in their rat chow.
Abbreviations: EBN, edible bird’s nest; PI3K, phosphoinositide-3-kinase; IRS2, insulin receptor substrate 2; OVX, ovariectomy; Insr, insulin receptor.
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Edible bird’s nest prevents insulin resistance
Normal Sham Estrogen EBN
Rat groups
Relative expression
NormalSham Estrogen EBN
Relative expression
Rat groups
NormalSham Estrogen EBN
Relative expression
Rat groups
Figure 5 Hepatic mRNA levels of (A) GLUT4, (B) IKBKB, and (C) MAPK1 in ovariectomized rats fed with EBN for 12 weeks.
Notes: Different letters for bars in each panel indicate a statistically signicant difference (P,0.05). All rat groups received standard rat chow for 12 weeks, and in addition,
the estrogen treated groups received 0.2 mg/kg/day of estrogen, while EBN groups received 3% or 1.5% EBN in their rat chow.
Abbreviations: EBN, edible bird’s nest; GLUT4, glucose transporter type 4; IKBKB, inhibitor of kappa light polypeptide gene enhancer in B-cells, kinase beta; MAPK1, mitogen-activated
protein kinase 1; OVX, ovariectomy.
Figure 6 Hepatic mRNA levels of (A) GCK, (B) KCNJ11, and (C) LPK in ovariectomized rats fed with EBN for 12 weeks.
Notes: Different letters for bars in each panel indicate a statistically signicant difference (P,0.05). All rat groups received standard rat chow for 12 weeks, and in addition,
the estrogen treated groups received 0.2 mg/kg/day of estrogen, while EBN groups received 3% or 1.5% EBN in their rat chow.
Abbreviations: EBN, edible bird’s nest; GCK, glucokinase; KCNJ11, potassium inwardly rectifying channel, subfamily J, member 11; OVX, ovariectomy; LPK, pyruvate kinase-liver
Drug Design, Development and Therapy 2015:9
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Figure 7 Proposed schematic showing targets of EBN action in the insulin signaling pathway. EBN prevents insulin resistance in ovariectomized rats by inuencing the
transcriptional regulation of multiple genes.
Abbreviations: EBN, edible bird’s nest; GLUT, glucose transporter; MAPK, mitogen-activated protein kinase; GCK, glucokinase; IKBKB, inhibitor of kappa light polypeptide
gene enhancer in B-cells, kinase beta; IRS, insulin receptor substrate; KCNJ11, potassium inwardly rectifying channel, subfamily J, member 11; INSR, insulin receptor; LPK,
pyruvate kinase-liver isoform; Pik3ca, phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha.
OVX promotes metabolic perturbations that may give
rise to cardiometabolic disease, and although the use of
estrogen may offer some protection against some of these
cardiometabolic problems, as suggested by the present data,
use of estrogen therapy is limited by side effects. EBN has
demonstrated an ability to improve cardiometabolic indices
and enhance transcriptional regulation of insulin signaling
genes even better than estrogen. These results demonstrate for
the first time the potential for EBN to be used as a functional
food for prevention of cardiometabolic disease associated
with estrogen deficiency. These findings are worth studying
further in humans to ascertain the clinical validity of EBN
in preventing these diseases.
The authors acknowledge the financial support of the
Ministry of Science, Technology and Innovation, the
e-ScienceFund, Malaysia (vote 5450666); and the staff of
the Laboratory of Molecular Biomedicine for their assistance
during the study.
The authors report no conflicts of interest in this work.
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... This is thought to be achieved by enhancing antioxidant enzyme activity but inhibiting microglial activation, nitric oxide formation, and lipid peroxidation. Besides, Zhiping et al. (2015) and Hou et al. (2015) also found that EBN has protective effects on nerve damage caused by estrogen deficiency, and ready-to-eat EBN can be used as a new strategy for the clinical treatment of menopausal neurodegenerative diseases (Zhiping et al., 2015;Hou et al., 2015). These studies suggest EBN may be a viable nutritional option for improving neurodegenerative diseases. ...
... This is thought to be achieved by enhancing antioxidant enzyme activity but inhibiting microglial activation, nitric oxide formation, and lipid peroxidation. Besides, Zhiping et al. (2015) and Hou et al. (2015) also found that EBN has protective effects on nerve damage caused by estrogen deficiency, and ready-to-eat EBN can be used as a new strategy for the clinical treatment of menopausal neurodegenerative diseases (Zhiping et al., 2015;Hou et al., 2015). These studies suggest EBN may be a viable nutritional option for improving neurodegenerative diseases. ...
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Edible bird's nest is built by swiftlet during breeding using salivary gland secretions, which have rich nutritional value, such as anti-aging, immunomodulatory, and antioxidant activity. As a result, the global demand for edible bird's nests has increased significantly. Swiftlet farmers, consumers, traders, and authorities are increasingly concerned about obtaining safe and high-quality edible bird's nests. On the other hand, subject to the limitations of the number of swiftlet populations and the ecological environment, exploring new food processing technologies to improve the utilization efficiency of edible bird's nest nutrition has also become the research frontier. Therefore, this study introduced the origin and classification of edible bird's nests in detail, presented the current situation of the edible bird's nest industry and the corresponding review measures of various countries, reviewed the efficacies of edible bird's nest, and introduced the new form of edible bird's nest utilization: edible bird's nest hydrolysates and their efficacies.
... In addition, a study done by Ghassem et al. suggested that protein hydrolysate of EBN possesses antioxidant properties and can scavenge the free radical (72). A similar study was reported on improving the level of superoxide dismutase (SOD), estrogen, malondialdehyde, and lipid profile of the ovariectomized rats with 12 weeks of EBN supplementation in the diet (77). These findings highlight the value of EBN to prevent cardiometabolic disease induced by estrogen deficiency. ...
... In addition, EBN contains glycoproteins such as lactoferrin (LF) and ovotransferrin (OVF), which were reported to have neuroprotective activity and antioxidant through scavenging free radical species in SH-SY5Y cells (80,81). When EBN was tested on SH-SY5Y cells, Hou et al. found that the antioxidant and protective effects on the cells were also due to its components LF and OVF (77). These findings showed that EBN has antiaging and antineurodegenerative properties. ...
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Cognitive enhancement is defined as the augmentation of the mind's core capabilities through the improvement of internal or external information processing systems. Recently, the focus has shifted to the potential therapeutic effects of natural products in improving cognitive function. Edible bird's nest (EBN) is a natural food substance derived from the saliva of swiftlets. Until today, EBN is regarded as a high-priced nutritious food with therapeutic effects. The effectiveness of dietary EBN supplementation to enhance brain development in mammals has been documented. Although the neuroprotection of EBN has been previously reported, however, the impact of EBN on learning and memory control and its potential as a cognitive enhancer drug remains unknown. Thus, this article aims to address the neuroprotective benefits of EBN and its potential effect as a cognitive enhancer. Notably, the current challenges and the future study direction in EBN have been demonstrated.
... Yida et al. (2015) melaporkan bahwa SBW secara signifikan menurunkan kadar insulin, kolesterol total dan leptin, yang diduga karena pengurangan stres oksidatif oleh SBW. Sarang burung walet juga menghasilkan regulasi transkripsional gen pensinyalan insulin hati yang meningkatkan homeostasis lipid dan glukosa serta meningkatkan sensitivitas insulin (Hou et al., 2015). ...
... Sifat antioksidan SBW bermanfaat untuk penyakit kardiometabolik (Hou et al., 2015). Sarang burung walet mengandung bahan mudah dicerna dan bahan sulit dicerna. ...
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Sarang burung walet (SBW) merupakan sarang yang berasal dari saliva beberapa spesies burung walet keluarga Apodidae, terutama spesies Aerodramus fuciphagus dan A. maximus. Indonesia merupakan negara penghasil SBW terbesar dengan menyumbang 85% dari pasar dunia. Sarang burung walet sejak lama telah digunakan dalam pengobatan tradisional Tiongkok. Komponen utama dari SBW adalah glikoprotein, yang diyakini terlibat dalam jalur biologis yang beragam untuk meningkatkan kesehatan. Berbagai metode penelitian telah dilakukan untuk mengkarakterisasi peptida dan glikoprotein SBW sebagai bahan bioaktif makanan fungsional. Ulasan ini bertujuan untuk memberikan informasi mengenai potensi SBW sebagai produk makanan fungsional berdasarkan kandungan bahan bioaktif dan sifat fisikokimia yang dimilikinya. Sarang burung walet digunakan sebagai bahan makanan, baik dengan menyajikan dalam bentuk utama atau menggabungkan dengan bahan lain yang meningkatkan nilai tambah produk pangan seperti minuman siap saji, yoghurt, roti daging, es krim, mie dan cokelat. Potensi komponen bioaktif SBW sebagai pangan fungsional meliputi klaim penurunan risiko penyakit dan klaim fungsi lain. Klaim penurunan risiko penyakit antara lain anti inflamasi, aktifitas antivirus, meningkatkan kesehatan jantung dan pembuluh darah, meningkatkan imunitas, efek neuroprotektif, dan mencegah penyakit diabetes. Klaim fungsi lain meliputi ploriferasi sel, aktifitas epidermal growth factor (EGF) dan anti penuaan, memperbaiki fungsi saluran pencernaan, peningkatan kekuatan tulang, meningkatkan fungsi saluran reproduksi, dan antioksidan.
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Objective: Hypercholesterolemia is a strong risk factor for cardiovascular diseases. Side effects associated with the use of pharmaceutical agents can cancel out their benefits. Dietary management of hypercholesterolemia is, therefore, receiving much attention due to fewer side effects. In this study, we explored the effectiveness of edible bird's nest (EBN) in the prevention of hypercholesterolemia in rats. Methods: High-cholesterol diet (HCD) (4.5% cholesterol and 0.5% cholic acid) with or without EBN (low (2.5%) or high dose (20%)) was given to rats for 12 weeks, and their weights were observed. Simvastatin (10 mg/kg/day) was administered for the same period as a control drug. Serum and tissue samples were collected at the end of the study, from which biochemical parameters (lipid profiles, oxLDL, liver enzymes, urea, creatinine, uric acid, and lipase activity) and hepatic mRNA levels were measured. Results: The HCD group had higher levels of serum lipids, liver enzymes, uric acid, urea, and lipase activity compared with those of the other groups. The hepatic mRNA levels of cholesterol metabolism genes (APOB, PCSK9, HMGCR, LDLR, and CYP7A1) in the HCD group also tended toward increased cholesterol production and reduced cholesterol clearance. EBN, especially the highest dose, attenuated the HCD-induced changes, partly through improving the transcriptional regulation of hepatic cholesterol metabolism genes with fold changes of 0.7, 0.6, 0.5, 1.7, and 2.7, respectively, in comparison to the HCD group. In fact, EBN produced better results than simvastatin. Conclusion: Thus, the results suggest that EBN can regulate cholesterol metabolism and, therefore, be a source of functional ingredients for the management of hypercholesterolemia.
... This work brings together several seemingly disparate fields: EBN as a traditional Chinese health food, also known as Collocalia mucoid, long recognized by Sias researchers as a rich source of the human dominant sialic Neu5Ac; a novel mechanism for the risk of increased atherosclerosis associated with red meat consumption; and potential interventions using Collocalia mucoid-the primary component of Sia-rich EBN. There are some prior studies indicating that EBN could ameliorate HFDinduced hyperlipidemia and hypercoagulation 39 and insulin resistance, 40,41 but these studies were done in rats (which unlike our mouse model did not have the human-like Cmah deficiency). The mechanisms involved are unclear, and it was suggested that EBN might reduce oxidative stress via upregulation of hepatic antioxidant genes and contribute to the downregulation of inflammatory cytokine genes such as CCL2 or IL-6. ...
Objective Species-specific pseudogenization of the CMAH gene during human evolution eliminated common mammalian sialic acid N -glycolylneuraminic acid (Neu5Gc) biosynthesis from its precursor N -acetylneuraminic acid (Neu5Ac). With metabolic nonhuman Neu5Gc incorporation into endothelia from red meat, the major dietary source, anti-Neu5Gc antibodies appeared. Human-like Ldlr −/ − Cmah −/− mice on a high-fat diet supplemented with a Neu5Gc-enriched mucin, to mimic human red meat consumption, suffered increased atherosclerosis if human-like anti-Neu5Gc antibodies were elicited. Approach and Results We now ask whether interventional Neu5Ac feeding attenuates metabolically incorporated Neu5Gc-mediated inflammatory acceleration of atherogenesis in this Cmah −/− Ldlr −/− model system. Switching to a Neu5Gc-free high-fat diet or adding a 5-fold excess of Collocalia mucoid-derived Neu5Ac in high-fat diet protects against accelerated atherosclerosis. Switching completely from a Neu5Gc-rich to a Neu5Ac-rich diet further reduces severity. Remarkably, feeding Neu5Ac-enriched high-fat diet alone has a substantial intrinsic protective effect against atherosclerosis in Ldlr −/− mice even in the absence of dietary Neu5Gc but only in the human-like Cmah -null background. Conclusions Interventional Neu5Ac feeding can mitigate or prevent the red meat/Neu5Gc-mediated increased risk for atherosclerosis, and has an intrinsic protective effect, even in the absence of Neu5Gc feeding. These findings suggest that similar interventions should be tried in humans and that Neu5Ac-enriched diets alone should also be investigated further.
... The heavy metals analyzed were arsenic, cadmium, cobalt, mercury, nickel, and lead. Five hundred milligram EBN samples were digested with a microwave digester coupled with an SK-10 high-pressure rotor and analyzed on the ICP-MS (Perkin Elmer, Waltham, MA, USA) [10]. The ICP-MS system was calibrated using a blank consisting of multi-element standards in 1% nitric acid at concentrations ranging from 5-200 µg/L and 1% nitric acid in ultrapure water. ...
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Edible bird’s nest (EBN) produced by Aerodramus fuciphagus has a high demand for nutritional and medicinal application throughout the world. The present study was to evaluate the authentication of a man-made house EBN, which are half cup and stripe-shaped by FTIR. Next, both samples were compared according to their metabolite, nutritional, and mineral composition. The results indicated that the FTIR spectra of both EBN samples were identical and similar to the reference, suggesting the authenticity of the EBN used. The metabolites that contribute to the possible medicinal properties of EBN were found by using GC-MS. The results of the proximate analysis, followed by the standard AOAC method, inferred that both EBN shapes to be rich in crude protein and carbohydrate contents. However, the proximate composition between the half cup and stripe-shaped EBN showed significant differences. Major mineral elements detected were calcium and sodium, and magnesium contents were significantly different between both EBN. Additionally, the half cup and stripe-shaped EBN had a low level of heavy metal content than the maximum regulatory limit as set by the Malaysian Food Act 1983. This study concludes that the nutritional composition varied between the samples and thus suggests that nutrient content should be considered as criteria for the grading requirement of commercialized EBN.
Edible bird's nest (EBN) is a nutritious food with many beneficial effects, including protecting cells against oxidation and infection due to wounds, bacteria, or viruses. EBN has shown anti‐aging, anti‐inflammatory, and wound‐healing properties in skin cells. Here, we investigated whether EBN has protective effects against photoaging, inflammation, and immunosenescence in hairless mice treated with UVB irradiation. The skin thickness was lower in mice on an EBN diet than in mice treated with UVB alone. The level of hydration was significantly increased, while the index of transepidermal water loss decreased, in groups on the EBN diet. EBN also reduced erythema index in UVB‐irradiated mice. At the molecular level, skin elasticity and anti‐aging are associated with high expression of elastin, collagen, and filaggrin and low expression of the membrane metalloproteinases, MMP‐1 and MMP‐2. Inflammatory markers such as interleukins, IL‐1β and IL‐6, and TNF‐ decreased significantly in the EBN groups. Caspase‐3, an important factor in the apoptotic pathway and in congenital and adaptive immune responses, decreased in the EBN groups. Moreover, EBN diminished the overexpression of immunoglobulin E and elevated mast cell counts in UVB‐irradiated mice. Overall, these findings suggest that EBN protects skin against aging and alleviates inflammation in UVB‐irradiated hairless mice.
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Edible-nest swiftlets have many health benefits. The availability of edible-nest swiftlets from caves is decreasing, while the demand for edible-nest swiftlets is getting higher. Swiftlet farming is carried out to meet this demand. The location of swiftlet farming should be close to the feeding sources. Swiftlet is flying insectivorous animals. A financial feasibility assessment is carried out to determine the feasibility of the business. This study aims to determine the composition of land cover, determine the insect order of feed sources, and analyze the production and financial feasibility of swiftlet farming. The study was carried out from June to December 2019. The composition of land cover was determined using the supervised classification method, the order of insects was known using the insect determination key, while production and financial feasibility were analyzed using the Net B/C, NPV, IRR, and PP methods. The observed location and swiftlet farming were determined purposefully. The results of this study show that the land cover was dominated by shrubs (56.58%) and secondary forest (27.3%); both types of land cover are suitable for swiftlet farming locations. The dominant insects found in shrubs and wetland shrubs are Diptera (78.25%), in rice fields are Diptera (86.7%) and in oil palm plantations are Diptera (29.4%) and Hymenoptera (27.78%). Edible-nest swiftlets harvest begins in the third year, with a production period of between 17-34 years. From the financial feasibility, it can be concluded that swiftlet farming is feasible.
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Edible bird’s nest (BN) is a Chinese traditional medicine with innumerable health benefits, including anti-viral, anti-inflammatory, neuroprotective, and immunomodulatory effects. A small number of studies have reported the anti-viral effects of EBN against influenza infections using in vitro and in vivo models, highlighting the importance of sialic acid and thymol derivatives in their therapeutic effects. At present, studies have reported that EBN suppresses the replicated virus from exiting the host cells, reduces the viral replication, endosomal trafficking of the virus, intracellular viral autophagy process, secretion of pro-inflammatory cytokines, reorient the actin cytoskeleton of the infected cells, and increase the lysosomal degradation of viral materials. In other models of disease, EBN attenuates oxidative stress-induced cellular apoptosis, enhances proliferation and activation of B-cells and their antibody secretion. Given the sum of its therapeutic actions, EBN appears to be a candidate that is worth further exploring for its protective effects against diseases transmitted through air droplets. At present, anti-viral drugs are employed as the first-line defense against respiratory viral infections, unless vaccines are available for the specific pathogens. In patients with severe symptoms due to exacerbated cytokine secretion, anti-inflammatory agents are applied. Treatment efficacy varies across the patients, and in times of a pandemic like COVID-19, many of the drugs are still at the experimental stage. In this review, we present a comprehensive overview of anti-viral and anti-inflammatory effects of EBN, chemical constituents from various EBN preparation techniques, and drugs currently used to treat influenza and novel coronavirus infections. We also aim to review the pathogenesis of influenza A and coronavirus, and the potential of EBN in their clinical application. We also describe the current literature in human consumption of EBN, known allergenic or contaminant presence, and the focus of future direction on how these can be addressed to further improve EBN for potential clinical application.
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Edible bird’s nest (EBN) is recognized as a nourishing food among Chinese people. The efficacy of EBN was stated in the records of traditional Chinese medicine and its activities have been reported in many researches. Malaysia is the second largest exporter of EBNs in the world, after Indonesia. For many years, EBN trade to China was not regulated until August 2011, when a safety alert was triggered for the consumption of EBNs. China banned the import of EBNs from Malaysia and Indonesia due to high level of nitrite. Since then, the Malaysia government has formulated Malaysia Standards for swiftlet farming (MS 2273:2012), edible bird’s nest processing plant design and management (MS 2333:2010), and edible bird’s nest product quality (MS 2334:2011) to enable the industry to meet the specified standards for the export to China. On the other hand, Indonesia's EBN industry formulated a standard operating procedure (SOP) for exportation to China. Both countries can export EBNs to China by complying with the standards and SOPs. EBN contaminants may include but not limited to nitrite, heavy metals, excessive minerals, fungi, bacteria, and mites. The possible source of contaminants may come from the swiftlet farms and the swiftlets or introduced during processing, storage, and transportation of EBNs, or adulterants. Swiftlet house design and management, and EBN processing affect the bird’s nest color. Degradation of its optical quality has an impact on the selling price, and color changes are tied together with nitrite level. In this review, the current and future prospects of EBNs in Malaysia and Indonesia in terms of their quality, and the research on the contaminants and their effects on EBN color changes are discussed.
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Edible birds' nest (EBN) is reported to be antioxidant-rich. However, the fate of its antioxidants after oral consumption is not yet reported. To explore this, we hypothesized that EBN antioxidants are released from their matrix when subjected to in vitro simulated gastrointestinal digestion. EBN samples were extracted using hot water (100[degree sign]C) with or without subsequent sequential enzymatic digestion using pepsin (10,000 units), pancreatin (36 mg) and bile extracts (112.5 mg). Additionally, pH changes (8.9 to 2 and back to 8.9) similar to the gut were applied, and a 10 KDa dialysis tubing was used to simulate gut absorption. The antioxidant capacities of the water extracts of EBN before and after digestion were then determined using ABTS and oxygen radical absorbance capacity (ORAC) assays, while the protective effects of the EBN samples against hydrogen peroxide-induced toxicity in HEPG2 cells were determined using MTT assay and acridine orange (AO)/propidium iodide (PI) staining. Antioxidant assays (ABTS and ORAC) showed that the undigested EBN water extract had little antioxidant activity (1 and 1%, respectively at 1000 mug/mL) while at similar concentrations the digested samples had significantly (p < 0.05) enhanced antioxidant activities, for samples inside (38 and 50%, respectively at 1000 mug/mL) and outside (36 and 50%, respectively at 1000 mug/mL) the dialysis tubing, representing absorbed and unabsorbed samples, respectively. Cell viability and toxicity assays also suggested that the EBN extracts were non-toxic to HEPG2 cells (cell viabilities of over 80% at 1000 mug/mL), while AOPI showed that the extracts protected HEPG2 cells from hydrogen peroxide induced-toxicity. Based on the findings, it is likely that EBN bioactives are released from their matrix when digested in the gut and then absorbed through the gut by passive-mediated transport to exert their functional effects. However, there is need to confirm these findings using in vivo systems to determine their clinical significance.
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Background: Parkinson's disease (PD) is the second most common neurodegenerative disorder affecting the senile population with manifestation of motor disability and cognitive impairment. Reactive oxygen species (ROS) is implicated in the progression of oxidative stress-related apoptosis and cell death of the midbrain dopaminergic neurons. Its interplay with mitochondrial functionality constitutes an important aspect of neuronal survival in the perspective of PD. Edible bird's nest (EBN) is an animal-derived natural food product made of saliva secreted by swiftlets from the Aerodamus genus. It contains bioactive compounds which might confer neuroprotective effects to the neurons. Hence this study aims to investigate the neuroprotective effect of EBN extracts in the neurotoxin-induced in vitro PD model. Methods: EBN was first prepared into pancreatin-digested crude extract and water extract. In vitro PD model was generated by exposing SH-SY5Y cells to neurotoxin 6-hydroxydopamine (6-OHDA). Cytotoxicity of the extracts on SH-SY5Y cells was tested using MTT assay. Then, microscopic morphological and nuclear examination, cell viability test and ROS assay were performed to assess the protective effect of EBN extracts against 6-OHDA-induced cellular injury. Apoptotic event was later analysed with Annexin V-propidium iodide flow cytometry. To understand whether the mechanism underlying the neuroprotective effect of EBN was mediated via mitochondrial or caspase-dependent pathway, mitochondrial membrane potential (MMP) measurement and caspase-3 quantification were carried out. Results: Cytotoxicity results showed that crude EBN extract did not cause SH-SY5Y cell death at concentrations up to 75 μg/ml while the maximum non-toxic dose (MNTD) of water extract was double of that of crude extract. Morphological observation and nuclear staining suggested that EBN treatment reduced the level of 6-OHDA-induced apoptotic changes in SH-SY5Y cells. MTT study further confirmed that cell viability was better improved with crude EBN extract. However, water extract exhibited higher efficacy in ameliorating ROS build up, early apoptotic membrane phosphatidylserine externalization as well as inhibition of caspase-3 cleavage. None of the EBN treatment had any effect on MMP. Conclusions: Current findings suggest that EBN extracts might confer neuroprotective effect against 6-OHDA-induced degeneration of dopaminergic neurons, particularly through inhibition of apoptosis. Thus EBN may be a viable nutraceutical option to protect against oxidative stress-related neurodegenerative disorders such as PD.
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This minireview looks back at a century of glycolysis research with a focus on the mechanisms of flux regulation. Traditionally, glycolysis is regarded as a feeder pathway that prepares glucose for further catabolism and energy production. However, glycolysis is much more than that, in particular in those tissues that express the low affinity glucose-phosphorylating enzyme glucokinase. This enzyme equips the glycolytic pathway with a special steering function for the regulation of intermediary metabolism. In beta cells, glycolysis acts as a transducer for triggering and amplifying physiological glucose-induced insulin secretion. On the basis of these considerations, I have defined a glycolytic flux regulatory unit composed of the two fructose ester steps of this pathway with various enzymes and metabolites that regulate glycolysis.
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Edible bird's nest (EBN) is a popular delicacy among the Chinese diaspora associated with various health claims. This study investigated the anti-inflammatory effects of white-EBN acid hydrolysate on tumour necrosis factor-alpha (TNF-α) and nitric oxide (NO) generation, while examining its cytotoxic effect on a lipopolysaccharide-stimulated RAW 264.7 macrophage cell line. Processed commercial EBN and unprocessed raw EBN collected from different geographical zones and at different harvesting seasons were studied. The cytotoxic effect was determined by cell viability assessed by MTS assay, while NO production was determined by the Griess reaction and TNF-α concentration was measured using an ELISA kit. The results showed that both commercial and raw EBN inhibited TNF-α and NO generation, the highest inhibition 58% and 63%, respectively without significant cytotoxic effect was brought about by raw EBN from the South zone. The results suggest that EBN may possess anti-inflammatory properties that should be further studied.
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Glucose and other carbohydrates are transported into cells using members of a family of integral membrane glucose transporter (GLUT) molecules. To date 14 members of this family, also called the solute carrier 2A proteins have been identified which are divided on the basis of transport characteristics and sequence similarities into several families (Classes 1 to 3). The expression of these different receptor subtypes varies between different species, tissues and cellular subtypes and each has differential sensitivities to stimuli such as insulin. The liver is a contributor to metabolic carbohydrate homeostasis and is a major site for synthesis, storage and redistribution of carbohydrates. Situations in which the balance of glucose homeostasis is upset such as diabetes or the metabolic syndrome can lead metabolic disturbances that drive chronic organ damage and failure, confirming the importance of understanding the molecular regulation of hepatic glucose homeostasis. There is a considerable literature describing the expression and function of receptors that regulate glucose uptake and release by hepatocytes, the most import cells in glucose regulation and glycogen storage. However there is less appreciation of the roles of GLUTs expressed by non parenchymal cell types within the liver, all of which require carbohydrate to function. A better understanding of the detailed cellular distribution of GLUTs in human liver tissue may shed light on mechanisms underlying disease pathogenesis. This review summarises the available literature on hepatocellular expression of GLUTs in health and disease and highlights areas where further investigation is required.
The etiology of type 2 diabetes is characterized by obesity, insulin and leptin resistance, and compensatory P cell hyperplasia followed by islet degeneration, resulting in the eventual dysregulation of glucose and lipid homeostasis. The recent identification of insulin receptor substrate 2 (IRS2) as a central player in the pathophysiology of many of these processes suggests a potentially unifying molecular link underlying the initiation and progression of type 2 diabetes (see the related articles beginning on pages 908 and 917).
White rice (WR) is the staple food for many people around the world, but it is linked to increased risk of cardiovascular diseases (CVDs). Brown rice (BR) and germinated brown rice (GBR) are conceived to be the healthier alternatives. The present study evaluated the effects of WR, BR and GBR in the dietary management of CVD. Diet-induced hypercholesterolaemic rats were fed with WR, BR and GBR, in comparison with normal, high-fat diet (HFD) and Simvastatin-treated rats. Weight, lipid profile, plasma oxidized low-density lipoprotein (ox-LDL) and F2-isoprostane were evaluated. GBR reduced weight gain and improved lipid parameters, ox-LDL and F2-isoprostane, partly through transcriptional regulation of hepatic lipoprotein lipase (LPL), peroxisome proliferator-activated receptor gamma (PPARγ), adiponectin, ATP-binding cassette, subfamily A (ABCA), and v-akt murine thymoma viral oncogene homologue 1and homologue 3 (AKT1 and AKT3). The results suggest GBR could ameliorate CVD risk by modulating lipid metabolism and oxidative stress.
Antioxidative properties of prepared clove buds deodorized aqueous extract (CDAE) in chicken meatballs are studied. Total phenolic and flavonoid contents were found to be 271.9 ± 12.0 mg gallic acid equivalent per gram and 161.6 ± 7.7 mg rutin equivalent per gram CDAE, respectively. Chicken meatball samples were: (1) C (control, i.e., without CDAE), and those supplemented with 200 ppm of; (2) T1 (CDAE); (3) T2 (ascorbic acid); and (4) T3 (butylated hydroxyanisole [BHA] : butylated hydroxytoluene [BHT] = 1:1). Oxidative stability was assessed by measuring peroxide value (PV) and 2-thiobarbituric acid reactive substances (TBARS) besides determination of color and sensory acceptability, over 12 days of chilled storage (8 ± 1C). All the treated samples showed higher induction period as well as lower PV and TBARS values than “C” throughout 12 days of storage (*P < 0.05). Color analysis showed that CDAE greatly improved redness of meatballs as compared with ascorbic acid and BHA-BHT (*P < 0.05). Meanwhile, hedonic test indicated that treatment T1 did not affect sensory acceptability of chicken meatballs for all the tested attributes (color, aroma, taste, texture and overall acceptance) (*P > 0.05) up to comparable extent with T2 and T3. The study provides a valuable method for the preparation of meatballs by replacing harmful synthetic antioxidants with natural ones with promising antioxidant and shelf-life potential besides maintaining sensory attributes. This adaptation may result in massively enhanced consumption of these meatballs with disease-preventive and health-promoting effects. The main hurdle in commercialization of spicy meatballs is the pungent smell of spices as well as use of toxic organic solvents for extraction. The problem has been overcome by developing a method for the preparation of deodorized extracts in aqueous medium, which may significantly enhance the commercialization potential of meatballs and meatball-based functional foods.
Context Although postmenopausal hormone replacement therapy (HRT) is widely used in the United States, new evidence about its benefits and harms requires reconsideration of its use for the primary prevention of chronic conditions.Objective To assess the benefits and harms of HRT for the primary prevention of cardiovascular disease, thromboembolism, osteoporosis, cancer, dementia, and cholecystitis by reviewing the literature, conducting meta-analyses, and calculating outcome rates.Data Sources All relevant English-language studies were identified in MEDLINE (1966-2001), HealthSTAR (1975-2001), Cochrane Library databases, and reference lists of key articles. Recent results of the Women's Health Initiative (WHI) and the Heart and Estrogen/progestin Replacement Study (HERS) are included for reported outcomes.Study Selection and Data Extraction We used all published studies of HRT if they contained a comparison group of HRT nonusers and reported data relating to HRT use and clinical outcomes of interest. Studies were excluded if the population was selected according to prior events or presence of conditions associated with higher risks for targeted outcomes.Data Synthesis Meta-analyses of observational studies indicated summary relative risks (RRs) for coronary heart disease (CHD) incidence and mortality that were significantly reduced among current HRT users only, although risk for incidence was not reduced when only studies that controlled for socioeconomic status were included. The WHI reported increased CHD events (hazard ratio [HR], 1.29; 95% confidence interval [CI], 1.02-1.63). Stroke incidence but not mortality was significantly increased among HRT users in the meta-analysis and the WHI. The meta-analysis indicated that risk was significantly elevated for thromboembolic stroke (RR, 1.20; 95% CI, 1.01-1.40) but not subarachnoid or intracerebral stroke. Risk of venous thromboembolism among current HRT users was increased overall (RR, 2.14; 95% CI, 1.64-2.81) and was highest during the first year of use (RR, 3.49; 95% CI, 2.33-5.59) according to a meta-analysis of 12 studies. Protection against osteoporotic fractures is supported by a meta-analysis of 22 estrogen trials, cohort studies, results of the WHI, and trials with bone density outcomes. Current estrogen users have an increased risk of breast cancer that increases with duration of use. Endometrial cancer incidence, but not mortality, is increased with unopposed estrogen use but not with estrogen with progestin. A meta-analysis of 18 observational studies showed a 20% reduction in colon cancer incidence among women who had ever used HRT (RR, 0.80; 95% CI, 0.74-0.86), a finding supported by the WHI. Women symptomatic from menopause had improvement in certain aspects of cognition. Current studies of estrogen and dementia are not definitive. In a cohort study, current HRT users had an age-adjusted RR for cholecystitis of 1.8 (95% CI, 1.6-2.0), increasing to 2.5 (95% CI, 2.0-2.9) after 5 years of use.Conclusions Benefits of HRT include prevention of osteoporotic fractures and colorectal cancer, while prevention of dementia is uncertain. Harms include CHD, stroke, thromboembolic events, breast cancer with 5 or more years of use, and cholecystitis. Approximately 38% of postmenopausal women in the United States in 1995 used hormone replacement therapy (HRT), estrogen with or without progestin, to treat symptoms of menopause and prevent chronic conditions such as cardiovascular disease and osteoporosis.1 Although treatment of symptoms of menopause, such as hot flashes and urogenital atrophy, among others, is a common indication for short-term use, potential preventive effects of HRT on long-term health outcomes have become an increasingly important consideration. In 1996, the second US Preventive Services Task Force (USPSTF) determined that there was insufficient evidence to recommend for or against HRT for all women but thought that individual decisions should be based on patient risk factors, an understanding of the probable benefits and harms, and personal preferences.2 Many studies have been published since these recommendations were released, including the first report from the Women's Health Initiative (WHI),3 a large randomized primary prevention trial, and the Heart and Estrogen/progestin Replacement Study (HERS),4 a secondary prevention trial reporting multiple outcomes.4- 6 This review was initiated to aid the current USPSTF in making new recommendations that will be released this fall. The focus of the USPSTF is to develop recommendations on screening, counseling, and chemoprophylaxis for asymptomatic populations. We conducted systematic searches of the literature on postmenopausal HRT use and its effectiveness for primary prevention of chronic conditions and its effects on harmful outcomes. Treatment of symptoms of menopause and use of HRT for treatment of a preexisting condition are outside the scope of the USPSTF recommendation, and this literature was not reviewed. We focused on primary outcomes such as myocardial infarction (MI) rather than intermediate outcomes such as lipid levels. To provide an overview of benefits and harms, we conducted several meta-analyses and used these results, as well as those from selected published articles, to calculate numbers of events prevented or caused by HRT in a hypothetical population of postmenopausal women.
A few species of swiflets (genus Aerodramus) build edible nests that are consumed by humans worldwide, as a delicacy known as the “Caviar of the East” or as a medicinal food. This study reports on the compositional properties of two types of nest, the white nest and the red “blood” nest. The order of composition (from lowest to highest) was found to be identical for both types of nests, i.e., lipid (0.14–1.28%), ash (2.1%), carbohydrate (25.62–27.26%) and protein (62–63%). It was also found that both nests share a common 77 KDa protein that has properties similar to those of the ovotransferrin protein in eggs. This protein may be partially responsible for the severe allergic reactions that sometimes occur among young children who consume edible bird’s nest products. It was found that SDS–PAGE electrophoretic fingerprinting might serve as a useful analytical technique for differentiating between white and red nests and for determining if the more expensive “blood” nest was adulterated with the less expensive white nest. Also evaluated were different analytical methodologies for detecting adulterants. Three of the most common adulterants found in retail bird’s nests are karaya gum, red seaweed, and tremella fungus, and they are routinely incorporated during commercial processing prior to final sale. Using crude protein determination, it was found that these adulterants (which typically accounted for 2–10% of the finished nest), reduce the overall crude protein content of the genuine white bird’s nest by as much as 1.1–6.2%. A modified xanthoproteic nitric acid test for proteins proved to be a rapid, and simple test to detect adulteration in both whole and finely ground nests, and would be suitable in the field where analytical facilities are not readily available.