Antihypertensive and antioxidant effects of dietary black sesame meal in pre-hypertensive humans

Article (PDF Available)inNutrition Journal 10(1):82 · August 2011with55 Reads
DOI: 10.1186/1475-2891-10-82 · Source: PubMed
Abstract
It has been known that hypertension is an independent risk factor for cardiovascular disease (CVD). CVD is the major cause of morbidity and mortality in developed and developing countries. Elevation of blood pressure (BP) increases the adverse effect for cardiovascular outcomes. Prevention of increased BP plays a crucial role in a reduction of those outcomes, leading to a decrease in mortality. Therefore, the purpose of this study was to investigate the effects of dietary black sesame meal on BP and oxidative stress in individuals with prehypertension. Twenty-two women and eight men (aged 49.8 ± 6.6 years) with prehypertension were randomly divided into two groups, 15 subjects per group. They ingested 2.52 g black sesame meal capsules or placebo capsules each day for 4 weeks. Blood samples were obtained after overnight fasting for measurement of plasma lipid, malondialdehyde (MDA) and vitamin E levels. Anthropometry, body composition and BP were measured before and after 4-week administration of black sesame meal or a placebo. The results showed that 4-week administration of black sesame meal significantly decreased systolic BP (129.3 ± 6.8 vs. 121.0 ± 9.0 mmHg, P < 0.05) and MDA level (1.8 ± 0.6 vs. 1.2 ± 0.6 μmol/L, P < 0.05), and increased vitamin E level (29.4 ± 6.0 vs. 38.2 ± 7.8 μmol/L, P < 0.01). In the black sesame meal group, the change in SBP tended to be positively related to the change in MDA (R = 0.50, P = 0.05), while the change in DBP was negatively related to the change in vitamin E (R = -0.55, P < 0.05). There were no correlations between changes in BP and oxidative stress in the control group. These results suggest the possible antihypertensive effects of black sesame meal on improving antioxidant status and decreasing oxidant stress. These data may imply a beneficial effect of black sesame meal on prevention of CVD.
RESEARCH Open Access
Antihypertensive and antioxidant effects of
dietary black sesame meal in pre-hypertensive
humans
Jatuporn Wichitsranoi
1
, Natthida Weerapreeyakul
2
, Patcharee Boonsiri
3
, Chatri Settasatian
4
, Nongnuch Settasatian
5
,
Nantarat Komanasin
6
, Suchart Sirijaichingkul
7
, Yaovalak Teerajetgul
5
, Nuchanart Rangkadilok
8
and
Naruemon Leelayuwat
9*
Abstract
Background: It has been known that hypertension is an independent risk factor for cardiovascular disease (CVD).
CVD is the major cause of morbidity and mortality in developed and developing cou ntries. Elevation of blood
pressure (BP) increases the adverse effect for cardiovascular outcomes. Prevention of increased BP plays a crucial
role in a reduction of those outcomes, leading to a decrease in mortality. Therefore, the purpose of this study was
to investigate the effects of dietary black sesame meal on BP and oxidative stress in individuals with
prehypertension.
Methods: Twenty-two women and eight men (aged 49.8 ± 6.6 years) with prehypertension were randomly
divided into two groups, 15 subjects per group. They ingested 2.52 g black sesame meal capsules or placebo
capsules each day for 4 weeks. Blood samples were obtained after overnight fasting for measurement of plasma
lipid, malondialdehyde (MDA) and vitamin E levels. Anthropometry, body compos ition and BP were measured
before and after 4-week administration of black sesame meal or a placebo.
Results: The results showed that 4-week administration of black sesame meal significantly decreased systolic BP
(129.3 ± 6.8 vs. 121.0 ± 9.0 mmHg, P < 0.05) and MDA level (1.8 ± 0.6 vs. 1.2 ± 0.6 μmol/L, P < 0.05), and increased
vitamin E level (29.4 ± 6.0 vs. 38.2 ± 7.8 μmol/L, P < 0.01). In the black sesame meal group, the change in SBP
tended to be positively related to the change in MDA (R = 0.50, P = 0.05), while the change in DBP was negatively
related to the change in vitam in E (R = -0.55, P < 0.05). There were no correlations between changes in BP and
oxidative stress in the control group.
Conclusions: These results suggest the possible antihypertensive effects of black sesame meal on improving
antioxidant status and decreasing oxidant stress. These da ta may imply a beneficial effect of black sesame meal on
prevention of CVD.
Keywords: blood pressure, oxidative stress, malondialdehyde, sesamin, sesamolin, tocopherol
Background
Hypertension is an i mportant risk fa ctor for cardiovascu-
lar disease (CVD) in developing countries. Elevation of
blood pressure (BP) is a risk factor for adverse cardiovas-
cular outcomes, including stroke, myocardial infarction,
renal failure and death [1]. Prevention of increased BP
the refore p lays a crucial role in a red uction of those out-
comes. Impaired balance between relaxing and contract-
ing factors in t he endothelium of blood vessels is an
important pathogenic mechanism of hypertension.
Increased pro-oxidant and decreased antioxidant activ-
ities h ave been sho wn to be some of the mechanisms of
the pathogenesis of hypertension [2].
It has been reported that sesame seeds can improve oxi-
dative stress due to actions of their contents of vitamin E
and lignans including sesamin, sesamolin and sesamol
* Correspondence: naruemon@kku.ac.th
9
Department of Physiology, Faculty of Medicine, Khon Kaen University, Khon
Kaen 40002, Thailand
Full list of author information is available at the end of the article
Wichitsranoi et al. Nutrition Journal 2011, 10:82
http://www.nutritionj.com/content/10/1/82
© 2011 Wichitsranoi et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative
Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permi ts unrestricted use, distribution, and
reproduction in any medium, provided the original work is properly cited.
[3-7]. Thus, sesame is likely to have potential health bene-
fits in relation to CVD by its antihypertensive effects
[8-11]. Although many previous studies have shown differ-
ent effects of vitamin E on BP [12-14], these studies inves-
tigated the effect of supplementation of either alpha-
tocopherol alone or mixed with gamma-tocopherol on BP
in diabetic [12,13] or hypertensive [14] patients who took
antihyperte nsive drugs. Interactions between alpha-toco-
pherol and the drug may diminish the antihypertensive
effect on BP [15]. Moreover, the dose of vitamin E in
those previous studies may have been so high that it
caused increased or unchanged effects on BP.
Interestingly, the antihypertensive effect of black
sesame (Sesamum indicum Linn.) meal, a product of
sesame oil manufacturing, does not seem to have been
previously investigated. Positive results may provide addi-
tional value to the manufactured product. Sinc e we
wanted to examine preventive effects, we performed the
research on pre-hypertensive [16] healthy individuals
who did not take any medicine; hence the vitamin E
could exercise its antioxidant activity without interfer-
ence with any a ntihypertensive drug. Moreover, black
sesame meal c ontains gamma-tocopherol which was
reported to be lower in patients with coronary heart dis-
ease than control subjects [17]. Taken together with the
safety dose of vitamin E in black sesame meal in this
study [18], this may reveal an anti-hypertensive effect of
black sesame meal.
Based on knowledge of the e ffects of sesame seed and
lignans on oxidative stress, which is one of mechanisms of
the pathogenesis of hypertension [2], it was hypothesized
that black sesame meal may have an antihypertensive
effect in pre-hypertensive humans via improving antioxi-
dan t status and decr easing oxidant stress. Therefore, the
aim of this study was to investigate th e effects of 4-week
administration of black sesame meal on BP and oxidative
stress in pre-hypertensive humans.
Methods
Study design
A double-blind, placebo-controlled investigation was
undertaken. Subjects were divided into two groups, with
11 men and 4 women in each group, matched by age, BMI
and BP: a black sesame meal group (SG) (N = 15, aged
49.3 ± 7.7 years), and a placebo group (PG) (N = 15, aged
50.3 ± 5.6 years). Subjects and investigators were blinded
as to the composition of the black sesame meal and pla-
cebo capsules. After being screened by physical and blood
examination, all subjects were asked to complete health
questionnaires in order to provide health information
including cardiovascular risk factors. Subjects were seen
on two visits: before and after 4-week administration of
either black sesame meal capsules or plac ebo capsules.
During the 4 weeks, subjects were asked to take 6 capsules
each time, three times a day, with water after a meal. They
were asked to avoid vitamins and o ther dietary supple-
ments during the administration period. Subjects w ere
instructed not to change their diet and exercise routine
throughout the trial. At both visits, after a 12-h fasting
period, blood samples were collected to m easure blood
parameters. Anthropometry (height, weight, and waist and
hip circumferences), bod y composit ion and BP were also
measured.
Subjects
Thirty middle-aged subjects (22 men and 8 women) were
recruited from the general population, supported by an
annual health checkup program performed at the Faculty
of Associated Medical Sciences, Khon Kaen University,
during 2008-2009. Subjects had no other diseases except
prehypertension as indicated either by systolic blood pres-
sure (SBP) from 120 to 139 mmHg or diastolic BP (DBP)
from 80 to 89 mmHg [16]. The patients were not currently
taking any medication or dietary supplementation that
affected BP. This study was conducted according to the
guidelines laid down in the Declaration of Helsinki, and all
procedures involving humans were approved by the Ethics
Committee of Khon Kaen University (HE 510254). Writ-
ten and verbal informed consent was obtained from all
subjects; verbal consent was witnessed and formally
recorded.
Power calculation
A change in SBP after the ingestion of black sesame
meal was used to calculate the sample size of this study
[9]. The magnitude of the change in SBP was 5 mmHg
for the power calculation. It was decided to require 90%
power at a significance level of 0.05. Thus, having at
least 15 subjects was required to finish this study.
Preparation of black sesame meal
The black sesame meal was prepared at the Faculty of
Pharmaceutical Sciences, Khon Kaen University, Thailand.
The sesame seeds were roasted before being pressed. The
remaining sesame meal was grounded into powder and
mixed with an adsorbent. This process is the same as that
used for commercial preparation. Each capsule of black
sesame meal was formulated to contain 0.42 g of black
sesame meal. The contents (mean ± SD) of carbohydrate,
protein and fiber of the black sesame meal were 46.37%,
21.57% and 14.12%, respectively. Moreover, sesa min and
sesamolin contents were 1 .172 ± 0.002 mg/g DW and
0.605 ± 0.003 mg/g DW, respectively [19]. Total toco-
pherol was 105.41 ± 2.49 μg/g DW, mostly consisting of
gamma-tocopherol (102.78 ± 2.46 μg/g DW); alpha-toco-
pherol was not detectable [19]. The placebo capsule con-
tained the same contents, but without any black sesame
meal. Both capsules were the same shape and color.
Wichitsranoi et al. Nutrition Journal 2011, 10:82
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Measurement of BP
BP (mmHg) and heart rate (HR,/min) were measured in
the morning, a fter a 20-min rest, using an automatic
sphygmomanometer (Accurtorr 1A; Datascope, Japan)
on the right upper arm while the subject was in a sitting
position. Average BP and HR were calculated from three
measur ements afte r an almost stable BP seemed to have
been reached. SBP and DBP were used to calculate
mean arterial pressure (MAP) by t he formula: MAP =
DBP + 1/3 (SBP - DBP).
Measurement of malondialdehyde (MDA)
A plasma lipid peroxidation marker, MDA, was estimated
using thiobarbituric acid, as previously described [20]. In
brief, 150 μl of plasma was reacted with 125 μl 10% tri-
chlo roacetic acid, 125 μl 5 mM et hylenediaminetetraace-
tic acid, 125 μl 8% sodium dodecyl sulfate, and 10 μl
0.5 μg/ml butylated hydroxytol uene. After vort exing vig-
orously for 30 s, the mixture was incubated for 10 min at
room temperature. Then 500 μl 0.6% thiobarbituric acid
was added, and the mixture was heated at 95°C for
30 min. After cooling to room temperature, the mixture
was centrifuged at 10,000 rpm for 10 min. The absor-
bance of the supernatant was measured at 532 nm using
a spectrophotometer (Genesys 20 , SN: 35 gk 130009;
Thermo Fisher Scientific, USA). A standard curve was
gen erated with appropriate concentrations of 1,1,3, 3-tet-
raethoxypropane standard (0.3-10 μmol/L); the plasma
MDA concentration was expressed as μmol/L of plasma.
Measurement of vitamin E
Serum vitamin E was determined using high performance
liquid chromatography (HPLC), according to the method
of Thurnham [21], by injection into a reversed-phase C-18
Spherisorb ODS2 column (diameter 5 μm, 4.6 × 100 mm;
Waters, USA). The mobile phase consisted of methanol/
acetonitrile/dichloromethane at a ratio of 4:4:1 with a flow
rate of 1 mL/min. A wavelength UV-visible detector
(model 2847, Waters) was set at a wavelength of 292 nm
for the detection of vitamin E. Quantification was based
on peak-height measurement, using the Clarity 2.2.0.67
software program, version C22 (DataApex, Czech
Republic).
Statistical analysis
All statistics were generated using Stata statistical soft-
ware, version 10 (StataCorp, USA). Data were expressed
as means ± SD. Changes in BP, MDA and vitamin E
levels between groups were compared by analysis of cov-
ariance (ANCOVA), with adjustment for basel ine values.
The variables under study before and after the adminis-
tration within groups were compared by Studentspaired
t-test. The relationships between changes in oxidative
stress variables and BP were analyzed by Pearson s
correlation. Statistical analyses were two-sided. If the sta-
tistical probability (P -value) was less than 0.05, the dif-
ferences were considered to be statistically significant.
Results
Baseline characteristics of subjects are shown in Table 1.
All subjects were pre-hypertensive individuals. No sig-
nificant differenc es in age, anthropometry, body compo-
sition, and levels of MDA a nd vitamin E, SBP, DBP,
MAP and HR were found between SG and PG groups.
In the SG group, after 4 weeks of administration of black
sesame meal, SBP was significantly decreased when com-
pared with before administration (121.0 ± 9.0 vs. 129.3 ±
6.8 m mHg, P < 0.05) (Figure 1A). Meanwhile, in the PG
group, SBP was slightly decreased after the placebo admin-
istration when compared with before administration
values (130.4 ± 4. 8 vs. 130.6 ± 9.5 mmHg, P =0.52).The
decrease in SBP in the SG group was significantly greater
than that in the PG group (P < 0.05) with adjustment for
baseline values. There were no apparent side effects
induced by black sesame meal throughout the study.
In the SG group, after 4 weeks of administration of
black sesame meal, DBP was decre ased when compared
with before administration (72.8 ± 9.8 vs. 77.0 ± 7.4
mmHg, P = 0.20) (Figure 1B). Me anwhile, in the PG
group (85.9 ± 12.1 vs. 80.6 ± 7.7 mmHg, P = 0.14),
where the level was higher than before administration.
Table 1 Characteristics and baseline outcome of the
subjects at baseline
PG
(n = 15)
SG
(n = 15)
P-value
Age (yr) 50.3 ± 5.6 (39-58) 49.3 ± 7.7 (38-59) 0.70
Height (cm) 161.4 ± 5.4 (154-171) 159.5 ± 7.5 (150-173) 0.45
BW (kg) 66.9 ± 8.7 (53.9-78.5) 68.1 ± 12.1 (57.5-92.7) 0.71
BMI (kg/m
2
) 25.6 ± 2.4 (21.8-29.1) 26.6 ± 3.2 (22.7-34.3) 0.29
%BF 31.5 ± 4.6 (24.7-37.6) 31.6 ± 3.4 (26.7-37.2) 0.92
FM (kg) 21.3 ± 5.1 (13.3-28.5) 21.7 ± 5.2 (15.9-32.7) 0.81
FFM (kg) 45.6 ± 4.7 (37.6-52.9) 46.4 ± 7.6 (37.7-60.9) 0.69
W (cm) 84.6 ± 6.9 (72-94) 85.8 ± 9.6 (74.5-107) 0.66
H (cm) 95.3 ± 4.9 (86-101.5) 96.9 ± 5.4 (88-108) 0.35
W/H ratio 0.89 ± 0.1 (0.77-0.94) 0.88 ± 0.1 (0.79-1.02) 0.75
MDA (μmol/L) 1.9 ± 0.62 (0.86-2.78) 1.8 ± 0.6 (1.19-2.81) 0.67
Vitamin E
(μmol/L)
26.5 ± 5.5 (17.2-34.4) 29.4 ± 6.0 (19.1-45.8) 0.18
SBP (mmHg) 130.4 ± 4.8 (127-138) 129.3 ± 6.8 (121-137) 0.43
DBP (mmHg) 80.6 ± 7.7 (72-99) 77.0 ± 7.4 (65-87) 0.63
MAP (mmHg) 97.2 ± 4.7 (90.3-108.7) 94.4 ± 6.1 (84.7-103.7) 0.51
HR (/min) 66.8 ± 7.4 (59-85) 68.7 ± 9.1 (53-93) 0.61
Values are expressed as means ± SD (minimum-maximum).
PG, placebo group; SG, black sesame meal group; BW, body weight; BMI, body
mass index; %BF, percentage of body fat; FM, fat mass; FFM, fat-free mass; W,
waist circumference; H, hip circumference; W/H ratio, waist and hip
circumference ratio; MDA, malondialdehyde; SBP, systolic blood pressure; DBP,
diastolic blood pressure; MAP, mean arterial pressure; HR, heart rate
Wichitsranoi et al. Nutrition Journal 2011, 10:82
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However, the changes in DBP between groups with
adjustment for baseline values were n ot significantly
different.
Moreover, there was no significant difference in
changes of average HR with adjustment for baseline
values in both PG and SG subjec ts (66.8 ± 7.4 and 68.7 ±
9.1/min before and 71.2 ± 11.1 and 71.4 ± 6.4/min after
4-week administration of black sesame meal and placebo,
P = 0.76).
Plasma MDA concentrations significantly d ecreased
after the 4-week administration of black sesame meal
when compared with before administration concentrations
(1.2 ± 0.6 vs. 1.8 ± 0.6 μmol/L, P <0.05).Therewereno
significant differences in MDA concentrations, ho wever,
before and after 4-week administration of a placebo (1.8 ±
0.5 vs. 1.9 ± 0.6 μmol/L, P =NS).Whencomparedwith
the PG subjects, the SG subjects had significantly lower
plasma MDA concentrations after the 4-week administra-
tion with adjustment for baseline values (1.8 ± 0.5 (PG),
1.2 ± 0.6 (SG) μmol/L, P < 0.05) (Figure 2).
As shown in Figure 3, plasma vitamin E (total toco-
pherol) concentrations after 4-week administration of
black sesame meal were significantly increased when
compared with before administration concentrations
(38.2 ± 7.8 vs. 29.4 ± 6.0 μmol/L, P < 0.01). There were
no significant differences in vitamin E concentrations
before and after 4-week admin istration of the placebo
(29.8 ± 6.0 vs. 26.5 ± 5.5 μmol/L, P = NS). When co m-
pared with the PG group, the SG group had significantly
greater plasma vitamin E concentrations after 4-week of
Figure 1 Average levels of SBP (A) and DB P ( B) before and
after 4-week administration of black sesame meal and a
placebo in subjects with prehypertension. Values are expressed
as means ± SD. SBP, systolic blood pressure; DBP, diastolic blood
pressure; PG, placebo group; SG, black sesame meal group.
Figure 2 Plasma MDA c oncentrations before and after 4-week
administration of black sesame meal and a placebo in subjects
with prehypertension. Values are expressed as means ± SD. PG,
placebo group; SG, black sesame meal group; MDA,
malondialdehyde.
Figure 3 Plasma vitam in E concentrations before and after 4-
week administration of black sesame meal and a placebo in
subjects with prehypertension. Values are expressed as means ±
SD. PG, placebo group; SG, black sesame meal group.
Wichitsranoi et al. Nutrition Journal 2011, 10:82
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administration with adjustment for baseline values (29.8
± 6.0 (PG), 38.2 ± 7.8 (SG) μmol/L, P < 0.01).
Only in the black sesame me al group did the change
in SBP tend to be positively related to the change in
MDA concentration (R = 0.50, P =0.05),whilethe
change in DBP was negatively relate d to the change in
vitamin E concentration (R=0.55,P<0.05).There
were no significant correlations between changes in BP
and oxidative stress indicators in the placebo group.
Discussion
This study appears to b e the first to reveal the possible
antihypertensive effects of black sesame meal in partici-
pants with prehypertension. The results demonstrated that
after matching for age, BMI and BP, 4-week daily adminis-
tration of 2.52 g black sesame meal caused a significant
reduction in SBP, by an average of 8.2 mmHg.
Interestingly, the INTERSALT study reveal ed that a
reduction of 2 to 3 mmHg of SBP was associated with a
4% decrease in mortal ity from CVD in the USA and UK
[22] and a 6.4% decrease in mortality from cerebral vas-
cular disease in Japan [1]. Based on these longer term
studies, if the present reduction in BP with sesame meal
(8.2 mmHg) was sustained in the long term, this could
reduce the risk of CVD and stroke by 16.4% and 26.2%
respectively. This s tudy shows that the ingestion of black
sesame meal may have a potential effect on reduction in
mortality from CVD and stroke.
Although no previous study has directly investigated the
effect of black sesame meal on BP, many studies have
reported the potential antihypertensive effect of sesames
contents (i.e. lignan and vitamin E) in humans and rats
[8-11,23]. However, this is inconsistent with many other
previous studies which reported d ifferent results [12-14].
Some previous studies have reported that supplementation
of either alpha-tocopherol alone or mixed with gamma-
tocopherol increased [12] or did not change [13] BP in dia-
betic or treated hypertensive patients [14]. This may be
attributed to an interference of alpha-tocopherol and the
antihypertensive drug taken by some subjects in previous
studies; whereas subjects in this study we re healthy and
did not take any antihypertensive drug. Moreover, the dose
of vitamin E in those previous studies may have been so
high that it caused increased or unchanged effects on BP.
A possible mechanism responsible for the antihype r-
tensive effect of black sesame meal in this study may be
an improved balance between relaxing and contracting
factors in the endothelium of blood vessels. In this
study, black sesame meal may have enhanced the relax-
ing factor, resulting in improved endothelium-dependent
vasorelaxation in the pre-hypertensive participants relat-
ing to oxidati ve stress. The antihypertensive effect of
sesamin, in mildly hypertensive humans was supported
by a previous study [9]. The authors reported that the
ingestion of 60 g of sesamin per day for 4 weeks
decreased SBP by an average of 3.5 mmHg, and DBP by
1.9 m mHg [9]. M oreover, the increased plasma vitamin
E in this study may be due to the increased vitamin E
or the inhibition of catabolism of vitamin E. In addition,
bioavailability of vitamin E may be inc reased by interac-
tions between sesame lignan and tocopherols [24]. The
accumulation of vitamin E acts by detoxifying the
hydroxyl and proxy radicals, leading t o reduced lipid
peroxidation, or by reducing excess tissue aldehydes
[11]. This is supported by many previous studies, in
which supplementation of either vitamin E or sesamin
and sesamolin demonstrated that these antioxidants
inhibit lipid peroxidation [3-7,25] . The antioxidant effect
is likely to contribute to the decreased endothelial dys-
function from free radicals [26], resulting in a n increase
in the vasorelaxing factor, nitric oxide (NO) [27].
However, a mechanism that is not relevant to oxidative
stress cannot be ruled out. This was supported by a study
by Ward et al. (2004) which failed to show a link between
oxidative stress and BP [28]. It was shown that gamma-
tocopherol supplementation increased protein expression
of nitric oxide synthase [29], which stimulates vasorelaxa-
tion. Moreover, the potential effect of vitamin E on mem-
brane fluidity is likely to be another mechanism of
antihypertension. In vitro study, vitamin E was shown to
preserve endothelial cell (E C) migration in oxidized low-
density lipoprotein cells (oxLDL) and restore the endothe-
lial monolayer after injury by inhibitin g changes in mem-
brane integrity caused by oxLDL [30]. A previous study in
rats demonstrated that antihypertensive rats had lower BP
than normotensive rats due to reduced membrane fluidity
after ingestion of vitamin E 3 d/week for 3 weeks [31].
These non-ant ioxidant properties of vitamin E could be
important in the prevention of atherosclerosis, resulting in
a reduction in BP in humans. Sesamin supplementation
also induced NO and inhibited endothelin-1 production by
EC [32]. These findings indicate an improved ability of the
endothelium to relax. In addition, a recent study has shown
that sesamin inhibited some CYP450 enzymes and the pro-
duction of 20-hydroxyeicosatetraenoic acid (20-HETE),
which might influence BP independently of any effects on
oxidative stress [33]. Moreover, sesamin increased Ca
2+
antagonistic vasorelaxing activity [34]. It should be empha-
sized in this discussion that these hypotheses are only on
the basis of the decrease in MDA and increased vitamin E,
because other possible mechanisms were not measured.
A limitation of this study is a lack o f data on endothe-
lium-dependent vasorelaxation determined by NO and
other antioxidants such as vitamin C. Moreover, the
potential effect of vitamin E on membrane fluidity and
the ability of sesame lignans to inhibit 20-HETE synthesis
in human renal and liver microsomes were not investi-
gated by this study. Thus, further investigation of these
Wichitsranoi et al. Nutrition Journal 2011, 10:82
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Page 5 of 7
variables explaining the mechanisms of black sesame
meal on prevention of hypertension is needed. Impor-
tantly, having no discernible side effects from the inges-
tion of black sesame meal throughout this study implies
that it may be safe as a nutritional supplement for health
promotion.
Conclusions
This study suggests a beneficial effect of dietary black
sesame meal on a reduction in blood pressure in pre-
hypertensive humans. It is likely that the antihyperten-
sive effect is due t o decreased oxidative stress. Taken
together with the absence of side effects and inexpensive
preparation, the regular ingestion of dietary black
sesame meal may be beneficial for CVD prevention in
individuals with prehypertension, or even those with
hypertension. A future study that investigates this
advantageous effect is suggested.
Acknowledgements
We appreciate the assistance of the physical therapists at Queen Sirikit Heart
Center of Northeast Thailand. We also appreciate Exercise and Sport
Sciences Development and Research Group and Cardiovascular Research
Group, Khon Kaen University (a grant number 511010008), Thailand for
financial supports. We also would like to thank all subjects for their
enthusiastic participation.
Author details
1
Faculty of Physical Therapy, Mahidol University, Nakhon Pathom 73170,
Thailand.
2
Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon
Kaen 40002, Thailand.
3
Department of Biochemistry, Faculty of Medicine,
Khon Kaen University, Khon Kaen 40002, Thailand.
4
Department of
Pathology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002,
Thailand.
5
Department of Clinical Chemistry, Faculty of Associated Medical
Sciences, Khon Kaen University, Khon Kaen 40002, Thailand.
6
Department of
Clinical Microscopy, Faculty of Associated Medical Sciences, Khon Kaen
University, Khon Kaen 40002, Thailand.
7
Department of Clinical Immunology,
Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen
40002, Thailand.
8
Laboratory of Pharmacology, Chulabhorn Research Institute
(CRI), Vibhavadee-Rangsit Highway, Laksi, Bangkok 10210, Thailand.
9
Department of Physiology, Faculty of Medicine, Khon Kaen University, Khon
Kaen 40002, Thailand.
Authors contributions
JW participated in the design of the study and carried out the plasma MDA
and vitamin E assay, physiologi cal measurements and statistical analysis. NW
prepared the black sesame meal. PB carried out the vitamin E assay. SS
performed the medical cover. NL conceived the study, participated in its
design and coordination. NR analyzed vitamin E and lignans in black sesame
meal. JW and NL drafted the manuscript. NL is a member of Exercise and
Sport Sciences Development and Research Group. NW, CS, NS, NK, SS and
YT are members of Cardiovascular Research Group. All authors have read
and approved the final manuscript.
Competing interests
The authors are applying for a patent on black sesame meal.
Received: 11 March 2011 Accepted: 9 August 2011
Published: 9 August 2011
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doi:10.1186/1475-2891-10-82
Cite this article as: Wichitsranoi et al.: Antihypertensive and antioxidant
effects of dietary black sesame meal in pre-hypertensive humans.
Nutrition Journal 2011 10:82.
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Wichitsranoi et al. Nutrition Journal 2011, 10:82
http://www.nutritionj.com/content/10/1/82
Page 7 of 7
    • "Lignan glycosides have been purified from defatted sesame seeds and identified as sesaminol glucosides, pinoresinol glycosides, and sesamolinol glycosides; however, they have been reported to possess low antioxidant capacity compared to the corresponding aglycones (Kang et al., 1999; Katsuzaki, Kawakishi, & Osawa, 1994). A recent study also reported that black sesame seed meal exhibited anti-hypertensive effect in pre-hypertensive human subjects; this activity has been attributed to lignans (sesamin and sesamolin) and tocopherol remaining in black sesame seed meal after oil extraction (Wichitsranoi et al., 2011). Moreover, some reports suggested that defatted sesame seed flour contains antioxidant compounds other than lignan glycosides (Kansoula & Liakopoulou-Kyriakides, 2010; Mohdaly, Smetanska, Ramadan, Sarhan, & Mahmoud, 2011; Xu et al., 2005). "
    [Show abstract] [Hide abstract] ABSTRACT: Defatted white and gold sesame seed flour, recovered as a byproduct after sesame oil extraction, was extracted with 70% ethanol to obtain polar-soluble crude extracts. The in vitro antioxidant activity of the extract was evaluated by DPPH free radical scavenging activity and oxygen radical absorbing capacity (ORAC). The polar-soluble crude extracts of both sesame seed types exhibited good antioxidant capacity, especially by the ORAC method with 34,720 and 21,700 μmol Trolox equivalent/100 g of white and gold sesame seed extract, respectively. HPLC, butanol extraction, and UPLC–MS analyses showed that different compounds contributed to the antioxidant activity of the polar-soluble crude extracts. Sesaminol glycosides were identified in the butanol-soluble fractions; whereas, purified water-soluble fraction contained ferulic and vanillic acids. This study shows that hydrophilic antioxidants in the purified water-soluble fraction contributed to the antioxidant activity of white and gold sesame seed polar-soluble crude extracts.
    Article · May 2015
    • "Antioxidants substances like sesamol, sesamolin and sesaminol can be found in S. indicum L. [4]. Kiran and Asad [5] showed that seeds and oil of S. indicum L. have considerable healing activity when administered orally or topic. "
    [Show abstract] [Hide abstract] ABSTRACT: In Brazilian folk medicine, black sesame (Sesamum indicum L) seeds are one of the most important ingredients present in the tea used to treat stroke victims. Nevertheless, extracts by supercritical extraction of black sesame seeds have not been applied in neuroprotection studies. The objective of this work was to investigate some process variables of supercritical fluid extraction in black sesame to generate extracts applicable in stroke research. Two isothermal (40 and 60 degrees C) were explored, combined with pressures that ranged from 200 to 400 bar, at a constant mass flow rate of 5.9 x 10(-5) kg/s. The global yields ranged from 37 to 53% in dry basis. The highest mass yield was obtained at 60 C and 400 bar. The fatty acid composition comprised a high unsaturated/saturated ratio. Chromatographic analysis of phytosterol content in the high global yield extract revealed higher amounts of p-sitosterol+ sitostanol, cholesterol, campesterol + campestanol + 24-methylene cholesterol, triangle-5 avenasterol and stigmasterol, while lower levels of triangle-5,24 stigmastadienol, brassicasterol, clerosterol+ triangle-5-23 stigmastadienol, triangle-7 avenasterol, eritrodiol and triangle-7 stigmasterol were present in the black sesame extract. Overall extraction curves from the supercritical fluid extraction (SFE) in lower and higher global yields (200 and 400 bar at 60 degrees C) fitted the Tan and Liou, Goto et al. and Sovova models. These models presented the best residual sum of squares values. Pilot experiments suggest that black sesame extract is neuroprotective following endothelin-1 -induced focal ischemia into the motor cortex of adult male rat, observing a decrease in leukocyte infiltration in the group treated with SFE of black sesame seeds when compared with control group.
    Full-text · Article · Sep 2014
    • "However, we did not find any difference in CK concentration between groups, which, combined with the lack of differences in immune cell counts and inflammatory responses to the exercise between groups suggests that the development of cell damage and inflammation in this exercise was not attenuated by PA supplementation. Improved oxidative stress after exercise by PA supplementation might be useful for some medical conditions generating high oxidative stress, such as type 2 diabetes mellitus [40] or for individuals with pre-hypertension who got benefit effect from the reduced oxidative stress [41] but further study would be required to prove this possibility. It is likely that acute supplementation during exercise may provide protection until patients can adapt to oxidative stress by modifying their own antioxidant status, which require a bit of time. "
    [Show abstract] [Hide abstract] ABSTRACT: Phyllanthus amarus (PA) is a herbal plant containing antioxidant compounds that scavenge free radicals. The reduced oxidative stress may decrease muscle damage leading to early recovery from muscle soreness. This study aimed to evaluate the effects of PA powder on oxidative stress, muscle damage, leukocyte counts, inflammation, and muscle soreness after a single bout of high-intensity exercise. Twelve men participated in two 3-day phases separated by a 1-week washout in a randomized double-blinded, crossover design. On day 1, randomly divided participants ingested two capsules of either PA (PA group) or placebo (PLA group) 20 min before a single bout of cycling at high intensity for 20 min followed by four capsules (two capsules after lunch and dinner), and six capsules/day for the next 2 days. Blood samples were collected before, immediately after, and 24 and 48 h after the exercise. Pain threshold was measured at the mid-thigh on both legs. Malondialdehyde concentration in the PA group was lower than that in the PLA group (p < 0.05) 48 h after high-intensity exercise. Vitamin C concentration was greater in the PA than in the PLA group (p < 0.05) immediately after high-intensity exercise. Pain threshold in both legs in the PA group was higher than in the PLA group 24 and 48 h after high-intensity exercise. There were no significant differences in creatine kinase, leukocyte counts or inflammation between groups. Acute PA supplementation reduced oxidative stress and muscle soreness induced by high-intensity exercise.
    Full-text · Article · Mar 2014
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