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Antihypertensive activities of processed garlic on spontaneously hypertensive rats and hypertensive humans

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This study evaluated the effects of processed garlic (PG) on the systolic blood pressure (SBP) and the diastolic blood pressure (DBP) of spontaneously hypertensive rats (SHR) and on the BP of hypertensive humans. The color of raw garlic changed to black through enzymatic browning over two-week processing periods, and the active compound S-allyl-L-cysteine was analyzed and calculated as 75.3 mg/100 g in PG. PG was found to effectively reduce the blood pressure of SHR after 4, 6, and 8 weeks with a single daily dose of 30 and 50 mg/kg. We conducted a placebo-controlled trial to test the efficacy of PG on lowering SBP and DBP of 44 hypertensive subjects over a period of 8 weeks. PG significantly lowered SBP after only 2 weeks (p<0.01), while a significant reduction in DBP (p<0.05) took 8 weeks. This significant DBP reduction was also found in the placebo group (p<0.05), which might be attributed to a placebo effect. After 8 weeks, PG lowered SBP by 8.05 mmHg. In conclusion, taking two 500 mg capsules of PG for 8 weeks can significantly lower blood pressure in hypertensive subjects.
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INTRODUCTION
A number of risk factors are associated with stroke,
including age, gender, elevated cholesterol, smoking,
alcohol consumption, excessive weight, race, family his-
tory and hypertension (Mark and Davis, 2000). Although
some of these risk factors cannot be modied, the control-
lable factor that has the greatest impact on the etiology of
stroke is high blood pressure (Dunbabin, 1992). A recent
review paper (Chen et al., 2009) pointed out that nutra-
ceuticals and functional foods might have blood pressure-
lowering abilities. The endogenous molecule nitric oxide
(NO), which is released by endothelial cells through NO
synthesis, is a major factor in blood vessel relaxation,
Botanical Studies (2011) 52: 277-283.
9These authors contributed equally to this study.
* Corresponding authors: E-mail: wchou@tmu.edu.tw; Fax:
+886-2-2378-0134.
which may result in lowering blood pressure (Chalup-
sky et al., 2004; Bruckdorfer, 2005; Moon et al., 2006).
Spontaneously hypertensive rats (SHR) are the most
acceptable animal model for evaluating the antihyperten-
sive effects of natural products or functional foods (Lin
et al., 2006; Liu et al., 2007; Lin et al., 2008; Liu et al.,
2009a; Liu et al., 2009b; Huang et al., 2010).
Garlic (Allium sativum) is reported to have many
biological activities, including protective roles in
cardiovascular function (Rahman and Lowe, 2006;
Yeh and Yeh, 2006; Mukherjee et al., 2009), as an
antihypertensive (Harauma and Moriguchi, 2006; Reinhart
et al., 2008; Ried et al., 2008), an antioxidant (Dhawan
and Jain, 2005), and for hypocholesterolemia (Stevinson
et al., 2000; Yeh and Liu, 2001). Aged garlic extracts are
considered superior to those of raw garlic in terms of their
anti-oxidation properties and for ameliorating physiologi-
cal and psychological stress (Imai et al., 1994; Harauma
and Moriguchi, 2006; Morihara et al., 2006). In the present
Antihypertensive activities of processed garlic on spon-
taneously hypertensive rats and hypertensive humans
Chuan-Hsiao HAN1,9, Ju-Chi LIU2,3,9, Kwan-Han CHEN4,5,9, Yin-Shiou LIN1, Ching-Tan CHEN5,
Chien-Teng FAN5, Hu-Lun LEE5, Der-Zen LIU6, and Wen-Chi HOU7,8,*
1School of Pharmacy, Taipei Medical University, Taipei, Taiwan
2Department of Internal Medicine, School of Medicine, Taipei Medical University, Taipei, Taiwan
3Department of Internal Medicine, Taipei Medical University-Shuang Ho Hospital, Jhonghe City, Taiwan
4Institute of Food Science and Technology, National Taiwan University, Taipei, Taiwan
5AGV Food & Health Research Institute, AGV Products Co., Chia-Yi, Taiwan
6Institute of Biomedical Materials and Engineering, Taipei Medical University, Taipei, Taiwan
7Traditional Herbal Medicine Research Center, Taipei Medical University Hospital, Taipei, Taiwan
8Graduate Institute of Pharmacognosy, Taipei Medical University, Taipei, Taiwan
(Received October 12, 2010; Accepted November 12, 2010)
ABSTRACT. This study evaluated the effects of processed garlic (PG) on the systolic blood pressure (SBP)
and the diastolic blood pressure (DBP) of spontaneously hypertensive rats (SHR) and on the BP of hyperten-
sive humans. The color of raw garlic changed to black through enzymatic browning over two-week processing
periods, and the active compound S-allyl-ʟ-cysteine was analyzed and calculated as 75.3 mg/100 g in PG. PG
was found to effectively reduce the blood pressure of SHR after 4, 6, and 8 weeks with a single daily dose
of 30 and 50 mg/kg. We conducted a placebo-controlled trial to test the efcacy of PG on lowering SBP and
DBP of 44 hypertensive subjects over a period of 8 weeks. PG signicantly lowered SBP after only 2 weeks
(p<0.01), while a significant reduction in DBP (p<0.05) took 8 weeks. This significant DBP reduction was
also found in the placebo group (p<0.05), which might be attributed to a placebo effect. After 8 weeks, PG
lowered SBP by 8.05 mmHg. In conclusion, taking two 500 mg capsules of PG for 8 weeks can signicantly
lower blood pressure in hypertensive subjects.
Keywords: Antihypertensive; Blood pressure; Feeding trial; Processed garlic (PG); Spontaneously
hypertensive rats (SHR).
Abbreviations: PG, processed garlic; DBP, diastolic blood pressure; NO, nitric oxide; SBP, systolic blood
pressure; SHR, spontaneously hypertensive rat.
BIOCHEMISTRY
278 Botanical Studies, Vol. 52, 2011
study, the goals were rst, to evaluate the antihypertensive
effects of processed garlic powder (PG) on SHRs, and
second,to conduct a feeding trial in hypertensive subjects.
In SHR, PG significantly lowered SBP and DBP after 8
weeks (p<0.05). In human subjects, taking two daily 500
mg capsules of PG for 8 weeks also lowered BP.
MATERIALS AND METHODS
Materials
PG powders, PG capsules and the placebo were
provided by AGV Products Co. (Chia-Yi, Taiwan) for
the animal and clinical trials. PG was manufactured as
follows: raw garlic was washed then put in a reactor for
two weeks. After completion of the enzymatic reaction
process, the processed garlic was de-hulled, lyophilized
and then powdered. The active components of S-allyl-ʟ-
cysteine were determined to be 75.3 mg/100 g in PG, and
total phenolics were 775 mg/100 g. Other chemicals were
from Sigma Chemical Co. (St. Louis, MO, USA).
Effects of antihypertensive activity of PG on
SHR
Before the rat feeding trial, effects of PG on the SBP
and DBP of SHR were determined using the method of
Liu et al. (2009a, b). All animal experimental procedures
were approved by the Institutional Animal Care and Use
Committee and followed published guidelines (National
Science Council, 1994). The male SHRs (5 weeks of age,
National Laboratory Animal Center, Taipei) were housed
individually in steel cages kept at 24°C with a 12-h light-
dark cycle and had free access to a standard mouse/rat
chow (Prolab RMH2500, 5P14 Diet, PMI Nutrition
International, Brentwood, MO) and water. After being
housed up to 14 weeks, they were randomly divided into
three groups (eight rats per group), one of these the control
group. All were given 30 mg of PG/Kg and 50 mg of PG/
Kg (suspended in 0.5 ml water) once a day for 8 weeks,
and the control group was then orally administered 0.5 ml
water. SHR tail blood pressure was measured once every 2
weeks before each oral administration. Before each blood
pressure measurement, SHRs were warmed for 10 min
in a 39°C thermostated box. SHR tail blood pressure was
measured every two weeks. An indirect blood pressure
meter (BP-98A, Softron Co. Ltd. Tokyo, Japan) was used
to measure SBP and DBP four times in each determination
for each treatment.
Subjects and clinical trials
The Institutional Review Board of Taipei Medical Uni-
versity approved the clinical trial design (approval number
P970401). Subjects were males and females aged 20 to 60
years with pre-hypertension (SBP, 130 to140 mmHg and
DBP, 85 to 90 mmHg) or hypertension (SBP, 140 mmHg
or higher and DBP, 90 mmHg or higher) that was con-
rmed by an internal medicine physician at Taipei Medical
University Hospital. Exclusion criteria included pregnant
and lactating women, people who had received trace ele-
ment supplements in the previous three months, people
receiving gastric or diuretic treatments, patients with acute
renal failure, or people with recent history of surgery or
acute infections. All subjects were informed of the pur-
poses of the study, were free to ask questions throughout
the study, and signed an informed consent form witnessed
by one of the investigators. This clinical trial was designed
as a randomized, placebo-controlled parallel feeding trial
(Figure 1). Forty-six subjects (35 males and 11 females)
were randomly assigned to either control or treatment
groups. GP or placebo capsules kept in a dark bottle were
then given to subjects. They were instructed to take two
500 mg capsules of PG or placebo daily, together with 200
ml of water, 30 min after breakfast for 8 weeks. Eating
habits were not restricted during the treatment. However,
to avoid possible interference with the effects of PG, the
consumption of vitamin supplements and functional foods
was prohibited during the trial. Each subject’s BP was
measured at the beginning of the trial, then once every two
weeks during the trial. Their BP was measured using a dig-
ital BP analyzer (ES-P110, Terumo Corp., Tokyo, Japan)
and recorded as the average of two measurements. Mea-
surements were always made at the same place and time
after 15 min of rest. Venous blood was also collected from
each subject before and after the trial. Blood samples were
assayed for serum lipid proles and for other biochemical
cardiovascular risk markers (e.g., total cholesterol (TC),
triglyceride (TG), glutamate oxaloacetate transaminase
(GOT), low density lipoproteins (LDL), high density
lipoproteins (HDL), and blood urea nitrogen (BUN)) in
the Department of Laboratory Medicine, Taipei Medical
University Hospital.
Statistical analysis
Each data was expressed as mean ± S.D. Effects of
PG on SHR BP were assessed by a one-way ANOVA fol-
lowed by a post hoc Tukey’s test to compare SBP or DBP
between PG (30 and 50 mg/Kg) and the control group at
the xed week, and values at the same time point not shar-
ing an alphabetic letter are signicantly different (P<0.05).
Effects of the PG on BP of subjects or serum lipid proles
Figure 1. Summary of subject trials experimental design.
HAN et al. — Antihypertensive activity of processed garlic 279
and other biochemical measurements from venous blood
collection of subjects were assessed by a paired t-test to
compare SBP or DBP before and after the feeding trial
with PG and the placebo at 2, 4, 6, 8 weeks. A difference
was considered statistically signicant when P<0.05 (*) or
P<0.01 (**).
RESULTS AND DISCUSSION
Potential drawbacks to using fresh garlic in the experi-
ment were the possibility of subject indigestion and its
unacceptable odors, which are mainly from alliin (S-allyl-
ʟ-cysteine sulfoxide). Instead, a process that combined
aging at 37°C and water extraction for over 20 months
produced aged garlic extracts which contained S-allyl
mercaptocysteine and S-allyl-ʟ-cysteine. The S-allyl-ʟ-
cysteine was reported to have a 98% absorption rate into
the blood system and was used for standardizing aged
garlic extracts (Nagae et al., 1994).
Before investigating the long-term effects of PG on
the SHR BP, a 24 h BP change was performed by a single
oral administration. A single dose of 30 or 50 mg/Kg
of PG was orally administered to SHR, and the BP was
then measured after 2, 4, 6, and 24 h. PG significantly
lowered SBP and DBP (P<0.05) at four time points (data
not shown). On the basis of this result, a long-term study
(8 weeks) of the effects of PG on SBP (Figure 2A) and
DBP (Figure 2B) was performed. At the beginning of the
experiment, the average SBPs of the control and the two
treatment groups (30 and 50 mg/Kg of PG) were 194.5 ±
13.1, 190.9 ± 8.6, and 191.1 ± 12.1 mmHg, respectively.
The corresponding mean DBPs were 169.2 ± 11.5, 164.8 ±
9.5, and 166.3 ± 11.7 mmHg, respectively. During the test
period, the control showed a continuous increase (Harauma
and Moriguchi, 2006; Liu et al., 2009a) of SBP and DBP,
respectively, up to 212.6 ± 9.0 and 186.8 ± 7.3 mmHg
after 8 weeks’ administration. In contrast, PG signicantly
decreased the SBP (Figure 2A) and DBP (Figure 2B) of
SHR at these two doses. This effect was not dose-depen-
dent but was statistically signicant, except for DBP at 50
mg/Kg for 4 and 6 weeks, when compared with the control
group at 4, 6, and 8 weeks. Therefore, a clinical trial was
performed to evaluate the effects of PG on hypertension in
humans.
Forty-four subjects were divided into control (17 males
and 5 females) and treatment (16 males and 6 females)
groups (Figure 1). The effects of PG on the BPs of hyper-
tensive subjects are shown in Figure 3. For the PG group,
the initial mean SBP and DBP measurements were 138.91
± 9.95 and 87.23 ± 8.83 mmHg, respectively (Figure 3A).
The corresponding values for the placebo group were
133.64 ± 11.11 and 84.95 ± 7.69 mmHg, respectively
(Figure 3B). There were no signicant differences in the
initial SBP and DBP measurements in the placebo or PG
groups as shown by t-test. Figure 3A shows the changes
in BP after PG treatment for 8 weeks. The mean SBPs
were 130.14 ± 10.77, 129.23 ± 15.68, 130.55 ± 14.73,
and 130.86 ± 9.45 mmHg after 2, 4, 6, and 8 weeks, re-
spectively. The corresponding mean DBPs were 87.05 ±
12.51, 86.55 ± 12.01, 88.00 ± 13.43, and 83.09 ± 10.98
mmHg, respectively. All reductions in SBP were signi-
cant (P<0.01), as shown by paired t-test, whereas only the
reduction in DBP after 8 weeks was statistically signifi-
cant (P<0.05). Figure 3B shows the changes in BP for the
control group. The reductions in SBP were not statistically
signicant (P>0.05), as shown by paired t-test. However,
the reduction in DBP after 8 weeks was statistically signif-
icant (P<0.05). Thus, daily consumption of PG produces
a statistically significant reduction in SBP that can be
sustained for 8 weeks. Figures 2 and 3 show that PG has a
long-term antihypertensive effect in both SHR and hyper-
tensive human subjects. Venous blood collection was per-
formed for each subject after the assigned feeding and at
the end of 8 week PG or placebo intervention. There were
no signicant differences in TC, TG, GOT, LDL, HDL, or
BUN levels (P>0.05) after 8 weeks between the PG treat-
ment group (Figure 4A) and the placebo group (Figure
4B), as shown by paired t-test. Thus, PG did not have any
Figure 2. Effects of processed garlic powders at concentrations
of 30 mg/Kg and 50 mg/Kg SHR (suspended in 0.5-mL water)
on systolic blood pressure (A) and diastolic blood pressure (B)
of SHR (N=8) over eight weeks. 0.5-mL water was orally ad-
ministered to the control group. A one-way ANOVA followed
by a post hoc Tukey’s test to compare SBP or DBP between PG
(30 and 50 mg/Kg) and the control group at the xed week, and
values at the same time point not sharing an alphabetic letter are
signicantly different (P<0.05).
280 Botanical Studies, Vol. 52, 2011
effect on serum lipid proles or on other biochemical car-
diovascular risk markers.
Our stepwise results showed that PG had
antihypertensive activities in SHR animal models
and hypertensive subjects. This is the first report to
use processed garlic, PG, to conduct simultaneous
antihypertensive studies in animals and human subjects.
The antihypertensive activities against SHR were the
same as those of a previous study using aged garlic extract
(Harauma and Moriguchi, 2006), however, the advantage
of aged garlic powder in this report was the timesaving
fermentation (two weeks) and the simple processing, rath-
er than the several months required of aged garlic extracts.
There were several reports concerning the placebo group
with statistical effects in nutrient supplements (Venn et
al., 2003; Binkoski et al., 2004; Theobald et al., 2007;
Edwards et al., 2007; Liu et al., 2009a). The placebo was
shown to lower DBP in this feeding trial, which might be
attributed to a placebo effect.
Oxidative stresses might be involved in hypertension
(Dhawan and Jain, 2005). Various kinds of processed
garlic are reported to have radical scavenging activities
Figure 3. Effects of the processed garlic powder (A) and the placebo (B) on the systolic blood pressure (SBP) and diastolic blood
pressure (DBP) of hypertensive subjects in the feeding trial. Two capsules (each 500 mg) together with 200-mL water were admin-
istered daily for 8 weeks. The paired t-test was performed to compare the changes of the blood pressure (SBP and DBP) between the
originals vs. processed garlic powder or placebo at 2, 4, 6, and 8 week intervals, and a difference was considered statistically signi-
cant when P<0.05 (*) or P<0.01 (**) or P<0.001 (***).
Figure 4. Effects of (A) the processed garlic powder (PG) and (B) the placebo on serum lipid proles and other biochemical measure-
ments of total cholesterol (TC), triglyceride (TG), glutamate oxaloacetate transaminase (GOT), low density lipoproteins (LDL), high
density lipoproteins (HDL), and blood urea nitrogen (BUN) of clinical trials. The paired t-test was performed, and a difference was
considered statistically signicant when P<0.05.
HAN et al. — Antihypertensive activity of processed garlic 281
(Imai et al., 1994; Borek, 2001; Banerjee et al., 2003) and
the ability to elevate the antioxidant status of hypertensive
subjects (Dhawan and Jain, 2005), which might explain
the antihypertensive mechanism of garlic products.
One water-soluble component, S-allyl-ʟ-cysteine, the
represented compound derived from γ-glutamyl-S-
allylcysteine in aged garlic preparations (Lawson and
Gardner, 2005; Harauma and Moriguchi, 2006; Borek,
2006) was reported to increase the antioxidant status of
MCD-induced hepatotoxic mice (Lin et al., 2008), to
prevent CCl4-induced acute liver injury and reduce hepatic
lipid peroxidation in rats (Kodai et al., 2007), to inhibit
the formation of advanced glycation end products (Ah-
mad et al., 2007) and to increase the antioxidant status of
cyclosporine-induced nephrotoxicity in Wistar rats (Ma-
gendiramani et al., 2009). Kim et al. (2001) reported that
garlic extract and S-allyl-ʟ-cysteine could significantly
increase NO production in endothelial cells. The NO is a
major endogenous factor in blood vessel relaxation which
may result in lowering blood pressure (Chalupsky et al.,
2004; Bruckdorfer, 2005; Moon et al., 2006). Our present
results showing antihypertensive activities in SHR and in
hypertensive subjects might partially be due to the high
contents of S-allyl-ʟ-cysteine (753 µg/g) in the processed
garlic powders. Though garlic has been reported to have
hypocholesterolemia activities (Stevinson et al., 2000; Yeh
and Liu, 2001) the clinical trial did not appear to effect
serum lipid profiles or other biochemical measurements
for cardiovascular risk in the present feeding trial. It was
proposed that the criteria of enrolled subjects focused pri-
marily on blood pressure and they were thus not as aware
of the other reported activities.
In conclusion, the timesaving (two-week) and simply-
processed garlic products, PG, could effectively lower the
SBP and DBP of SHR during the 8 week treatment period,
and this effect was statistically signicant compared to the
control group. Furthermore, daily consumption of two 500
mg PG capsules over 8 weeks had regulatory effects on
the SBP of hypertensive subjects.
Acknowledgments. The authors want to express thanks
for financial support from Taipei Medical University-
Shuang Ho Hospital (99TMU-SHH-04-3) and from the
Promotion Program for the Commercialization of Biotech-
nology, Industrial Development Bureau, Ministry of Eco-
nomic Affairs, Republic of China and the AGV Products
Corp., Taiwan.
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Selenium supplements do not increase plasma total homo-
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418-420.
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another potential cardiovascular protective factor of aged
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HAN et al. — Antihypertensive activity of processed garlic 283
加工大蒜對於自發性高血壓鼠與高血壓民眾降血壓活性研究
韓傳孝1 劉如濟2,3 陳冠翰4,5 林音秀1 陳鏡譚5
樊謙騰5 李惠倫5 劉得任6 侯文琪7,8
1臺北醫學大學 藥學系
2臺北醫學大學 內科學科
3雙和醫院 心臟內科
4臺灣大學 食品科技研究所
5愛之味股份有限公司
6臺北醫學大學 生醫材料暨工程研究所
7臺北醫學大學 附設醫院中草藥研究中心
8臺北醫學大學 生藥學研究所
本研究評估加工大蒜對於自發性高血壓鼠與高血壓民眾降血壓活性研究。生大蒜經過兩週酵素褐
變,將原本白色變成黑色。活性成分,S-allyl-ʟ-cysteine,經分析與測定,含量為 753 µg/g加工大蒜在
30 50 mg/K g 劑量下,每天餵食一次,在第四、六與八週能有效降低高血壓鼠的血壓。以安慰劑控制
組平行進行加工大蒜對於 44 位高血壓民眾降血壓之人體試驗,總共進行八週,血壓每兩週於固定時間
與地點,以電子血壓計進行血壓量測。結果顯示,每天吞食 500 毫克膠囊兩顆之加工大蒜,在兩週後具
有顯著性差異(P<0.01)降低收縮壓,降幅達 8.05 毫米汞柱。
關鍵詞:加工大蒜;降壓;血壓;人體試驗;自發性高血壓鼠。
... Similar antihypertensive effects have been also demonstrated in other animal models of hypertension. For instance, a single daily dose of processed garlic (30-50 mg/kg) administered for 8 weeks promoted antihypertensive properties in spontaneously hypertensive rats (SHR) [59]. Processed garlic, containing 75.3 mg/100 g of S-allylcysteine (SAC), significantly, although doseindependently, prevented the progressive increase in systolic and diastolic blood pressure These preliminary results of the H 2 S-releasing properties of polysulfide compounds and natural ITCs, respectively derived from Alliaceae, Brassicaceae, and Moringa, and the characterization of the molecular mechanism leading to the formation of H 2 S in the presence of free thiols, established the basis for further pharmacological investigations about their potential antihypertensive effects. ...
... Similar antihypertensive effects have been also demonstrated in other animal models of hypertension. For instance, a single daily dose of processed garlic (30-50 mg/kg) administered for 8 weeks promoted antihypertensive properties in spontaneously hypertensive rats (SHR) [59]. Processed garlic, containing 75.3 mg/100 g of S-allylcysteine (SAC), significantly, although dose-independently, prevented the progressive increase in systolic and diastolic blood pressure levels observed in the control group. ...
... Conversely, there was no significant change in blood pressure values observed in the placebo group. Finally, in a randomized, placebo-controlled clinical trial not included in the meta-analysis by Ried [78], daily consumption of processed garlic (1 g daily for 8 weeks, corresponding to 0.8 mg of SAC/day) significantly reduced systolic blood pressure in 23 hypertensive subjects (about 8 mmHg) from the baseline [59]. The antihypertensive effects of garlic were observed after 2 weeks of treatment. ...
Article
After the discovery of hydrogen sulfide (H2S) in the central nervous system by Abe and Kimura in 1996, the physiopathological role of H2S has been widely investigated in several systems such as the cardiovascular. In particular, H2S plays a pivotal role in the control of vascular tone, exhibiting mechanisms of action able to induce vasodilation: for instance, activation of potassium channels (KATP and Kv7) and inhibition of 5-phosphodiesterase (5-PDE). These findings paved the way for the research of natural and synthetic exogenous H2S-donors (i.e., molecules able to release H2S) in order to have new tools for the management of hypertension. In this scenario, some natural molecules derived from Alliaceae (i.e., garlic) and Brassicaceae (i.e., rocket or broccoli) botanical families show the profile of slow H2S-donors able to mimic the endogenous production of this gasotransmitter and therefore can be viewed as interesting potential tools for management of hypertension or pre-hypertension. In this article, the preclinical and clinical impacts of these natural H2S-donors on hypertension and vascular integrity have been reviewed in order to give a complete panorama of their potential use for the management of hypertension and related vascular diseases.
... Similar antihypertensive effects have been also demonstrated in other animal models of hypertension. For instance, a single daily dose of processed garlic (30-50 mg/kg) administered for 8 weeks promoted antihypertensive properties in spontaneously hypertensive rats (SHR) [59]. Processed garlic, containing 75.3 mg/100 g of S-allylcysteine (SAC), significantly, although doseindependently, prevented the progressive increase in systolic and diastolic blood pressure These preliminary results of the H 2 S-releasing properties of polysulfide compounds and natural ITCs, respectively derived from Alliaceae, Brassicaceae, and Moringa, and the characterization of the molecular mechanism leading to the formation of H 2 S in the presence of free thiols, established the basis for further pharmacological investigations about their potential antihypertensive effects. ...
... Similar antihypertensive effects have been also demonstrated in other animal models of hypertension. For instance, a single daily dose of processed garlic (30-50 mg/kg) administered for 8 weeks promoted antihypertensive properties in spontaneously hypertensive rats (SHR) [59]. Processed garlic, containing 75.3 mg/100 g of S-allylcysteine (SAC), significantly, although dose-independently, prevented the progressive increase in systolic and diastolic blood pressure levels observed in the control group. ...
... Conversely, there was no significant change in blood pressure values observed in the placebo group. Finally, in a randomized, placebo-controlled clinical trial not included in the meta-analysis by Ried [78], daily consumption of processed garlic (1 g daily for 8 weeks, corresponding to 0.8 mg of SAC/day) significantly reduced systolic blood pressure in 23 hypertensive subjects (about 8 mmHg) from the baseline [59]. The antihypertensive effects of garlic were observed after 2 weeks of treatment. ...
Article
Full-text available
Citation: Piragine, E.; Citi, V.; Lawson, K.; Calderone, V.; Martelli, A. Potential Effects of Natural H 2 S-Donors in Hypertension Management. After the discovery of hydrogen sulfide (H2S) in the central nervous system by Abe and Kimura in 1996, the physiopathological role of H2S has been widely investigated in several systems such as the cardiovascular. In particular, H2S plays a pivotal role in the control of vascular tone, exhibiting mechanisms of action able to induce vasodilation: for instance, activation of potassium channels (KATP and Kv7) and inhibition of 5-phosphodiesterase (5-PDE). These findings paved the way for the research of natural and synthetic exogenous H2S-donors (i.e., molecules able to release H2S) in order to have new tools for the management of hypertension. In this scenario, some natural molecules derived from Alliaceae (i.e., garlic) and Brassicaceae (i.e., rocket or broccoli) botanical families show the profile of slow H2S-donors able to mimic the endogenous production of this gasotransmitter and therefore can be viewed as interesting potential tools for management of hypertension or prehypertension. In this article, the preclinical and clinical impacts of these natural H2S-donors on hypertension and vascular integrity have been reviewed in order to give a complete panorama of their potential use for the management of hypertension and related vascular diseases.
... Garlic (Allium sativum L.) is a widely grown vegetable condiment with both edible and medicinal values [1][2][3][4]. Studies have shown that garlic consumption is effective in reducing the risk of diseases such as hypertension and diabetes [5,6]. In addition to its disease-prevention function, garlic has antibacterial, anti-inflammatory, and insecticidal properties [7][8][9][10]. ...
... This means that the frictional resistance between the root disc and the surface of the round blade is greater than that between the root whisker and the surface of the round blade. The force curve was in the range from point p 5 to p 6 , and the minimum value of −0.032 kg was obtained at point p 5 . The comprehensive analysis shows that the double round blades cutting garlic roots have the problem of not cutting cleanly enough to ensure the neat cutting surface of garlic roots. ...
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In this study, we quantified and analyzed the root-cutting process of garlic with a test bench with pressure sensors on the basis of the comparative analysis of various information perception methods. On the basis of the output value of the pressure sensor, the force curve of garlic roots was plotted, and the double round blade cutting module is optimized on the basis of the force curve diagram. The innovative proposal of slotted round blades for garlic root cutting is presented here. The round blade diameter is 110 mm, the center distance is 100 mm, the blade thickness is 1 mm, and the blade speed is 1200 r/min. According to the analysis of the force curve, it was found that the slotted round blade with the slanted blade could generate a strong thrust to cut the roots. The cutting effect was better and the cutting surface of the roots was straight. The slotted blade meets the need for cutting garlic roots.
... Administration of aqueous garlic extracts, either orally [32] or intravenously [33], significantly reduced BP in two-kidney-one-clip (2K1C) hypertensive rats. Chronic daily treatment with raw garlic and aged garlic extract [34] or processed garlic standardized in S-allylcysteine (SAC) [35] content also promoted antihypertensive effects in spontaneously hypertensive rats (SHRs). Finally, in a deoxycorticosterone acetate salt-induced rat model of hypertension, oral treatment for seven weeks with black garlic extract standardized in diallyl sulfide (DAS), diallyl disulfide (DADS) and diallyl trisulfide (DATS) content, significantly attenuated the increased systolic BP in hypertensive animals [36]. ...
Article
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... [169] In a placebo-controlled experiment, 44 hypertensive patients were given enzymatic browning processed garlic, and both their systolic and diastolic blood pressures were dramatically decreased. [170] Garlic's antihypertensive mechanisms are demonstrated in Fig. 5. ...
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The medicinal characteristics of garlic's (Allium sativum L.) dynamically bioac-tive constituents such as alliin, allicin, ajoene, S-allyl-cysteine, S-trityl-L-cysteine, diallyl sulfide, and S-allylmercaptocysteine, have gained a lot of scientific attention from a large number of investigators who have occupied the related pre-clinical and clinical studies, as well as in the industrial sector. The outcomes from basic investigations demonstrated that, depending on the type of food processing, the presence of bioactive compounds in the matrix of garlic have a coherent and direct relation with the appearance/ development of health-promoting effects in the host. Besides, it can be acknowledged that at present spectroscopic and chemometric techniques are powerful tools to detect fraud, prevent criminal activities of fraudsters, and ensure food chain safety, and future studies should lead to further progress, such as portable and hand-held spectroscopy devices for rapid on-site analysis, in this field. There have been also many issues on the effects of processing on garlic's bioactive compounds, potential toxicities, pharmaco-kinetics, and safety profile of these elements that should be studied to validate the health advantages of garlic in humans. In this review, the outcomes of recent experimental and clinical reports are reviewed and metabolism pathway, bioavailability, biological/therapeutically effects, food-related applicability, methods of adulteration detection, potential toxicities, and safety profile of garlic's derived bio-compounds are discussed.
... Black garlic has many health benefits. Black garlic contains high concentration bioactive compounds that have hepatoprotective effect [5], photoprotective effect [6], cardioprotective effect [7], anti-inflammatory effect [8], immunomodulatory [9], anti-tumour potency [4], anti-cancer potency [10], anti-allergic activity [11], anti-diabetic activity [12], and anti-hypertensive activity [13]. ...
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... Garlic (Allium sativum L.) has been known as the "aroma" vegetable, which is widely used as a food ingredient in many countries and different cultures as a result of its characteristic flavour and potential health benefits. Many studies have shown evidence of a significant reduction in the risk of developing chronic diseases (e.g., cardiovascular, cancer, obesity, diabetes, high blood pressure) associated with garlic consumption [1][2][3][4]. Together with therapeutic functions, garlic possesses additional biological activities such as antibacterial, antifungal, and antioxidant properties [5][6][7], resulting in garlic being one of the most important vegetables/spices worldwide [8]. It has been suggested that the biological properties and health benefits of garlic are derived from its phytochemicals, mainly organosulfur compounds, saponins and polyphenols. ...
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BACKGROUND: It was reported in a previous paper that the yam tuber storage protein dioscorin exhibited antihypertensive effects on spontaneously hypertensive rats. The aim of the present study was to evaluate and compare the effects of packets of instant food (30 g) with (treated meal) and without (placebo) lyophilised yam powder on hypertensive subjects.RESULTS: A placebo-controlled feeding trial was conducted daily for 5 weeks (stage 1), followed by a 1 week washout and then a 5 week crossover (stage 2). Twenty-one subjects finished the trial. One packet of treated meal contained 140 ± 2.54 mg of dioscorin according to enzyme-linked immunosorbent assay. The blood pressure results of the treated meal and placebo groups at stage 1 end versus originals, but not at stage 2 end versus stage 2 beginning, were significantly different by the paired t test. Systolic (SBP) and diastolic (DBP) blood pressure readings after treated meal intervention, but not after placebo intervention, differed significantly from the original values based on one-way analysis of variance followed by the post hoc Tukey test; the reductions in SBP and DBP were 6.52 and 4.76 mmHg respectively. The feeding trial did not appear to affect serum lipid profiles or other biochemical measurements of cardiovascular risk.CONCLUSION: Intake of an instant food containing 140 mg of dioscorin over 5 weeks had a regulating effect on human blood pressure. Copyright © 2008 Society of Chemical Industry
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Stroke is the leading cause of long-term disability in the United States and affects more people than any other neurologic disorder. Hypertension is a major risk factor associated with stroke. Several anti-hypertensive agents have been used to treat chronic hypertension to reduce the morbidity and mortality of stroke. Previous experimental studies have shown reduced stroke mortality with angiotensin-converting enzyme (ACE) inhibitors. This review discusses the development of stroke and potential use of ACE inhibitors in prevention and treatment of this disease. Furthermore, this review focuses on current investigations aimed at cellular mechanisms involved in stroke-induced microvascular alterations.
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Garlic has been used as a traditional medicine for prevention and treatment of cardiovascular diseases. However, the molecular mechanism of garlic’s pharmacological action has not been clearly elucidated. We examined here the effect of garlic extract and its major component, S-allyl cysteine (SAC), on nitric oxide (NO) production by macrophages and endothelial cells. The present study demonstrates that these reagents inhibited NO production through the suppression of iNOS mRNA and protein expression in the murine macrophage cell line RAW264.7, which had been stimulated with LPS and IFNγ. The garlic extract also inhibited NO production in peritoneal macrophages, rat hepatocytes, and rat aortic smooth muscle cells stimulated with LPS plus cytokines, but it did not inhibit NO production in iNOS-transfected AKN-1 cells or iNOS enzyme activity. These reagents suppressed NF-κB activation and murine iNOS promoter activity in LPS and IFNγ-stimulated RAW264.7 cells. In contrast, these reagents significantly increased cGMP production by eNOS in HUVEC without changes in activity, protein levels, and cellular distribution of eNOS. Finally, garlic extract and SAC both suppressed the production of hydroxyl radical, confirming their antioxidant activity. These data demonstrate that garlic extract and SAC, due to their antioxidant activity, differentially regulate NO production by inhibiting iNOS expression in macrophages while increasing NO in endothelial cells. Thus, this selective regulation may contribute to the anti-inflammatory effect and prevention of atherosclerosis by these reagents.
Article
In this study, we compared the cardioprotective effects of freshly crushed garlic vis-a-vis that of processed garlic. Two groups of rats were gavaged with respective garlic preparations while the control group received vehicle only. After 30 days, all of the rats were sacrificed and isolated the hearts were subjected to 30 min ischemia followed by 2 h of reperfusion. Both of the garlic preparations provided cardioprotection, but superior cardiac performance was noticed for those fed with freshly crushed garlic. Consistent with these results, the freshly crushed garlic group displayed significantly greater phosphorylation of antiapoptotic ERK1/2 proteins, reduced Bax/Bcl-2 ratio, and reduced phosphorylation of proapoptotic p-38MAPK and JNK. Moreover, the survival signaling network consisting of Akt-FoxO1 was increased in the freshly crushed garlic treated hearts. Freshly crushed garlic, but not the processed garlic, showed enhanced redox signaling as evident by increased level of p65 subunit of NFkappaB, Nrf2, and enhanced GLUT 4, PPARalpha, and PPARdelta. The results thus show that although both freshly crushed garlic and processed garlic provide cardioprotection, the former has additional cardioprotective properties presumably due to the presence of H2S.
Article
The aim of the present study was to investigate different yam treatments, including powdered-yam-products (PYP) and liquid-yam-products (LYP), with respect to spontaneously hypertensive rats (SHRs) blood pressure. PYP included alcohol-insoluble-solids of yam tuber, hot-air-drying (HAD) of yam tuber slices, steam-cooked once or twice followed by HAD which were subsequently powdered. LYP included water extracts of yam tuber (WEY) heated at 90 degrees C (WEY90H) or 95 degrees C for 10 min (WEY95H), and then stored at 4 degrees C for different numbers of day. PYP, WEY, and WEYH were found effectively to reduce the blood pressure of SHR and should be beneficial in food processing in the development of functional foods for blood pressure regulation.