J Ginseng Res 38 (2014) 244e250

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Journal of Ginseng Research
journal homepage: http://www.ginsengres.org

Research article

Rg3-enriched Korean Red Ginseng improves vascular function in
spontaneously hypertensive rats
Jung-Bum Park 1, Sun Kwan Kwon 1, Harsha Nagar 1, Saet-byel Jung 2, Byeong Hwa Jeon 1,
Chang Sup Kim 3, Jin-Hwan Oh 4, Hee-Jung Song 5, *, Cuk-Seong Kim 1, **1

Department of Physiology, School of Medicine, Chungnam National University, Daejeon, Korea
Department of Endocrinology, Chungnam National University Hospital, Daejeon, Korea
Department of Chemical and Biological Engineering, Hanbat National University, Daejeon, Korea
4
BTGin Company Limited, Daejeon, Korea
5
Department of Neurology, Chungnam National University Hospital, Daejeon, Korea
2
3

a r t i c l e i n f o

a b s t r a c t

Article history:
Received 20 March 2014
Received in Revised form
28 April 2014
Accepted 30 May 2014
Available online 11 June 2014

Background: Panax ginseng has distinct and impressive health beneﬁts, such as improved blood pressure
and immune system functioning. Rg3-enriched Korean Red Ginseng (REKRG) isolated from Korean Red
Ginseng contains a high percentage of Rg3.
Methods: In this study, we examined the effects of REKRG on endothelial cell nitric oxide synthase(eNOS) activation and adhesion molecules in endothelial cells and vascular function in rats.
Results: REKRG dose-dependently increased eNOS phosphorylation and nitric oxide (NO) production inendothelial cells. In addition, REKRG markedly inhibited the tumor necrosis factor-a (TNF-a)-mediated induction of intercellular adhesion molecule (ICAM)-1 and cyclooxygenase (COX)-2 expressions in endothelial
cells. REKRG improved endothelium-dependent vasorelaxation in the Wistar-Kyoto (WKY) rat and spontaneously hypertensive rats (SHRs) compared with controls. Furthermore, REKRG treatment for 6 weeks
increased serum NO levels and reduced the mean aortic intima-media thickness compared with controls.
Conclusion: Taken together, these results suggest that REKRG increased vascular function and improved
immune system functioning. Therefore, REKRG is a very useful food for preventing or improving various
cardiovascular diseases.
Copyright Ó 2014, The Korean Society of Ginseng, Published by Elsevier. All rights reserved.

Keywords:eNOSNO
Panax ginseng
REKRG
SHR

1. Introduction
Hypertension is one of the major risk factors for the development of cardiovascular disease and modulation of the immune
system [1,2] and is characterized by impaired vascular endothelial
function [2e4]. Vascular endothelial cells are located in the intima,
which is the inner lining of the vasculature, and they play animportant role in the regulation of vascular tone by various vasoactive factors, such as nitric oxide (NO) [5]. Disruption of endothelial cell function is characterized by impaired bioavailability ofNO [2,6] and induces vascular disease, which in turn contributes tosmooth muscle cell proliferation [7] and stimulation of inﬂammatory molecules, such as intercellular adhesion molecule (ICAM)-1,

vascular cell adhesion molecule (VCAM)-1, and cyclooxygenase(COX)-2. NO is a major endothelium-dependent relaxing factor. It is
produced from L-arginine by the activity of endothelial cell nitricoxide synthase (eNOS) [8] and induces vascular smooth muscle
relaxation by activation of guanylate cyclase [9]. Some studies haveshown that blood pressure was enhanced in eNOS knockout mice
[10,11] as well as in rats in which eNOS was inhibited with Nunitro-L-arginine methyl ester (L-NAME) [12]. It was also reported
that the bioavailability of NO was reduced in patients with established hypertension compared with the control group [2,6].
For thousands of years, Panax ginseng has been used as a
traditional tonic medicine. The protective effects of P. ginseng
related to cardiovascular functions are reportedly associated with* Corresponding author. Department of Neurology, Chungnam National University Hospital, Daejeon 301-712, Korea.
** Corresponding author. Department of Physiology, School of Medicine, Chungnam National University, 55 Munhwa-ro, Jung-Gu, Daejeon 301-131, Korea.
E-mail addresses: nrsono@naver.com (H.-J. Song), cskim@cnu.ac.kr (C.-S. Kim).
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0)
which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
1226-8453/$ e see front matter Copyright Ó 2014, The Korean Society of Ginseng, Published by Elsevier. All rights reserved.
http://dx.doi.org/10.1016/j.jgr.2014.05.011

J.-B. Park et al / Effect of Rg3-enriched KRG on vascular function

245

randomly: a normal saline group and a REKRG group. REKRG(10 mg/kg) was orally administered to animals for 6 weeks.

vasorelaxation and stimulation of NO produced by eNOS [13,14].
Ginsenosides consist of two major groups according to the chemical
structure of the fraction. The ﬁrst is the panaxadiol group, which
includes Rb1, Rb2, Rb3, Rc, Rd, Rg3, Rh2, and Rs1. The second is thepanaxatriol group, which includes Re, Rf, Rg1, Rg2, and Rh1. Individual ginsenosides exert different effects via different mechanisms
in various tissues. The combination of ginsenosides in ginseng extracts may be important for providing more powerful therapeuticand pharmacological effects [15e17]. Notably, ginsenoside Rg3
provides various protective effects, including anti-inﬂammatory[18] and antitumor effects [19], and it also enhances NO productionand eNOS activity [20].
The aim of this study was to investigate whether Rg3-enriched
Korean Red Ginseng (REKRG), a ginsenoside fraction enriched in
Rg3, increases eNOS activity and NO production and exhibits antiinﬂammatory effects.

Anti-ICAM-1, anti-eNOS, and anti-COX-2 antibodies were purchased from Santa Cruz Biotechnology (Santa Cruz, CA, USA).
Antiphospho-eNOS, antiphospho-Akt, and anti-Akt antibodies
were purchased from Cell Signaling Technology (Beverly, MA, USA).
Western blot analysis of whole cell lysates (30 mg) was performed
using the appropriate primary and secondary antibodies. Blots
were imaged using a chemiluminescence assay kit from PharmaciaAmersham (Freiburg, Germany), and band densities were quantiﬁed using a Gel Doc 2000 ChemiDoc system and Quantity One
software from Bio-Rad (Hercules, CA, USA). Values were normalized to a b-actin loading control.

2. Materials and methods

2.6. Real-time polymerase chain reaction

2.1. Preparation of ginsenoside Rg3-enriched Korean Red Ginseng

Total RNA was isolated from cells using the acid guanidinium
thiocyanateephenolechloroform method. Real-time polymerase
chain reaction (PCR) was performed using the Prism 7000 Sequence
Detection System (Applied Biosystems, Foster City, CA, USA) with
the Super Script III Platinum SYBR Green One-Step qRT-PCR Kit(Invitrogen, Carlsbad, CA, USA). Primers used to amplify human
ICAM-1 were as follows: 50 -CAGTGACCATCTACAGCTTTCCG-30 and
50 -GCTGCTACCACAGTGATGATGACAA-30 . Primers used for human
COX-2 were as follows: 50 -GGTCTGGTGCCTGGTCTGATGATG-30 and
50 -GTCCTTTCAAGGAGAATGGTGC-30 . Primers used for human glyceraldehyde 3-phosphate dehydrogenase (GAPDH), which was used as
an internal control, were as follows: 50 -ATGACATCAAGAAGGTGGTG30 and 50 -CATACCAGG AAAATGAGCTTG-30 . Dissociation curves weremonitored to check for aberrant formation of primer-dimers.

Dried Korean Red Ginseng (P. ginseng) root was purchased fromGumsan Nonghyup (Gumsan, Korea). Korean ginseng was extracted
two times with 10 volumes of ethanol at 50 C for 7 hours (1st 50%, 2nd85%), and then concentrated under vacuum at 50 C. The crude extract
was dissolved in water and enzyme-acid hydrolysis to maximize
ginsenoside Rg3 was performed (raw ginsenoside was hydrolyzed toRg3) in acidic (pH 2.5w3.5) and thermophilic (65w80 C) condition.
The enzyme, which has b-glycosidase activity including cellulase,
hemicellulose, and glucosidase activity, was produced by Aspergillus
niger. To remove acid solution and concentrate Rg3, the reactant was
passed through DIAION HP20 resin (Mitsubishi Chemical Industries,
Tokyo, Japan) packed column. The ginsenoside Rg3 was concentrated
to powder under vacuum conditions. It was kindly provided by BTGin
Corporation (Occheon, Korea).
2.2. High-performance liquid chromatography analysis
The powder was dissolved in 70% methanol, and ginsenosides
including Rg3 was analyzed by high-performance liquid chromatography (HPLC). HPLC was carried out on an Liquid chromatography (LC) system equipped with a quaternary gradient pump(Spectra 4000) and UV detector (Spectra 2000; Thermo Scientiﬁc,
San Jose, CA, USA). A reversed-phase column (Hypersil gold C18,
100 mm 4.6 mm, internal diameter 5 mm; Thermo Scientiﬁc) wasused for quantitative determination of ginsenosides Rg3. The mobile phase consisted of acetonitrile and water with a ﬂow rate at
1.6e2.5 mL/min, and the column was kept at room temperature.
The detection wavelength was set at 203 nm.
2.3. Cell culture
Human umbilical vein endothelial cells (HUVECs) were purchasedfrom Clonetics (San Diego, CA, USA) and cultured in Endothelial
Growth Medium-2 from Lonza (Walkersville, MD, USA). Subconﬂuent, proliferating HUVECs were used between passages 2 and 8.
2.4. Animals and experimental protocols
The Animal Care Committee of Chungnam National University
approved the animal care and all experimental procedures conducted in this study. All instrumentation was used under aseptic
conditions. Male Wistar rats and spontaneously hypertensive rats
(SHRs; 3 months old) were each divided into two groups (n ¼ 5)

2.5. Antibodies and Western blotting

2.7. Nitrite and nitrate measurements
The NO metabolites nitrite (NO2) and nitrate (NO3), the stablebreakdown products of NO, were quantiﬁed using a commerciallyavailable kit (Nitrate/Nitrite Fluorometric Assay Kit, Cayman
Chemicals, Lexington, KY, USA), as per the manufacturer’s instructions. Medium and blood plasma were deproteinized using a
10-kDa cutoff ﬁlter (Microcon YM10, Millipore, Billerica, MA, USA).
After subtraction of background ﬂuorescence, the total protein
amounts were determined from the normalized values.
2.8. Vascular reactivity
Wistar-Kyoto (WKY) rats and SHRs were sacriﬁced via sodium
pentobarbital overdose. A mid-sternal split was performed quickly, andthe descending thoracic aorta excised carefully and placed in ice-cold
Krebs buffer (118.3mM NaCl, 4.7mM KCl, 2.5mM CaCl2,1.2mM KH2PO4,
25mM NaHCO3, 1.2mM MgSO4, 11mM glucose, 0.0026mM CaNa2
EDTA). The aorta was cleaned of excess fat and cut transversely into 5e
10 rings (2.0e3.0 mm). Endothelium-dependent vasorelaxation wasmeasured by the aortic rings as described previously [21].
2.9. Histology
A 1.5-cm section of the ascending thoracic aorta was dissectedfrom the heart. Parafﬁn sections were cut (5 mm) and stained withhematoxylin and eosin. The mean values of the vessel wall thickness
and cross sectional area from the endothelial surface to the adventitia
were determined from digitalized microphotographs using commercial imaging analysis software (Axio Scope software, Thornwood,
NY, USA).

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J Ginseng Res 2014;38:244e250

Fig. 1. High-performance liquid chromatography (HPLC) chromatograms of Korean Red Ginseng and Rg3 enriched Korean Red Ginseng. (1) Rg1. (2) Re. (3) Rf. (4) Rh1(S). (5) Rh1(R)þ
Rg2(S). (6) Rg2(R). (7) Rb1. (8) Rc. (9) Rb2. (10) Rg3(S). (11) Rg3(R). (12) Rk1. (13) Rg5.

2.10. Statistical analysis
All experiments were performed at least three times. Statisticalanalysis was performed according to the SPSS version 13.0 (SPSS
Inc., Chicago, IL, USA). Data are presented as the mean  standard
deviation. Statistical signiﬁcance was determined using analysis ofvariance (ANOVA) followed by a multiple comparison test with a
Bonferroni adjustment and by p < 0.05.
3. Results

mL REKRG for 24 hours. Cells were then harvested and processed forWestern blot analysis. REKRG concentration-dependently stimulatedSer-437 phosphorylation of Akt and Ser-1177 phosphorylation ofeNOS (Fig. 2A, 2B). We also examined NO levels in the culture medium
after HUVECs were exposed to 0.1e1 mg/mL REKRG for 24 hours. NO
levels were increased compared with control (Fig. 2C). These results
show that REKRG stimulates the Akt/eNOS signaling pathway, leading
to increased NO production in endothelial cells.
3.3. REKRG inhibits ICAM-1 and COX-2 expression induced by TNFa in HUVECs

3.1. Comparison of HPLC chromatograms REKRG and KRG
11 ginsenosides (Rg1, Re, Rf, Rh1, Rg2, Rb1, Rc, Rb2, Rg3, Rk1, andRg5) were analyzed by HPLC. HPLC chromatograms of REKRG and
KRG are shown in Fig. 1. The amount of Rg1, Re, Rf, Rh1, Rg2, Rb1, Rc,
Rb2, Rg3, Rk1, and Rg5 was 0.6, 1.9, 12.3, 5, 4.2, 3.8, 1.2, 1, 100, 12, and21 in REKRG and 2.9, 4.2, 0.3, 0.1, 0.2, 5.9, 2.2, 2.1, 0.3, 0.05, and 0.12
in KRG. These results show that the concentration of ginsenoside
Rg3 in REKRG is w300 times greater than in KRG (Table 1).
3.2. REKRG stimulates the phosphorylation of Akt and eNOS andincreases NO production in HUVECs

It is well known that Rg3 has an anti-inﬂammatory effect [18].
Therefore, we next examined the effect of REKRG on TNF-a-induced
increases in ICAM-1 and COX-2 expression in HUVECs. TNF-a increased
ICAM-1 and COX-2 expression at both the protein and messenger RNA(mRNA) levels in HUVECs (Fig. 3A, 3B). However, the TNF-a-induced
increases in VCAM-1 and COX-2 expression at the protein and mRNAlevels in HUVECs were blunted by REKRG in a concentration-dependent manner (Fig. 3A, 3B), suggesting that REKRG can inhibit inﬂammatory proteins and possibly the early stage of atherosclerosis.
3.4. REKRG improves impaired endothelial-dependent vascularrelaxation in the aorta in SHRs

Because Rg3 enhances eNOS phosphorylation and NO production[20], we next examined whether REKRG has an effect on Akt and eNOS
activation in endothelial cells. HUVECs were incubated with 0.1e1 mg/

Many studies have shown that various ginsenosides, including
Rg3, have a beneﬁcial effect on vascular function [20]. Therefore, weTable 1The saponin contents in Rg3-enriched Korean Red Ginseng and Korean Red Ginseng (mg/g)

REKRG
KRG

Rg1

Re

Rf

Rg2

Rh1

Rb1

Rc

Rb2

Rg3(S)

Rg3(R)

Rk1

Rg5

0.6
2.9

1.9
4.2

12.3
0.3

5
0.1

4.2
0.2

3.87
5.9

1.2
2.2

1
2.1

45
0.2

55
0.1

12
0.05

21
0.12

J.-B. Park et al / Effect of Rg3-enriched KRG on vascular function

investigated whether REKRG affects acetylcholine-induced relaxation in rat aortic rings. Acetylcholine-induced relaxation wasmeasured in the presence of REKRG in an organ bath. In WKY rat
aortic rings, endothelium-dependent vasorelaxation was notaffected by 1 mg/mL REKRG treatment (Fig. 4A). However, comparedwith control rings, 1 mg/mL REKRG treatment improved impaired
endothelium-dependent vasorelaxation in SHR aortic rings(Fig. 4B).
3.5. REKRG increases serum NO levels and reduces aortic intimamedia thickness in SHRs
REKRG (10 mg/kg) was administered to rats for 6 weeks bygastric gavage. We next examined the effect of REKRG on serum NO
levels. Compared with controls, 10 mg/kg REKRG increased serum
NO levels in SHRs (Fig. 5A).
NO inhibits smooth muscle cell migration and proliferation [7];therefore, we next examined the vascular structure is changed by
REKRG in SHR. Digitalized microphotographs of histological sections were used to measure vessel wall thickness and crosssectional area (Fig. 5B, 5C). The aortic intima-media thickness andcross-sectional area in SHR were signiﬁcantly thicker than it in
WKY. Interestingly, REKRG administration for 6 weeks resulted indecreased aortic intima-media thickness and cross sectional area in
SHRs, suggesting that chronic administration of REKRG may change
vascular tone and structure.
4. Discussion
High blood pressure produces chronic stress in the body and is amajor risk factor for vascular disease. It is associated with247

morphological alteration and dysfunction of vascular endothelial
cells, which can lead to atherosclerosis. The protective effects ofginseng and ginsenosides have been widely studied and shown tohave new beneﬁcial effects on hypertension [14] and various diseases, such as atherosclerosis, cancer, and thrombosis [19,22e24].
In this study, we showed that REKRG increases NO production andinduces endothelium-dependent vasorelaxation in aortic rings
from SHRs. Furthermore, REKRG administration via gastric gavage
increased serum NO levels and reduced blood pressure and aortic
intima-media thickness.
It is unclear whether absorption of intact ginsenosides can takeplace in the human gastrointestinal tract and whether their hydrolysis products, protopanaxadiol (PPD) and protopanaxatriol(PPT), reach the systemic circulation. Pharmacokinetic analysis of
Rg3 showed that the time to reach the peak plasma concentration
after oral administration was 150.0  73.5 h [25]. The data showedthat the oral bioavailability of Rg3 was 2.63, which limits its
beneﬁcial effect. Furthermore, the amount of Rg3 in Korean Red
Ginseng is usually less than 0.5%, even when steam heat treatmentof ginseng roots, which strongly increases the amount of Rg3, isused. Therefore, in order to improve the biodistribution of Rg3 invivo, we used REKRG, a ginsenoside fraction containing a highpercentage of Rg3 isolated from P. ginseng, in this study.
NO from vascular endothelial cells plays an important role in theregulation of vascular function, as well as in inhibition of platelet
aggregation and adhesion to the endothelium [26]. In addition,
endothelium-derived NO inhibits not only smooth muscle cellproliferation but also migration to form the neointima. It is wellknown that the reduction in blood pressure by Korean Red Ginseng
may be mediated by vascular endothelial cell-derived NO, and that
Korean Red Ginseng promotes NO production in vascularFig. 2. The effect of Rg3-enriched Korean Red Ginseng (REKRG) on endothelial nitric oxide synthase (eNOS) activation in human umbilical vein endothelial cells (HUVECs). (A,B) The
phosphorylation of Akt and eNOS was increased dose-dependently in HUVECs treated with various concentrations (0.1e1 mg/mL) of REKRG for 24 hours. The cells were harvested
and subjected to Western blot analysis for p-eNOS (upper panels). b-actin is shown as a loading control. p-eNOS expression levels were quantiﬁed by densitometric analysis (lower
panels of A and B). Western blots are representative of three independent experiments. *p < 0.05, **p < 0.01 compared with untreated cells. (C) REKRG treatment dose-dependently
increased nitric oxide (NO) production. Metabolites of NO (nitrite and nitrate) were measured in the media of HUVECs treated with 0.1e1 mg/mL REKRG. *p < 0.05 compared withuntreated cells. Data are presented as mean  standard deviation (n ¼ 3).

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J Ginseng Res 2014;38:244e250

Fig. 3. The effect of Rg3-enriched Korean Red Ginseng (REKRG) on the expression of intercellular adhesion molecule (ICAM)-1 and cyclooxygenase (COX)-2 induced by tumor
necrosis factor-a (TNF-a) in human umbilical vein endothelial cells (HUVECs). (A) and (C) REKRG dose-dependently inhibited TNF-a-induced ICAM-1 and COX-2 protein expressionin HUVECs. Cells were pretreated with various concentrations (0.1e1 mg/mL) of REKRG for 30 minutes and then treated with 15 ng/mL TNF-a for 8 hours in the presence of REKRG.
The cells were harvested and subjected to Western blot analysis for ICAM-1 (upper panel of A) and COX-2 (upper panel of C). b-actin is shown as a loading control. The levels of
ICAM-1 and COX-2 were quantiﬁed by densitometric analysis (lower panel of A and C). All Western blots shown are representative of three independent experiments. *p < 0.05
compared with control cells. (B,D) REKRG dose-dependently inhibited TNF-a-induced ICAM-1 and COX-2 mRNA expression in HUVECs. *p < 0.05 compared with untreated cells.
Data are presented as mean  standard deviation (n ¼ 3).

endothelial cells [13,14]. Korean Red Ginseng induces angiogenesisby activating PI3K/Akt-dependent extracellular signal-regulated
kinase 1/2 and eNOS pathways in HUVECs [27]. The ginsenoside Re
activates potassium channels of vascular smooth muscle cells

through PI3k/Akt and NO pathways [28]. Moreover, the ginsenoside
Rg3 increases NO production through the PI3K/Akt pathway [20].
This can lead to stimulation of eNOS phosphorylation and expression in ECV-304 endothelial cells [20] and inhibition of TNF-a-

Fig. 4. The effects of Rg3-enriched Korean Red Ginseng (REKRG) on vascular tone. (A) REKRG treatment did not affect endothelium-dependent vasorelaxation in Wistar-Kyoto(WKY) rats. (B) REKRG treatment improved impaired endothelium-dependent vasorelaxation in rats. Endothelium-dependent vasorelaxation was assessed after pre-treatment ofaortic rings with REKRG (1 mg/mL) for 30 min. *p < 0.05 compared with untreated aortic rings. Data are presented as mean  standard deviation (n ¼ 4e5).

J.-B. Park et al / Effect of Rg3-enriched KRG on vascular function

249

Fig. 5. The effect of Rg3-enriched Korean Red Ginseng (REKRG) on aortic structure. (A) REKRG treatment increased nitric oxide (NO) production. Metabolites of NO (nitrite andnitrate) were measured in the serum. *p < 0.05 compared with control. Data represent the mean  standard deviation (SD; n ¼ 4e5). (B,C) The intima-media thickness and crosssectional area were quantiﬁed using a computer-assisted imaging device. The mean value of the vessel wall thickness from the endothelial surface to the adventitia was determinedfrom ﬁve different locations spanning the entire cross-section. *p < 0.05 compared with Wistar-Kyoto rats. **p < 0.05 compared with SHR. Data represent the mean  SD (n ¼ 5e6).
(D) Representative images of hematoxylin and eosin-stained aortic rings.

induced expression of cell adhesion molecules, including VCAM-1
and ICAM-1, in human endothelial cells [18]. Our results also
showed that REKRG not only stimulates eNOS phosphorylation and
NO production but also decreases VCAM-1 and COX-2 expression.
These ﬁndings suggest an important role for Rg3-enriched ginseng
extract in vascular protection.
In conclusion, this study showed that the stimulatory effect of
REKRG administration on vascular endothelial NO production
through phosphorylation of eNOS is likely to have relevance for not
only inhibition of VCAM-1 and COX-2 expression but also decreased
aortic intima-media thickness, which improves cardiovascularfunction and prevents atherosclerosis.

Conﬂict of interest
All authors declare no conﬂicts of interest.

Acknowledgments
This work was supported by a National Research Foundation of
Korea (NRF) grant funded by the Korean Government (MEST; no.
2011-0023858). The English in this document has been checked byat least two professional editors, both native speakers of English.
For a certiﬁcate, please see: http://www.textcheck.com/certiﬁcate/
H2CZjI.

References[1] Harrison DG, Guzik TJ, Lob HE, Madhur MS, Marvar PJ, Thabet SR, Vinh A,
Weyand CM. Inﬂammation, immunity, and hypertension. Hypertension
2011;57:132e40.
[2] Panza JA, Quyyumi AA, Brush Jr JE, Epstein SE. Abnormal endotheliumdependent vascular relaxation in patients with essential hypertension. N Engl
J Med 1990;323:22e7.

250

J Ginseng Res 2014;38:244e250[3] Panza JA, Casino PR, Kilcoyne CM, Quyyumi AA. Role of endothelium-derived
nitric oxide in the abnormal endothelium-dependent vascular relaxation ofpatients with essential hypertension. Circulation 1993;87:1468e74.
[4] Walsh T, Donnelly T, Lyons D. Impaired endothelial nitric oxide bioavailability: a common link between aging, hypertension, and atherogenesis? J Am
Geriatr Soc 2009;57:140e5.
[5] Conger JD. Endothelial regulation of vascular tone. Hosp Pract (Off Ed)
1994;29:117e22. 125e6.
[6] Hermann M, Flammer A, Luscher TF. Nitric oxide in hypertension. J Clin
Hypertens (Greenwich) 2006;8:17e29.
[7] Luscher TF, Noll G. The pathogenesis of cardiovascular disease: role of theendothelium as a target and mediator. Atherosclerosis 1995;118(Suppl.):S81e
90.
[8] Palmer RM, Ashton DS, Moncada S. Vascular endothelial cells synthesize nitricoxide from L-arginine. Nature 1988;333:664e6.
[9] Palmer RM, Ferrige AG, Moncada S. Nitric oxide release accounts for the
biological activity of endothelium-derived relaxing factor. Nature 1987;327:
524e6.
[10] Stauss HM, Godecke A, Mrowka R, Schrader J, Persson PB. Enhanced bloodpressure variability in eNOS knockout mice. Hypertension 1999;33:1359e63.
[11] Shesely EG, Maeda N, Kim HS, Desai KM, Krege JH, Laubach VE, Sherman PA,
Sessa SC, Smithies O. Elevated blood pressures in mice lacking endothelial
nitric oxide synthase. Proc Natl Acad Sci U S A 1996;93:13176e81.
[12] Bobadilla NA, Gamba G, Tapia E, Garcia-Torres R, Bolio A, López-Zetina P,
Herrera-Acosta J. Role of NO in cyclosporin nephrotoxicity: effects of chronic
NO inhibition and NO synthases gene expression. Am J Physiol 1998;274:F791e8.
[13] Jeon BH, Kim CS, Kim HS, Park JB, Nam KY, Chiang SJ. Effect of Korean Red
Ginseng on blood pressure and nitric oxide production. Acta Pharmacol Sin
2000;21:1095e100.
[14] Jeon BH, Kim CS, Park KS, Lee JW, Park JB, Kim KJ, Kim SH, Chang SJ, Nam KY.
Effect of Korea red ginseng on the blood pressure in conscious hypertensive
rats. Gen Pharmacol 2000;35:135e41.
[15] Huu Tung N, Uto T, Morinaga O, Kim YH, Shoyama Y. Pharmacological effects
of ginseng on liver functions and diseases: a minireview. Evid Based Complement Alternat Med 2012;2012:173297.
[16] Choi KT. Botanical characteristics, pharmacological effects and medicinalcomponents of Korean Panax ginseng C A Meyer. Acta Pharmacol Sin 2008;29:
1109e18.

[17] Qi LW, Wang CZ, Yuan CS. Isolation and analysis of ginseng: advances andchallenges. Nat Prod Rep 2011;28:467e95.
[18] Hien TT, Kim ND, Kim HS, Kang KW. Ginsenoside Rg3 inhibits tumor necrosis
factor-alpha-induced expression of cell adhesion molecules in human endothelial cells. Pharmazie 2010;65:699e701.
[19] Zhang C, Liu L, Yu Y, Chen B, Tang C, Li X. Antitumor effects of ginsenoside Rg3
on human hepatocellular carcinoma cells. Mol Med Rep 2012;5:1295e8.
[20] Hien TT, Kim ND, Pokharel YR, Oh SJ, Lee MY, Kang KW. Ginsenoside Rg3
increases nitric oxide production via increases in phosphorylation andexpression of endothelial nitric oxide synthase: essential roles of estrogen
receptor-dependent PI3-kinase and AMP-activated protein kinase. Toxicol
Appl Pharmacol 2010;246:171e83.
[21] Jung SB, Kim CS, Kim YR, Naqvi A, Yamamori T, Kumar S, Kumar A, Irani I.
Redox factor-1 activates endothelial SIRTUIN1 through reduction of conserved
cysteine sulfhydryls in its deacetylase domain. PLoS One 2013;8:e65415.
[22] Zhang YG, Zhang HG, Zhang GY, Fan JS, Li XH, Liu YH, Li SH, Lian XM, Tang Z.
Panax notoginseng saponins attenuate atherosclerosis in rats by regulating
the blood lipid proﬁle and an anti-inﬂammatory action. Clin Exp Pharmacol
Physiol 2008;35:1238e44.
[23] Jin YR, Yu JY, Lee JJ, You SH, Chung JH, Noh JY, Im JH, Han XH, Kim TJ, Shin KS,
et al. Antithrombotic and antiplatelet activities of Korean Red Ginseng extract.
Basic Clin Pharmacol Toxicol 2007;100:170e5.
[24] Helms S. Cancer prevention and therapeutics: Panax ginseng. Altern Med Rev
2004;9:259e74.
[25] Ren HC, Sun JG, Wang GJ, A JY, Xie HT, Zha WB, Yan B, Sun FZ, Hao HP, Gu SH,
et al. Sensitive determination of 20(S)-protopanaxadiol in rat plasma using
HPLC-APCI-MS: application of pharmacokinetic study in rats. J Pharm Biomed
Anal 2008;48:1476e80.
[26] Radomski MW, Palmer RM, Moncada S. Endogenous nitric oxide inhibits
human platelet adhesion to vascular endothelium. Lancet 1987;2:1057e8.
[27] Kim YM, Namkoong S, Yun YG, Hong HD, Lee YC, Ha KS, Lee H, Kwon HJ,
Kwon YG, Kim YM. Water extract of Korean Red Ginseng stimulates angiogenesis by activating the PI3K/Akt-dependent ERK1/2 and eNOS pathways inhuman umbilical vein endothelial cells. Biol Pharm Bull 2007;30:1674e9.
[28] Nakaya Y, Mawatari K, Takahashi A, Harada N, Hata A, Yasui S. The phytoestrogen ginsensoside Re activates potassium channels of vascular smoothmuscle cells through PI3K/Akt and nitric oxide pathways. J Med Invest
2007;54:381e4.