Glycative Stress Research
Online edition : ISSN 2188-3610
Print edition : ISSN 2188-3602
Received : August 19, 2022
Accepted : September 7, 2022
Published online : September 30, 2022
doi:10.24659/gsr.9.3_170

Original article

Effects of hot water extract of mangosteen pericarp on vascular function:
Re-analysis focusing on factors affecting vascular function.
Kenjiro Hayashi, Aoi Kiyokawa, Kazuhiro Maejima
Food Science Laboratories, Functional Food Division, Nippon Shinyaku Co., Ltd., Kyoto Japan

Abstract

Purpose: Advanced glycation endproducts (AGEs) are involved in age-related deterioration of vascular function. In ourclinical study, we evaluated the vascular stiffness of mangosteen pericarp (water extract of mangosteen: WEM), which has
an inhibitory effect on the formation of AGEs, and found a trend toward improvement in vascular stiffness, however the
improvement was not significant. Factors that affect vascular function include age, blood glucose, blood pressure, and lowdensity-lipoprotein-cholesterol (LDL-C) or triglycerides (TG). In the present study, we examined the effect of WEM on
vascular flexibility by performing a stratified analysis focusing on factors that affect vascular function. In the present study,
we performed a stratified analysis focusing on factors affecting vascular function and examined the effect of WEM on
vascular flexibility.
Methods: In a previous report, 38 women (19 in the WEM group and 19 in the placebo group) aged 25 to 59 years wereadministered WEM (200 mg) or a placebo for 12 weeks, and blood tests and vascular function tests were performed before,
4, 8, and 12 weeks after intake in a placebo-controlled, double-blind, randomized, parallel-group comparison study. Whereas,in the present study, we reanalyzed the results of the above studies, focusing on factors affecting vascular function (age, blood
glucose, blood pressure, and LDL-C or TG). First, we excluded subjects who exceeded the scope indicated in Attachment
2, "Points to Consider in Preparing Application Forms for Foods for Specified Health Use" of "Permission for Labeling ofFoods for Specified Health Use." (Notice No. 109 of April 1, 2020, by the Deputy Director-General of the Consumer Affairs
Agency). Next, we reanalyzed the effect of WEM on vascular stiffness by selecting subjects who were at least 30 years of age,
had borderline blood glucose, normal hypertension and I-degree hypertension, borderline and mild LDL-C, and normal highand slightly high TG, respectively. Vascular stiffness was assessed by PASESA AVE-1500 (Shisei Datum, Japan), API (Arterial
Pressure Index) and AVI (Arterial Velocity Pulse Index) in the right upper arm.
Results: Subjects with blood LDL-C levels above (≥ 160 mg/dL) those in the mild disease range were excluded (2 subjects
in the WEM group and 4 subjects in the placebo group). Subjects with blood glucose levels of 110 ~ 125 mg/dL, systolic bloodpressure of 130 ~ 159 mmHg or diastolic blood pressure of 85 ~ 99 mmHg, and TG of 120-199 mg/dL were not extracted foranalysis. There were 7 subjects in the WEM group and 9 subjects in the placebo group with an LDL-C of 120 ~ 159 mg/dL,
but no significant difference in API and AVI. 14 subjects in the WEM intake group and 13 subjects in the placebo group aged
30 years or older could be extracted, and WEM intake significantly reduced API after 8 and 12 weeks of intake. However,there was no difference in AVI.
Conclusion: The results of this reanalysis results showed that WEM intake, which inhibits glycation, reduced AP I in
healthy women aged 30 years or older. This suggests that WEM intake alleviates age-related vascular stiffening and maintains
flexibility.

KEY WORDS: mangosteen (Garcinia mangostana), glycation, advanced glycation endproducts (AGEs),		

vascular flexibility

Correspondent to: Kenjiro Hayashi
Food Science Laboratories, Functional Dood Division, Nippon Shinyaku Co., Ltd.,
Nishinosho-Monguchi-cho, Kisshoin, Minami-ku, Kyoto 601-8550 Japan
TEL : + 81-75-321-9130 e-mail: ke.hayashi@po.nippon-shinyaku.co.jp
Co-authors: Kiyokawa A, a.kiyokawa@po.nippon-shinyaku.co.jp;
Majima K, k.maejima@po.nippon-shinyaku.co.jp_ 170 _

Glycative Stress Research 2022; 9 (3) : 170-174(c) Society for Glycative Stress ResearchGlycative Stress Research

Introduction
Glycation is a non-enzymatic reaction between proteinsand carbohydrates, also known as the Maillard reaction. AGEs
are known to accumulate in the human body proceeds inan age-dependent manner 1, 2). AGEs are believed to crosslink proteins such as collagen in the vascular wall, thereby
causing functional impairment of the vascular wall 3), andbind to the receptor for AGEs (RAGE) expressed on vascularendothelial cells, thereby causing atherosclerosis 4).
To prevent the accumulation of AGEs, daily exercise
and dietary habits are important, concurrently it is important
to consume food components that prevent the productionof AGEs. It has been reported that polyphenols, which areantioxidants found in fruits and other foods, inhibit the
production of AGEs by inhibiting the Maillard reaction 5 -7).
Water-soluble components of mangosteen pericarp havebeen reported to have strong antioxidant properties 8), andParengkuan et al. reported that mangosteen pericarp extract
has a strong Maillard reaction inhibitory effect 9).
We have previously reported that women aged 25 to 59
years who intook a hot water extract of mangosteen pericarp(WEM) for 12 weeks showed significantly lower Arterial
Pressure Index (API) measured by the PASESA AVE-1500(Shisei Datum, Tokyo, Japan) than those in the placebo group
after 8 weeks of intake, whereas there was no significant
difference between the groups after 12 weeks of intake 10).
Factors that decrease vascular function include aging,blood glucose, blood pressure, and increases in blood LDLcholesterol (LDL-C) or triglycerides (TG) 11, 12). The analysis
of subjects in the previous clinical trial did not focus on
these factors. This resulted in a mixture of subjects who did
and did not benefit from WEM intake, and no significant
differences were found overall. We thought that analysis bythese factors would clarify the effect of WEM intake on
vascular stiffness.
In this study, we reanalyzed the subjects in the previous
study 10) with a focus on factors affecting vascular function(age, fasting plasma glucose [FPG], blood pressure [BP],and LDL-C or TG) to determine the impact of WEM on
vascular flexibility. The above reanalysis was performed
after excluding subjects who exceeded the indicated ranges
according to the "Permission for Labeling of Foods forSpecified Health Use" as shown in Attachment 2 "Points inconcern when preparing forms for applications for food forspecified health use" (Notice of the Deputy Director- Generalof the Consumer Affairs Agency No. 109, dated April 1,
2020) 13).

Methods

1) Study methods of prior studies

Study design

The study was a placebo-controlled, double-blind,randomized, parallel-group comparative study. Forty healthy
Japanese women in their 20s to 50s were randomly assigned
to the WEM or placebo group. One person in each group
dropped out during the study period, ultimately there were
19 in the WEM group and 19 in the placebo group. The test
food was ingested in 2 capsules (200 mg as WEM containing
0.078 % rhodanthenone B) per day, and endpoints were
measured before (0 week) and 4, 8, and 12 weeks after intake.
This study was registered and conducted in the University
Hospital Medical Information Network Clinical Trial System(UMIN-CTR, Registration number UMIN#000032310).

Endpoints: vascular function
PASESA AVE-1500 (Shisei Datum, Machida, Tokyo,
Japan) was used as an index of vascular function, and API(Arterial Pressure Index) and AVI (Arterial Velocity Pulse
Index) 14) were measured on the right upper arm before and 4,
8 and 12 weeks after intake. The results are shown in Table 1.
API is a measure of local vascular flexibility in the upper
arm, while AVI is a measure of systemic hemodynamics,
including the aorta.

2) Analysis in this study

Exclusion of subjects in the disease range

Subjects were initially excluded from the study if they
met the following criteria for factors affecting vascularfunction (FPG, BP, LDL-C, or TG): FPG ≥ 126 mg/dL,
systolic BP (sBP) ≥ 160 mmHg or diastolic BP (dBP) ≥ 100
mmHg, LDL-C ≥ 160 mg/dL, and subjects with TG of 200
mg/dL or higher 13).

Table 1. Subject profiles.
LDL-C(120 ~ 159 mg/dL)

Age(≥ 30 years old)

WEM (n = 7)

Placebo (n = 9)

WEM (n = 14)

Placebo (n = 13)Age45.4 ± 10.7

48.4 ± 5. 5

45.0 ± 7.8

45.2 ± 7.6

Weight (kg)51. 5 ± 8.7

52.3 ± 7. 5

52. 3 ± 7. 4

52.6 ± 6. 5

Height (cm)156. 5 ± 3.9

156.0 ± 5. 5

157.9 ± 5.0

156.3 ± 6.1

Results are expressed as means ± SD. WEM, water extract of mangosteen; LDL-C, low-density-lipoprotein-cholesterol; SD, standard deviation.

_ 171 _

Effects of Mangosteen Pericarp Extract on Vascular Function: Re-analysis

Selection of subjects for analysis
Subjects with elevated factors affecting vascularfunction (age, FPG, BP, LDL-C or TG) were included in theanalysis. Criteria were as follows: age ≥ 30 years, subjects
with borderline FPG (110 ~ 125 mg/dL), normotensive (sBP
130 -139 mmHg or dBP 85-89 mmHg) or grade I hypertension(sBP 140-159 mmHg or dBP 90 ~ 99 mmHg), LDL-C in
the borderline (120 ~ 139 mg/dL) or mild (140 ~ 159 mg/dL)
range, or TG in the normal high (120 ~ 149 mg/dL) or slightly
elevated (150 ~ 199 mg/dL) range were included in theanalysis.

Statistical analysis
Results are presented as mean ± standard deviation.
Pre- and post-intake comparisons were performed using
the Sidak method, and between-group comparisons were
performed with an unpaired t-test. p-values less than 5%
were considered statistically significant differences.

ResultExclusion of subjects in the disease range
There were no subjects with FPG, BP, or TG in the
diseased range, LDL-C >160mg/dL in 2 subjects in the WEM
group (161 mg/dL, 207 mg/dL) and 4 subjects in the placebogroup (192 mg/dL, 167 mg/dL, 214 mg/dL, 174 mg/dL); 17
subjects in the WEM group and 15 patients in the placebogroup were included in the sampling.

Extraction of subjects
After excluding the above subjects, when subjects wereextracted byFPG (subjects with 110 ~ 125 mg/dL), the numberof subjects was 0 in the WEM group and 0 in the placebogroup. Then, when subjects were selected by BP (sBP: 130 ~159 mmHg or dBP: 85 ~ 99 mmHg), there was one subject
in the WEM group and 2 subjects in the placebo group; whensubjects were selected by TG (120 ~ 199 mg/dL), there were
3 subjects in the WEM group and 2 subjects in the placebogroup; both were not reanalyzed due to small numbers.
Whereas, when subjects were selected for LDL-C (120
~ 159 mg/dL), there were 7 subjects in the WEM group and9 subjects in the placebo group; when subjects were over 30
years of age or older, there were 14 subjects in the WEM
group and 13 subjects in the placebo group, both of which
could be re-analyzed (Table 1).

API and AVI
Reanalysis of API and AVI results was limited to subjects
with LDL-C in the 120 ~ 159 mg/dL range or subjects
over 30 years of age or older; subjects with LDL-C in theborderline and mild range showed no significant differences
before and after API and AVI intake or between groups(Fig. 1-a, b). Alternatively, for subjects over 30 years of age
or older, API was -9.1%, -7.0 %, and -13.9 % in the WEM
group and +8.3%, +11.2 %, and +6.1% in the placebo group

after 4, 8, and 12 weeks of intake, respectively, compared tobefore intake and after 8 and 12 weeks of intake compared tothe placebo group, a significant decrease was observed in the
WEM group (p < 0.05, Fig. 1-c). With regard to AVI, there
was a significant decrease in the WEM group after 4 and 8
weeks of intake compared to before intake (p < 0.05), while
no significant difference from the placebo group ( Fig. 1-d ).

Discussion
This study attempted a stratified analysis of previous
studies focusing on factors affecting vascular function: age,
FPG, BP, LDL-C or TG. The number of cases for blood
glucose, blood pressure, and TG was small (0 to 3) and could
not be analyzed. The number of subjects with LDL-C in theborderline and mild disease range was considered insufficient
to detect differences due to the small number of subjects
extracted. It was not possible to verify in this study whether
WEM intake improves the decline in vascular function
caused by hyperglycemia, hypertension, and increases in
LDL-C and TG in the blood, excluding aging, among thefactors that reduce vascular function.
The decline of estrogen in the blood begins after age
30, and this decline decreases vascular function 15). In aprevious study 10), WEM intake decreased API and AVI 14),indices of vascular stiffness, however, not significantly. In an
analysis limited to healthy subjects aged 30 years or older,a significant decrease in API was observed in the WEM
intake group compared to the placebo group after 8 and
12 weeks (Fig. 1-c), and vascular flexibility was improved.
This suggested that vascular function declines with age, but
the effects of WEM intake on vascular function are likely
to become apparent. Regarding the fact that no apparent
effect was observed for AVI in this study, we speculatethat WEM intake may have affected API earlier than AVI.
WEM has been reported to reduce fluorescence levels,
which reflect the amount of AGEs in the skin, in humaningestion studies, as well as pentosidine levels in the blood 16).
In addition, skin fluorescence and blood pentosidine levels
correlate with atherosclerosis 17, 18), and there is a report that
vascular function was improved by intake of alagebrium, an
AGEs cross-link scission agent 19). Based on the above, thedecrease in API with WEM intake is thought to be due to theglycation inhibitory effect of WEM.
In addition to the vascular endothelial protective effectof estrogen 20), it also inhibits AGE generation 21). Consideringthat estrogen levels begin to decline over the age of 30 15), it
is likely that the ability to inhibit AGE generation begins todecrease over the age of 30. The fact that WEM intake had
an effect on API items in an analysis limited to those aged
30 years or older, in which age group the blood estrogen and
AGE-formation inhibiting ability begins to decrease, also
supports the possibility that WEM's inhibitory effect on
glycation is responsible for the improvement in API withWEM.
In the previous study 10), there was no clear significant
difference in API with WEM intake, while, in the present
report, a significant decrease in API with WEM intake wasobserved in subjects aged 30 years or older, when vascular_ 172 _Glycative Stress Researchfunction begins to decline. Thus, the state of vascular
stiffness varies even among healthy subjects, and it wasconsidered important to consider the state of vascular
stiffness of subjects prior to intake in order to verify theeffects of WEM.

Conflict of interest declaration

Conclusion
In healthy women aged 30 years or older, WEM intake
improved API, suggesting that WEM improves age-relateda)
AVI (change ratio %)

0

-50

100

API (change ratio %)

100

50

-100

0W

4W

8W

0

*

##

-50

0W

0

-50

100

c)

4W

8W

*

Time (weeks)

0W

4W

8W

12 W

d)

50

0

#

##
-50

-100

12 W

b)

50

-100

12 W

50

-100

The clinical trial for the previous study was funded by
Nippon Shinyaku Co., Ltd. and conducted at TES Holdings( Tokyo, Japan).

AVI (change ratio %)API (change ratio %)

100

vascular stiffening and maintains vascular flexibility.
Consumption of WEM with its anti-glycation properties
is highly expected as a food that reduces the risk ofatherosclerosis in middle-aged and older adults.

0W

4W

8W

12 W

Time (weeks)

Fig. 1. Values of API and AVI

Change ratio (%) of WEM group ( ) and Placebo group ( ) are expressed as means ± SD. a ) and b) indicate API and AVI of subjects
with LDL-C between 120 -159 mg/dL, respectively. WEM group includes 7 subjects and Placebo group includes 9 subjects. c ) andd ) indicate API and AVI of subjects aged 30 years or older, respectively. WEM group includes 14 subjects and Placebo group includes
Fig.compared1.
13 subjects. * p < 0.05,
with the Placebo group by t-test., # p < 0.05, ## p < 0.01, comparison with before intake by Sidak
test. WEM, water extract of mangosteen; API, Arterial Pressure Index; AVI, Arterial Velocity Pulse Index; LDL-C, low-densitylipoprotein-cholesterol; SD, standard deviation.

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Effects of Mangosteen Pericarp Extract on Vascular Function: Re-analysis

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