Glycative Stress Research
Online edition : ISSN 2188-3610
Print edition : ISSN 2188-3602
Received : October 22, 2022
Accepted : November 26, 2022
Published online : December 31, 2022
doi:10.24659/gsr.9.4_221

Review article

Antiglycative effect and Antiviral effect of Kuromoji( Lindera umbellata Thunb.) extract
Akihiko Shimode 1), Bunichiro Ashibe 1), Shigeru Matsumi 1), Masayuki Yagi 2), Yoshikazu Yonei 2)
1) Yomeishu Seizo Co. Ltd., Tokyo, Japan2) Anti-Aging Medical Research Center/Glycative Stress Research Center,
Graduate School of Life and Medical Sciences, Doshisha University, Kyoto, Japan

Abstract

Kuromoji (Lindera umbellata Thunb.) is a deciduous shrub of the camphoraceae family endemic to Japan. It has long
been used as an ingredient for tea and essential oil, and its dried trunk branches have been used for medicinal drinks using
an ingredient known as “usho,” a crude drug with stomachic actions. This paper describes the antiglycative and antiviral
activities of a non-volatile extract of kuromoji extract (KE), which we have recently revealed. In absorption and metabolism
studies, KE was found to have inhibitory activity against the formation of advanced glycation endproducts (AGEs). AGEs
accumulate between collagen fibers in the bone matrix, thus reducing bone strength, and studies using bone glycation
samples suggest that KE may ameliorate the reduction in bone strength caused by glycation. Furthermore, an 8-week oral
administration of KE to streptozotocin-induced diabetic rats showed that it suppressed renal inflammation in diabetic
nephropathy. The antiviral action of KE was confirmed by plaque assay to act against influenza viruses even after infection
and to inhibit viral growth. The TCID50 assay showed that KE has antiviral activity against adenovirus and enterovirus,
which are viruses that cause colds, as well as new strains of influenza virus and their drug-resistant strains, confirming thatthe antiviral activity of KE has a wide spectrum of action. A randomized, double-blind, placebo-controlled, parallel-groupcomparative study on the effects of taking KE-containing candies showed a reduction in the incidence of influenza and in thesymptomatic period of cold symptoms. KE is expected to develop as a functional food material unique to Japan in the future
because of its various functionalities as described above due to its antiglycative and antiviral effects.

KEY WORDS: Kuromoji (Lindera umbellata Thunb.), antiglycative effect, advanced glycation endproducts (AGEs),		Introduction

antiviral effect, influenza virus

Kuromoji (Lindera umbellata Thunb.) is a deciduous
shrub of the camphoraceae family endemic to Japan, andgrows widely from southern Hokkaido to Kyushu. Kuromoji
has a refreshing aroma and has been used since ancient times
as a material for high-quality toothpicks to be attached toJapanese traditional sweets, as well as for various otherpurposes, such as boiling the branches and drinking the liquid
as tea. Kuromoji are steam-distilled to extract essential oilthat is rich in linalool and geraniol. Kuromoji essential oil isreported to have relaxant and antibacterial effects, and is usedin aromatherapy as a domestically produced essential oil 1, 2).

The dried trunk and branches of Kuromoji are known
as “usho,” a herbal medicine, and have been used as aningredient in folk medicines such as stomachic medicines andmedicinal liquors 3, 4). Non-volatile extracts of Kuromoji
branches (hereinafter referred to as KE) are rich in polyphenols
such as proanthocyanidins, i.e., (+)-catechin, (-)- epicatechin,procyanidin B1, procyanidin B2, and flavan-3-ol and theirmultimeric forms 5), and flavonoids, i.e., kaempferol, quercetin,
hyperin, isoquercitrin 6). KE has been reported to possess
various functional properties, including antioxidant 7), antiulcer 8), and immune function improvement effects 9). In thisreport, we describe the antiglycative and antiviral activities
of KE, which we have recently revealed.

Contact Address: Akihiko Shimode.
Product Development Center, Yomeishu Seizo Co., Ltd.
2132-37 Nakaminowa, Minowa-machi, Kamiina-gun, Nagano, 399-4601, Japan
TEL : +81-80-9159-4459 TEL: +81-265-79-9279 e-mail: a-shimode@yomeishu.co.jp
Co-authors; Ashibe B, b-ashibe@yomeishu.co.jp; Matsumi S, s-matsumi@yomeishu.co.jp;
Yagi M, myagi@mail.doshisha.ac.jp; Yonei Y, yyonei@mail.doshisha.ac.jp_ 221 _

Glycative Stress Research 2022; 9 (4): 221-227(c) Society for Glycative Stress ResearchAntiglycative and Antiviral Effect of Kuromoji

KE is a dried brown powder of non-volatile extract ofKuromoji and is used as a food ingredient. KE is produced
by using a 10 : 1 ratio of water to crushed Kuromoji stem
and branches. The mixture is heated at 95 °C for 60 minutes,
centrifugally filtering the extract, concentrating it in a
decompressor, sterilizing it by liquid continuous sterilization,
followed by drying it.

Antiglycative action of KE(1) Inhibition of advanced glycation endproduct (AGE)
accumulation
The following screening test revealed that KE is aparticularly useful antiglycative material among various
food material extracts 10). First, in order to screen the foodmaterials with antiglycative effects, hot water extractsof 536 materials were examined using the AGE-forming
reaction model between human serum albumin (HSA)
and glucose (Glu). Next, considering the absorption of the
top 93 materials in the intestinal tract, the AGE formation
inhibitory activity of the culture medium permeated throughthe intestinal epithelial absorption model using human colon
adenocarcinoma-derived cells (Caco-2 cells) was measured
in the same way 10). As a final step, considering the absorption
and metabolism of the top 34 extracts, the AGE formation
inhibitory activity was examined using the serum specimen 3hours after oral administration of each test extract to rats 10).
The results showed that the antiglycative activity of KE
was the 21st highest of 536 species in the first selection, the6 th highest of 93 species in the second selection, and the
4 th highest of 34 species in the final selection. The activity
in rat serum was 75% of that of aminoguanidine, a positive
control. These results indicate that the high AGE formation
inhibitory effect of KE is demonstrated even after absorption
and metabolism in vivo.
Furthermore, KE has strong activity against HSA as
well as collagen and elastin distributed in skin, bone andcartilage, and concurrently inhibits the formation of AGEs,
i.e., fluorescent AGEs, N ε-(carboxymethyl) lysine (CML),
and intermediate aldehydes, i.e., 3 deoxyglucosone, glyoxal,
methylglyoxal 7). KE has also been shown to enhance theactivity of oxidized protein hydrolase (OPH), an enzymethat degrades oxidized and glycated proteins, and to cleave
the cross-linked structure of AGEs, thereby promoting theirdegradation 7).
The antiglycative effect of KE may inhibit the formationof AGEs that occur in multiple pathways, and may further
inhibit the AGE accumulation in the tissue by degrading theAGEs that are once formed.
(2) Effects on bone glycation
It is known that the risk of bone fracture is significantly
higher in diabetic patients than in non-diabetic patients 11). The
risk is thought to be independent of bone mineral density andis caused by deterioration of bone quality due to glycation12, 13).
To reproduce the degradation of bone quality caused bythis glycation, bone glycated samples were prepared, followedby evaluation for the bone strength by a three-point bending
test 14). The bone samples were prepared by immersing
chicken radius bones from which the bone marrow had

been removed in phosphate buffer solution with Glu andheating at 60°C for 20 days. For the 3-point bending test, aweight load was applied perpendicularly to the bone stemof the bone sample until fracture using a universal testingmachine (Instron, Kawasaki, Kanagawa, Japan), and the bonedisplacement and maximum load at the time of fracture were
measured. As a result, the load-displacement curves of thethree-point bending test for both the glycated and control
samples showed that the load increased proportionally tothe displacement until rupture ( Fig. 1 ). The displacement
to rupture was significantly reduced by about 30 % in theglycated bone compared to the control (Fig. 2-a). In contrast,
the addition of KE to the buffer solution during glycationof the bone samples tended to suppress the decrease indisplacement at break, although the difference was not
significant (p = 0.078). No difference in maximum load atbreak was observed between the glycated bone and control(Fig. 2-b).
The bone matrix is known to be rich in collagen type 1
which provide suppleness and strength to bone through theformation of physiological cross-links between collagenfibers. When non-physiological, pathological cross-links
are formed in these collagen fibers due to glycation, thebone loses suppleness and bone strength decreases due
to deterioration of the bone matrix 13). In a same manner,
the glycated bone samples lost bone suppleness and weresusceptible to fracture due to a greater load applied at agiven displacement. Whereas, the addition of KE may haveameliorated the loss of bone suppleness caused by glycation.
0.12

Fructure

0.1

Load (kN)

Kuromoji extract (KE)

0.08
0.06
0.04
0.02
0

0.0

0.5

1.0

1.5

2.0

Displacement (mm)Fig. 1. Example load-displacement plot from three-point

bending test to assess bone strength (Control sample).

(3) Action on diabetic nephropathy
Accumulation of AGEs in vivo is a known factor in thedevelopment of diabetic nephropathy 15). We investigated theeffect of KE on the renal inflammatory response observed ina diabetic rat model 16).
Diabetic model rats were prepared by administering asingle intraperitoneal dose of streptozotocin (STZ) to maleSprague Dawley (SD) rats (STZ rats). Oral administrationof chromophyll extract to STZ rats was 100 mg/kg/day forthe low-dose group (KE-LD group) and 300 mg/kg/day forthe high-dose group (KE-HD group), and the administration
period was 8 weeks. Oral administration of KE to STZ rats

_ 222 _Glycative Stress Research

(a)

(b)
0.12

*

2.50

0.10

2.00

0.08

Load (kN)

Displacement (mm)

3.00

1.50
1.00
0.50
0.00

0.06
0.04
0.02

ControlGB

0.00

GB + KE

ControlGB

GB + KEFig. 2. Bone strength parameters by Three-Point Bending test.

(a) Displacement at fracture, (b) Load at fracture. Load was applied vertically to the shaft of bone sample at 5 mm/min.
Results are expressed as mean ± SD, n = 6. * p < 0.05 vs Control, Statistical analysis by Mann-Whitney U test. SD, standard
deviation; GB, glycated bone; KE, kuromoji extract.

Figure 2.

was 100 mg/kg/day for the low-dose group and 300 mg/kg/day
for the high-dose group, and the administration period was 8
weeks. The following three groups were designed to serve ascomparison controls: normal group (SD rats were administereddistilled water), Vehicle group (STZ rats were administereddistilled water), and AG group (STZ rats were administered
100 mg/kg/day of aminoguanidine hydrochloride).
For each group, anti-CML autoantibody levels 17) inserum, which may reflect the formation and accumulation of
AGEs in vivo, were measured as glycation indices. TNF-α
and IL-6 levels in renal tissue supernatants were also measured
as renal inflammatory indices.
As a result, the amount of serum anti-CML autoantibody
in the Vehicle group was significantly higher than that in thenormal group. And that in the KE-LD group, KE-HD group,and the AG group were significantly lower than the Vehicle
group (Fig. 3-a). The tissue TNF-α amount in the Vehicle
group was significantly higher than that in the control group.
And that in the KE-LD group and the AG group weresignificantly lower than the Vehicle group (Fig. 3-b). IL-6
levels in the Vehicle group were not different in the normalgroup, while those in the KE-LD, KE-HD, and AG groups
were significantly lower than the Vehicle group (Fig. 3-c).
An increase in inflammatory cytokines due to infiltrationof inflammatory cells such as macrophages has beenreported in renal tissues of diabetic nephropathy 18). It has
been suggested that CML-modified proteins induce an
inflammatory response mediated by Receptor for AGEs
(RAGE) present in macrophages or other inflammatory cells 19).
KE may have reduced the accumulation of AGEs throughits antiglycative properties, suppressed the activation of
inflammatory cells via the AGEs/RAGE signaling pathway,
and reduced the development of inflammatory reactions in
the kidney.

Antiviral action of KE(1) Antiviral action
The viral growth inhibitory activity of KE was examinedusing a plaque assay, and it was reported that KE inhibited

plaque formation in an infection test system using influenza
A virus (A/Puerto Rico/8/34) and Madin-Darby canine
kidney (MDCK) cells (Fig. 4 ) 20).
The antiviral activity of KE added after viral infection
was measured by the TCID50 (50% tissue culture infectiousdose) method using crystal violet staining in infection test
systems using three types of influenza A virus strains, A/
Puerto Rico/8/34, A/Nagasaki/HA-4/2009 (a porcine-derived
strain of the 2009 epidemic) 21) and A/Nagasaki/HA-58/2009(oseltamivir-resistant strain) 21), and MDCK cells. The results
showed that KE exhibited dose-dependent antiviral activity
against all strains 22). In the infection test systems using humanadenovirus (Type V) and Hep2 cells, and human enterovirus(Type 71) and Vero cells, the antiviral activity when KE was
added simultaneously with viral infection was measured by
the TCID50 method using crystal violet staining and showed
dose-dependent antiviral activity for both viruses. These
results indicate that KE can inhibit the growth of influenza
viruses even after infection and has a broad spectrum ofactivity against viruses, including mutant viruses.
(2) Antiviral effects of KE-containing candy
A randomized, double-blind, placebo-controlled,parallel-group study was conducted to investigate the effectsof the consumption of 1.8% KE-containing candy on
influenza incidence and cold symptoms 24, 25).
Subjects were male and female nurses working at Ehime
University Hospital (Matsuyama, Ehime Japan). Subjects were
given 3 pieces of KE-containing candy (KE group) or candy
without KE (placebo group) per day for 3 months from
December 2017 to March 2018. The presence or absence of
influenza, type of influenza, onset of cold symptoms (fever,throat symptoms, nasal symptoms), and duration of onset ofcold symptoms were evaluated using a questionnaire.
The results showed that the number of influenza cases
was significantly lower in the KE group (2 out of 67) thanin the placebo group (9 out of 67, Table 1 ) 24). The durationof onset of cold symptoms (fever, throat symptoms, or nasal
symptoms) was significantly reduced in the KE groupcompared to the placebo group. When the data was collected_ 223 _

(a)Anti-CML autoantibody (µg/mL)

Antiglycative and Antiviral Effect of Kuromoji

700
600

#

500

**

*

*

400
300
200
100
0

Normal Vehicle KE-LD KE-HDAG

STZ-induced diabetic rats

TNF-α (ng/mg protein)

3.0
2.5

**

#

2.0
1.5
1.0
0.5
0.0

Normal Vehicle KE-LD KE-HD

10.0

(c )

**

IL- 6 (ng/mg protein)

( b)

*

6.0
4.0
2.0
0.0

AG

*

8.0

**

Normal Vehicle

KE-LD

KE-HD

AG

STZ-induced diabetic rats

STZ-induced diabetic rats

Fig. 3. The values of blood anti-CML autoantibody and the values of kidney cytokine after treatment in the STZ rats.

(a) Anti-CML autoantibody in serum, (b) TNF-α in renal tissue supernatant, (c) IL-6 in renal tissue supernatant. Normal, No

STZ-treat and vehicle treated group; Vehicle, STZ and vehicle treated group; KE-LD, STZ and 100 mg/kg/day KE treated group;
KE-HD, STZ and 300 mg/kg/day KE treated group; AG, STZ and 100 mg/kg/day AG treated group. Results are expressed as mean
± SD, n = 8, # p < 0.05 vs. Normal, Statistical analysis by Wilcoxon rank sum test; * p < 0.05, ** p < 0.01 vs. Vehicle, Statisticalanalysis by Bonferroni multiple comparison test. STZ, streptozotocin (i.p.); KE, kuromoji extract (p.o.); AG, aminoguanidine(p.o.); CML, N ε-(carboxymethyl) lysine; SD, standard deviation; i.p., intraperitoneal administration; p.o., oral administration.

(a)Control(b)

Kuromoji extract

Fig. 4. Inhibition on plaque formation by influenza virus of Kuromoji extract (KE).

KE was added to monolayers of MDCK cells 1 hour after inoculation with influenza virus (A/Puerto Rico/8/34), and the cells
were incubated for 72 hours and stained with crystal violet.

Figure 4.

_ 22 4 _Glycative Stress Research

Table 1. Number of Influenza cases.
Placebo candy group(n = 67)

Kuromoji candy group(n = 67)

Influenza prevalence (n (%))

9 (13.4)

2 (3.0) *Type A (n (%))

6 ( 9. 0)

0 (0) *

Type B (n (%))

3 (4. 5)

2 ( 3. 0)* p < 0.05 vs Placebo group, Statistical analysis by chi-square test.

Cumulative incidence (%)

3.5

Placebo candy group**

Kuromoji candy group

3.0

**

2.5

**

2.0
1.5
1.0
0.5
0.0

cold symptoms(one of fever, throat or
nasal symptoms)

feverthroat symptoms

nasal symptoms

Fig. 5. The cumulative incidence of common cold symptoms (one of fever, throat or nasal
symptoms) and each symptom during 75 days.

** p < 0.001 vs Placebo group, Statistical analysis by log-rank test.

over a period of 75 days, excluding the period after March,when pollen dispersal in the test area increased sharply,
the decrease in the duration of onset on cold symptoms
was more pronounced than for the 90-day data, and theduration of onset of throat and nasal symptoms were reduced
significantly (Fig. 5) 25).
The above results indicate that taking three KE-candy
per day can be expected to assist prevention of influenza
infection and shorten the symptomatic period.

Mechanism of antiglycative andantiviral effects of KE

In a living body, proteins react with reducing sugars
in a non-enzymatic manner and undergo various glycationintermediates such as aldehydes, leading to the formation of
AGEs. AGE-modified proteins lead to protein browning,hardening due to cross-link formation, and inflammationinduced by RAGE. These are known as exacerbating factorsof aging, including age-related diseases such as diabetic
complications, aging of skin appearance 26) and bone fragility 27).
To suppress AGE accumulation, it is important to inhibit
AGE formation in the body and to promote their degradation.
KE is characterized by its AGE inhibitory activity in tests

considering absorption and metabolism, and its ability toinhibit AGE formation through multiple pathways bysuppressing the formation of multiple intermediate aldehydes.
KE may also inhibit renal inflammation in diabetic
nephropathy and bone quality deterioration caused byglycation. As for the antiglycative activity components,(+)-Catechin, procyanidin B1, and procyanidin B2 in KE havebeen reported to contribute significantly to the activity 28).
These low-molecular-weight flavan-3-ols have strong
antiglycative activity, and their activity was maintained evenafter permeabilization of Caco2 cells, suggesting that they
are some of the major active components in KE in vivo.
Exploratory studies have been conducted on theantiglycative effects of food ingredients in a wide range offood groups, including teas 29), herbs 30), spices 31), vegetables 32),
and fruits 33). Among the many antiglycative ingredientsthat have shown efficacy in clinical trials are mangosteen
peel extract for improving skin water content and vascular
stiffness 34) and a mixed herbal extract of dokudami, Romanchamomile, hawthorn, and grape leaves (AG Herb Mix) for
improving skin elasticity 35). In particular, mangosteen pericarp
extract has been put to practical use as a food with functional
claims that retains skin moisture through its antiglycative
mechanism. KE is expected to be applied to functional foods_ 225 _

Antiglycative and Antiviral Effect of Kuromoji

as a material that shows effects on renal inflammation andbone quality due to its antiglycative action.
Influenza causes systemic symptoms, i.e., high fever,headache, arthralgia, fatigue, and upper respiratory tract
symptoms, i.e., cough, rhinorrhea, and can lead to fatal
pneumonia and encephalopathy when severe in infants andthe elderly 36). The primary target sites of influenza virus
infection in the early stages are the epithelial cells of theupper and lower airways, including the pharyngeal mucosa 37).
Influenza is being mitigated by vaccination, however the
emergence of new strains due to mutation reduces its
effectiveness. Cold syndrome (so-called “common cold”) has
upper respiratory tract symptoms, i.e., sneezing, rhinorrhea,
nasal obstruction as its main symptoms, and symptoms
usually peak on the second or third day of onset, withsymptoms becoming mild within one week to 10 days 38). KE
showed antiviral activity against influenza virus as well as
against adenovirus and enterovirus, which are viruses thatcause colds. It was also effective against the new strain of
influenza virus that caused a pandemic in 2009 and its drugresistant strain. KE is characterized by its antiviral activity
against several types of viruses as described above, therefore
it is desirable to identify the active ingredients in order toelucidate the mechanism of this activity.
The proanthocyanidin fraction of KE has been reported
to have influenza virus growth inhibitory activity 22), andfurther studies are expected to identify more antiviral active
molecules. As an example of a clinical trial demonstrating
the inhibitory effect of a food ingredient on influenza
infection, a five-month gargle test using black tea extract
showed that the influenza incidence rate was 35 % in thetest group versus 48 % in the control group, indicating asignificant inhibitory effect 39). Black tea extract has antiviral
activity, and it is thought that influenza infection was
suppressed by the direct action of its antiviral component on
the target site of infection, the pharynx, through gargling.
Consumption of KE-containing candies had been shownto suppress the incidence of influenza and shortened thesymptomatic period of cold symptoms. Influenza virus
infection is established promptly after contact with target

cells, but KE has growth inhibitory activity against influenza
viruses, therefore it may have been effective even after
influenza infection. Ingestion of the KE-candies wasconsidered to be a more effective method of exerting antiviraleffects because it prolonged the residence time of the active
ingredients in the pharynx when ingested, compared togargling.

Conclusion
Kuromoji trees grow throughout Japan and have long
been used for crafts, tea, essential oil in everyday life.
However, they are often treated as miscellaneous trees not as
forest resources, and it is difficult to say that the resources
are being effectively utilized. On the other hand, the various
functional properties of kuromoji have been elucidated inrecent years, and its utilization is expected to further expandin the future, possibly leading to the revitalization of theforest industry. The future development of kuromoji as afunctional food material is expected.

Acknowledgement
This work was supported by the Japanese Council
for Science, Technology and Innovation, SIP (Project ID
14533567), “ Technologies for creating next-generation
agriculture, forestry and fisheries” (funding agency: Biooriented Technology Research Advancement Institution,
NARO). A part of this study was presented at the 24th
Meeting of Society for Glycative Stress Research on May 20,
2022, Tokyo.

Declaration of conflict of interest
A part of this study was supported by Yomeishu Seizo
Co. Ltd.

Reference
1) Akakabe Y, Kamikawa T. The relaxation effect of the barkoil of Lindera umbellata. Jpn J Taste Smell Res. 2011; 18,591-594.
2) Chiba R, Sato M, Tsuruta K, et al. Antibacterial activity of
two Japanese endemic tree essential oils on oral bacteria
and Candida. Aroma Research. 2016; 17: 376-380. (inJapanese)3) Liu W. Bencao Pinhui Jingyao. p.551, Commercial Press,
Shanghai, 1956. (in Chinese)
4) Ezaki N, Sakai S, Kojima A, et al. Effect of continuous
taking of medicinal tonic liqueur (Yomeishu®) on sensationof cold syndrome and peripheral body temperature in
women: Preliminary study on open design. Jpn Pharmacol
Ther. 2007; 35: 335-341. (in Japanese)5) Morimoto S, Nonaka, G, Nishioka I, et al. Tannins

and related compounds. XXI X. Seven new methyl
derivatives of flavan-3-ols and a 1, 3-diarylpropan-2-olfrom Cinnamomum cassia, C. obtusifolium and Lindera
umbellata var. membranacea. Chem Pharm Bull. 1985;
33: 2281-2286.
6) Takizawa N. Studies on the constituents of Lindera species( I ) : On the flavonoid compounds of Lindera families.
Japan J Pharmacog. 1984; 38: 194-197. (in Japanese)
7) Yagi M, Takabe W, Matsumi S, et al. Biochemistry ofkuromoji (Lindera umbellata) extract: Anti-oxidative andanti-glycative actions. Glycative Stress Res. 2017; 4: 329340.

_ 22 6 _Glycative Stress Research8) Ezaki N, Kato M, Takizawa N, et al. Pharmacologicalstudies on Linderae umbellatae Ramus: IV. Effects ofcondensed tannin related compounds on peptic activity
and stress-induced gastric lesions in mice. Planta Med.
1985; 51: 34-38.
9) Matsumi S, Maruyama T. The effect of kuromoji (Lindera
umbellata Thunb.) on the immune function of stressloaded
mice. Proceedings of the 24th Meeting of the Japan Mibyo
System Association. 2017: F1-3. (abstract in Japanese)10) Yagi M, Takabe W, Matsumi S, et al. Screening andselection of anti-glycative materials: Kuromoji (Lindera
umbellata). Glycative Stress Res. 2017; 4: 317-328.
11) Vestergaard P. Discrepancies in bone mineral density andfracture risk in patients with type 1 and type 2 diabetes: A
meta-analysis. Osteoporos Int. 2007; 18: 427- 444.
12) Yamamoto M, Yamaguchi T, Yamauchi M, et al. Diabetic
patients have an increased risk of vertebral fractures
independent of BMD or diabetic complications. J Bone
Miner Res. 2009; 24: 702-709.
13) Saito M, Fujii K, Mori Y, et al. Role of collagen enzymaticand glycation induced cross-links as a determinant ofbone quality in spontaneously diabetic WBN/Kob rats.
Osteoporos Int. 2006; 17: 1514 -1523.
14) Shimode A. Diverse functionalities of kuromoji: Focus on
antiviral effect. Proceedings of 24th Meeting of Society
for Glycative Stress Research. 2022. (abstract in Japanese)15) Yagi M, Yonei Y. Glycative stress and anti-aging: 6.
Glycative stress and kidney disease. Glycative Stress Res.
2017; 4: 275-278.
16) Akiyama K, Shimode A, Matsumi S, et al. Involvementof glycative stress in diabetic nephropathy and effects
of anti-glycation material Kuromoji (Lindera umbellata
Thunb.). Glycative Stress Res. 2020; 7: 287-297.
17) Ashraf JM, Abdullah SMS, Ahmad S, et al. Prevalence of
Autoantibodies against 3-DG-Glycated H2A Protein in
Type 2 Diabetes. Biochemistry (Mosc). 2017; 82: 579-586.
18) Okada S, Shikata K, Yokono H. Inflammatory mechanism
involved in the onset and progression of diabetic
nephropathy. Journal of Okayama Medical Association.
2005; 117: 9-15. (in Japanese)
19) Kislinger T, Fu C, Huber B, et al. N ε-(carboxymethyl)
lysine adducts of proteins are ligands for receptor foradvanced glycation end products that activate cellsignaling pathways and modulate gene expression. J Biol
Chem. 1999; 274: 31740-31749.
20) Ashibe B, Matsumi S, Maruyama T, et al. Various virus
growth inhibitory activities of Lindera umbellata.
Proceedings of the 138th Annual Meeting of thePharmaceutical Society of Japan. 2018; 2: 161 27PA-am221.
(abstract in Japanese)21) Kawano H, Haruyama T, Hayashi Y, et al. Genetic analysis
and phylogenetic characterization of pandemic (H1N1)
2009 influenza viruses that found in Nagasaki, Japan. Jpn
J Infec Dis. 2011; 64: 195-203.
22) Ashibe B, Akiyama K, Shimode A, et al. Anti-influenza
virus activity of Kuromoji (Lindera umbellata Thunb.)
extract and its use. Proceedings of the 46 th Annual
Meeting of the Society for Antibacterial and Antifungal
Agents, Japan. 2020: 229. (abstract in Japanese)
23) Ashibe B, Akiyama K, Shimode A, et al. Components
and antiviral effect in Lindera umbellata (Lauraceae).
Proceedings of the 84th Annual Meeting of the BotanicalSociety of Japan. 2020: 229. (abstract in Japanese)24) Igase M, Matsumi S, Shimode A, et al. Effectivenessof kuromoji (Lindera umbellate Thunb.) extract in theprevention of influenza infection: A randomized, doubleblind, placebo- controlled, parallel-group study. Jpn
Pharmacol Ther. 2018; 46: 1369-1373.
25) Igase M, Matsumi S, Akiyama K, et al. Effects ofkuromoji (Lindera umbellata Thunb.) extract containing
candy on cold symptoms: Reanalysis of 2017-2018 season
randomized, double -blind, placebo-controlled, parallelgroup study. Glycative Stress Res. 2019; 6: 151-158.
26) Yagi M, Yonei Y. Glycative stress and anti-aging: 7.
Glycative stress and skin aging. Glycative Stress Res.
2018; 5: 50-54.
27) Kanazawa I, Sugimoto T. The mechanism of bone
fragility in diabetes mellitus. Glycative Stress Res. 2017; 4:
267-274.
28) Shimode A, Akiyama K, Matsumi S, et al. Search forcomponents involved in the Anti-glycative effect ofkuromoji (Lindera umbellata Thunb.). 19th Scientific
Meeting of Japanese Society of Anti-Aging Medicine.
2019: P 01-1. (abstract in Japanese)29) Otake K, Yagi M, Takabe W, et al. Effect of tea (Camelliasinensis) and herbs on advanced glycation endproductformation and the influence of post-fermentation.
Glycative Stress Res. 2015; 2: 156-162.
30) Hori M, Yagi M, Nomoto K, et al. Inhibition of advanced
glycation end product formation by herbal teas and its
relation to anti-skin aging. Anti-Aging Med. 2012; 9: 13514 8.
31) Moniruzzaman M, Parengkuan L, Yagi M, et al. Effectof proteins, sugars and extraction methods on theantiglycation activity of spices. Glycative Stress Res.
2015; 2: 129-139.
32) Ishioka Y, Yagi M, Ogura M. et al. Antiglycation effect ofvarious vegetables: Inhibition of advanced glycation end
product formation in glucose and human serum albumin
reaction system. Glycative Stress Res. 2015; 2: 22-34.
33) Parengkuan L, Yagi M, Matsushima M, et al. Anti-glycation
activity of various fruits. Anti-Aging Med. 2013; 10: 70-76.
34) Maejima K, Ohno R, Nagai R, et al. Effect of mangosteen
pericarp extract on skin moisture and arterial stiffness:
Placebo-controlled double-blinded randomized clinical
trial. Glycative Stress Res. 2018; 5: 95-103.
35) Matsuo N, Yuasa E, Kawai H, et al. Evaluation of the effectsof mixed herb extract on skin based on anti-glycation
effect: A randomized, double-blind, placebo-controlled,parallel-group study. Glycative Stress Res. 2021; 8: 98-109.
36) Kaji M. Way of thinking of common cold syndrome. OtoRhino-Laryngology, Tokyo. 2000; 43: 421-428. (in Japanese)37) Shimada M. Differential diagnosis of common cold. The
Journal of Japan Society for Infection and Aerosol in
Otorhinolaryngology. 2020; 8: 172-175. (in Japanese)38) Lee KH, Gordon A, Shedden K, et al. The respiratory
microbiome and susceptibility to influenza virus infection.
PLoS One. 2019; 14: e0207898.
39) Iwata M, Toda M, Nakayama M, et al. Prophylactic
effect of black tea extract as gargle against influenza.
The Journal of the Japanese Association for Infectious
Diseases. 1997; 71: 487-494. (in Japanese)_ 227 _