Glycative Stress Research
Online edition : ISSN 2188-3610
Print edition : ISSN 2188-3602
Received : January 13, 2020
Accepted : February 8, 2020
Published online : March 31, 2020
doi:10.24659/gsr.7.1_22

Original article

Influence on the oxidized protein hydrolase (OPH) activity of herbal tea extract
Kaori Ishizaki, Masayuki Yagi, Chieko Sakiyama, Yoshikazu Yonei
Anti-Aging Medical Research Center and Glycative Stress Research Center,
Graduate School of Life and Medical Sciences, Doshisha University, Kyoto, Japan

Abstract

Glycative stress is a comprehensive concept meaning biological stress caused by the formation and accumulation ofadvanced glycation end products (AGEs). The increase of glycative stress leads to the risk of onset and development ofaging, diabetic complications, Alzheimer’s, and arteriosclerosis. The countermeasures against glycative stress are called antiglycation, which includes inhibitions of postprandial hyperglycemia and glycation, the decrease of AGEs, and the loweringof dietary-derived AGEs. Oxidized protein hydrolase (OPH) is a kind of protease which is the decrease of aged protein andAGEs and is broadly distributed within living tissues. In this research, for the purpose of investigating components which
decrease glycative stress, the effect of herbal tea extracts on OPH activity were verified. The extracts of 58 products (38categories) of herbal teas on OPH activity and OPH activity enhancing action was recognized in 47 herbal tea products (81%).
OPH activity was observed in 34 categories (89%) of herbal tea. On the other hand, the extracts of 12 products inhibited
OPH activity. Green tea (unfermented tea) and black tea (fermented tea) derived from Camellia sinensis showed an inhibitory
effect; however, roasted green tea ( houji tea) and pu-er tea (late fermented tea) enhanced the activity. The comparison ofutilized portions of herbal teas in which an OPH activity enhancing action was observed showed that seed tea had a stronger
influence than leaf tea. The active components enhancing OPH activity are possibly included in various plants. It was foundthat the roasting and fermenting process for tea leaves have an influence on OPH activity. It is possible that herbal teas could
prevent the accumulation of aged protein and AGEs by enhancing OPH activity, and as a result, contribute to the prevention of
the progression of aging caused by glycative stress.

KEY WORDS: oxidized protein hydrolase (OPH), herbal tea extract, glycative stress, anti-glycation

Introduction

The non-enzymatic reactions between reducing
sugar such as glucose and proteins are called glycation.
Glycation occurs in vivo and as a result, advanced glycation
end products (AGEs) are accumulated in the tissues. The
formation and accumulation of AGEs induces browning ofproteins and the decline in function caused by stiffness oftissues by crosslinking. AGEs combine with the receptor for
AGEs (RAGE), and causes various inflammatory changes
in various tissues. Therefore, the comprehensive concept of
biological stress caused by formation and accumulation of
AGEs is called “glycative stress” 1, 2). The increase of glycative
stress leads to the risks of the onset and development of aging,diabetic complications, Alzheimer’s and arteriosclerosis.
Countermeasures against glycative stress are called antiglycation, which includes the inhibitions of postprandial
hyperglycemia, generation and the dissolution of AGEs 3).
Oxidized or glycated proteins in vivo are called aged
proteins. Oxidized protein hydrolase (OPH) is a kind of serine
protease, which is called acylamino-acid releasing enzyme(AARE) 4, 5) or acylaminoacyl-peptide hydrolase (APEH) 6) andrelease N-terminal acylated amino acid of aged protein. OPH
is widely distributed in living tissues, such as liver 7, 8), brain 9),
blood 10), red cell membrane 11, 12), and placenta 13).
Serum OPH activity of rats with diabetic mellitus

Contact Address: Professor Masayuki Yagi, PhD
Anti-Aging Medical Research Center / Glycative Stress Research Center,
Graduate School of Life and Medical Sciences, Doshisha University
1-3, Tatara Miyakodani, Kyotanabe-shi, Kyoto, 610- 0394 Japan

Tel / Fax: + 81-774-65-6394 e-mail: myagi@mail.doshisha.ac. jp
Co-authors: Ishizaki K, ko-sei12@mail.doshisha.ac.jp ;Sakiyama C, csakiyam@mail.doshisha.ac.jp ; Yonei Y, yyonei@mail.doshisha.ac.jp_ 22 _

Glycative Stress Research 2020; 7 (1) : 22 - 28(c) Society for Glycative Stress ResearchGlycative Stress Researchremarkably increased and the blood carbonyl-modifying
protein decreased 14). OPH contributes to the breakdownof aged protein in cooperation with proteasome 15). OPH
decreased AGEs including CML and fluorescent AGEs. OPH
also exists in the stratum corneum and has a weak negative
correlation with aging. However, no components influencing
OPH activity have been found.
In this research, for the purpose of investigating thecomponents contributing to stress reduction, the effect ofherbal tea extracts on OPH activity was verified.

OPH activation rate (%) = { (S60 – S0 ) / (R60 – R0 )} x 100
S: pNA concentration of reaction mixture added with sample
extract
R : concentration of pNA of reference reaction mixture
60 : 60 minutes
0 : initial (0 time)
For the measurement of OPH activity, three
concentrations were verified. The highest value out of thethree was set as the representative value.

Materials and Method

Statistics Analysis

1) Reagents
Acylamino-acid releasing enzyme (AARE) (Takara Bio
Inc. Shiga, Japan) was used. AARE was adjusted withphosphate buffer solution of 50 mmol/L (pH 7.2) to 0.025
U/mL, N-acetyl-L-alanine p-nitroanilide (AAPA) (Bachem;
Bubendorf, Switzerland) was used as the oxygen substrate.
The AAPA was adjusted with 50% ethanol water solution
to 25 mmol/L. For other regents of Special Grade werepurchased from Fujifilm Wako Pure Chemical (Osaka,
Japan) and Nakarai Tesque (Kyoto, Japan)

The OPH activation rate was expressed as mean value± standard deviation. For the test of the result of analysis,
BellCurve for Excel (Social Information Service Co., Tokyo,
Japan), a statistics software, was used and Tukey’s multiple
comparison test was conducted for the comparison amonggroups. As the result of a statistics analysis, a risk ratio of <5% was regarded as significant.

2) Herbal teas
Fifty- eight commercially released dried herbal tea
products (38 categories) were provided by Hikawa Co. Ltd.
(Shimane, Japan).
3) Preparation of Sample Extract
A sample extract was obtained by putting 2g herbal
tea powder into 40 mL purified water and incubating it in awater bath set at 80℃ for 60 minutes. The extract was cooled
to room temperature and filtered. The solid content of thesample solution was calculated by tea extract 5 mL placed in
an aluminum tray, water being dried and evaporated at 120 ℃
for two hours and the evaporation residue being weighed.
The concentration of the sample extract was calculated fromthe solid content and dilution rate and it was shown as a final
reaction concentration.
4) Measurement of OPH Activity and Calculation of OPH
Activation Rate
Reaction mixture to which a sample extract for themeasurement of OPH activity was quantitatively added at
a rate of 1/25 and was composed as follows: 0.1 mol/L Tris
( tris (hydroxymethyl) aminomethane) – hydrochloric acidbuffer solution (pH 7.4), 2 mmol/L AAPA, 1 mU/mL OPH,
sample extract. The reaction mixture of 250 μL was incubatedat 37℃ for 60 minutes and the amount of p-nitroanilide( pNA), which was released by AAPA and decomposed by
OPH, was spectrophotometrically measured at 405 nm (S).
For the reference of OPH activity, distilled water, instead of
the sample, was added to the above-mentioned compound
liquid (R). The OPH activation rate (%) was calculated using
the following equation, presuming that the amount of pNA
that was isolated and formulated during the 60 minutes
immediately after the start of the reference reaction (0 minute)is 100 %:Results
As the result, the OPH activity enhancing action wasobserved in 46 products out of the 58 hot water extracts of 58
herbal tea products (81%, Table 1 ). Out of the 46 products
in which the OPH activity enhancing action was recognized,
the OPH activation rate of 24 products was over 50% (66.5± 12.9%), and that of 22 products was more than 0% or lessthan 50% (35.5 ± 13.4%, Table 2 ). On the other hand, 12
products inhibited OPH activity, 8 products inhibited morethan 0% and less than 50% (− 23.7 ± 10.8) and 4 products
inhibited over 50% (− 58.7 ± 4.4%).
By categories, the OPH activity enhancing action wasrecognized in 34 categories (89%) out of 38 categories.
High values of OPH activation rates were observed inbrown rice (89.2%: average, n = 2), barley (83.6 ± 2.7%, n= 3), dandelion (78.3%) and rose hip (77.2%), all of whichshowed a higher value than 70% (Fig. 1 ). On the other hand,four categories inhibited OPH activity. The OPH activation
rate of black tea showed the largest negative value (−55.7%),
which indicates a strong inhibitory action. followed by greentea (−52.1 ± 9.3%, n = 3), meigui (−16. 5%: average value,n = 2), and jasmine tea (− 0.8%).
Regarding the effect of tea extracts from Camelliasinensis on OPH activity, green tea (unfermented tea) andblack tea (fermented tea) showed inhibitory action of morethan − 40%, on the other hand, roasted green tea (houji tea)and pu-er tea (late fermented tea) enhanced the activity.
Three products of oolong tea used in this experiment showedboth activity enhancing action and inhibitory action.
The comparisons of utilized portions of the herbal teasin which OPH activity enhancing actions were recognizedshowed that their activation rates increased in the order ofseed (72.7 ± 17.4%, n = 9), root (52.6 ± 17.8%, n = 4), andleaf (43.9 ± 17.8%, n = 29), and the activation rate of seedtea was significantly larger than that of leaf tea (p < 0.01,
Fig. 2).

_ 23 _

Influence on the OPH Activity of Herbal Tea

Table 1. Influence on the OPH activity of 58 sample (38 category) herbal tea extract
SampleID

Sample name

Japanese generaltea category

Use fortea

Scientific name

Family name41

Dokudami

Dokudami-cha

leaf

Houttuynia cordata

Saururaceae

Hatomugi-cha

seed

Coix lacryma-jobi var. ma-yuen

1
4

22
26
21
55
56
8

46
38
49
13
15
36
40
43
16
20
25
54
28
44
58
59

45
42
6

52
37
47
33
34
32
31
27
35
19
3

29

Job's tears (non-caramel)
Job's tears
Brown rice (crushed)
Brown rice (crushed)

Genmai

seed

24.8

0.120

48.9

387.7

0.120

48.8

0.9

224.0

Oryza sativa
PoaceaeBarley tea

pNA Activation
Sample
conc.
ratio
conc.
(μg/mL) (mmol/L) (%)

163.8
93.1

mugi-chaseed

Hordeum vulgare

116.6

Lemon grass

Lemon grass

leaf

Cymbopogon citratus

Kuma bamboo grass

Kumazasa-cha

leaf

384.1

Sasa veitchii

AmachaAmachaleaf

Hydrangea macrophylla var. thunbergii

Saxifragaceae

Salacia

Salacia-cha

root

Salacia sp.

Celastraceae

Five-leaf ginseng

Amachazuru-cha

leaf

Gynostemma pentaphyllum

Cucurbitaceae

Cassia seedHabu-chaseed

Senna obtusifolia

Candle bush

Candle bush

leaf

Cassia alata

Sword bean

Natamame-cha

seed

Canavalia gladiata

Rooibos

Rooibos-cha

leaf

Aspalathus linearis

Kuwa-no-ha-cha

leaf

Morus sp.

Nijo Barley tea

95.1

Rokujo Barley tea

Mulberry leaf
Mulberry leaf (Shimane Pref.)Rugosa rose

Fabaceae

Moraceae

Rosa rugosa spp.

Rose hipfruit

Rosa canina

Ten-chaleaf

Rubus suavissimus

BanabaBanaba-cha

leaf

Lagerstroemia speciosa

Lythraceae

Guava leaf

Guava leaf-cha

leaf

Psidium guajava

Myrtaceae

Tsukimiso-cha

leaf

Oenothera sp.

Onagraceae

MoringaMoringaleaf

Moringa oleifera

Moringaceae

Kaki leaf

Kaki-no-ha-cha

leaf

Diospyros kaki

Ebenaceae

TenchaTenchaRosaceae

Evening primrose

Green tea (Kagosima Pref.)Green tea (autum-winter harvest)

Roasted green tea
Roasted green tea

34.6

77.0
31.7
53.0
20.5
8.9
2.5
1.6

61.0

208.0
18.9

45.8
63.5

Green tea (3rd harvest)
Coarse tea (roasted )

50.3

56.6

Green tea (2nd harvest)

43.3

Ban-chaHoji-chaleaf

Camellia sinensis

Theaceae

Jasmine-cha

0.147
0.146
0.118

6.1

51.9

0.110
0.129
0.125
0.140

0.108
0.089
0.089
0.088
0.080
0.125
0.124

9

48
39
2

51
30

Pu'er-chaGymnemaGymnema-cha

leaf

Gymnema sylvestre

Apocynaceae

Shiso

Shiso-chaleaf

Perilla frutescens var. crispa

Lamiaceae

Olive leaf

Olive-ha-cha

leaf

Olea europaea

Oleaceaeleaf_ 2 4 _ intybus
Cichorium

root

Arctium lappa

chicory (raw)chicory
Burdock tea

Chicory

4.0

6.7

29.1
51.3
50.3

384.0

1448.2

55.7
74.0
-5.5

53.4
34.9
10.5
10.2
9.6

-0.5

55.2
53.8

-42.9

0.047
0.041
0.028
0.108
0.093
0.125

0.104

Pu'er tea (leaf)

60.3

0.046

0.035

38.4

11

49.2

-57.7

Oolong-cha

37.0

36.3

0.034

0.036

43.9

73.6

24.9

62.7

Pu'er tea (tea bag)

65.3

0.100

0.123

Koh-chaOolong tea (Taiwan)

41.0

77.2

Black tea

7

47.0

0.142

0.076

12

24

81.2

-27.4

0.080

Oolong tea (tea bag)

83.0

0.058

6.2

17

86.5

37.4

0.133

(oolong tea scented
with the aroma ofjasmine blossoms)

51.7

92.7

0.109

0.113

Jasmine tea

Oolong tea (leaf)

85.8

67.4

5

14

53.5

0.134

0.120

25.1

Ryoku-cha

0.150

114.9

273.1

41.9

Green tea (saemidori)

0.155

0.140

59.9

Green tea (benifuki)

0.149

97.2

2.1

Tencha (fermented)

Evening primrose

74.7

214.2

22.3

flowerRose hip

63.7

99.6

Meigui

Rugosa rose

165.3

0.123

-56.2
-41.2
-49.3
-65.1
34.5
15.4
55.2
-0.8
-55.7

0.063

-21.9

0.108

34.9

0.115
0.114

29.2
43.4
42.2

0.133

65.5

0.121

50.7

0.082
0.124
0.128
0.117

39.8
54.7
59.7
46.2

29

Hoji-cha

Roasted green tea

leaf

Camellia sinensis

Theaceae

Jasmine-cha

51.9

0.125

55.2

5

Jasmine tea(oolong tea scented
with the aroma ofjasmine blossoms)

-0.8
6.2
0.080
Glycative Stress Research

12Black tea

Koh-cha

62.7

0.036

Oolong-cha

38.4

0.104

14
17

51.7

Oolong tea (leaf)
Oolong tea (tea bag)

Table 1. Influence on the OPH activity of 58 sample (38 category) herbal tea extract
24

Oolong tea (Taiwan)

Pu'er-chatea category

Japanese general

Use fortea

Scientific name

Family name

Dokudami
Gymnema

Dokudami-cha
Gymnema-cha

leaf

Houttuyniasylvestre
cordataGymnema

Saururaceae
Apocynaceae

Job's
Olivetears
leaf

Shiso-cha
Hatomugi-cha
Olive-ha-cha

leaf
seed
leaf

Perilla frutescens var. crispa
Coix lacryma-jobi var. ma-yuen
Olea europaea

Lamiaceae

GenmaiChicoryseedleaf

Oryza sativa
Cichorium
intybus

Sample7
Pu'er
teaname(tea bag)
SampleID
11
Pu'er tea (leaf)
41
9
1
48
4
39
22
2
26
51
21
30
55
53
56
18
8
23
46
50
38
10

49
Ref

Job's
Shisotears (non-caramel)
Brown(crushed)chicoryrice
(raw)
Brown
chicoryrice (crushed)
BarleyteateaBurdock

Gobo-chamugi-cha

root
seed

Arctium lappa
Hordeum vulgare

RokujoBarley tea
Safflower

Benibana-cha

flowerCarthamus tinctorius

Kuma
bamboo grass
Chrysanthemum
flowerKumazasa-cha
Kikuka-cha

leaf
flower

Nijo
BarleyBurdock
tea tea
Lemon
grass
Dandelion

AmachaLingzhi mushroom
Salacia

Lemon grass
Tanpopo-ne-cha
AmachaLingzhi

Salacia-cha

leaf
root

leaf
mushroom
root

Hydrangea macrophylla
Ganoderma
lucidum var. thunbergii
Salacia sp.

-21.9
29.2

43.9
0.108
34.9
pNA Activation
Sample
37.0
0.115
43.4
conc.
ratio
conc.
(μg/mL)(%)(mmol/L)
4.0
0.114
42.2
24.8
6.7

0.120
0.133

48.9
65.5

Oleaceae

387.7
51.3

0.120
0.121

48.8
50.7

Poaceae93.1
1448.2Asteraceae

0.9
29.1

224.0
50.3
163.8
384.0
116.6
714.7
95.1
88.2

384.1
936.0

Cymbopogon
Taraxacum
sp.citratus
Sasa veitchii
Chrysanthemum
morifolium

0.063

-55.7

165.3
35.7

Saxifragaceae
63.7
Ganodermataceae
109.5
Celastraceae

74.7
-

0.123
0.082
0.149
0.124
0.155
0.128
0.150
0.117
0.147
0.119
0.146
0.119
0.118
0.143

53.5
39.8
85.8
54.7
92.7
59.7
86.5
46.2
83.0
48.4
81.2
47.7
47.0
78.3

0.134
0.126

67.4
56.9

0.109
0.080

37.4
0.0

0.113
0.126

41.0
57.0

13 conc,Gynostemma
pentaphyllum
Cucurbitaceae
Five-leaf
ginseng
214.2
0.133
65.3
Samplefinal sample
concentration inAmachazuru-cha
reaction reagent; pNAleaf
conc, concentrationof pNAseparated in reaction
liquid in 60 minutes;
Activation
ratio, activation

p-nitroanilide.
ratio
to reference;
OPH, oxidized proteinhydrolase; pNA,seed
15of OPH
Habu-cha
Senna obtusifolia
Cassia
seed

36
40
43
16
20
25

Candle bush

Candle bush

leaf

Cassia alata

Sword bean

Natamame-cha

seed

Canavalia gladiata

Rooibos

Rooibos-cha

leaf

Aspalathus linearis

Kuwa-no-ha-cha

leaf

Morus sp.

Mulberry leaf
Mulberry leaf (Shimane Pref.)Rugosa rose

MeiguiTable
OPH rose
activity by processing of green tea
54 2.Rugosa
28

Rose hipTea
44 category
TenchaRose hip

Processing

58
Ten-chaTenchaGreen tea
unfermented
59
Tencha (fermented)
Coarsetea
45
Banaba-cha
Banabaroasted42
Guava leaf-cha
Guava
leaf
Roastedgreen tea
6
Evening primrose
Black tea
Tsukimiso-cha
52
Evening primrose
Oolongtea
fermented Moringa
37
Moringa
47 teaKaki leaf
Pu'er
33

Kaki-no-ha-chan3

flowerRosa rugosa spp.

fruit

Rosa canina

leaf

Rubus suavissimus

1 leaf

Activation ratio(%)

34. 5 speciosa
Lagerstroemia
Psidium 35.3
guajava

2 leaf- 55.7
Oenotherasp.

3 leafMoringa oleifera

14.1 ± 31.3

Diospyros
kaki
42.8

Moraceae

31
27
35
19
3

29

Green tea (Kagosima Pref.)Green tea (autum-winter harvest)

Rosaceae

Roasted green tea

0.120

49.2

50.3
34.6

77.0
31.7
59.9

Lythraceae
Myrtaceae
Onagraceae
Moringaceae
Ebenaceae

53.0
20.5
8.9
2.5
1.6

61.0

208.0
18.9
41.9
25.1

Ryoku-cha

56.6
45.8
63.5

Green tea (3rd harvest)
Roasted green tea

114.9

2.1

Green tea (2nd harvest)
Coarse tea (roasted )

73.6

22.3

Green tea (benifuki)
Results are expressed as mean ± SD or average values. Green tea, tea of Camellia sinensis source; activation
34 activation
Greenratiotea (saemidori)ratio,of OPH to reference; OPH, oxidized protein hydrolase; SD, standard deviation.

32

0.140

99.6

- 52.1 ± 9. 3

2 leaf

2 leafFabaceae

97.2

273.1

43.3

Ban-chaHoji-chaleaf

Camellia sinensis

Theaceae

Jasmine-cha

6.1

51.9

0.110
0.129
0.125
0.140

77.2

0.100

24.9

0.123
0.108
0.089
0.089
0.088
0.080
0.125
0.124

0.047
0.041
0.028
0.108
0.093
0.125

Koh-cha

62.7

0.036

Oolong-cha

38.4

0.104

7

11
9

48
39
2

51
30

43.9

Pu'er tea (tea bag)Pu'er tea (leaf)

37.0

Pu'er-chaGymnemaGymnema-cha

leaf

Gymnema sylvestre

Apocynaceae

Shiso

Shiso-chaleaf

Perilla frutescens var. crispa

Lamiaceae

Olive leaf

Olive-ha-cha

leaf

Olea europaea

Oleaceaeleaf_ 25 _ intybus
Cichoriumchicory (raw)chicory
Burdock tea

Chicoryroot

Arctium lappa

4.0
6.7

29.1
51.3
50.3

384.0

1448.2

10.5
10.2
9.6

-0.5

55.2
53.8

-42.9

Black tea

Oolong tea (Taiwan)

34.9

0.046

0.035

12

Oolong tea (tea bag)

53.4

-57.7

0.080

24

-5.5

0.034

6.2

17

74.0

0.142

0.076

(oolong tea scented
with the aroma ofjasmine blossoms)

51.7

55.7
-27.4

Jasmine tea

Oolong tea (leaf)

60.3

0.058

5

14

36.3

-56.2
-41.2
-49.3
-65.1
34.5
15.4
55.2
-0.8
-55.7

0.063

-21.9

0.108

34.9

0.115
0.114
0.133
0.082
0.121
0.124
0.128
0.117

29.2
43.4
42.2
65.5
39.8
50.7
54.7
59.7
46.2

Categoryof herbal
tea (numberof sample)
Categoryof herbal
tea (numberof sample)

Influence on the OPH Activity of Herbal Tea

OPHOPH
activation
activationratio
ratio (%)(%)
Fig. 1. Influence on the OPH activity of 38 category herbal tea extract.

OPH activation ratio, activation ratio of OPH to reference; Extract condition, dry herb powder 2g + 40 mL hot water (80℃),
incubated for 60 min; OPH, oxidized protein hydrolase.

_ 26 _Glycative Stress Research**

OPH
activation ratio
ratio (%)(%)
OPH activation

100

OPH Activity Enhancing action from the Viewpointof Inhibition of Glycative Stress

80

60
40
20
0

leaf (29)root (4)seed (9)Fig. 2. Influence on the OPH activity use for tea.

Fig. 2

Results are expressed as mean ± SD. Parenthesis shows numberof samples. **: p < 0.01, Tukey's multiple comparison test. OPH
activation ratio, activation ratio of OPH to reference; Extract
condition, dry herb powder 2 g + 40 mL hot water (80℃),
incubated for 60min; OPH, oxidized protein hydrolase; SD,
standard deviation.

OPH is broadly distributed in living tissues 7-13). Because
OPH has the action of decreasing the amounts of AGEs andN ε-(carboxymethyl) lysine (CML) 16), it is possible that the
intake of herbal tea leads to the enhancement of OPH activity,
which promotes the decrease of aged protein that waschanged to AGEs in vivo. Furthermore, OPH-like activity
is also recognized in the stratum corneum, so it is possiblethat it is involved in the decrease of CML in the stratum
corneum. However, it has been observed that OPH activity
in the stratum corneum has a weak negative correlation
with aging, and the amount of CML in the stratum corneum
and the increase of accumulation of AGEs in skin (skinautofluorescence; SAF) is observed 16). The increase of AGEs
in the skin is involved in lost texture 23), yellowing of skin, thelowing of barrier function 24), and progression of skin aging.
The use of herbal teas as skin care medicine possibly inhibits
reduction of OPH activity, contributing to the inhibition of
SAF. Using herbal tea as both food and skincare medicine
could prevent the accumulation of AGEs by enhancing OPH
activity and it is possible that it could inhibit aging caused byglycative stress.

Conclusion
Discussion

Components of Herbal Teas Affecting OPH Activity
Herbal tea extracts effect on OPH activity. Activity
enhancing action was recognized in 46 products (81%) of 34
categories (89%) out of 58 samples of 38 categories verified.
This result shows that compounds enhancing OPH activity
are possibly included in various plants. The characteristic
components at various family and genus levels have alreadybeen reported from the stand point of chemical taxonomy 17, 18).
The OPH activation rate was higher in herbal teas using
seeds over leaves; however, no relationship between strong
and weak activities from the view point of plant taxonomy
was observed.
The action inhibiting OPH activity was recognized ingreen tea (unfermented tea); however, the inhibitory action
was reduced by the roasting or fermenting process. Greentea includes caffeine, theophylline and tannins 19). It is also
known that catechin changes to theaflavin by tea leaves
being oxidatively fermented 20-22). The roasting and fermenting
processes of tea leaves is possibly associated with the changesof OPH activity inhibiting action caused by the change of thecomponents of tea leaves.

The effect of hot water extract of herbal teas on OPH
activity was recognized. OPH activity enhancing action wasrecognized in 46 products (81%) out of 58 samples of which
the activity was evaluated. It was found that active components
enhancing OPH activity are included in various plants. The
effect of the herbs on OPH activity differed by kinds ofherbs, processing methods such as roasting and fermentation
and utilized portions. The OPH activity enhancing actionof herbal teas is expected for its effect on the prevention of
the accumulation of aged protein and AGEs, and it could
possibly contribute to the inhibition of aging caused byglycative stressStatement of conflict of interest
This research received support from Courage Co. Ltd.
(Tokyo, Japan).

Acknowledgments
This work was supported by JSPS KAKENHI Grant
Number #26350917.

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Influence on the OPH Activity of Herbal Tea

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