!" J. Hot Spring Sci. 0* 0/ῌ11 ,*+*῍ ῌ

#$ % &+ ,,.

+

  ,,/++

E#ects of Nozawa Spa (Sulfur Hot Spring Water)
with Reductive Characteristic on the Skin
Shoichi OKOUCHI+

Abstract
In Nozawa spa area (Nagano Prefecture), ORP (Oxidation-Reduction Potential)-pH
measurements were made on hot spring waters fresh out of wellheads (sulfur-containing
sodium-calcium-sulfate springs, and sulfur springs) and hot spring waters at bathtubs of+- communal bathhouses, showing the favorable results that both the wellhead waters
and bathhouse waters are reductive in terms of ORP-pH relationship. More speciﬁcally,
just a slight di#erence was found in ORP between these waters ; hence it can be appreciated that, at the communal bathhouses, reductive hot spring waters are almost as freshas the wellhead waters. In skin ORP-pH measurements, it was observed that experimental daily bathing in reductive hot spring waters over a period of two months brought
about a decreasing tendency in ORP of the skins of the volunteer subjects. This signiﬁesthat habitual bathing in reductive water could suppress oxidation of the skin and lipid
thereof.
We also revealed that habitual bathing in Nozawa spa can improve or recover skinelasticity, and that the reductive sulfur spring water has an advantageous e#ect ofsuppressing melanin formation causes blotches and freckles or pigmentary deposits at
sunburn. The data obtained provide collaborative support for the generally accepted
notion that sulfur spring water will make the skin lustrous. Further, as having been
generally said that the beneﬁcial e#ects and e$cacies of hot spring water are lost with its
aging, the present work has conﬁrmed that the aging of hot spring water results in nulliﬁcation of its beneﬁcial e#ect of suppressing melanin formation in the skin.
Key wards : Nozawa spa, Sulfur hot spring water, Skin Elasticity, ORP, Melanin, Cutaneous
permeability, Aging of hot spring water+ +2.ῌ2/2.  -ῌ1ῌ, + Fuculty of Bio Science and Applied Chemistry, Hosei University, Kajinocho -ῌ1ῌ,, Koganei-shi, Tokyo +2.ῌ2/2., Japan.

65

ῒῑ ῌ  +! "#  ORP-pH $%& '()* +,-./0123&4' 5(678 ORP 9:;<8 ! 8.=>? @0 A 8BC)*DE(  ORP 8: FG0 AH ORP IJKDLE- AHMDN-CODPQN-(
G0AH !"DKRSCT= NEAU VWXY#Z[0\AC$%&']^(_=0C`abc)*d* S0ef+,d*&-SCT=&.
E<A8B( g-h T-58i7 +/d*&-SC=j+0kE-lB(d*1&m.SCT=D8B( '<' nopcqD2r' 123Dse-(8:g`abc)*d*Dse-CT=..E<A'(
touov :   !" ORP `abc 34 nopcq+ῌ ῏ ῍ ῐ ῎
: 5I +,*** m wR6N<E7"AH&xyRzCT=D8(H9{# :LN-l +*** ;wR|H }"8< ==B~'[l+C0}>=~8
C ?8=~@ ABE ,*+* .C g_: 8 :T-58i7 +/d*Dj+0kE-lB(_8.C
D6E:

T-58EF='lG'lB( ORP Oxidation-Reduction Potential ; 

M12H F&(AA.I ' B_J:123AH =~
7A=.0+MD2rSCnopcq aging

&@M8BCT=&.E<A'lB( NEA .1238KA=.0+MN-l+T=<E 1230AG
A SCT=: M&' g-hLMY_MACK
(_ ,ῌo ; M@N ;  ,**+ )*AN8BCT=& (0d='lG E +332 +333 ,*** ,**, ,**- ,**/a, ,**/b, ,**2 ,**3 ,*+* ; ,**- ; Okouchi et al., ,**, ; Ohnami et al., ,**- ; OE ,**2 'lB(
gT8 D6E:T-EF&A.I SC= A AC+/d*='l G0AH!"APkCd*Y NEA:U VWXY#Z[AC$%&']^(_=0C`abc)*d*AC+,d*O+lQ&rlB(
NEA: nopcqAH T-Ed*Dse-CT=..E<A'( '<'0D
E{# CR8 STYM

UV¡N0\<E &¢ £¤' ¥¦.§¨© ' ST'(y&Wª §¨« D¬ N-lBl+C §¨«8
: 8>¤XYDZ[=0CT=<E £¤D­\][E-l+C

<[^' 

58.D 5_}®`AH£¤&­\][Cab0\DN-lBl+C £¤(¯=:h A%cSCT=8 :7SC°[8.nopcqD2rSCA
B_Jd8C123&se± &e²JM3 E ,**/a A
fkl'5ªgT8 Tª0g³&h5k 8: ,**2 ; / ´Aiµj¶&kl='(<[^'·&)*'

<[^' mj n . ¦ <[^' ¸U¹ &r+ 

0123-d&eºA»o:p'({¦ J¼A(H T-58AD6EDo½'lB(A$SC - qr
E ,**3 ,*+* ; OE ,**2 &klA JYAPkCd*0\A66

 0*  ,*+*

 

 ,  

 ORP-pH 

! Fig. +a "#$%& ,* '()* +, - +- ./ 01 23 4567 89: ;<!=>)23?@AB CDEFG"  Fig. +b ! =>) +-Fig. +a

Locations of wellheads and communal bathhouses in Nozawa spa area.
 +a 
 

Fig. +b

Appearances of +- communal bathhouses in Nozawa spa area.
 +b  +-  67

    ! Ooyu "#$%&'() *+ ,-+ . Ogama ; / 0 "+- 

. 12 3 

45  6  7  8 
9:; 2 <=>?@9A B
AC  D E9:;FGH I "JKJL0 M
NO?PJ@Q+ RJN0 "ST
U VWX!YZ  + gῌkg [\>@9A J]>^" + gῌkg _1`abcdefῌg&#efhijJ_k  l  aj>  mNJ+ M'N JN>T>n'Fig. , ORP-pH relationships of hot spring waters freshout of wellheads and those at bathtubs of communal bathhouses.
 ,  ORP-pHo"Z la !^>"[p^jqX@Q+jrsNJ+
Figure , >" tuv / j0

/  ORP-pH wx '9 Fig. ,1kyz" JKJ ῌ 9:; ῍ {  Nernst {>|}Z ~h9:;
S-+]zJKJ@Q+ῌ

ORP+.,-*.*/3 pHO,.H .e

 ,H,O῍

ORP*.*/3 pH,H ,e z"H,pN N +332 ; Okouchi et al., ,**, y >!NM>~hj>m+" ORP z ῎ { -῎ORP*.2.*.*.1 pH-'῎ {" ORP #:AnQhPQ

z1""

$-+ '9 ORP "~%|&h% V -
0 "QJ!&gdX

ORP #'Z Q( =>MA ORP-pH

wx>!RJN0 QJ!qX^@Q+RjM+ '9.0 ". . ). *.9:;k.MNTPJ@Q+ QJ! ORP-pH wx"*  Fig. , 0 j ORP-pH wx

JN>MoMQRjMN +pu ¡$¢j£¤¥¦@Q'QRjM+ RRj" -§@ 0 j,N¨8©' ~>- n+Rj$@Q+-

->:A.ª«¬m+/0>­Q@ /0hX *+®m 'Z

pN"/0>*A ¯1>2QhPJ ORP #"1° N +333 @QZRj"±@!N
M> PN>  ~9:;i²³PJPN>-´/0 ORP #"[p 'k \p 1°-+Rj3µ N ,**/a  J¶  ~·¸¹'-"
68

¯1>2º/0 ORP 1°4»/054»>¼½ n+Rj6

( 0* ) ,*+*    !"#*+,-.$/01 23

1 ,/ 456

789:;,*%0* <= > ? 

 @A > /

B



;

C D+ /1 ORP EF>G!H2I>JK.$ /LM#> Fig. N!$ OP
STC  pH QO;R

 U C VW>XY,Z[O;RSTA ORP E\]
^_` ORP EVW>XY,
? ORP EQ_a+ ?bcdAefg
&C +.$ h PFd C 11Q ORP EQij!HM#
&C >N+.$ 0L^kVWQ lmn\oHp , qBrsQctuH$v. 6789:;+,w

xyzov? +,`{`45

Fig. - ORP-pH relationships of skins on ﬂexural sides
of forearms measured before and immediately after
bathing in hot spring water (kawarayu).
,  : Before and after bathing in hot spring water( : Kawarayu), respectively.
,  : Before and after bathing in tap water warmed(), respectively.
 - 
 ORP-pH  ::   :   

,*%0* <= ,* > ? x |, }~B ,**0+*%+, ~  {,\ /


k

 >`+H ORP-pHVW>.$Figure .   , }~B+.6789:; +/ ORP-pH @A >N!$ , }~B{1nQL{[K.\ ORP EQ[1oHp_a!Hp1-.$h Figs. /  0    @A  + }~ , }~B  H  F> /LL678
9:;E+,N+.  ,**2${ Q Fig. . ORP-pH relationships of skins on ﬂexural sides
of forearms measured in experimental daily bathingover two months.
 . , 
 ORPpH

Cutometer SEM /1/, Courage Khazaka
Electronic GmbH  Germany >`+,  +33- ;¡ +33, +.$ 0 Q ¢£ ,mm ¤¥>¦§¨©ª«Zh¬­a1>®¯+ /®¯ ®¯°±
K.>²!H01 >³´H\1oH$ ?µ¶p-`xz p- poH0>N+,`H$
Figure / N! @A1Q , }~B1p_a ·¸ p'*.*+ +.$ hFig. 0 1Q @A¹{? º»¼ ·¸ p'*.*/ !H>N+.$ ½
69

!" +* #$%& +, #%'()*+,-& -$*./&01&'2345'6-78
 9: ;<=>? @ABCDE ?F  7>GHI JK L;<= 6 $- MNOPQ$RSTUVWXY6
Z[Y-V\ ' & ]$RSTU$Y'GH7+ ^#

_`abTcde?F& ff9:3 7
Fig. / Changes in viscoelastic modulus of skins on
ﬂexural sides of forearms in experimental daily
bathing.
 /  

gh>$ , ^#7 ijklmVn
 GHo' pqPrW
X$sm
Figures. 1  2  -* .* tu /* 0* t

u$vu.$;<=$w)xV Iy
I JK %y GHo[lmV]
zn Po v ,* u lm + 
7gh-&{N|T}~V+
Ph ]$lm;<=
' /* 0* tu7

WXvu

-* .* tu7I JK$;<=$YP P&h  GH7> /* 0* tu7&;<=$ij1 p*.*/ Vn
vu.WBC$' kP,

 WX'vu7 I JKWXGH
 RSTU$Y'$$r
smWX ,
Fig. 0 Changes in viscoelastic modulus of skins onbacks of hands in experimental daily bathing.
 0  

$;<=BCV
 $  f  $_
T`PQ$ Iy$$W[ =W6P

X<=>k 6P<= 9:k $

I JKWXG

H6 <= 9:k %y$$P$_T` vu 
MNOPQWX ¡¢ $<=V£ =>9:'6 ¤¥ I J
K7 @AP45$BCWXY6 $sm¥X GH7@A45$BC

V$sm¥h  $_T`PQ$ $¦¡ªP«Vmk-& §=¨©V¬­k®¯=$°±§=¨©

$<=$

² g' RSTU$³ῌ´µs ]$ smV78$®¯=$¶[7P6 ·$¸¹ªº, -$-»'
%¼½

70

 0*  ,*+*

  . 
 ! " #$ %& '()*+,-.
/0,  
ORP 3,45

95:;<='>?0 @ (12 

Fig. ,

678  ';0.A 'BC: DEFG H

IJKLMNO*PQRS TU V

*WXYZ[\' ]*^ ,_ 
Fig. 1 Changes in viscoelastic modulus of skins on ﬂexural sides of forearms classiﬁed by age bracket.
 1  

* WXYZ@ 6`a bc*
WXdefgh Fig. 3( i jkF

Z'6V l: mnoQ jkFpqr!WXYZ,[s\ Shirota et. al., +33. ;tu ,**0 v/* w/x 12y *zmn@jkFpqr mn{' ]l WXYZ[\' ]*^ ,|}v/*
~@ WXYZ[\{ pH , 1

h*^

'l

ZmIqh

pH ' 1l0 .

,**3 ' 5 w/. 6Vh*jkFZL-tyrosine mnoQr Tyrosinase ' Fig. 3
YZ[\

(WXuh*qk

DOPAchromeFig. 2 Changes in viscoelastic modulus of skins
on backs of hands classiﬁed by age bracket.
 2  

jkFpq

 .1/ nmn' l0 Shirota et. al., +33. ; tu WXYZ[\{,**0  Fig. +*¡>;i¢£ P n'(l0 ¤C P¥. *5¦Z§P¨y © WXYZ[\
Figure ++*ªP ?0  «*qk  .1/ nml0£ ¬ h@ 

n'( pH1;5@$­lqk,[\l WXY

Z[\{,¡>l0 ®  ¬ h@ @$­¯° qk@[\v/° WXYZ[\{, ]v/*+'(l0 12± l:¢²K³´µZm µ¶GZ C · ¬h¸* Figure +,95:; @$­¯° WXYZ[\' ]l:5*^ ,@  ²K³´µZm· P n'(l0 £h@ Fig. ++ h(l0 i qk,@$­l SP,¡>l:5*;i·; [\ll  ²K³´µZm· ;  SP@¹./°WXYZ[\{, ]v/*+'(l0 º» 12y y 1
2± l: ²K³´µZm·@ mnyoQ jkFpqr A ' w/ ¼ 12\, ]l0+ ½./*
71



Fig. 3 Melanin formation mechanism.
 3  

Fig. +*

Chromatic change of aqueous solution with time in melanin formation reaction.
 +* 
  

/  !"#$%&'()* !"#$%&'()*+,$%-./*0123456
4789:; ;<,01=+>?@AῌBCDEF , GH IJ1KL /3

0/ m-ῌm,ῌ

Mῌatm ;NO=PQRS Figure +- . 9:TUVWX;Y2 ?@AῌBCDEF
H;Z[.=S-.\]; ^-;*_S= `ab;cdee*fg=+#b H*hibaS\]- ORP-pH jk;lmn.op=S "#\]-.H;012
aq ORP rstu23
Figure +. . `vw;Y2 xIy*z{ ORP r.|RS\] } s m~lK.

 pH s=+># ORP rs.

} =S s"J#H;=P\]-.01=Svwba3 Js$%.01=IJ
;  +33. 23#baP .3$%"+5$% ¡#¢£*¤3 `a¥ "#$%.¦§23()*+, $%/*01="¨I©ª+5# «¬=S$%­®y¯. ¡°±72

+ 0* , ,*+*    !"#$%&'

Fig. ++ Variation in absorbance (.1/ nm) with time of water samples from Nozawa
spa and ascorbic acid aqueous solution in melanin formation reaction.
 : Puriﬁed water.  : Water sample from Nozawa spa.  : Ascorbic acidaqueous solution.
 ++    C  !" .1/ nm #$%&'
 :   :  :   C 

Fig. +, Chromatic change with time of water samples from Nozawa spa and ascorbic
acid aqueous solution in melanin formation reaction.
 +, 
()*#+, 
-#$%&'-./01234( 56"7

!829:4;<=>?@ABC"/DE234:"

F4(
GH

27 Fig. +/ "I%2JKL )M "N4O P8Q M  ORP-pH RS7TUVW *M 5XY/Z[X\F`:Oab4(OP]^_-7cdd27 !"^_-e`:b6 fgh"7 !"73

Fig. +-



Scheme of experimental arrangement for ﬁlm permeation of reductive components.
 +- 
 C 

 C !"#$%&'%()$%*+,-./01234567898
, :;<=> ?@A!B C)
,DEF G

H,S &'H4I

J=9 KLMNOPQ4RS=9,TN!UV

0

Fig. +. Changes in ORP-pH of puriﬁed water (contained
in ﬁlm enclosure) with the lapse of time in ﬁlm permeation experiment.
 +.
    ORP-pH !"#$%&'()*+,
-./0

>W7X=YZ[\>MN4],4^_`a8bcdeaging 4fgV<%>MN40h0,Wi4 j_k
lm6789V WWi> n
opq= r4YZ\^_`a%st <4uv8hWi!wx%yz89VWi!{|,}W= :;<!bcde*+8 ?@AB C)MN4~7,1!gV bcde 3i8 :;</V!#q%^_`a*+, 3 bc
de!stf*+,V<%#!()$%9 3 ],> 3!


}76< ORP i pH 6bcdefg!IJ?@AB %V
Figure +0 %74

<bcdefg%8

ORP-pH !Uq

- 0* . !,*+*"



! #"

$%

&'()*+,,,/&012 ORP

3456

37869 : 
78&;pH 3<&=6

>?$@A$B&CDE69 FG3H&IJ
KL>?$  &M)
N%&KLOP6 pH Q=R



S9T %UVAGN FGA 
69 Q;2 WX69%&YZ[\]^&_`Nab !.1/ nm"Qc69

Figure +1 & d;&e^69YZ[\]fgh
Fig. +/ Variations in ORP-pH in ﬁlm permeation experiment on ascorbic acid aqueous solution.
 : Puriﬁed water in ﬁlm enclosure at time *.  :Variation with time in puriﬁed water in ﬁlm enclosure.
 : Ascorbic acid aqueous solution.
 +/ 
 ORP-pH : 
 :  :  !Fig. 3" &_`Nij klmgn ab !.1/ nm" Qo69 
78 d; !!",,,/" &e^ab3456 YZ[\62 ]p*+LqrGNs+Qo69 &tu

*+ :LqrGNF%Lvwx9 yGz  3{|RL}%~u ORP 3{|RQ)
}~ %~NF%L!@N

1" #  $

" !#

_t +-

" 3$~Qo6 %iw
3@w

ORP

"w3%({|~# &&#wxNs+Qo69
ORP w3 &#&tuyGA=LAG '~ &#&tuLpRGN($Qwx9
Fig. +0 Inﬂuence of aging of Nozawa spa on ORP-pH
relationships
 : Nozawa spa. , ,  : aged Nozawa spa.
 : puriﬁed water +0 
 ORP-pH !
 :   :

 : 

yGz p&tN)*\]  p&~LN%wxN +,$w3, i '~&#w W- B.+$/3¡

9¡0¢J1&~19:w W- Btu£¤~¥&¦RG§Y¨x;© 2 w

3 <& .+ $ / L4)Ns+L 3 AG
9 4ª F 3 -* .* «¬tu§Y ¨x; /* 0* «¬wtu­5&®G9W- B s+w3 ¯° L±@A6&@²³´w µ¶L7· %:76 4ª!8T¸¹69F%@A s+%UVAG9 6@6 W- B&9º §Y ¨x;©2
w3<& ³´'»¼Q:V+,$L½)N$~s+L3AG9
RA&  w3YZ[\]p*+Q;)NF%Lvwx y YZ[375

 !" #$% $& '()* '  $+,-%
'./012 3

H, S

3&  4)356! 4 78 9$:;<=
>?@6!%A B=@ $C$DEFG H> %AIJ6 K
C'! LML N1OPQL! 
R STUPV%ARWX 4)I?
M 6!
Fig. +1 Absorbance of dopachrome (.1/ nm) as
an intermediate of melanin formation reaction during the aging of Nozawa spa.
 : Puriﬁed water (pH 1). , , ,  :Hot spring water samples (Nozawa spa) as
shown in Fig. +0.
 +1  

 !"#$%&' .1/ nm () :    :+0 


4Y 9'%A3 ) :;<=>?@6!' 4?$ZAR <=>$L$R[ '?M 6!)\>?

LML 9R]^'_` ab

D$Cc3 ) 4)M? d*e$f )g@RhTij$kl)I*mn

$%A378% 5o*I$  !"R p qg! !"*e$6"rFM*st)u!*#v'$ )wX*+,xy%z +33. : )f$&2'{|}~ +++ +/0+ῌ+/0/.

 ,**- : 6@= )RM& FL=& = 3st  pp. +2ῌ
/* `Y( ) Aileem Tamura, * +z ,- './ xy%z 01234 ,**2 : 1)5'$ 7Tj11$ ORP Oxi-

dation-Reduction Potential ) pH $  /1+2/ῌ+3/.

 ,- 6 +z 1234 xy%z ,**3 : +,-9

7 STUPV%A  /3 ,ῌ+*.


 7 8 ¡9 ¢k£ ¤:¥;< +332 :  $N1OPQ¦=)L@$§¨+,>©  .2 ,3ῌ-/.
 +z ª?@A './ 1234 ,**/a : ORP B« ¬­`®C¯°L!
 $cD¨  /. +//ῌ+0,.
 +z ±²EF ³´ 1234 xy%z Gk* HI J ,**/b :>µ+,-$f¶ $7K L> %A  // //ῌ0-.
 ·4¸6 ¹'ºA HIº» ¤:¥;< ¼M ½ +333 :  7
$ ORP §¨+,>© ) pH $  .3 /3ῌ0..
 ·4¸6 HIº» ¤:¥;< ,*** : N§¨OC$ ORP ) pH $  /* 3.ῌ+*+.
Ohnami, S., Koumura, K., Ikeda, S. and Okouchi, S. (,**-) : ORP (oxidation-reduction potential)
pH relationship between hot spring waters and human body ﬂuids. Proceedings of the-2th Conference of Societe Internationale des Techniques Hydrothermales (Beppu, Ohita,Japan), -,*ῌ-,/.
Okouchi, S., Suzuki, M., Sugano, K., Kagamimori, S. and Ikeda, S. (,**,) : Water desirable for76 0*  ,*+*

 

the human body in terms of oxidation-reduction potential (ORP) to pH relationship. J.
Food Sci., 01, +/3.ῌ+/32.

  !"# $%& '()& *+,-. /012 ,**- : 34567 89
:;< => /- +ῌ3.
  !"# $%& ?@)A /012 BCDEF '()& ,**, : GHIJ
KLMNOPQRST, U6VWXI:;< => /, +,ῌ+3.

  Y0Z[ \]F /012 '()& ,*+* :  ^_`abcdefaghijk lm => /3 ,1-ῌ,2+.
$%& nopq rs t /012  ,**2 : 567 uvLM wx
yzMlm => /1 ,+/ῌ,,/.
{ |} ,**+ : ~_LM ghij Bio Indusutry, +2 .*ῌ...
Shirota, S., Miyazaki, K., Aiyama, R., Ichioka, M. and Yokokura, T. (+33.) : Tyrosinase Inhibitors from Crude Drugs. Biol. Pharm. Bull., +1, ,00ῌ,03.

6U +33- :  I  Fragrance J., No. +* +0ῌ,/.
0 ,**0 :  I a^`ab_ , pp. 21ῌ3- ^ῌ_ῌ^   ¡ pF +33, : f¢_£¤ wx¥LM8wx

 ¦=> +*, ++++ῌ+++1.
nopq §¨%|   $%& ,*+* : HI563©ª«  k¬­ => 0* + ®¯W77