Carotenoid Science Vol. 14, 2009, 26-36

ISSN 1880-5671

Structural Studies of Natural Carotenoids by Our Research Group
During the Three Decade
Takashi Maoka
Research Institute for Production Development, 15 Shimogamo-morimoto-cho, Sakyo-ku, Kyoto
606-0805.
E-mail : maoka@mbox.kyoto-inet.or.jp
Abstract – Since 1978, our research group determined more than one hundred natural carotenoids. In thepresent paper, structural studies of natural carotenoid during the three decade by our group werereviewed.

elucidation.
In the graduate thesis of Kyoto Pharmaceutical
University (1978), carotenoids of a red dragonfly,
Sympetrum frequens were investigated. About 0.2 mgof unidentified carotene (β,γ-carotene) was isolated
from one thousand dragonflies, along with β-carotene
and β-zeacarotene. Because of limitation amount,
NMR spectrum of this compound could not bemeasured. Therefore, this compound was identified by
UV-Vis and chromatographic behavior compared withsemi-synthetic β,γ-carotene, which was derived from
β-carotene [3].
In the thesis at master course in Kyoto
Pharmaceutical University (1980), carotenoids of asea mussels, Mytilus coruscus were investigated. A
new carotenoid named, pectenol A (1) (3 mg) was
isolated from 10 kg of shellfish. This structure wascharacterized from UV-Vis, IR, EI-MS, 1H NMR(using 80 MHz electro magnetic Fourier-transform
instrument) spectral data and some chemical
derivatizations such as acetylation, trimethyl sililation,and methylation [4]. In 80 MHz 1H NMR, only methyl
signals in 1 could be assigned by comparison withalloxanthin and diatoxanthin. Signals of methin andmetylen protons could not be assigned because ofoverlapping.
Therefore,
stereochemistryof
3,4-dihydroxy group in 1 was determined bycomparison with semi-synthetic diastereomeric triols

1. IntroductionMore than 750 naturally occurring carotenoids havebeen reported as of 2004 [1]. Since 1978, I havecontributed structural studies of various natural
carotenoids. In the previous paper [2], I describedsome experimental techniques for structural
elucidation and analysis of natural carotenoids. In thepresent paper, I will review the structural studies ofnatural carotenoids done in Kyoto Pharmaceutical
University and Research Institute for Production
Development during the three decade.
2. Structural study of carotenoid using 80 MHz
NMR and chemical derivatizations (1978-1985)
In 1970s, column chromatography and preparative
thin layer chromatography were mainly used forseparation tools of natural carotenoid. Purification of
carotenoids was accomplished by re-crystallization.
UV-Vis, IR, 1H NMR using 60-100 MHz continuous
wave instrument, and electro inonization mass (EIMS) were available for instruments of structural
elucidation. Chemical derivatizations such asacetylation,
trimethylsililation,
methylation,
epoxide-furanoxide rearrangement reduction ofcarbonyl group etc. were also essential procedures forcharacterization. Therefore, more than 10 mg crystal
state carotenoid was required for structural
OH

OH

HO

HO
OH

Pectenol A (1)O

Pectenolone
NaBH4
OH

HO

Isorenieradicistene (2)

OH

HO
OH

Pectenol A (1)Scheme 1

26

OH

Pectenol B

Carotenoid Science Vol. 14, 2009, 26-36

ISSN 1880-5671

obtained from pectenolone by NaBH4 reduction asshown in Scheme 1 [5].
A novel sterically hindered (7Z,7’Z)-aryl-carotenoid,
named isorenieradicisten (2), was isolated from thesea sponge, Suberites sericeus and its structure wascharacterized by 80 MHz 1H NMR, IR, EI-MS
spectral data and I2-catalysis isomerization comparing
with isorenieratene [6].

Carotenoids in animals are sometimes presented as
mixture of optical isomers. European research groupused diastereomric derivatization method for the
separation of optical isomers of carotenoids [7]. On
the other hand, our group achieved the separation of
optical isomers of carotenoids using chiral phasecolumns, Sumichiral OA-2000 or Chiral cell OD [8].
Three
new
stereoisomersofluteins,(3R,3’S,6’S)-lutein [lutein D (3), first report as anatural product], (3R,3’R,6’S)-lutein [lutein F (4)],and (3S,3’R,6’S)-lutein [lutein G (5)], from marine
fish [9], (3S,6R,3’R,6’S)-tunaxanthin [tunaxanthin D

3. Separation and characterization of stereo(optical)-isomers of natural carotenoids using
chiral phase HPLC (1985-1989)
P

OH

HO

Lutein D (3) : a-P-d
Lutein F (4) : a-P-e
Lutein G (5) : b-P-e
Tunaxanthin D (6) : c-P-e
meso-Zeaxanthin (7) : a-P-b(3S,3'S)-Zeaxanthin (8) : b-P-b

d
a
HO

HO

HO

b

e

c
P

(2S)-β,β-caroten-2-ol (9) : g-P-h
meso-β,β-carotene-2,2'-diol (10) : f-P-g(2S,2'S)-β,β-carotene-2,2'-diol (11) : g-P-g(2S)-2-Hydroxyechinenone (12) : i-P-h(4S)-β-Isocryptoxanthin (13) : j-P-h
meso-Isozeaxanthin (14) : j-P-k(4S,4'S)-Isozeaxanthin (15) : j-P-j(4'S)-4'-Hydroxyechinenone (16) : l-P-j

HO

h

g
HO

HO

f

O

OH

OH

O

i

j

k

l

P1

Scheme 2

OH

Cucurbitaxanthin A (17) : a-P1-b
Cucurbitaxanthin B (18) : a-P1-c
Pectenol B (19) : f-P2-b
4-Hydroxyalloxanthin A (20) : d-P3-b
4-Hydroxyalloxanthin B (21) : e-P3-b4,4'-Dihydroxydiatoxanthin (22) : e-P2-e4,4'-Dihydroxyalloxanthin (23) : e-P3-e
4-Keto-4'-hydroxydiatoxanthin (24) : f-P2-e
4-Keto-4'-hydroxyalloxanthin (25) : f-P3-e
4-Hydroxymytiloxanthin (26)4-Hydroxyzeaxanthin (27) : d-P1-b
4-Hydroxylutein A (28) : d-P1-g
4-Hydroxylutein B (29) : d-P1-h
4-Keto-4'-hydroxyalloxanthin (30) : f-P3-d
4-Keto-4'-hydroxydiatoxanthin (31) : f-P2-d
2-Keto-3,4-didehydro-β-carotene (32) : j-P1-k4,4'-Dihydroxypirardixanthin (33) : l-P1-l
3,4,4'-Trihydroxypirardixanthin (34) : m-P1-l
3,4,3',4'-Tetrahydroxypirardixanthin (35) : m-P1-m
4-Keto-4'-hydroxypirardixanthin (36) : n-P1-l5',6'-dihydro-4'-hydroxyechinenone (37) : o-P1-l
Pectenolone (38) : f-P2-b
Papirioerythrinone (39) : f-P1-i
4-Ketoalloxanthin (40) : f-P3-b
Salmoxanthin (41) : c-P1-p
Deepoxysalmoxanthin (42) : b-P1-p

b
a

O

P2

OH

OH

b
e
HO

P3

OH

OH

b

d
HO

OH O

OH

OH

4-Hydroxymytiloxanthin (26)

HO
OH

O
O
HO

HO

HO

HO

O

O

c

g

f

h

i

j

OH
HO

k

HO

OH

OH

O

O

l

m

n

o

p

Scheme 327

Carotenoid Science Vol. 14, 2009, 26-36

ISSN 1880-5671(6)] from marine fish [10], two new optical isomers of
zeaxanthins,meso-zeaxanthin(7)and(3S,3’S)-zeaxanthin (8) [first report as natural
products] from marine fish [11], four new opticalisomersof2-hydroxy
carotenoids,(2S)-β,β-caroten-2-ol (9) [first report as a natural
product],
meso-β,β-carotene-2,2’-diol(10),(2S,2’S)-β,β-carotene-2,2’-diol
(11),
and
(2S)-2-hydroxyechinenone (12) from the sea louse,
Ligia exotica and the stick insect, Neophirosea
japonica [12], four new optical isomers of 4-hydroxy
carotenoids,(4S)-β-isocryptoxanthin(13),meso-isozeaxanthin (14), (4S,4’S)-isozeaxanthin (15),and (4’S)-4’-hydroxyechienone (16) from the sea
urchins [13] were isolated and were characterized by
CD and NMR spectroscopy. They were my Ph. D.
thesis works in Kyoto Pharmaceutical University.

In middle of 1980s, preparative HPLC wasroutinely used for isolation tool. By using 1H NMR(300 MHz), EI MS, and CD spectroscopy, it madepossible to structural determination of natural
carotenoids with a few hundred μg. Our researchgroup studied various animal carotenoids from thecomparative biochemical points. Through thisresearch, several new carotenoids were isolated.
Structures of three new acetylenic carotenoids,
pectenol B (19), 4-hydroxyalloxanthin A (20), and4-hydroxyalloxanthin B (21) from the sea mussel,
Mytilus coruscus [16], five new acetylenic polyoxygenatedcarotenoids,(3S,4S,3’S,4’S)-4,4’-dihydroxydiatoxanthin(22),(3S,4S,3’S,4’S)-4,4’-dihydroxyalloxanthin(23),(3S,3’S,4’S)-4-keto-4’-hydroxy- diatoxanthin (24),(3S,3’S,4’S)-4-keto-4’-hydroxyalloxanthin (25), and4-hydroxymytiloxanthin (26) from the starfishes,
Asterina pectinifera and Asterias amurensis [17], two
new tri-hydroxy carotenoids, 4-hydroxyzeaxanthin(27) and 4-hydroxylutein A (28) from the chiton,
Acanthopleura japonica [18], three tri-hydroxy
carotenoids,
4-hydroxylutein
B(29),(3S,3’S,4’R)-4-keto-4’-hydroxyalloxanthin (30), and(3S,3’S,4’R)-4-keto-4’-hydroxydiatoxanthin (31) fromthe gold fish, Carassius auratus [19], a new
2-oxo-carotenoid,
2-keto-3,4-didehydro-β-carotene(32) from the stick insect, Neophirosea japonica [20]were determined. Furthermore, five unique 5,6 and/or
5’, 6’-hydro carotenoids, named pirardixanthins(33-37) from the spindle shell, Fushinus perplexus,
were isolated and characterized by UV-Vis, 1H NMR,EI MS, and chemical derivatizations such asacetylation, trimethyl sililation, reduction of carbonylgroup with NaBH4 [21]. Later (2001), the absolutestereochemistry
of
33-37
were
completely
characterized by 500 MHz 1H NMR using modified
Mosher method [22].
The absolute configurations of pectenlone (38) [16,4. Structural study of carotenoid using 300 MHz
NMR and preparative HPLC (1985-1995)
In middle of 1980s, 300 MHz NMR instrument was
introduced in our university. This instrument strongly
improved the sensitivity and resolution of signals than
80 MHz instrument and also enable to routinely
measurement of 13C NMR of carotenoids with several
mg scale. Unique 3,6-epoxy carotenoids, named
cucurbitaxanthin A (17) and cucurbitaxanthin B (18)were isolated from the pumpkin, Cucurbita maxima as
crystal states. These structures were elucidated bydetailed analysis of 1H, 13C NMR, EI MS, CD spectral
data and by chemical derivatization such as reductuinwith LiAlH4 [14]. Our group reported the structures of
17 and 18 in Phytochemistry (1986) [14]. Immediately
after our publication, Hungarian research groupreported the isolation and structural elucidation of 17
from the red paprika, Capsicum annuum in
Tetrahedron Letters [15].
P

OH

HO

Monohydroxyanhydroescholtzxanthin (44) : b-P-a
New retro carotenoid (45) : c-P-b

HO

a

c

b

Anhydroescholtzxanthin (43)OHC

O

8'-Apoalloxanthinal (46)

HO

H3CO

Rhodobacterixanthin (47)
OCH3
OH
OH

O

OH

Mytiloxanthin (48)

HO

O
HO

Diadinoxanthin B (50)

OH

O
HO

HO

Antheraxanthin B (49)OH
HO

Scheme 428

Gobiusxanthin (51)Carotenoid Science Vol. 14, 2009, 26-36

ISSN 1880-5671

23], papyrioerythrinone (39) [24], 4-ketoalloxanthin
(40)
[16],
salmoxanthin
(41),
and
deepoxysalmoxanthin (42) [25] were determinedusing CD, NMR spectrometry and chemical
derivatization such as reduction with NaBH4. The
additive rule of CD was used for estimation of thechirality of these carotenoids. (Scheme 3)
These stereochemical studies of carotenoids inanimals provided the information of food chains andmetabolic pathways of carotenoids in animals.

NMR and soft ionization mass spectrometry wereroutinely available. In 1998, 500 MHz NMR
instrument was introduced in my present workplace,
Research Institute for Production Development. Nano
ProbeTM (Varian) enables to measuring 13C NMR ofseveral hundred μg. 1H-13C correlations were
elucidated by 1H detected spectroscopy (HSQC and
HMBC). Pulse filed gradient (PFG) technique has
been dramatically improved two-dimensional NMR
measurement [2]. Soft ionization mass spectrometry,
FAB, APCI, ESI, FD, and MALDI MS, provided themolecular ion or molecular weight related ions, suchas M+H, M-H, M+Na predominantly. Therefore, thesesoft ionization mass spectrometry afforded molecularweight information of complex carotenoid such as
carotenoid glycoside and carotenoid esters. Although
soft ionization MS showed less fragment ion spectrum,
MS/MS experiment provided several fragment ionswhich had structural informations. For example, FAB
MS/MS of carotenoid, using molecular ion as aprecursor ion, provides EI MS like fragmentation [2].
Furthermore, separation techniques were also
improved. Reverse phase HPLC using C8, C18 (ODS),
and C30 columns provided fine separation of
carotenoids. Gel filtration chromatography (GPC)
could effectively remove lipid impurity fromcarotenoid [2]. Combination of these experimental
techniques, it was possible to determine complex
structural carotenoid below 1 mg.

Retro-carotenoids are presented as mixtures ofgeometrical isomers in nature. Predominantgeometrical isomer of anhydroeschscholtzanthin (43)in the leaves of Buxus sempervirens was determined tobe (6E, 6’E) configuration by NOE using NOE
difference experiment [26]. Furthermore, structures oftwonewretro-carotenoids,
mono-anhydroeschscholtzanthin (44) from the leavesofB.
sempervirens[26]
andtrihydroxy-retro-carotenoid (45) from the petals ofEschscholtzia californica [27] were determined by 1H
NMR, including NOE experiment, 13C NMR, CD, andMS spectroscopy.
Structures of 8’-apoalloxanthinal (46) from themarine shellfish [28] and novel purple carotenoid,
rhodobacterioxanthin (47) from the photosynthetic
bacterium, Rhodobactor capsulatus [29] were
determined (Scheme 4).

5-1. Animal carotemoids
5. Structural study of complex structural
carotenoid using high magnetic filed NMR andsoft ionization MS spectrometry (1995-2008)

The absolute configurations of mytiloxanthin (48)[30] and a series of carotenoids with 5,6 and/or
5’,6’-hydro carotenoids (33-37) [22], whose chiralities
could not be determined by CD spectroscopy because

In 1990s, several new experimental techniques of
O

OH O

O
O

O

Crassostreaxanthin A (52)

HO

HO

O

Crassostreaxanthin B (53)

O

O

O

O

O
OH

O
HO

54
O

55

OH

H
O

H
O

O

.
OH

O
OH

HO

56

OH

O

58

OH
O

OH

.

O

O

59

OH
O

O
O
O
OH

60

Scheme 5

29

OH
OH

O

OH
O

OH

O

OH

HO

57

OH
H

61

Carotenoid Science Vol. 14, 2009, 26-36

ISSN 1880-5671

lacking of chromophore neighbors of asymmetriccarbon, were determined by modified Mosher method
using NMR spectroscopy.
A novel 3,5-syn epoxy carotenoids, antheraxanthin
B (49) and diadinoxanthin B (50), were isolated fromthe fresh water goby, Rhinogobius brunneus. They
were first reports of 3,5-syn epoxy carotenoids asnatural products. Furthermore, a new acetylenic triol,
having a 3,6-dihydroxy-ε-end group, gobiusxanthin(51) was isolated. Their structures were completely
characterized by 500 MHz 1H NMR and CD spectral
data [31] (Schem 4).
Crassostreaxanthin A (52) and crassostreaxanthin B(53), isolated from the Japanese oyster, Crassostrea
gigas, were unique carotenoids having previous
unknown end groups. These structures were
elucidated by detailed analysis of NMR including
two-dimensional NMR experiments [32]. Later, the(3R,3’S) configurations of crassestreaxanthin B (53)were confirmed based on total synthesis by Tode et al[33].
Two new carotenoids having crassestreaxanthin A
end group, 54 and 55 were isolated [34, 35].
Furthermore,
three
mytiloxanthin
analogues
containing a 3,6-epoxy end group (56), an allenic end
group (57), and a 3,4-dihydroxy-β end group (58)were isolated from the oyster [34, 35]. A 3,6-epoxy
derivativeof
diadinoxanthin,
named
cycloidadinoxanthin (59), was also isolated [34]. In
addition to these C40-skeletal carotenoids describedabove, two new C37-skeletal carotenoids, 60 and 61,
OH

were isolated from the oyster [34, 35] (Scheme 5).
Six new carotenoids, corbiculaxanthin (62),corbiculaxanthin 3’-acetate (63), 6-epiheteroxanthin(64), and 7’,8’-didehydrodeepoxyneoxanthin (65),
cyclopyrrhoxanthin (66), and hydratedperidinin (67),were isolated from the brackish water clam, Corbicula
japonica [36]. Furthermore, hydratopyrrhoxanthinol
3’-esters (68) was isolated from the red marine clam,
Paphia amabillis [37]. Fatty acids consisted withcompound 68 were characterized by FAB MS data.
The stereochemistry of 3, 5, 6-trihydroxy-β-end groupin butenolide carotenoids 67 and 68 were postulatedby NOE and CD data as shown in Scheme 6. I thinkthat synthetic approach is necessary to confirm theabsolute stereochemistry of 67 and 68.
Furthermore, the structures of some minor
carotenoids in marine animals were determined.
2,3’-Dihydroxycanthaxanthin (69) from the hermit
crab,Paralithodes
brevipes[38],
purplenor-carotenoid, 2,3-dihydroserythrin (70) from thecrawfish,
Procambarus
clarkii[39]
and
2,3-didehydrocanthaxanthin (71), which was firstreport as a natural carotenoid, from the spiny lobster,
Panulirus japonicus [40] were characterized by 1H
NMR and MS spectral data. Compounds 69 and 70
were obtained as mixtures of optical isomers (Scheme
6).
5-2. Plant carotemoids
OH

OR

.
OH

Corbiculaxanthin (62) R=H
Corbiculaxanthin 3'-acetate (63) R=Acetyl

HO
OH

HO

OH

6-Epiheteroxanthin (64)

OH

O
O

O

O

.

O

7',8'-Didehydrodeepoxyneoxanthin (65)

HO

OH

OH
O

O

OAcyl
O

O

.

O

O
OH

OH
HO

OH

Cyclopyrrhoxanthin (66)OH

Hydratoperidinin (67)

HO

OH

O

Hydratopyrrhoxanthinol 3'-ester (68)

OH

OH

HO
O
O

O

2,3'-Dihydroxycanthaxanthin (69)

2,3-dihydroserythrin (70)OOO

2,3-didehydrocanthaxanthin (71)
Scheme 630

Carotenoid Science Vol. 14, 2009, 26-36

ISSN 1880-5671
3,4-dehydroxy-3’-deoxycapsanthin (80), were isolated
from paprika as very minor components [43]. These
carotenoids have a 6-oxo-κ-end group, which had notbeen reported previously in nature (Scheme 7).
Seco-carotenoids in the seeds of Pittosporum tobira
The seeds of Pittosporum tobira contained various
interesting structural carotenoids. A series of acylatedseco-carotenoids
havinga3-acyloxy-5,6-diseco-5,6-diketo-β-end group, named
tobiraxanthin A (81), B (82), C (83), and D (84), wereisolated from red seeds as major carotenoids [44].

Carotenoids in paprika
Paprika, Capsicum annuum, is a good source ofinteresting structural carotenoids. A series of new
apocarotenoids (72-77), which were formed byoxidative degradation from capsanthin, were isolated
from paprika [41]. A new 3,6-epoxy carotenoid,
capsanthone 3,6-epoxide (78) were determined by
NMR and FAB MS including MS/MS experiment [42].
Furthermore, two new carotenoids, named
3’-deoxycapsanthin
(79)
and
O

O

HO

O

HO

HO

Apo-12'-zeaxanthinal (72)Apo-14'-zeaxanthinal (73)Apo-13-zeaxanthinone (74)

O

HO

O

HO

O

O

Apo-12'-capsanthinal (76)Apo-12'-capsanthinal (75)
(71)

O

O

O

O
O

9,9'-Diapo10,9'-retro-carotene-9,9'-dione (77)

Capsanthone 3,6-epoxide (78)

OH

O

O

HO

3,4-Dehydroxy-3'-deoxycapsanthin (80)3'-Deoxycapsanthin (79)
Scheme 7
P1

Myristyl
O

O

O

6
1
O
Myristyl
OH O
6 P1
5
3
1
O
5

3'

1'

3

OH

MyristylO

OH

MyristylO

Tobiraxanthin B (82)
6

5

3

P2

1

O

OH
3'

.

O

3'
OH

Myristyl
O

OH
HO

6

1

Scheme 8

Tobiraxanthin C (83)

5

3

6'

1
O

Tobiraxanthin D (84)
P3

1

87
O

O
R1

O

11'

O

R2

HO

O

12'

H
H

R1

OH

O

12'
11'

O

R2

OH
O

HO

-R1 -R2
Pittosporumxanthin A1 (88) A1 :Pittosporumxanthin A2 (89) A2 :-R1 -R2

H
H

Pittosporumxanthin B1 (90)
Pittosporumxanthin B2 (91)

B1:
B2:

H
H

H
H

O

R1

.
HO

O

12'

-R1 -R2

OH

11'
R2

Pittosporumxanthin C1 (92)
Pittosporumxanthin C2 (93)O

OH

Scheme 8

31

6'

86

O

6'

6
3

6
1

P3

O

5

3

P2

O

85

6
3

5

5'

O
O
Myristyl

Tobiraxanthin A (81)

MyristylO

5

Myristyl
O

6'

OH
O

O

C1 :
C2 :

H
H

H
H

OH
3'

Carotenoid Science Vol. 14, 2009, 26-36

ISSN 1880-5671

These structures were elucidated by the detailed
analysis of MS and NMR spectral data. Tobiraxanthin
A, B, C, and D are corresponding oxidative cleavage
products of C5-C6 (C5’-C6’) bonds in theviolaxanthin diester, (9Z)-violaxanthin 3’-ester,
neoxanthin 3’-ester, and 6-epilatoxanthin 3’-ester,
respectively. Moreover, seco-carotenoids with a3-acyloxy-5-hydroxy-5,6-diseco-6-keto-β-end group(85-87) were also isolated from the red seeds of P.
tobira [45]. They were corresponding reduction
product of (81-83) (Scheme 8).

grandiflorm and these structures were completely
characterized by NMR using isomerization shift
values and NOESY experiment, CD, and MS spectral
data. Compounds 96 was first report as a natural
product [49]. This work was done by collaboration
with Dr. S. Kishimoto, National Institute of
Floricultural Science. Furthermore, for new
carotenoids having a 5,6-dihydroxy-β-end groupnamed ipomoeaxanthins (102-105) were isolated fromthe yellow sweet potato “Benimasari”, Ipomoea
batatas [50] (Scheme 9). This work was done bycollaboration with Dr. K. Ishiguro, National
Agricultural Research Center for Kyusyu Okinawa
Region.

Carotenoid and α-tocopherol complexes in the seedsof Pittosporum tobira
A series of carotenoid and α-tocopherol complexes
named pittosporumxanthins were isolated from the
red-colored seeds of P. tobira [46, 47].
Pittosporumxanthin A1 (88) and A2 (89) werediastereomeric pairs of the cycloaddition product of(9Z)-violaxanthin at the C-11’ and C-12’ positions,with α-tocopherol showing a O-C12’-C11’-C28’’
linkage. Furthermore,(9Z)-antherxanthin andα-tocopherol complexes, named pittosporumxanthin
B1 (90) and B2 (91) and (9’Z)-neoxanthin, andα-tocopherol complexes, named pittosporumxanthin
C1 (92) and C2 (93), were isolated. These structures
were elucidated by the detailed analysis of NMR andMS, including EI MS/MS experiment and CD spectral
data (Scheme 8).

5-3. Bacterial carotenoids
Bacteria contain interesting structural carotenoids.
Novel C50-skeletal carotenoid, flavuxanthin (106) was
isolated from Corynebacterium glutamicum [51].
Structures of some carotenoid glycosides,
dihydroxylycopene diglucoside diesters (107) andmethoxyhydroxyylcopene glucoside (108) from thephototrohic purple sulfur bacteria, Halorhodospiraabdelmalekii and H. halochloris [52], myxol
2’-dimethyl-fucoside
(109)
and
deoxymyxol
2’-dimethyl-fucoside (110) from Synechocystis sp.
PCC 6803 [53], hydroxy-diaponeurosorene glucoseide
ester (111) from the alkaliphilic heliobacteria,
Heliorestis daurensis and H. baculata [54], andadonixanthin diglucoside (112) from Paracoccus
schoinia NBRC 100637T [55] were determined bydetailed analyses of NMR, soft ionization MS
spectrometry such as FD and FAB MS. These sugar
moiety were completely characterized by 2D NMR
such as TOCSY and HSQC. Parts of them werecharacterized after acetylation in order to resolve
overlapping oxymethin signals. The glycosylated
position of carotenoid and stereochemistry of glycosyl

Other new carotenoids from the plants
Two epimeric pair of dinochromes, 94 and 95, wereisolated from the fresh water red tide, Peridinium
bipes and were characterized by spectral data [48].
(3S,5S,6R,3’S,6’R)-5,6-dihydro-5,6-dihydroxylutein(96) and five novel di-cis-isomer of lutein
5,6-epoxides, 9Z,13’Z (97), 13Z,9’Z (98), 9’Z,13’Z(99), 9Z,13Z (100), and 9Z,9’Z (101) were isolated
from the petals of chrysanthemum, Dendranthema
OH

O

.

8

OH

O

OH
HO

O
HO

8R: Dinochrome A (94)
8S: Dinochrome B (95)OH

(3S,5S,6R,3'S,6'R)-5,6-dihydro-5,6-dihydroxylutein (96)
OH

OH
13'

O

9

9'

OH

13

HO

OH

Ipomoeaxanthin A (102)

Geometrical isomers of lutein 5,6-epoxide
9Z,13'Z (97), 13Z,9'Z (98), 9'Z,13'Z (99), 9Z,13Z (100),9Z, 9'Z (101)
OH
8' O

HO
OH

OH
OH

OH

Ipomoeaxanthin B (103)
Scheme 932

8'R: Ipomoeaxanthin C1 (104)8'S: Ipomoeaxanthin C2 (105)Carotenoid Science Vol. 14, 2009, 26-36

ISSN 1880-5671

bond were determined by HMBC and NOE
experiments and coupling constant of anmomeric
proton. These works were done by collaboration with
Dr. S. Takaichi, Nippon Medical School.
Furthermore, a series of diapolycopenedionic acidxylosyl esters (113-115) were isolated from the marine
bacterium, Rubritalea squallenifaciens [56-57]. They
were first report carotenoids to include xylose(Scheme 10). This work was done by collaboration
with Dr. K. Shindo, Japan Women’s University and Dr.
N. Misawa, Marine Biotechnology Institute.

5-4. Carotenoids in transgenic plants.
A new carotenoid, 4-ketoantheraxanthin (116) was
isolated from the leaves of tobacco plant, Nicotiana
tabacum, introduced the genes coding CrtW (marine
bacterial enzyme β-carotene ketolase) [58]. This
works were done by collaboration with Dr. K. Shindo,
Dr. N. Misawa, and Dr. T. Hasunuma, ResearchInstitute of Innovative Technology for the Earth.
5-5. Chemical reaction products of carotenoids
CH2OH
O
OCH3
CH3O
O

Flavuxanthin (106 )

HOH2C

R

O-glucose

R=OH Myxol dimethoxyfucoside (109)
R=H Deoxymyxol dimethoxyfucoside (110)O-glucose

Dihydroxylycopene diglucoside (107 )O-glucose

OCH3

O glucose

Methoxyhydroxyycopene glucoside (108)glucose O

Acyl O

O

O
OH
HO
OH

4-Adonixanthin diglucoside (112)

Hydroxy-diaponeurosorene glucoseide ester (111)Acyl=C16:0 or C16:1

OH

O
OO
OH

O

OH

HO

O

HO

4-Ketoantheraxanthin (116)

R=

O

R

O

A
B
C
Diapolycopenedionic acid xylosyl ester A (113), B (114 ), C (115 )Scheme 10

O

OH
O
R2

H3CO

R1

R1=NO2, R2=H 11'-Nitoro-β-carotene (119)
R1=H, R2=NO2 15'-Nitoro-β-carotene (120)

117
O
O
H3CO

R2

HO

118

O

O

O

R=NO2 12'-Apo-15'-nitoroastaxanthin (123)
Scheme 1133

R1

R1=NO2, R2=H 11-Nitoroastaxanthin (121)
R1=H, R2=NO2 15-Nitoroastaxanthin (122)

R

HO

O
OH

OH

Carotenoid Science Vol. 14, 2009, 26-36

ISSN 1880-5671

HO

7',8',9',10'-Tetrahydro-β-cryptoxanthin(6'S)-β,γ-Carotene

HO(3'Z,5'Z)-Celaxanthin(3'Z,5'Z)-Torulene
Scheme 12

Tobiraxanthins,
havinga3-acyloxy-5,6-diseco-5,6-diketo-β-end group (81-84),
showed lability in alkaline medium. Structures ofalkaline reaction products of tobiraxanthins, having anovel 3-methoxy-5-keto-5,6-seco-4,6-cyclo-β endgroup, 117 and 118 were determined [59].
Structures of nitro-β-carotenes (119, 120) andnitro-astaxanthins (121-123), formed by reacted withperoxy nitrite with β-carotene and astaxanthin, were
determined [60-61] (Scheme 11). This work was doneby collaboration with Prof. H. Etoh, Shizuoka
University.

Acknowledgements
I thank for emeritus Profs. T. Matsuno, M. Kozuka,
K. Hashimoto, and Drs. Y. Fujiwara, and M. Tsushima,
Kyoto Phramaceutical University, and Dr. N. Akimoto,
Kyoto University. I wish to thank all collaborators of
my works described here.
References and Notes[1] Carotenoids Hand Book, G. Britton, S.
Liaaen-Jensen, H. Pfander Eds, Birkhäuser, Basel,
Switerland, 2004.
[2] T. Maoka, N. Akimoto, Carotenoid Science, 13, inpress (2008).
[3] This work was presented at the annual meeting of
Kinki branch of the Pharmaceutical Society of Japan(1979). Derivation of β,γ-carotene from β-carotene
was as follows ; β-carotene to β-carotene-5,6-epoxideby epoxidation,
β-carotene-5,6-epoxide to
5,6-dihydro-β-caroten-5-olbyepoxy-furanoid
rearrangement and cleavage of furanoxide with
LiAlH4, 5,6-dihydro-β-caroten-5-ol to β,γ-carotene bydehydroxylation with POCl3[4] T. Matsuno, T. Maoka, Bull. Jap. Soc. Sci. Fish.,47, 377-384 (1981).
[5] T. Matsuno, T. Maoka, S. Sakaguchi, T. Nishizawa,
Bull. Jap. Soc. Sci. Fish., 50, 1251-1253 (1984).
[6] T. Matsuno, T. Maoka, K. Katagiri, T. Komori,Bull. Jap. Soc. Sci. Fish., 50, 1071-1075 (1984).
[7] R.K. Műller, K. Bernhart, H. Mayer, A. Rűttimann,
M. Vecchi, Helv. Chim. Acta, 63, 1654-1664 (1980).
[8] T. Maoka, T. Komori, T. Matsuno, J.
Chromatography, 318, 122-124 (1985).
[9] T. Matsuno, T. Maoka, M. Katsuyama, T. Hirono,
Y. Ikuno, M. Shimizu, T. Komoro, Comp. Biochem.
Physiol., 85B, 77-80 (1986).
[10] T. Matsuno, T. Maoka, Bull. Jap. Soc. Sci. Fish.,51, 1349-1351 (1985).
[11] T. Maoka, A. Arai, M. Shimizu, T. Matsuno,Comp. Biochem. Physiol., 83B, 121-124 (1986).
[12] T. Maoka, T. Matsuno, J. Chromatography, 478,
379-386 (1989).
[13] T. Maoka, T. Matsuno, J. Chromatography, 482,
189-195 (1989).
[14] T. Matsuno, Y. Tani, T. Maoka, K. Matsuo, T.
Komori, Phytochemistry, 25, 2837-2840 (1986).
[15] K. E. B. Parkes, G. Pattenden, M. Baranyai, P.

6. Conclusion
Structures of 116 natural carotenoids and sevenchemical reaction products of carotenoids were
determined by our research group during the three
decades. The improvement of analytical tools such as
NMR, MS, CD, HPLC, etc., has made it possible toperform the structural elucidation of natural
carotenoids with small amount. Structures of theses
new carotenoids provide information on the function,biosynthesis in plants and bacteria, and a key to thefood chain as well as metabolic pathways in animals.
Appendix
Unpublished works of natural carotenoids were
described here.
The structure of β,γ-carotene including 6S chirality,
isolated from a red dragonfly, S. frequens, wasconfirmed by 1H NMR, MS, and CD spectral data [62].
Novel carotenoid having a tetrahydro-ployene-chain,
7’,8’,9’,10’-tetrahydro-β-cryptoxanthin, was isolated
from the Japanese common catfish, Parasilurus asotus.
This structure was characterized from 1H NMR, MS,and UV-Vis spectral data [63].
A series of sterically hindered cis carotenoids,(3’Z,5’Z)-celaxanthin and (3’Z,5’Z)-torulene wereisolated from the ripe fruits of the bittersweet,
Celastrus orbiculartus. These structures wereconfirmed by isomerization shift values of 1H and 13C
NMR data and I2 chatarized isomerization. They werefirst reports of carotenoids with 3’Z,5’Z geometry
[64].

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Molnár, J. Szabolcs, G. Tóth, Tetrahedron Lett., 27,2535-2538 (1986).
[16] T. Maoka, T. Matsuno, Nippon Suisan Gakkaishi,
54, 1443-1447 (1988).
[17] T. Maoka, M. Tsushima, T. Matsuno, Comp.
Biochem. Physiol., 93B, 829-834 (1989).
[18] M. Tsushima, T. Maoka, T. Matsuno, Comp.
Biochem. Physiol., 93B, 665-671 (1989).
[19] M. Ookubo, M. Tsushima, T. Maoka, T. Matsuno,Comp. Biochem. Physiol., 124B, 333-340 (1999).
[20] T. Matsuno, T. Maoka, Y. Toriiminami, Comp.
Biochem. Physiol., 95B, 583-587 (1990).
[21] T. Matsuno, K. Katagiri, T. Maoka, T. Komori,Comp. Biochem. Physiol., 81B, 905-908 (1985).
[22] M. Tsushima, T. Maoka, T. Matsuno, J. Nat.
Prod., 64, 1139-1142 (2001).
[23] T. Matsuno, K. Hiraoka, T. Maoka, Bull. Jap. Soc.
Sci. Fish., 47, 385-390 (1981)[24] T. Matsuno, T. Maoka, Nippon Suisan Gakkaishi,
54, 1443-1447 (1988).
[25] T. Matsuno, M. Tsushima, T. Maoka, J. Nat.
Prod., 64, 507-510 (2001).
[26] K. Ida, K. Masamoto, T. Maoka, Y. Fujiwara, S.
Takeda, E. Hasegawa, J. Plant Res., 108, 369-376(1995).
[27] T. Maoka, Y. Fujiwara, K. Hashimoto, S. Takeda,
S. Takagaki, K. Ida, J. Nat. Prod., 63, 1288-1289(2000).
[28] T. Maoka. J. Nat. Prod., 60, 616-617 (2000).
[29] T. Maoka, K. Mochida, Y. Okuda, Y. Ito, Y.
Fujiwara, Chem. Pharm. Bull., 45, 1225-1227 (1997).
[30] T. Maoka, Y. Fujiwara, J. Jpn. Oil Chem. Soc., 45,
667-670 (1996).
[31] M. Tsushima, E. Mune, T. Maoka, T. Matsuno, J.
Nat. Prod., 63, 960-964 (2000).
[32] Y. Fujiwara, T. Maoka, M. Ookubo, T. Matsuno,
Tetrahedron Lett., 33, 4941-4944 (1992).
[33] C. Tode, Y. Yamano, M. Ito, J. Chem. Soc. Perkin
Trans. 1, (2001) 3338-3345.
[34] T. Maoka, K. Hashimoto, N. Akimoto, Y.
Fujiwara, J. Nat. Prod., 64, 578-581 (2001).
[35] T. Maoka, Y. Fujiwara, K. Hashimoto, N.
Akimoto, Chem. Pharm. Bull., 53, 1207-1209 (2005).
[36] T. Maoka, K. Hashimoto, N. Akimoto, Y.
Fujiwara, J. Nat. Prod., 68, 1341-1344 (2005).
[37] T. Maoka, N. Akimoto, M. Yim, M. Hosokawa, K.
Miyashita, J. Agric. Food. Chem., 56, 12069-12073(2008).
[38] T. Maoka, N. Akimoto, Chem. Pharm. Bull., 54,
1462-1464 (2006).
[39] T. Maoka, S. Ando, Fisheries Science, 73,
967-968 (2007).
[40] T. Maoka, N. Akimoto, J. Oleo Sci. 57, 145-152(2008) .
[41] T. Maoka, Y. Fujiwara, K. Hashimoto, N.
Akimoto, J. Agric. Food. Chem., 49, 1601-1606(2001).
[42] T. Maoka, Y. Fujiwara, K. Hashimoto, N.
Akimoto, J. Agric. Food. Chem., 49, 3965-3968(2001).
[43] T. Maoka, N. Akimoto, Y. Fujiwara, K.
Hashimoto, J. Nat. Prod., 67, 115-117 (2004)..
[44] Y. Fujiwara, K. Hashimoto, K. Manabe, T. Maoka,
Tetrahedron Lett., 43, 4385-4388 (2002).
[45] T. Maoka, Y. Fujiwara, K. Hashimoto, N.
Akimoto, Phytochemistry, 67, 2120-2125 (2006).
[46] Y. Fujiwara, T. Maoka, Tetrahedron Lett., 42,
2693-266 (2001).
[47] T. Maoka, N. Akimoto, Y. Kuroda, K. Hashimoto,Y. Fujiwara, J. Nat. Prod., 71 , 622-627 (2008).
[48] T. Maoka, M. Tsushima, H. Nishino, Chem.
Pharm. Bull., 50, 1630-1633 (2002).
[49] S. Kishimoto, T. Maoka, M. Nakayama, A.
Ohmiya, Phytochemistry, 65, 2781-2787 (2004).
[50] T. Maoka, N. Akimoto, K. Ishiguro, M.
Yoshinaga, M. Yoshimoto, Phytochemistry, 68,
1740-1745 (2007).
[51] P. Krubasik, S. Takaichi, T. Maoka, M.
Kobayashi, K. Masamoto, G. Sandmann, Arch.
Microbiol., 176, 217-223 (2001).
[52] S. Takaichi, T. Maoka, S. Hanada, J. F. Imhoff,Arch Microbio.l, 175, 161-167 (2001).
[53] S. Takaichi, T. Maoka, K. Masamtoto, Plant Cell
Physiol., 42, 756-762 (2001).
[54] S. Takaishi, H. Oh-oka, T. Maoka, D. O. Jung, M.
T. Madigan, Arch. Microbiol., 179, 95-100 (2003).
[55] S. Takaichi, T. Maoka, N. Akimoto, S. T. Khan, S.
Harayama, J. Nat. Prod., 69, 1823-1825 (2006).
[56] K. Shindo, K. Mikami, E. Tamesada, S. Takaichi,
K. Adachi, N. Misawa, T. Maoka, Tetrahedron Lett.,
48, 2725-2727 (2007).
[57] K. Shindo, E. Asagi, A. Sano, E. Hotta, N.
Minemura, K. Mikami, E. Tamesada, N. Misawa, T.
Maoka, J. Antibiot., 61, 181-191 (2008).
[58] K. Shindo, T. Hasunuma, E. Asagi, A. Sano, E.
Hotta, N. Minemura, C. Miyake, T. Maoka, N.
Misawa, Tetrahedron Lett., 49, 3294-3296 (2008).
[59] Y. Fujiwara, H. Maruwaka, F. Toki, K. Hashimoto,
T. Maoka, Chem. Pharm. Bull., 49, 985-987 (2001).
[60] R. Yoshioka, T. Hayakawa, K. Ishizuka, A.
Kulkarni, Y. Terada, T. Moaka, H. Etoh, Tetrahedron
Lett., 47, 3637-3640 (2006).
[61] T. Hyayakawa, A. Kulkarni, Y. Terada, T.
Maoka, H. Etoh, Biosci. Biotechnol. Biochem., 72,
2716-2722 (2008).
[62] (6’S)-β,γ-carotene from dragon fly: FAB MS(m/z) 536 [M+]; UV-Vis (Et2O) 412, 442, 471 nm; 1H
NMR δ (in CDCl3 at 300 MHz) 0.82 (3H, s, H-16’ or17’), 0.90 (3H, s, H-16’ or 17’), 1.03 (6H, s, H-16,17), ~1.46 (2H, m, H-2, 2’), ~1.63 (2H, m, H-3, 3’),
1.72 (3H, s, H-18), 1.95 (3H, s, H-19’), 1.97 (9H, s,
H-19, 20, 20’), ~2.02 (2H, t, J=7 Hz, H-4, 4’), 2.50
(1H, d, J=9.5 Hz, H-6’), 4.57 (1H, br. s, H-18’), 4.73
(1H, br. s, H-18’), 5.84 (1H, dd, J=15.5, 9.5 Hz,H-7’), 6.12 (1H, d, J=11.5 Hz, H-10’), 6.13 (1H, d,
J=15.5 Hz, H-8’), 6.14 (1H, d, J=16 Hz, H-8), 6.14
(1H, d, J=10 Hz, H-10), 6.15 (1H, d, J=16 Hz, H-7),

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6.24 (2H, m, H-14, 14’), 6.33 (1H, d, J=15.5 Hz,
H-12’), 6.35 (1H, d, J=15.5 Hz, H-12), 6.62 (1H, dd,
J=15.5, 11.5 Hz, H-11’), 6.63 (2H, m, H-15, 15’),
6.65 (1H, dd, J=15.5, 11.5 Hz, H-11’); CD (in Et2O):
λ nm (Δε) 216 (+3.0), 230 (0), 238 (-2.0), 249 (0),270 (+2.7), 225 (0), 340 (-1.0), 375 (-0.2).

H-3’), 1.74 (3H, s, H-18), 1.77 (1H, ddd, J=12, 5, 2
Hz, H-2eq), 1.89 (3H, s, H-20’), 1.89 (2H, t, J=7 Hz,H-4’), 1.96 (6H, s, H-19, 20), ~2.01 (4H, m, H-7’,10’), 2.04 (1H, dd, J=16, 10 Hz, H-4ax), 2.39 (1H,
ddd, J=16, 6, 2 Hz, H-4eq), 4.00 (1H, m, H-3), 5.73
(1H, dt, J=15, 7 Hz, H-11’), 6.10 (1H, d, J=16 Hz,
H-7), 6.14 (1H, d, J=11 Hz, H-10), 6.16 (1H, d, J=16
Hz, H-8), 6.23 (2H, m, H-14, 14’), 6.36 (2H, d, J=15
Hz, H-12, 12’), 6.60 (2H, m, H-15, 15’), 6.62 (1H, d,
J=15.5 Hz, H-11).

[63] 7’,8’,9’,10’-Tetrahydro-β-cryptoxanthin : FAB
MS (m/z) 556 [M+]; UV-Vis (Et2O) 385, 408, 432
nm; 1H NMR δ (in CDCl3 at 300 MHz) 0.93 (3H, d,
J=6.5 Hz, H-19’), 0.97 (6H, s, H-16’, 17’), 1.07 (6H,s, H-16, 17), 1.40 (2H, m, H-2’), 1.48 (1H, dd, J=12,
12 Hz, H-2ax), 1.57 (3H, s, H-18’), 1.58 (2H, m,[64] T. Maoka, Phytochemistry, 70, 920-923 (2009).

36