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Reaction of Paprika Carotenoids Capsanthin and Capsorubin with Reactive Oxygen Species Azusa Nishino, Hiroyuki Yasui, and Takashi Maoka J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.6b01706 • Publication Date (Web): 27 May 2016 Downloaded from http://pubs.acs.org on June 1, 2016
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Journal of Agricultural and Food Chemistry
Reaction of Paprika Carotenoids Capsanthin and Capsorubin with Reactive Oxygen Species
Azusa Nishino, † Hiroyuki Yasui, ‡ and Takashi Maoka*,§
†
Institute of Health Sciences, Ezaki Glico Co., Ltd, 4-6-5 Utajima, Nishiyodogawa-ku,
Osaka 555-8502, Japan ‡
Department of Analytical and Bioinorganic Chemistry, Division of Analytical and
Physical Chemistry, Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, Kyoto 607-8414, Japan §
Research Institute for Production Development, 15 Shimogamo, Morimoto Cho,
Sakyoku, Kyoto 606-0805, Japan
Corresponding author *T.M. Tel.: +81 75 781 1107; fax: +81 75 781 1118. E-mail address:
[email protected] Supporting Information
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ABSTRACT:
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The reaction of paprika carotenoids, capsanthin and capsorubin, with reactive oxygen
3
species (ROS) such as superoxide anion radical (.O2-), hydroxyl radical (.OH), and
4
singlet oxygen (1O2) was analyzed by LC/PDA ESI-MS and ESR spectrometry.
5
Capsanthin formed both the 5,6-epoxide and 5,8-epoxide by reaction with .O2- and .OH.
6
Furthermore, capsanthin also formed 5,6- and 5,8-endoperoxide on reaction with 1O2.
7
The same results were obtained in the case of capsanthin diacetate. On the other hand,
8
capsorubin showed higher stability against these ROS. Capsorubin formed 7,8-epoxide
9
on reaction with .O2- and .OH and 7,8-endoperoxide on reaction with 1O2.
10 11
KEYWORDS:
Capsanthin;
Capsorubin;
12
endoperoxide; Reactive oxygen species;
Capsanthin
13 14 15 16 17
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epoxide;
Capsanthin
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INTRODUCTION
19 20
Paprika (Capsicum annuum) is a good source of carotenoids and used widely as a
21
vegetable and food colorant. The red carotenoids are mainly capsanthin and capsorubin,
22
1-4
23
1), and their carotenoids account for 30-80% of the total carotenoids in fully ripe fruits.
24
1-4
25
Recently, Maeda et al. reported that these carotenoids showed effects to prevent and
26
improve obesity-related insulin resistance.15 Furthermore, it was reported that
27
capsanthin could take up peroxynitrite into its molecule by the formation of
28
nitrocapsanthin.16
along with capsanthin 3,6-epoxide5 and capsanthone6 as minor components (Figure
These carotenoids showed excellent anti-oxidative7-10 and anti-cancer11-14 activities.
29
It is known that carotenoids inhibit singlet oxygen (1O2) through physical quenching
30
and chemical reactions. 17 For example, β-carotene formed endoperoxides, epoxides and
31
apocarotenoids by the reaction with 1O2. 18-21 Very recently, we investigated reaction of
32
astaxanthin with 1O2, superoxide anion radical (.O2-), and hydroxyl radical (.OH), using
33
LC/PDA ESI-MS and ESR spectrometry.22 As the results, we found that astaxanthin
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formed astaxanthin endoperoxides on reaction with 1O2 and formed astaxanthin
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epoxides on reaction with .O2-, and .OH. 22
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However, there have been few reports on the reaction of capsanthin and capsorubin
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with reactive active oxygen species (ROS). In order to clarify the chemical scavenging
38
mechanism of these carotenoids with ROS, we investigated reaction products of these
39
paprika carotenoids with .O2-, .OH, and
40
spectrometry. This paper reports the scavenging effect of .O2-, .OH, and 1O2 with
41
capsanthin and capsorubin by ESR spin-trapping analysis and the reaction products of
42
these paprika carotenoids with these ROS. Furthermore, the reaction mechanisms of
43
ROS with capsanthin and capsorubin are discussed.
1
O2 using LC/PDA ESI-MS and ESR
44 45
MATERIALS AND METHODS
46
Chemicals. Hematoporphyrin, riboflavin, and hydrogen peroxide were purchased from
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Wako Pure Chemicals (Osaka, Japan). 2,2,6,6-Tetramethyl-4-piperidone (TMPD) was
48
purchased from Aldrich (Milwaukee, WI, USA). 5,5-Dimethyl-1-pyrroline-N-oxide
49
(DMPO) was purchased from Labotec (Tokyo, Japan). β-Carotene, zeaxanthin,
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capsanthin, and capsorubin were prepared from paprika according to the method
51
described previously.9,10,12 Astaxanthin was prepared from Paracoccus carotinifaciens.23
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Capsanthin diacetate and astaxanthin diacetate were prepared from capsanthin and
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astaxanthin, respectively by acetylation with acetic anhydride in pyridine at room
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temperature. syn- and anti-Capsanthin 5,6-epoxide and capsanthin 5,8-epoxide were
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prepared from capsanthin by epoxydation with m-chloroperbenzoic acid as described
56
below.
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Apparatus. The ESR spectra were recorded at room temperature on a JEOL
58
JES-RFR30 spectrometer (Tokyo, Japan). The LC/MS and MS/MS analysis of
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carotenoids was carried out using a Waters Xevo G2S Q TOF mass spectrometer
60
(Waters Corporation, Milford, CT, USA) equipped with an Acquity UPLC system. The
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1
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spectrometer (Agilent Technologies, Santa Clara, CA, USA) in CDCl3 with TMS as an
63
internal standard.
H NMR (500 MHz) spectra were measured with a Varian UNITY INOVA 500
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Reaction of Capsanthin with ROS. According to the method described previously,22
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after the addition of 200 µL of 8 mM H2O2 solution to 200 µL of 22 µg/mL capsanthin
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CH3CN solution, .OH was generated by UV-A irradiation using SUPERCURE-203S
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(SAN-Ei ELECTORIC) at room temperature. In a similar manner to that described
68
above, .O2- and 1O2 were generated by the addition of 200 µL of 25 µM of riboflavin or
69
200 µL of 250 µM hematoporphyrin, respectively to 200 µL of 22 µg/mL of capsanthin
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CH3CN solution. At regular intervals of UV-A irradiation, reaction products were
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analyzed by LC/PDA-ESI-MS.
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ESR spin-trapping analysis. ESR spectra were recorded at room temperature on a
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JEOL JES-RFR30 spectrometer (Tokyo, Japan) using an aqueous quartz flat cell
74
(Labotec, Tokyo, Japan). DMPO was used as a .O2- and .OH-trapping agent, and TMPD
75
was used as 1O2, respectively. The .O2- and .OH were generated by addition of either the
76
100 µL of 25 µM of riboflavin, or 100 µL of 8 mM H2O2 solution and 10 µL of 250 mM
77
DMPO to 100 µL of 14 nmol /mL capsanthin CH3CN solution by UV-A irradiation. In a
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similar manner described above, 1O2 was generated by the addition of both the 100 µL
79
of 250 µM hematoporphyrin and 10 µL of 500 mM TMPD to 100 µL of 14 nmol /mL
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capsanthin CH3CN solution by UV-A irradiation. ESR spectra were started
81
simultaneously to measure after UV-A irradiation. The all spin-trapped ESR spectra
82
were monitored between the third and fourth signals from the low magnetic field due to
83
the external standard, Mn(II) doped MnO. As the similar manner described above,
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reaction of capsanthin acetate and capsorubin (14 nmol /mL of both in CH3CN solution)
85
with ROS were also performed.
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Analysis of Reaction Products of Capsanthin with ROS Using LC/MS and
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MS/MS. The electro-spray ionization (ESI) time-of-flight (TOF) MS spectra were
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acquired by scanning from m/z 100 to 1,500 with a capillary voltage of 3.2 kV, cone
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voltage of 40 eV, and source temperature of 120 °C. Nitrogen was used as a nebulizing
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gas at a flow rate of 30 L/h. MS/MS spectra were measured with a quadrupole-TOF
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MS/MS instrument with argon as a collision gas at a collision energy of 30 V.
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UV-Visible (UV/vis) absorption spectra were recorded from 200 to 600 nm using a
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photodiode-array detector (PDA). An Acquity 1.7 µm BEH UPLC C18 column (Waters
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Corporation) was used as a stationary phase and 90%MeOH as a mobile phase, at a
95
flow rate of 0.2 mL/min for the HPLC system. In a similar manner to that described
96
above, reaction of capsanthin diacetate (27 µg/mL in CH3CN solution) and capsorubin
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(34 µg/mL in CH3CN solution) with ROS were performed.
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Capsanthin diepoxide. ESI TOF MS m/z 639.4217 (M+Na+, calcd for C40H56O5Na,
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639.4025);UV/vis 405~420 nm (in 90% MeOH).
100
Capsanthin 5,6-epoxide. ESI TOF MS m/z 623.4080 (M+Na+, calcd for C40H56O4Na,
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623.4076);UV/vis 463 nm (in 90% MeOH).
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Capsanthin 5,8-epoxide. ESI TOF MS m/z 623.4080 (M+Na+, calcd for C40H56O4Na,
103
623.4076);UV/vis 448 nm (in 90% MeOH).
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Capsanthone 5,6-epoxide. ESI TOF MS m/z 621.3920 (M+Na+, calcd for C40H54O4Na,
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621.3920);UV/vis 463 nm (in 90% MeOH).
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Capsanthin diendoperoxide. ESI TOF MS m/z 671.3937 (M+Na+, calcd for
107
C40H56O7Na, 671.3948);UV/vis 446 nm (in 90% MeOH).
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Capsanthin 5,6-endoperoxide. ESI TOF MS m/z 639.4056 (M+Na+, calcd for
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C40H56O5Na, 639.4025); UV/vis 463 nm (in 90% MeOH).
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Capsanthin 5,8-endoperoxide. ESI TOF MS m/z 639.4003 (M+Na+, calcd for
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C40H56O5Na, 639.4025); UV/vis 448 nm (in 90% MeOH).
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Capsanthin diacetate diepoxide. ESI TOF MS m/z 723.4258 (M+Na+, calcd for
113
C44H60O7Na, 723.4237);UV/vis 405~420 nm (in 90% MeOH).
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Capsanthin diacetae 5,6-epoxide. ESI TOF MS m/z 707.4280 (M+Na+, calcd for
115
C44H60O6Na, 707.4288); UV/vis 463 nm (in 90% MeOH).
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Capsanthin diacetate 5,8-epoxide. ESI TOF MS m/z 707.4280 (M+Na+, calcd for
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C44H60O6Na, 707.4288); UV/vis 448 nm (in 90% MeOH).
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Capsanthin diacetate diendoperoxide. ESI TOF MS m/z 755.4145 (M+Na+, calcd for
119
C44H60O9Na,755.4135);UV/vis 446 nm (in 90% MeOH).
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Capsanthin diacetate 5,6-endoperoxide. ESI TOF MS m/z 723.7229 (M+Na+, calcd for
121
C44H60O7Na, 723.4237); UV/vis 463 nm (in 90% MeOH).
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Capsanthin diacetate 5,8-endoperoxide. ESI TOF MS m/z 723.7229 (M+Na+, calcd for
123
C44H60O7Na, 723.4237); UV/vis 448 nm (in 90% MeOH).
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Capsorubin 7,8-epoxide. ESI TOF MS m/z 639.4003 (M+Na+, calcd for C40H56O5Na,
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639.4025); UV/vis 424 nm (in 90% MeOH).
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Capsorubin 7,8-endoperoxide. ESI TOF MS m/z 665.3962 (M+Na+, calcd for
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C40H56O6Na, 655.3975); UV/vis 424 nm (in 90% MeOH).
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Preparation of capsanthin 5,6-epoxides and 5,8-epoxides from capsanthin by
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epoxydation with m-chloroperbenzoic acid. According to the method described by
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Khachik et al,24 m-chloroperbenzoic acid 3.6 mg in 2 mL dichlorometane was added to
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a solution of capsanthin 2 mg in 2 mL dichlorometane. The solution was stand for 20
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min at room temperature in darkness. After the time, the reaction mixture was
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partitioned with 5% solution of NaHCO3 and ether. The ether layer was removed and
134
evaporated. The reaction products was submitted to preparative HPLC. HPLC
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separation provided syn-capsanthin 5,6-epoxide (0.8 mg) and anti-capsanthin
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5,6-epoxide (0.4 mg) and capsanthin diepoxides (0.2 mg mixtures). These spectral data
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were identical with those of published data by Deli at al.
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were prepared by epoxide-furanoxide rearrangement
139
5,6-epoxides. Preparative HPLC was performed on a Shimadzu LC-6AD with a
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Shimadzu SPD-6AV spectrophotometer (Shimadzu Corporation, Kyoto, Japan) set at
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450 nm. The column used was a 250 X 10 mm i.d., 10 µm Cosnosil 5C18-II (Nacalai
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Tesque, Kyoto, Japan) and a 250 X 10 mm i.d., 10 µm Cosnosil 5SL-II (Nacalai Tesque,
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Kyoto, Japan). Spectral data of syn-capsanthin 5,6-epoxide, anti-capsanthin 5,6-epoxide,
26
25
Capsanthin 5,8-epoxides
with HCl from capsanthin
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and capsanthin 5,8-epoxides were available for Supporting Information.
145 146
RESULTS AND DISCUSSION
147 148
Scavenging effect of ROS with capsanthin and capsorubin. Figure 2 shows the
149
scavenging effect of 1O2 (A) and .OH (B) with capsanthin and capsorubin. Astaxanthin,
150
astaxanthin diacetae, β-carotene, and zeaxanthin were used as positive controls. It was
151
reported that capsanthin and capsorubin quenched
152
peroxidation caused by free radicals.8,9
153
also revealed that capsanthin, capsanthin acetate, and capsorubin quenched not only 1O2
154
but also scavenged .OH. The order of quenching activity for 1O2 is astaxanthin diacetate
155
>capsorubin >astaxanthin >capsanthin diacetate> capsanthin> β-carotene> zeaxanthin.
156
It was reported that the 1O2 quenching activity of carotenoids depends on the number of
157
conjugated polyenes, polyene chain structures, and functional groups, especially
158
conjugated carbonyl groups.7,10,27
159
group improved carotenoid stability.22
160
conjugated double bonds including two conjugated carbonyl groups. Capsorubin has
161
eleven conjugated double bonds including two conjugated carbonyl groups. Capsanthin
1
O27,10 and inhibited lipid
In the present investigation, the ESR study
It was also reported that acetylation of the hydroxyl Astaxanthin and its acetate have thirteen
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and its acetate has eleven conjugated double bonds including one conjugated carbonyl
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group. On the other hand, β-carotene and zeaxanthin have eleven conjugated double
164
bonds without a conjugated carbonyl group. The results of the present investigation are
165
markedly consistent with this hypothesis.
166
On the other hand, capsanthin and capsorubin showed excellent scavenging activity
167
for .OH. Contrary to 1O2, astaxanthin and its acetate hardly showed scavenging activity
168
for .OH. The presence of the 3-hydroxy-κ-end group with a conjugated carbonyl group,
169
which is a characteristic structural moiety of paprika carotenoids, may enhance the
170
quenching activity of .OH.
171
Reaction products of capsanthin with .O2- and .OH. Structures of reaction products of
172
capsanthin with ROS are shown in Figure 1. Figure 3 shows HPLC chromatograms of
173
reaction products of capsanthin with .O2- by UV-A irradiation of riboflavin solution.
174
After 1 min of UV-A irradiation, reaction products assigned as capsanthin 5,6-epoxide
175
and capsanthin 5,8-epoxide were detected on HPLC. On UV-A irradiation, the amount
176
of these reaction products was increased and amount of capsanthin was decreased
177
time-dependently. After 6 min of UV-A irradiation, the HPLC peak of capsanthin
178
completely disappeared and the amount of reaction products reached a maximum. Then,
179
the reaction products were markedly decreased and the reaction solution was bleached.
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The structures of reaction products were assigned to capsanthin diepoxides (Peaks 1
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and 2), capsanthone 5,6-epoxide (Peak 3), capsanthin 5,6-epoxide (Peaks 4 and 5), and
182
capsanthin 5,8-epoxide (Peak 6) based on the ESI-TOF MS, MS/MS, and UV/vis
183
spectral data.
184
Both reaction products of peaks 4 and 5 showed the molecular formula of C40H56O4,
185
which corresponded to the molecular formula of capsanthin epoxide. The MS/MS
186
spectrum of sodium adduct ions [M+Na]+ of these compounds showed the characteristic
187
product ions [M+Na-92]+ (elimination of toluene moiety from polyene chain) and
188
[M+Na-106]+ (elimination of xylene moiety from polyene chain), which were
189
characteristic product ions of carotenoids in EI and ESI MS.28,29 Both compounds
190
showed an absorption maximum at 463 nm. These spectral data were in agreement with
191
those of capsanthin 5,6-epoxide. 25, 30 In order to confirm the structure of these reaction
192
products, capsanthin 5,6-epoxides were prepared from capsanthin by epoxydation with
193
m-chloroperbenzoic acid, as shown in Supporting Information. Peaks 4 and 5 were
194
identical
195
5,6-epoxide, respectively, on comparison with retention times in HPLC, MS, MS/MS,
196
and UV/vis spectra data. Therefore the structures of reaction products of peaks 4 and 5
197
were identified as capsanthin 5,6-epoxides.
with
semi-synthetic
syn-capsanthin
5,6-epoxide
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anti-capsanthin
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Reaction products of peak 6 showed the molecular formula of C40H56O4, consistent
199
with the molecular formula of capsanthin epoxide. Its absorption maximum was at 448
200
nm. The hypsochromic shift of about 15 nm from capsanthin 5,6-epoxide suggested that
201
these compounds were furanoid rearrangement products of capsanthin 5,6-epoxide, 26,31
202
namely capsanthin 5,8-epoxide. These compounds were identical to semi-synthetic
203
capsanthin 5,8-epoxides prepared from capsanthin 5,6-epoxides based on acid catalysis
204
on comparison of the retention times of HPLC and MS, MS/MS, and UV/vis spectral
205
data.
206
Both reaction products of peaks 1 and 2 showed the molecular formula of C40H56O5,
207
which corresponded to the molecular formula of capsanthin diepoxide. These absorption
208
maxima were at 405~420 nm. Therefore, these compounds were assigned to capsanthin
209
diepoxide. Epoxidation positions in capsanthin could not be determined.
210
Peak 3 showed the molecular formula of C40H54O4. Its absorption maximum was at
211
463 nm. These data suggest that this compound is a didehydro derivative of capsanthin
212
5,6-epoxide. Therefore, this reaction product was tentatively identified as capsanthone
213
5,6-epoxide. This compound was suggested to form from capsanthin 5,6-epoxide
214
through oxidation of the hydroxy group at C-3'. Superoxide anion radical might oxidize
215
the hydroxy group in carotenoids to ketone.
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As well as .O2-, the reaction of capsanthin with .OH hydroxyl radical generated by
217
UV-A irradiation in hydrogen peroxide solution provided capsanthin diepoxide,
218
capsanthone 5,6-epoxide, capsanthin 5,6-epoxide, and capsanthin 5,8-epoxide.
219
Reaction products of capsanthin with 1O2. Figure 4 shows the HPLC chromatograms
220
of the reaction products of capsanthin with 1O2 by UV-A irradiation in hematoporphyrin
221
solution. After 3 min of UV-A irradiation, reaction products assigned as capsanthin
222
diendoproxide and capsanthin 5,6-endoperoxide were detected in HPLC. The amounts
223
of these reaction products were increased and amount of capsanthin was decreased with
224
UV-A irradiation time-dependently. After 6 min of UV-A irradiation, the amount of the
225
reaction products reached a maximum. Then, the reaction products were markedly
226
decreased and the reaction solution was bleached. Both reaction products of peaks 2 and
227
3 showed the molecular formula of C40H56O5 and an absorption maximum at 463 nm.
228
These spectral data indicated that the dioxetane moiety was attached at the double bond
229
of C-5 to C-6 in capsanthin. Therefore, the structure of these compounds was assigned
230
as capsanthin 5,6-endoperoxide. Compounds of peak 2 and 3 were suggested to be
231
stereoisomers of C-5 and C-6. Reaction products of peak 1 showed the molecular
232
formula of C40H56O7, which indicated that two more oxygen atoms were attached to
233
capsanthin 5,6-endoperoxide. It absorption maximum was at 446 nm. The
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hypsochromic shift of the UV/vis spectrum of 15 nm from capsanthin 5,6-endoperoxide
235
comprised with the loss of one conjugated double bond from capsanthin
236
5,6-endoperoxide by attaching a dioxetane moiety.26,31
237
compound was tentatively assigned as capsanthin diendoperoxide.
238
Reaction products of capsanthin diacetate with .O2-, .OH, and 1O2. Results similar to
239
those for capsanthin were obtained in the case of capsanthin diacetate with these ROS.
240
Namely, capsanthin diacetate epoxides were obtained on reaction with .OH and .O2-,
241
while capsanthin diacetate endoperoxides were produced on reaction with 1O2. It was
242
found that oxidation products of capsanthin diacetate were more stable than those of
243
free capsanthin. Acetylation might protect the oxidation hydroxy groups of capsanthin
244
from ROS and inhibit rapid degradation of the capsanthin molecule.
245
Reaction products of capsorubin with .O2- and .OH. Figure 5 shows the HPLC
246
chromatograms of the reaction products of capsorubin with .O2-. Reaction products
247
assigned as capsorubin epoxide were increased with UV-A irradiation time-dependently.
248
After 12 min of UV-A irradiation, the amount of reaction products reached a maximum.
249
Then, the reaction solution was bleached. The major reaction products (Peaks 1 and 2)
250
showed the molecular formula of C40H56O5, which corresponded to the formula of
251
capsorubin epoxide. The epoxidation position of capsorubin in these compounds was
Therefore, the structure of this
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estimated from the UV/vis absorption spectra. These compounds showed an absorption
253
maximum at 424 nm. The hypsochromic shift of the UV/vis spectrum of 45 nm from
254
capsorubin indicated that these compounds lacked two conjugated double bonds (double
255
bond of a carbonyl group at C-6 and a double bond at C-7 to C-8 in the polyene chain)
256
from eleven conjugated double bonds of capsorubin by epoxidation.31 Therefore, the
257
epoxidation position of these compounds was assigned to a double bond at C-7 to C-8.
258
Reaction products of capsorubin with 1O2. Figure 6 shows the HPLC chromatograms
259
of the reaction products of capsorubin with
260
astaxanthin,22 capsorubin hardly formed oxidation products on exposure to 1O2. The
261
compound showed the molecular formula of C40H56O6, which corresponded to the
262
molecular formula of capsorubin endoperoxide, being slightly generated after 10 min of
263
UV-A irradiation. After 15 min of UV-A irradiation, capsorubin and its reaction product
264
were markedly decreased. Capsorubin showed greater stability on exposure to singlet
265
oxygen than β-carotene, capsanthin, or astaxanthin.22 Therefore, capsorubin showed a
266
strong quenching effect for 1O2.
1
O2. Contrary to capsanthin and
267
Previously, we investigated the reaction of astaxanthin and its acetate with .O2-, .OH,
268
and 1O2 by LC/PDA ESI-MS and ESR spectrometry.22 As the results, astaxanthin
269
endoperoxides were identified as major reaction products of astaxanthin with 1O2, and
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astaxanthin epoxides were found to be major reaction products of astaxanthin with .O2-
271
and .OH. The same results in this study were obtained in the case of astaxanthin acetate.
272
The ESR spin-trapping study revealed that astaxanthin and its acetate take up
273
superoxide anion radical by the formation of their epoxide through peroxide and oxide
274
radicals.22
275
In the present investigation, we found that capsanthin and capsorubin quenched not
276
only 1O2 but also scavenged .OH by the ESR spin-trapping study. Furthermore, we
277
found that capsanthin formed capsanthin epoxides by the reaction with .O2- and .OH and
278
also formed capsanthin endoperoxides by the reaction with 1O2. Contrary to astaxanthin,
279
capsanthin formed epoxide and endoperoxide more effectively and stably. It is
280
well-known that .O2- and 1O2 are electrophilic. Thus, they react with the electron-rich
281
double bond in carotenoids. The electron density of the double bond at C-5 (5') to C-6
282
(6') in the β-end group of astaxanthin is suggested to be lower than in parts of double
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bonds because of the presence of the electron withdrown effect of the carbonyl group at
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C-4 (4'). On the other hand, the electron density of the double bond at C-5 to C-6 in the
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β-end group of capsanthin is suggested to be higher than that astaxanthin.
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Therefore, .O2- and 1O2 might facilely attack the double bond at C-5 to C-6 in
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capsanthin and form 5,6-epoxide and 5,6-endoperoxide, respectively. Then, these
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5,6-epoxide and 5,6-endoperoxides are converted to the corresponding 5,8-epoxide and
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5,8-endoperoxide by acid catalisis.22
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capsanthin with .OH can be explained as follow: A hydroxyl radical was attached at C-5
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of capsanthin. Then, an epoxide ring was formed by intra-molecular homolytic
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substitution reaction.22 Capsorubin showed more stability against the attack of ROS,
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especially 1O2. Capsorubin has a long linier conjugated double bond system in its
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molecule. Capsorubin might exclusively quench 1O2 through a physical quenching
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system. Therefore, capsorubin showed the strongest quenching effect on 1O2 among the
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carotenoids.10 Therefore, we conclude that the reaction of carotenoids with ROS might
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depend on their structure, such as the conjugated polyene system and functional
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groups.32,33
The mechanism of epoxide ring formation in
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In conclusion, capsanthin and capsorubin formed their epoxides and endoperoxides on
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reaction with .O2-, .OH, and 1O2. The results indicate that capsanthin and capsorubin
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could trap .O2- and .OH by the formation of their epoxides. Furthermore, it was found
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that capsanthin and capsorubin could quench 1O2 through not only a pysical quenching
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system but also chemical direst reaction by the formation of their endoperoxide.
304 305
ASSOCIATED CONTENT
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Supporting Information
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The Supporting Information is available free of charge on the ACS Publications website
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at DOI:
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ESI TOF MS and MS/MS data of reaction products of capsanthin, capsanthin acetate,
310
and capsorubin. UV/vis, ESI TOF MS, MS/MS and 1H NMR data of syn- and
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anti-capsanthin 5,6-epoxide. UV/vis, ESI TOF MS and MS/MS data of capsanthin
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5,8-epoxide. Preparation scheme of capsanthin 5,6-epoxides and capsanthin
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5,8-epoxides from capsanthin by m-chloroperbenzoic acid (PDF).
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AUTHOR INFORMATION
315
Corresponding author
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*T.M. Tel.: +81 75 781 1107; fax: +81 75 781 1118. E-mail address:
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[email protected] 318
ACKNOWLEGEDMENTS
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We thank to Dr Yumiko Yamano, Kobe Pharmaceutical University for valuable
320
suggestion to this work.
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REFERENCES
325
(1) Almela, L.; Lopez-Roca, J.M.; Candela, M.E.; Alcazar N.D. Carotenoid composition
326
of new cultivates of red pepper for paprika. J. Agric. Food Chem. 1991, 39, 1606-1609.
327
(2) Minguez-Mosquera, M.I.; Hornero-Mendez, D. Separation and quantification of the
328
carotenoid pigments in red peppers (Capsicum annuum L.), paprika and oleoresin by
329
reversed-phase HPLC. J. Agric. Food. Chem. 1993. 41, 1616-1620.
330
(3) Minguez-Mosquera, M.I.; Hornero-Mendez, D. Comparative study of the effect of
331
paprika processing on the carotenoids in paprika (Capsicum annuumn) on the Bola and
332
Agridulce varieties. J. Agric. Food. Chem. 1994. 42, 1555-1560
333
(4) Deli, J.; Matus, Z.; Toth, G. Carotenoid composition in the fruits of Capsicum
334
annum Cv. Szentesi kosszarv during ripening. J. Agric. Food Chem. 1996, 44, 711-716.
335
(5) Deli, J.; Molnár, P.; Matus, Z.; Tóth, G.; Steck, A.; Pander, H. Reisolation of
336
carotenoid 3,6-epoxides from red paprika (Capsicum annuum). Helv. Chim. Acta 1996,
337
79, 1435–1443.
338
(6) Deli, J.; Matus, Z.; Molnár, P.; Tóth, G.; Steck, A.; S. Pander, H. Isolation of
339
capsanthone
340
(Capsicum annuum). Chimia 1995, 49, 69-71.
((all-E,3R,5’R)-3-hydroxy-β,κ-carotene-3’,6’-dione)
20
ACS Paragon Plus Environment
from
paprika
Page 21 of 41
Journal of Agricultural and Food Chemistry
341
(7) Hirayama, O.; Nakamura, K.; Hamada, S.; Kobayashi, K. Singlet oxygen quenching
342
ability of naturally occurring carotenoids. Lipids 1994, 29, 149–150.
343
(8) Matsufuji, H.; Nakamura, H.; Chino, M.; Takeda, M. Antioxidant activity of
344
capsanthin and fatty acid esters in paprika (Capsicum annuum). J. Agric. Food Chem.
345
1998, 46, 3468–3472.
346
(9) Maoka, T.; Goto, Y.; Isobe, K.; Fujiwrara, Y.; Hashimoto, K.; Mochida, K.
347
Antioxidative activity of capsorubin and related compounds from paprika (Capsicum
348
annuum). J. Oleo Sci. 2001, 50, 663–665.
349
(10) Nishino, A.; Ichihara, T.; Takaha, T.; Kuriki, T.; Nihei, H.; Kawamoto, K.; Yasui,
350
H.; Maoka, T. Accumulation of paprika carotenoids in human plasma and erythrocytes.
351
J. Oleo Sci. 2015, 64, 1135-1142.
352
(11) Murakami, A.; Nakashima,M.; Koshiba, T.; Maoka, T.; Nishino, H.; Yano, M.;
353
Sumida, T.; Kim., O.; Koshimizu, K.; Ohigashi, H. Modifying effects of carotenoids on
354
superoxide and nitric oxide generation from stimulated leukocyte. Cancer Lett. 2000,
355
149, 115–123.
356
(12) Maoka, T.; Mochida, K.; Kozuka, M.; Ito, Y.; Fujiwara, Y.; Hashimoto, K.; Enjo,
357
F.; Ogata, M.; Nobukuni, Y.; Tokuda, H.; Nishino, H. Cancer chemopreventive activity
358
of carotenoids in the fruits of red paprika Capsicum annuum L. Cancer Lett. 2001, 172,
21
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
359
103–109.
360
(13) Maoka, T.; Mochida, K.; Kozuka, M.; Enjo, F.; Kuchide, M.; Nobukuni, Y.;
361
Tokuda, H.; Nishino, H. Chemopreventive activity of paprika extract and capsanthin on
362
nitric oxide or peroxynitrite induced carcinogenesis (in Japanese). Syokuhin Rinsyou
363
Eiyo 2006, 1, 7–14.
364
(14) Molnár, J.; Serly, J.; Pusztai, R.; Vincze, I.; Molnár, P.; Horváth, G.: Deli, J.;
365
Maoka, T.; Zalatnai, A.; Tokuda, H.; Nishino, H. Putative supramolecular complexes
366
formed by carotenoids and xanthophylls with ascorbic acid to reverse multidrug
367
resistance in cancer cells. Anticancer Research 2012, 32, 507-518.
368
(15) Maeda, H.; Saito, S.; Nakamura, N,; Maoka, T. Paprika pigments attenuate
369
obesity-Ibduced Inflammation in 3T3-L1 adipocytes, ISRN Inflammation, 2013, Article
370
ID 763758, 9 pages
371
(16) Tsuboi, M.; Etoh, E.; Kato, K.; Nakatugawa, H.; Kato, H.; Maejima, Y.; Gaku, M.;
372
Matumoto, M.; Mori, H.; Hosokawa, M,; Miyashita, K.; Tokuda, H,; Suzuki, N.;
373
Maoka, T. Nitrocapsanthin and nitrofucoxanthin, respective products of capsanthin and
374
fucoxanthin reaction with peroxynitrite. J. Agric. Food. Chem. 2011, 59, 10872-10578.
375
(17) Footes, C.S.; Denny, R.W. Chemistry of singlet oxygen. VII. Quenching by
376
β-carotene. J. Am. Chem. Soc. 1968, 90, 6233-6235. 22
ACS Paragon Plus Environment
Page 22 of 41
Page 23 of 41
Journal of Agricultural and Food Chemistry
377
(18) Yamauchi, R.; Tsuchihashi, K.; Kato, K. Oxidation producta of β-carotene during
378
the peroxidation of methyl linolate in the bulk phase. Biosci. Biotech. Biochem. 1998,
379
62, 1301-1306.
380
(19) Martin, H.D.; Ruck, C.; Schmidt, M. Sell, S.; Beutner, S.; Mayse, B.; Walsh, R.
381
Chemistry of carotenoid oxidation and free radical reactions. Pure Appl. Chem. 1999,
382
71, 2253-2262.
383
(20) Fiedor, J.; Fiedor, L.; Haeβner, R.; Scheer, H. Cyclic endoperoxides of β-carotene,
384
potential pro-oxidants, as products of chemical quenching of singlet oxygen. Biochem.
385
Biophy. Acta. 2005, 1709, 1-4.
386
(21) Mordi, R. C.; Walton, J. C.; Burton, G. W., Hughes, L.; Krith, I. U.; David, L.A.;
387
Douglase, M. J. Oxidative degradation of beta-carotene and brta-apo-8’-carotenal.
388
Tetrahedron 1995, 49, 911-928.
389
(22) Nishino, A.; Maoka, T. Yasui, H. Analysis of reaction products of astaxanthin
390
and its acetate with active oxygen species using LC/PDA ESI-MS and ESR
391
spectrometry. Tetrahedron Lett. 2016, 57, 1967-1970.
392
(23) Tsubokura, A.; Yoneda, H.; Mizuta, H. Paracoccus carotinifaciens sp. nov., a new
393
aerobic gram-negative astaxanthin-producing bacterium. J. Syst. Bacteriol. 1999, 49,
23
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
394
277-282.
395
(24) Khachik, F.; Steck A.; Niggli, U. A.; Pfander, H. Partial synthesis and structural
396
elucidation of the oxidative metabolites of lycopene inentified in tomato paste, tomato
397
juice and human serum. J. Agric. Food Chem. 1998, 46, 4885-4874.
398
(25) Deli, J.; Molnár, P.; Matus, Z.; Tóth, G.; Steck, A.; Pfander, H. Partial synthesis and
399
characterization of capsokarpoxanthins and 3,6-epoxcapsanthins, Helv. Chim. Acta 1998,
400
81, 1242–1253.
401
(26) Eugster, C. H. Chemical derivatization: Microscale tests for the presence of
402
common functional group in carotenoids. in Carotenoids Volume 1A: Isolation and
403
analysis. Birkhäuser, Basel; 1995, pp 71-80.
404
(27) Shimidzu, N.; Goto, M.; Miki, W. Carotenoids as singlet oxygen quenchers in
405
marine organism. Fish. Sci. 1996, 62, 134-137
406
(28) Frassantio, R.; Cantonati,M.; Flaim, G.; Manchini, I.; G. Guella, G. A new method
407
for the identification and the structural characterization of carotenoid esters in
408
freshwater microorganisms by liquid chromatography-electrospray tandem mass
409
spectrometry. Rapid Commun Mass Spectrom. 2008, 22, 3531-3539.
410
(29) Weesepoel, Y.; Vincken, J-P.; Pop, P. M.; Liu, K.; Gruppen, H. Sodiation as a tool
411
for enhancing the diagnostic value of MALDI-TOF/TOF-MS spectra of complex
24
ACS Paragon Plus Environment
Page 24 of 41
Page 25 of 41
Journal of Agricultural and Food Chemistry
412
astaxanthin ester mixtures from Haematococcus pluvialis. J. Mass. Spectrum. 2013, 48,
413
862-874.
414
(30) Britton, G.; Liaaen-Jensen, S.; Pfander, H. Eds. Carotenoid Hand Bock,
415
Carotenoids Hand Book, Birkhäuser, Basel, Switerland, 2004.
416
(31) Britton, G.; UV/Visible spectroscopy in Carotenoids (Britton, G.; Liaaen-Jensen,
417
S.; Pfander, H. Eds. Birkhäuser, Basel; 1995; Vol. 1B, pp13-62.
418
(32) Woodall, A.A; Jackson, M.J.; Gruszecki, W.; Small, A.; Sielewiesuik, J.; Symons,
419
M.C.R.; Britton, G. Structure and properties of carotenoids in relation to function.
420
FASEB J. 1995, 9, 1551-1558.
421
(33) Woodall, A.A; Lee, S.W.; Weesie, R.J.; Jackson, M.J.; Britton, G. Oxidation of
422
carotenoids by free radicals: relationship between structure and reactivity. Biochem.
423
Biophys. Acta. 1997, 1366, 33-40.
424 425 426 427
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Figure legends Figure 1. Structures of carotenoids in this study Figure 2. Quenching effect on 1O2 (A) and scavenging effect on .OH (B) with capsanthin, capsanthin diacetate, and capsorubin. The vertical axis shows the relative rate (%) of the ESR signal intensity due to singlet oxygen (A) and hydroxyl radical (B) compared with the control group (100 %). Astaxanthin, astaxanthin diacetate, β-carotene, and zeaxanthin were used as positive controls. Significance compared with the control group: * p