Highly oxygenated monoterpene acylglucosides from Spiraea cantoniensis

Article abstract of DOI:10.1021/np900699e

Six new monoterpene acylglucosides named kodemariosides A-F (1-6) were isolated from the leaves and flowers of Spiraea cantoniensis. Their absolute structures including a highly oxygenated monoterpene aglycon part were determined by NMR experiments and chemical derivatization.

Full text of DOI:10.1021/np900699e

814
J. Nat. Prod. 2010, 73, 814–817
Highly Oxygenated Monoterpene Acylglucosides from Spiraea cantoniensis
Kaori Yoshida,† Atsuyuki Hishida,‡ Osamu Iida,‡ Keizo Hosokawa,§ and Jun Kawabata*,†
DiVision of Applied Bioscience, Graduate School of Agriculture, Hokkaido UniVersity, Sapporo 060-8589, Japan, Tsukuba DiVision, Research
Center for Medicinal Plant Resources, National Institute of Biomedical InnoVation, Tsukuba 305-0843, Japan, and Department of Nutritional
Management, Faculty of Health Sciences, Hyogo UniVersity, Kakogawa 675-0195, Japan
ReceiVed October 30, 2009
Six new monoterpene acylglucosides named kodemariosides A-F (1-6) were isolated from the leaves and flowers of
Spiraea cantoniensis. Their absolute structures including a highly oxygenated monoterpene aglycon part were determined
by NMR experiments and chemical derivatization.
In recent years, in the search for effective intestinal R-glucosidase
inhibitors from natural sources, much attention has been paid to
the development of physiological functional foods and lead
compounds for use as potential antidiabetic agents.1 In the course
of a continuing search for such inhibitors from cultivated temperate
plants from Japan, we have isolated three flavonol acylglycosides
from the flowers of Spiraea cantoniensis Lour. (Rosaceae) as rat
intestinal maltase inhibitors.2 S. cantoniensis is an ornamental
deciduous shrub. There have been only a few reports on the
chemical constituents of this plant,3-5 but no distinctive medicinal
usage is so far known. During the isolation of the active principles
above,2 we also found a series of novel monoterpene acylglucosides
(1-6) in the less active fractions from the flowers and leaves of
this plant. In this article, we describe the isolation and structural
determination of 1-6 from S. cantoniensis.
acylglucosides, named kodemariosides A (1), E (5), and F (6). A
further search for related compounds in the leaves of this plant
resulted in the isolation of 1 and its three stereoisomers, kodemari-
osides B (2), C (3), and D (4).
The molecular formula of compound 1 (kodemarioside A) was
assigned as C25H30O11 by HRFDMS. The 1H NMR spectrum (Table
1) showed signals characteristic of trans-p-coumaroyl [δH 6.88 and
7.56 (each 2H, d, J ) 8.7 Hz) and δH 6.39 and 7.63 (each 1H, d,
J ) 16.0 Hz)] and glucose [δH 4.41 (1H, d, J ) 7.7 Hz), 3.24 (1H,
dd, J ) 8.7, 7.7 Hz), 3.44 (1H, dd, J ) 8.8, 8.7 Hz), 3.39 (1H, dd,
J ) 9.2, 8.8 Hz), 3.57 (1H, ddd, J ) 9.2, 5.9, 2.1 Hz), 4.28 (1H,
dd, J ) 11.9, 5.9 Hz), and 4.54 (1H, dd, J ) 11.9, 2.1 Hz)] moieties.
The COSY spectrum supported the presence of these two substruc-
tures. The 1H NMR spectrum also showed a pair of nonequivalent
oxymethylene protons at δH 4.82 and 4.85 (each 1H, ddd, J ) 16.0,
5.6, 2.1 Hz) coupled with an olefinic proton at δH 6.54 [1H, dt, J
) 5.6 (t), 2.1 (d) Hz]. This olefinic proton gave a long-range allyl
correlation with an oxymethine proton at δH 4.51 [1H, dq, J ) 5.1
(d), 2.1 (q) Hz], which was coupled with another oxymethine at
δH 4.89 (1H, dd, J ) 9.1, 5.1 Hz). The latter oxymethine was further
coupled with an olefinic proton at δH 5.21 [1H, dsep, J ) 9.1 (d),
1.4 (sep) Hz]. Finally, this second olefinic proton had an allyl
coupling with signals of two methyl groups at δH 1.76 (6H, d, J )
1.4 Hz). This proton sequence of (O)-CH2-CHdC-CH(O)-CH(O)-
CHdC(CH3)2 was confirmed by the corresponding COSY cross-
peaks. The 13C NMR data (Table 2), including the DEPT spectrum,
showed two methyls (δC 18.5 and 25.8), two oxymethines (δC 75.1
and 82.7), one oxymethylene (δC 66.2), two olefinic methines (δC
122.4 and 142.3), two quaternary olefinic carbons (δC 131.4 and
141.0), and an ester carbonyl (δC 168.5) as well as the coumaroyl
[δC 127.0 and 160.5 (each C), δC 115.5, 116.6, 131.0, and 145.6
(each CH), and δC 167.6 (CO)] and the glucose [δC 71.2, 74.6,
75.1, 77.7, and 104.1 (each CH) and δC 64.2 (CH2)] carbons. The
ester carbonyl at δC 168.5 showed HMBC correlation peaks with
the olefinic proton at δH 6.54 and the oxymethine at δH 4.89,
consistent with being in a γ-lactone ring. Thus, the aglycon part of
1 was indicated to be 3-hydroxy-2-hydroxyethylidene-6-methylhept-
5-en-1,4-olide. The additional key HMBC correlations between the
oxymethylene protons (δH 4.82 and 4.85) and the anomeric carbon
of glucose (δC 104.1) and between the glucose methylene protons
(δH 4.28 and 4.54) and the p-coumaroyl carbonyl (δC 167.6) clearly
indicated that the lactone aglycon is glucosylated at the side chain
hydroxymethylene and that the C-6 hydroxy group on the glucose
is esterified with the trans-p-coumaric acid. The planar structure
of 1 was thus confirmed. The relative configuration was deduced
from the NOESY spectrum. The NOE peak between the olefin (δH
6.54) and the oxymethine (δH 4.51) protons revealed the Z-
configuration of the exocyclic double bond. The additional NOE
correlation appeared between the oxymethine at δH 4.51 and the
olefin proton at δH 5.21 and was supportive of the trans-
Results and Discussion
Flowers of S. cantoniensis were extracted and fractionated by a
series of chromatographic steps to yield three new monoterpene
* To whom correspondence should be addressed. E-mail: junk@
chem.agr.hokudai.ac.jp.
† Hokkaido University.
‡ National Institute of Biomedical Innovation.
§ Hyogo University.
10.1021/np900699e  2010 American Chemical Society and American Society of Pharmacognosy
Published on Web 03/23/2010

Monoterpene Acylglucosides from Spiraea cantoniensis
Journal of Natural Products, 2010, Vol. 73, No. 5 815
Table 1. 1H NMR Spectroscopic Data for Compounds 1-6 (acetone-d6)
proton
1
1
2
3
4
5
6
4.85 ddd (16.0, 5.6, 2.1)
4.82 ddd (16.0, 5.6, 2.1)
6.54 dt [5.6 (t), 2.1 (d)]
4.51 dq [5.1 (d), 2.1 (q)]
4.89 dd (9.1, 5.1)
4.83 ddd (16.0, 5.6, 2.1)
4.75 ddd (16.0, 5.6, 2.1)
6.53 dt [5.6 (t), 2.0 (d)]
4.48 m
4.87 dd (9.1, 4.9)
5.19 dsep [9.1 (d),
1.5 (sep)]
4.68 ddd (16.0, 5.7, 1.2)
4.62 ddd (16.0, 5.7, 1.2)
6.84 dt [5.7 (t), 3.2 (d)]
4.75 m
4.95 dd (9.1, 3.2)
5.12 dsep [9.1 (d),
1.5 (sep)]
4.64 ddd (16.0, 5.6, 1.2)
4.57 ddd (16.0, 5.6, 1.2)
6.82 m
4.84 ddd (16.0, 5.5, 2.0)
4.80 ddd (16.0, 5.5, 2.0)
6.53 dt [5.5 (t), 2.2 (d)]
4.50 m
4.89 dd (8.9, 5.2)
5.21 dsep [8.9 (d),
1.4 (sep)]
4.69 ddd (16.2, 5.4, 1.5)
4.62 ddd (16.2, 5.4, 1.5)
6.83 m
2
4
5
6
4.72 m
4.78 m
4.94 dd (9.1, 3.2)
5.12 dsep [9.1 (d),
1.4 (sep)]
4.96 dd (9.1, 3.2)
5.13 dsep [9.1 (d),
1.5 (sep)]
5.21 dsep [9.1 (d),
1.4 (sep)]
8
1.76 d (1.4)
1.76 d (1.4)
4.41 d (7.7)
3.24 dd (8.7, 7.7)
3.44 dd (8.8, 8.7)
3.39 dd (9.2, 8.8)
3.57 ddd (9.2, 5.9, 2.1)
4.54 dd (11.9, 2.1)
4.28 dd (11.9, 5.9)
7.56 d (8.7)
1.74 brs
1.74 brs
4.39 d (7.9)
3.22 dd (8.9, 7.9)
3.42 dd (9.1, 8.9)
3.35 dd (9.8, 9.1)
3.54 ddd (9.8, 5.9, 2.2)
4.48 dd (11.8, 2.2)
4.25 dd (11.8, 5.9)
7.72 d (8.6)
6.81 d (8.6)
6.81 d (8.6)
7.72 d (8.6)
6.86 d (12.8)
5.81 d (12.8)
1.72 d (1.5)
1.74 d (1.5)
4.46 d (7.6)
3.27 dd (8.6, 7.6)
3.44 dd (8.9, 8.6)
3.39 dd (9.1, 8.9)
3.59 ddd (9.1, 5.9, 2.1)
4.49 dd (12.1, 2.1)
4.28 dd (12.1, 5.9)
7.53 d (8.5)
1.72 d (1.2)
1.75 d (1.2)
4.43 d (7.9)
3.25 dd (8.9, 7.9)
3.43 dd (9.0, 8.9)
3.36 dd (9.5, 9.0)
3.56 ddd (9.5, 5.9, 2.2)
4.46 dd (12.1, 2.2)
4.24 dd (12.1, 5.9)
7.72 d (8.6)
1.73 d (1.4)
1.76 d (1.4)
4.41 d (7.6)
3.24 m
3.44 m
3.39 m
1.73 d (1.4)
1.75 d (1.4)
4.43 d (7.9)
3.28 dd (8.5, 7.9)
3.45 dd (8.9, 8.5)
3.41 dd (9.1, 8.9)
3.59 ddd (9.1, 5.7, 2.2)
4.49 dd (11.9, 2.2)
4.29 dd (11.9, 5.7)
7.16 d (2.0)
10
1′
2′
3′
4′
5′
6′
3.56 m
4.53 dd (11.9, 2.0)
4.28 dd (11.9, 5.7)
7.18 d (2.0)
2′′
3′′
5′′
6′′
7′′
8′′
6.88 d (8.7)
6.88 d (8.7)
7.56 d (8.7)
7.63 d (16.0)
6.87 d (8.5)
6.87 d (8.5)
7.53 d (8.5)
7.62 d (16.0)
6.81 d (8.6)
6.81 d (8.6)
7.72 d (8.6)
6.86 d (12.8)
6.85 d (8.4)
6.85 d (8.4)
7.06 dd (8.4, 2.0)
7.56 d (16.0)
6.32 d (16.0)
7.04 dd (8.4, 2.0)
7.56 d (16.0)
6.31 d (16.0)
6.39 d (16.0)
6.37 d (16.0)
5.80 d (12.8)
Table 2. 13C NMR Spectroscopic Data for Compounds 1-4
(acetone-d6)
di-MTPA ester (10S), respectively, in an NMR tube. In situ NMR
analysis clearly indicated the difference in chemical shifts of both
diesters, as shown in Figure 2. Consequently, the absolute config-
uration of C-4 in 1 was deduced to be S.
carbon
1
2
3
4
1
2
3
4
66.2
142.3
131.4
75.1
66.2
142.3
131.3
75.0
66.8
140.5
132.1
72.6
66.7
140.5
132.1
72.6
Compound 2 (kodemarioside B) gave the same molecular
formula, C25H30O11, as that of 1. The 1H NMR spectrum was similar
to that in 1 except for low-field signals arising from the p-coumaroyl
portion. A pair of olefinic doublets at δH 5.81 and 6.86 (J ) 12.8
Hz) were observed in 2 in place of the trans-double bond signals
at δH 6.39 and 7.63 (J ) 16.0 Hz) in 1. This higher field doublet
pair with a relatively small coupling constant compared to the trans-
p-coumaroyl side chain was characteristic of a cis-p-coumaroyl
residue. The other parts of the molecule, including the monoterpene
aglycon and the sugar unit, were in accordance with those in 1.
Hence, 2 was concluded to be a cis-p-coumaroyl analogue of 1.
Compound 3 (kodemarioside C) also gave a molecular formula
of C25H30O11. In the NMR spectrum, the signals of a trans-p-
coumaroylglucose unit were consistent with those in 1. However,
5
82.7
82.7
83.0
83.1
6
7
8
122.4
141.0
25.8
122.2
141.1
25.8
122.4
140.8
25.7
122.4
140.7
25.7
9
168.5
18.5
104.1
74.6
77.7
71.2
168.6
18.5
103.9
74.5
77.6
71.0
169.8
18.4
103.9
74.5
77.5
71.0
169.9
18.4
103.8
74.4
77.5
71.0
10
1′
2′
3′
4′
5′
75.1
64.2
74.8
64.1
75.1
64.1
74.9
64.0
6′
1′′
2′′(6′′)
3′′(5′′)
4′′
7′′
8′′
9′′
127.0
131.0
116.6
160.5
145.6
115.5
167.6
127.1
133.6
115.7
159.7
144.4
116.3
167.0
126.8
131.0
116.6
160.7
145.7
115.2
167.7
127.1
133.6
115.7
159.7
144.4
116.3
167.0
configuration of the hydroxy group and the 2-methyl-1-propenyl
substituents on the lactone ring (Figure 1).
The absolute configuration of the aglycon part of 1 was
determined by the advanced Mosher method6 as follows. Tannase
hydrolysis of 1 directly yielded the aglycon 7. All attempts for direct
MTPA esterification of 1 by MTPA chloride-pyridine or MTPA-
DCC-DMAP, however, failed. The in situ NMR analysis of the
reaction solution indicated the initial appearance of a mono-MTPA
ester on OH-1 and the subsequent rapid dehydration of OH-4,
probably after esterification, to a conjugated triene product due to
an easily dehydrating 3-hydroxy-1,5-diene system of 7. Removal
of the exo-double bond conjugated with the lactone carbonyl by a
nucleophilic addition of thiophenol gave a diastereomeric mixture
of 2-phenylthio compounds (8a and 8b). Both products showed a
similar coupling constant between H-3 and H-4, of 9.1 Hz for 8a
and 10.1 Hz for 8b, and an NOE enhancement between H-3 and
H-5. The relative configuration of C-3 and C-4 was inferred as
being trans in 8a and 8b, and hence, they are apparent C-2 epimers
of each other. The major product, 8a, was successively esterified
with 1 molar (S)-MTPA chloride to give the 1-O-(R)-MTPA ester,
9. Finally, careful esterification of the OH-4 group of 9 with (R)-
or (S)-MTPA yielded the 1R,4R-di-MTPA ester (10R) or the 1R,4S-
Figure 1. Key HMBC and NOE correlations for 1 and 3.

816 Journal of Natural Products, 2010, Vol. 73, No. 5
Yoshida et al.
koside, has been found in Sibiraea angustata, of the same family
as a plant affording an antiobesity compound.10
Experimental Section
General Experimental Procedures. Optical rotations were measured
on a JASCO DIP-370 digital polarimeter. NMR spectra were recorded
on a Bruker AMX500 instrument (1H, 500 MHz; 13C, 125 MHz).
Chemical shifts were determined relative to residual signals of acetone-
d6 (δH 2.04 ppm, δC 29.8 ppm) or chloroform-d (δH 7.24 ppm) as a
solvent. Field desorption (FD) and fast-atom bombardment (FAB) mass
spectra were determined using a JEOL SX102A instrument. Column
chromatography was performed with silica gel (Wakogel C-300, 300
mesh). HPLC was run on a JASCO PU-980 instrument equipped with
a UV detector. Preparative TLC was carried out on precoated silica
gel plates (0.5 mm thickness, Merck).
Plant Material. Spiraea cantoniensis was cultivated, collected in
May (flowers) and September (leaves) 2004 in an experimental field
in Tsukuba, Japan, and identified by one of the authors (A.H.). A
voucher specimen (No. 0131-79TS) is deposited in the Tsukuba
Division, Research Center for Medicinal Plant Resources, National
Institute of Biomedical Innovation, Tsukuba, Japan.
Extraction and Isolation. Dried flowers (6.5 g) of S. cantoniensis
were extracted with 50% MeOH. The aqueous methanol extracts were
partitioned with water and ethyl acetate. The ethyl acetate-soluble part
(0.38 g) was chromatographed with silica gel and eluted by a stepwise
mixture of chloroform-methanol (10:0, 10:1, 8:1, 6:1, 4:1, 2:1)
containing 1% formic acid. The chloroform-methanol (4:1) eluate (0.25
g) was rechromatographed with silica gel (chloroform-methanol, 3:1,
containing 1% formic acid) to yield 15 fractions. Fractions 4-6 were
combined (0.09 g) and further purified by preparative HPLC (column:
Inertsil PREP-ODS 20 × 250 mm, mobile phase: 27.5% MeCN in water
containing 0.1% TFA, flow rate: 5.0 mL/min, detection: UV 254 nm)
to yield 5 (tR 28 min, 3.4 mg) and 1 (tR 40 min, 5.0 mg). A larger scale
fractionation of the dried flowers (100 g) was conducted in a similar
manner. Half of the ethyl acetate-soluble part of the 50% methanol
extract (3.0 g) was chromatographed over silica gel (chloroform-
methanol). One-fifth of the amount (0.2 g) of the chloroform-methanol
(6:1) eluate was further fractionated by preparative HPLC (column: Inertsil
PREP-ODS 20 × 250 mm ×2 (serial connection), mobile phase: 20%
MeCN in water, flow rate: 7.0 mL/min for 0-30 min and 5.0 mL/min for
30-110 min, detection: UV 254 nm) to yield 6 (tR 82 min, 2.3 mg).
Dried leaves (50 g) of S. cantoniensis were extracted with 50%
MeOH. The aqueous methanol extracts were partitioned with water
and ethyl acetate. The ethyl acetate-soluble part (2.4 g) was chromato-
graphed with silica gel and eluted using a stepwise mixture of
chloroform-methanol (10:0, 10:1, 8:1, 6:1, 4:1, 2:1) containing 1%
formic acid. The chloroform-methanol (6:1) eluate (0.48 g) was
purified by preparative HPLC (column: Inertsil PREP-ODS 20 × 250
mm, mobile phase: 27.5% MeCN in water, flow rate: 5.0 mL/min,
detection: UV 254 nm) and yielded 3 (tR 38 min, 17 mg), 1 (tR 44 min,
90 mg), 4 (tR 53 min, 10 mg), and 2 (tR 58 min, 30 mg).
Figure 2. Determination of the absolute configuration of 1.
signals from the monoterpene aglycon part were slightly but
obviously different. The nonequivalent methylene protons (H-1)
of δH 4.82 and 4.85 in 1 were shifted to higher fields of δH 4.62
and 4.68, whereas the exocyclic olefin proton (H-2) at δH 6.54 in
1 was shifted to δH 6.84. This chemical shift change would be
expected to arise from an E-configuration of the exocyclic double
bond in 3 compared with the Z-geometry in 1. The olefinic proton,
H-2, was deshielded by the lactone carbonyl in 3, while the
nonequivalent methylene protons, H-1, were affected in 1. This
chemical shift change was consistent with a similar E-Z pair of
tuxpanolide-isotuxpanolide.7 The E-configuration of the double
bond was confirmed by the presence of a correlation peak between
H-1 (δH 4.62 and 4.68) and H-4 (δH 4.75) in the NOESY spectrum
(Figure 1). The structure of 3 was thus determined to be an
E-aglycon analogue of 1.
Compound 4 (kodemarioside D), C25H30O11, was also found to
be an isomer of compounds 1-3. The NMR spectrum of 4 showed
characteristic profiles of both 2 and 3 in contrast to 1. Hence, the
structure of 4 was deduced to be a cis-p-coumaroyl E-aglycon
analogue of 1.
Compound 5 (kodemarioside E) was assigned a molecular
formula of C25H30O12, which is one oxygen greater than those of
1-4. The major difference in the NMR spectra of 5 and 1 was in
the aromatic region of the phenolic acid part of the molecule. The
characteristic pair of doublets at δH 6.88 and 7.56 (J ) 8.7 Hz
each) in 1 was replaced with a typical 1,2,4-trisubstituted pattern
at δH 6.85 (d, J ) 8.4 Hz), 7.06 (dd, J ) 8.4, 2.0 Hz), and 7.18 (d,
J ) 2.0 Hz) in 5. The residual signals of the NMR spectra of 1
and 5 were nearly identical. Hence, the structure of 5 was concluded
to be a caffeoyl analogue of 1.
Kodemarioside A (1): yellow gum; [R]23 -10 (c 0.31, MeOH);
D
1H NMR data, see Table 1; 13C NMR data, see Table 2; FDMS m/z
506 [M]+; HRFDMS m/z 506.1767 [M]+ (calcd for C25H30O11,
506.1788).
Kodemarioside B (2): yellow gum; [R]23D +8 (c 0.21, MeOH); 1H
NMR data, see Table 1; 13C NMR data, see Table 2; FDMS m/z 506
[M]+; HRFDMS m/z 506.1790 [M]+ (calcd for C25H30O11, 506.1788).
Compound 6 (kodemarioside F) was found to be an isomer of
5, having a molecular formula of C25H30O12. In a similar manner
to 5, a comparison of the NMR spectra of 6 with those of 3 revealed
its structure as a caffeoyl analogue of 3.
Kodemarioside C (3): yellow gum; [R]23 -10 (c 0.49, MeOH);
D
1H NMR data, see Table 1; 13C NMR data, see Table 2; FDMS m/z
506 [M]+; HRFDMS m/z 506.1776 [M]+ (calcd for C25H30O11,
506.1788).
Kodemarioside D (4): yellow gum; [R]23D +5 (c 0.20, MeOH); 1H
NMR data, see Table 1; 13C NMR data, see Table 2; FDMS m/z 506
[M]+; HRFDMS m/z 506.1794 [M]+ (calcd for C25H30O11, 506.1788).
Kodemarioside E (5): yellow gum; [R]23D -9 (c 0.17, MeOH); 1H
NMR data, see Table 1; FDMS m/z 522 [M]+; HRFABMS (positive)
m/z 523.1825 [M + H]+ (calcd for C25H31O12, 523.1815).
Kodemarioside F (6): yellow gum; [R]23D -6 (c 0.22, MeOH); 1H
NMR data, see Table 1; FDMS m/z 522 [M]+; HRFDMS m/z 522.1755
[M]+ (calcd for C25H30O12, 522.1737).
Isolates 1-6 are novel acylglucosides based on a highly oxidized
monoterpene aglycon. The maltase-inhibitory activity was found
to be lower, 15% and 43% inhibition at 1 mM for 1 and 5,
respectively, than the previously identified flavonol glycosides,2
whereas the activity of the other isolates has not yet been
determined. It was reported that S. cantoniensis contains monot-
erpene ketone glucosides.5 In addition, a closely related monoter-
pene derivative, prunioside A, has been isolated from Spiraea
prunifolia.8,9 A prunioside A aglycon showed an inhibition of NO
production in stimulated macrophage-like cells.8 More recently, it
is interesting that a similar monoterpene lactone glucoside, sibis-
Tannase Hydrolysis of 1. To a solution of 1 (145 mg, 0.287 mmol)
in water (30 mL) was added tannase (150 mg, 41 units/mg, Sigma).
The mixture was stirred at 30 °C for 48 h. The reaction mixture was

Monoterpene Acylglucosides from Spiraea cantoniensis
Journal of Natural Products, 2010, Vol. 73, No. 5 817
extracted with EtOAc, and the extract was purified by silica gel
In the same manner, 9 was reacted with (S)-(-)-MTPA, DCC, and
DMAP in 0.3 mL of chloroform-d in an NMR tube for 2 h. (R,S)-
Diester (10S): 1H NMR (chloroform-d) δ 1.67 (3H, s, H-10), 1.80 (3H,
s, H-8), 3.08 (1H, dd, J ) 7.3, 4.1 Hz, H-3), 3.42 and 3.43 (each 3H,
s, MTPA-OMe), 3.74 (1H, ddd, J ) 8.9, 5.7, 4.1 Hz, H-2), 4.11 (1H,
dd, J ) 11.3, 8.9 Hz, H-1b), 4.57 (1H, dd, J ) 11.3, 5.7 Hz, H-1a),
4.93 (1H, dd, J ) 9.4, 5.9 Hz, H-5), 5.28 (1H, d, J ) 9.4 Hz, H-6),
5.64 (1H, dd, J ) 7.3, 5.9 Hz, H-4), 7.25-7.45 (15H, m, 2MTPA-
Ph,PhS).
preparative TLC (Rf ) 0.30, hexane-EtOAc-formic acid, 50:50:1) to
1
give an aglycon, 7 (25 mg, 44%). 7: colorless oil; H NMR (acetone-
d6) δ 1.72 (6H, d, J ) 1.3 Hz, H-8,10), 4.58 [1H, ddt, J ) 5.3 (d), 2.2
(t), 1.8 (d) Hz, H-4], 4.75 (1H, ddd, J ) 16.0, 5.6, 2.2 Hz, H-1b), 4.81
(1H, ddd, J ) 16.0, 5.9, 1.8 Hz, H-1a), 4.96 (1H, dd, J ) 9.1, 5.3 Hz,
H-5), 5.22 [1H, dsep, J ) 9.1 (d), 1.3 (sep) Hz, H-6], 6.64 (1H, ddd,
J ) 5.9, 5.6, 2.2 Hz, H-2); FDMS m/z 199 [M + H]+; HRFDMS m/z
199.0953 [M + H]+ (calcd for C10H15O4, 199.0971).
Thiophenol Addition of 7. To 7 (5.8 mg, 29 µmol) was added
thiophenol (10 µL, 97 µmol, 3.3 equiv) in EtOAc (10 drops). After 30
min at room temperature, the reaction mixture was directly separated
by silica gel preparative TLC (chloroform-MeOH, 19:1). 8a (Rf 0.40,
4.0 mg, 44%) and 8b (Rf 0.26, 2.4 mg, 27%) were obtained as oils. 8a:
colorless oil; 1H NMR (chloroform-d) δ 1.80 (3H, s, H-10), 1.82 (3H,
s, H-8), 2.97 (1H, dd, J ) 9.1, 2.5 Hz, H-3), 3.78 (1H, ddd, J ) 3.4,
2.5, 2.0 Hz, H-2), 3.81 (1H, dd, J ) 10.3, 2.0 Hz, H-1b), 3.91 (1H, dd,
J ) 10.3, 3.4 Hz, H-1a), 4.18 (1H, dd, J ) 9.1, 8.3 Hz, H-4), 4.87
(1H, dd, J ) 9.1, 8.3 Hz, H-5), 5.27 (1H, d, J ) 9.1 Hz, H-6), 7.31
[3H, m, PhS (H-3,4,5)], 7.55 [2H, d, J ) 7.1 Hz, PhS (H-2,6)]; FDMS
Maltase-Inhibition Assay. Compounds 1 and 5 were evaluated in
a maltase-inhibition assay, according to a previous protocol.2 Penta-
galloylglucose was used as a positive control (80% inhibition at
1 mM).11
Acknowledgment. The authors thank Mr. K. Watanabe and Dr. E.
Fukushi, GC-MS and NMR Laboratory, Faculty of Agriculture,
Hokkaido University, for their skillful measurements of mass spectra.
Note Added after ASAP Publication: This paper was published
on the Web on Mar 23, 2010, with an error regarding configuration at
the end of the third paragraph in the Results and Discussion section.
The corrected version was reposted on Apr 9, 2010.
1
m/z 308 [M]+. 8b: colorless oil; H NMR (chloroform-d) δ 1.77 (3H,
s, H-10), 1.80 (3H, s, H-8), 3.07 (1H, dd, J ) 10.1, 3.9 Hz, H-3), 3.70
(1H, ddd, J ) 6.9, 5.2, 3.9 Hz, H-2), 3.89 (1H, dd, J ) 12.1, 6.9 Hz,
H-1b), 4.01 (1H, dd, J ) 12.1, 5.2 Hz, H-1a), 4.43 (1H, dd, J ) 10.1,
8.1 Hz, H-4), 4.81 (1H, dd, J ) 8.6, 8.1 Hz, H-5), 5.22 (1H, d, J ) 8.6
Hz, H-6), 7.29 [1H, t, J ) 7.6 Hz, PhS (H-4)], 7.32 [2H, t, J ) 7.6 Hz,
PhS (H-3,5)], 7.49 [2H, d, J ) 7.6 Hz, PhS (H-2,6)]; FDMS m/z
308 [M]+.
1
Supporting Information Available: H NMR and 13C NMR (in
part) spectra of kodemariosides A-F (1-6) and the derivatives are
available free of charge via the Internet at http://pubs.acs.org.
References and Notes
Mono-(R)-MTPA Esterification of 8a. To 8a (5.9 mg, 19.2 µmol)
in MeCN (10 drops) and pyridine (5 drops) was added (S)-(+)-MTPA
chloride (15 µL, 60 µmol, 3.1 equiv). After 3 h at room temperature,
the reaction mixture was directly separated by silica gel preparative
TLC (hexane-EtOAc, 2:1). The mono-(R)-MTPA ester 9 (Rf 0.40, 3.6
mg, 36%) was obtained as an oil. 9: colorless oil; 1H NMR (chloroform-
d) δ 1.77 (3H, s, H-10), 1.81 (3H, s, H-8), 2.90 (1H, dd, J ) 8.6, 3.2
Hz, H-3), 3.53 (3H, s, MTPA-OMe), 3.77 (1H, ddd, J ) 5.3, 3.3, 3.2
Hz, H-2), 3.83 (1H, dd, J ) 8.6, 7.8 Hz, H-4), 4.24 (1H, dd, J ) 11.3,
3.3 Hz, H-1b), 4.73 (1H, dd, J ) 8.9, 7.8 Hz, H-5), 4.94 (1H, dd, J )
11.3, 5.3 Hz, H-1a), 5.08 (1H, d, J ) 8.9 Hz, H-6), 7.31 [3H, m, PhS
(H-3,4,5)], 7.43 [3H, m, MTPA-Ph (H-3,4,5)], 7.52 [2H, m, PhS (H-
2,6)], 7.61 [2H, m, MTPA-Ph (H-2,6)]; FDMS m/z 524 [M]+.
In Situ (R)- and (S)-MTPA Esterification of 9. The (R)-monoester
9 (0.8 mg, 1.4 µmol) was reacted with (R)-(+)-MTPA (1.0 mg, 4.3
µmol, 3.1 equiv), dicyclohexylcarbodiimide (DCC, 1.0 mg, 4.9 µmol,
3.5 equiv), and 4-dimethylaminopyridine (DMAP, 1.0 mg, 8.2 µmol,
5.9 equiv) in 0.3 mL of chloroform-d in an NMR tube for 2 h. (R,R)-
Diester (10R): 1H NMR (chloroform-d) δ 1.50 (3H, s, H-10), 1.75 (3H,
s, H-8), 3.10 (1H, dd, J ) 7.1, 4.2 Hz, H-3), 3.38 and 3.45 (each 3H,
s, MTPA-OMe), 3.76 (1H, ddd, J ) 9.3, 5.4, 4.2 Hz, H-2), 4.24 (1H,
dd, J ) 11.6, 9.3 Hz, H-1b), 4.70 (1H, dd, J ) 11.6, 5.4 Hz, H-1a),
4.80 (1H, dd, J ) 9.4, 5.9 Hz, H-5), 5.23 (1H, d, J ) 9.4 Hz, H-6),
5.62 (1H, dd, J ) 7.1, 5.9 Hz, H-4), 7.30-7.50 (15H, m, 2MTPA-
Ph,PhS).
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