Phenolic compounds from the fresh leaves of eucalyptus maideni

Article abstract of DOI:10.1002/hlca.201000067

Four new phenolic compounds, 7-O-methylcatechin 5-O-β-D- glucopyranoside (1), 6-O-feruloyl-D-glucopyranose (2), demethylpiperitol 4-O-β-D-glucopyranoside (3), and 2-episesaminol 2-O-β-D- glucopyranoside (4) were isolated from the fresh leaves of Eucalyptus maideni, together with six hydrolyzable tannins, 5-10, a flavonol glycoside, 11, three simple phenolics, 12-14, a monoterpene glucoside, 15, and a rosenoside, 16. Their structures were determined on the basis of detailed spectroscopic analysis, acidic hydrolysis, and enzymatic hydrolysis. The known compounds 10 and 13 were obtained from the genus Eucalyptus for the first time. Copyright 2010 Verlag Helvetica Chimica Acta AG, Zuerich, Switzerland.

Full text of DOI:10.1002/hlca.201000067

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Phenolic Compounds from the Fresh Leaves of Eucalyptus maideni
by Li-Wen Tiana)b), Chong-Ren Yanga)c), and Ying-Jun Zhang*a)
a) State Key Laboratory of Phytochemistry and Plant Resources of West China, Kunming Institute of
Botany, Chinese Academy of Sciences, Kunming 650204, P. R. China
(phone: þ 86-871-5223235; fax: þ 86-871-5150124; e-mail: zhangyj@mail.kib.ac.cn)
b) Graduate University of the Chinese Academy of Sciences, Beijing 100049, P. R. China
c) Weihe Biotech Research and Development Center, Yuxi 653101, P. R. China
Four new phenolic compounds, 7-O-methylcatechin 5-O-b-d-glucopyranoside (1), 6-O-feruloyl-d-
glucopyranose (2), demethylpiperitol 4-O-b-d-glucopyranoside (3), and 2-episesaminol 2-O-b-d-
glucopyranoside (4) were isolated from the fresh leaves of Eucalyptus maideni, together with six
hydrolyzable tannins, 5 – 10, a flavonol glycoside, 11, three simple phenolics, 12 – 14, a monoterpene
glucoside, 15, and a rosenoside, 16. Their structures were determined on the basis of detailed
spectroscopic analysis, acidic hydrolysis, and enzymatic hydrolysis. The known compounds 10 and 13
were obtained from the genus Eucalyptus for the first time.
Introduction. – The genus Eucalyptus (Myrtaceae), mainly growing in the tropical
and subtropical areas of the world, contains ca. 945 species, 300 of which are distributed
in China [1]. In this genus, some species, e.g., E. globulus, E. robusta, and E. melliodora,
are important folk-medicinal plants [2], and a series of terpenoids [3], tannins [4],
flavonoids [5], and phloroglucinol derivatives [6 – 9] with antiviral [8] and antibacterial
[9] effects have been reported.
E. maideni F. Muell is a tall timber tree growing widely in the southern part of
China [2]. The trunks are commonly used in forestry, while its leaves are extracted for
essential oil. Our previous study [10] on the fresh leaves has resulted in the isolation of
five new (þ)-oleuropeic acid derivatives. Further investigation on the same extract led
to the isolation of a new methyl-flavan-3-ol glucoside 1, a new glucose feruloyl ester 2,
and two new lignan glucosides, 3 and 4 (Fig. 1). In addition, twelve known compounds,
5 – 16 (Fig. 2), including six hydrolyzable tannins, 5 – 10, a flavonol glycoside, 11, three
simple phenolics, 12 – 14, a monoterpene glucoside, 15, and a reoseoside, 16, were also
obtained. This article presents the structure determination of these compounds by
means of NMR and MS techniques, acidic hydrolysis, and enzymatic hydrolysis.
Results and Discussion. – The 80% aqueous acetone extract of fresh leaves of E.
maideni was partitioned with CHCl3 and H2O. The H2O portion was then subjected to
Diaion HP20SS column chromatography (CC) to afford seven fractions. Further CC on
Fractions 1 – 3, 6, and 7 afforded four new compounds, 1 – 4. In addition, twelve known
compounds were identified as isocoriariin F (5) [11], oenothein C (6) [11], gemin D (7)
[12], 3-O-galloylglucose (8) [11], 4-O-galloylglucose (9) [13], punigluconin (10) [14],
quercetin 3-O-b-d-glucuropyranoside (11) [15], eucalmanioside C (12) [16], lysidisides
ꢀ 2010 Verlag Helvetica Chimica Acta AG, Zꢁrich

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Fig. 1. New compounds 1 – 4 isolated from the fresh leaves of E. maideni
C (13) [17], gallic acid (14) [16], 1,8-cineole 2-O-b-d-glucopyranoside (15) [18], and
(6S,9R)-reoseoside (16) [19], by comparison of the physical and spectral data with
literature values. The known compounds 10 and 13 were obtained from the genus
Eucalyptus for the first time.
Compound 1 was obtained as a pale amorphous powder. The molecular formula of
1
1 was determined as C22H26O11 by HR-ESI-MS (m/z 465.1410 ([M ꢀ H]ꢀ)). The H-
and 13C-NMR spectra (Table 1) showed signals of five aromatic H-atoms of a 1,3,4-
trisubstituted (d(H) 6.81 (d, J ¼ 2.0, HꢀC(2’)), 6.75 (d, J ¼ 8.5, HꢀC(5’)), and 6.70 (dd,
J ¼ 8.0, 2.0, HꢀC(6’))) and a 1,3,4,5-tetrasubstituted (d(H) 6.38, 6.14 (2d, J ¼ 2.4,
HꢀC(6), HꢀC(8))) phenyl group each, and of three aliphatic C-atoms at d(C) 82.9
(C(2)), 68.4 (C(3)), and 28.3 (C(4)), corresponding to a typical catechin moiety. The
larger coupling constant (J ¼ 7.5 Hz) between HꢀC(2) and HꢀC(3) indicated that it
was a (þ)-catechin moiety [20]. In addition, signals arising from a glucopyranosyl
moiety (d(C) 102.5, C(1’’), 78.2, C(3’’), 78.1, C(5’’), 74.8, C(2’’), 71.4, C(4’’), 62.5, C(6’’))
and a MeO group (d(H) 3.73 (s); d(C) 55.7) were also observed. The J value of the
anomeric H-atom (d(H) 4.83 (d, J ¼ 7.7)) indicated its b-configuration. In the ROESY
spectrum of 1, the MeO H-atoms showed correlations with both HꢀC(6) and HꢀC(8),
while the anomeric H-atom was correlated with HꢀC(6), indicating the locations of
the MeO group at C(7) and the glucosyl moiety at C(5). Thus, compound 1 was
elucidated to be 7-O-methylcatechin 5-O-b-d-glucopyranoside1).
Compound 2, a pale amorphous powder, had the molecular formula C16H20O9,
1
deduced from the HR-ESI-MS (m/z 391.0795 ([M þ Cl]ꢀ)). The H-NMR spectrum
1
)
Absolute configuration of glucose was assumed to be d from the same biogenetic considerations.

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Fig. 2. Known compounds 5 – 16 isolated from the fresh leaves of E. maideni
(Table 2) displayed signals of two trans-coupled CH H-atoms at d(H) 7.55 and 6.31 (2d,
J ¼ 15.0, HꢀC(7’), HꢀC(8’)), three aromatic H-atoms at d(H) 7.19 (d, J ¼ 1.7,
HꢀC(2’)), 7.05 (dd, J ¼ 1.7, 8.2, HꢀC(6’)), and 6.79 (d, J ¼ 8.2, HꢀC(5’)), and a MeO
group at d(H) 3.81 (s), corresponding to a feruloyl group. The MeO group at C(3’) of
the feruloyl group was confirmed by its ROESY correlation with HꢀC(2’). In addition,
a set of complex H-atom signals arising from the sugar moiety, as well as the
appearance of the anomeric H-atom signals at d(H) 5.09 (0.5 H, d, J ¼ 3.6) (a-form)

Helvetica Chimica Acta – Vol. 93 (2010)
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Table 1. 1H- and 13C-NMR Data of Compound 1. Recorded at 125 and 500 MHz, respectively, in CD3OD,
d in ppm, J in Hz.
d(H)
d(C)
Aglycone
C(2)
C(3)
4.61 (d, J ¼ 7.5)
82.9
68.4
4.01 – 3.97 (m)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
C(10)
C(1’)
C(2’)
C(3’)
C(4’)
C(5’)
C(6’)
MeOꢀC(7)
Glc
3.01 (dd, J ¼ 5.0, 16.5), 2.60 (dd, J ¼ 8.0, 16.5)
28.3
158.0
96.0
160.9
96.8
156.6
104.5
131.9
115.1
146.2
146.2
116.1
119.9
55.7
6.38 (d, J ¼ 2.4)
6.14 (d, J ¼ 2.4)
6.81 (d, J ¼ 2.0)
6.75 (d, J ¼ 8.5)
6.70 (dd, J ¼ 2.0, 8.0)
3.73 (s)
C(1’’)
C(2’’)
C(3’’)
C(4’’)
C(5’’)
C(6’’)
4.83 (d, J ¼ 7.7)
102.5
74.8
78.2
71.4
78.1
62.5
3.46 – 3.44 (m)
3.43 – 3.40 (m)
3.38 – 3.36 (m)
3.47 – 3.44 (m)
3.89 (dd, J ¼ 2.5, 12.0), 3.68 (dd, J ¼ 5.5, 12.0)
Table 2. 1H- and 13C-NMR Data of 2. Recorded at 125 and 500 MHz, respectively, in (D6)acetone and
D2O, d in ppm, J in Hz.
d(H)
d(C)
Glc
b
a
b
a
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
4.52 (d, J ¼ 7.9)
3.18 (t, J ¼ 8.5)
3.44 – 3.37 (m)
3.40 – 3.34 (m)
3.58 – 3.52 (m)
4.40 (d, J ¼ 12.0), 4.26 – 4.21 (m)
5.09 (d, J ¼ 3.6)
3.44 – 3.37 (m)
3.66 (t, J ¼ 9.5)
3.40 – 3.34 (m)
4.00 – 3.96 (m)
4.36 (d, J ¼ 11.0), 4.28 – 4.18 (m)
97.1
74.9
76.5
70.5
74.1
64.1
92.8
72.3
73.4
70.5
69.8
64.2
Feruloyl
C(1’)
C(2’)
C(3’)
C(4’)
C(5’)
C(6’)
C(7’)
C(8’)
C(9’)
MeOꢀC(3’)
126.7
111.2
146.3
148.4
115.8
123.6
146.3
114.5
168.3
56.0
7.19 (d, J ¼ 1.7)
6.79 (d, J ¼ 8.2)
7.05 (dd, J ¼ 1.7, 8.2)
7.55 (d, J ¼ 15.0)
6.31 (d, J ¼ 15.0)
3.81 (s)

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and d(H) 4.52 (0.5 H, d, J ¼ 7.9 ) ( b-form) in a ratio of 1:1, and the anomeric C-atom
signals at d(C) 92.8 and 97.1, indicated that 2 is an anomer mixture. Acidic hydrolysis of
2 liberated d-glucose, which was determined by GC analysis of its corresponding
trimethylsilylated l-cysteine adduct. The linkage of feruloyl moiety at C(6) of d-
glucose unit was established by HMBC of HꢀC(6) of glucose at d(H) 4.40 and 4.22 (b-
form), and 4.36 and 4.19 (a-form) with the CO group at d(C) 168.4 (C(9’)) of the
feruloyl moiety. Based on the above evidences, the structure of 2 was determined to be
6-O-feruloyl-d-glucopyranose.
Compound 3 was obtained as a pale amorphous powder. Its molecular formula
C25H28O11 was elucidated from the HR-ESI-MS (m/z 503.1566 ([M ꢀ H]ꢀ), calc.
1
503.1553). The H- and 13C-NMR spectra of 3 (Table 3) showed the presence of two
1,3,4-trisubstituted phenyl groups (d(H) 6.86 (d, J ¼ 1.3, HꢀC(2)), 6.76 (d, J ¼ 8.0,
Table 3. 1H- and 13C-NMR Data of Compounds 3 and 4. Recorded at 125 and 500 MHz, respectively, in
CD3OD, d in ppm, J in Hz.
3
4
d(H)
d(C)
d(H)
d(C)
Aglycone
HꢀC(1)
HꢀC(2)
HꢀC(3)
CH2(4)
HꢀC(5)
HꢀC(6)
HꢀC(7)
HꢀC(8)
CH2(9)
138.1
114.9
148.6
146.3
118.6
118.7
87.3
125.8
150.5
100.0
149.1
143.8
106.7
86.5
6.86 (d, J ¼ 1.3)
6.87 (s)
6.76 (d, J ¼ 8.0)
6.78 (dd, J ¼ 1.3, 8.0)
4.67 (d, J ¼ 5.4)
6.90 (s)
5.16 (d, J ¼ 4.7)
3.08 – 3.02 (m)
55.6
72.8
3.14 – 3.09 (m)
55.6
74.1
4.20 (dd, J ¼ 7.0, 9.0),
4.37 (dd, J ¼7.5, 9.0),
4.02 (dd, J ¼ 5.0, 9.0)
3.83 (dd, J ¼ 4.2, 9.0)
HꢀC(1’)
HꢀC(2’)
HꢀC(3’)
HꢀC(4’)
HꢀC(5’)
HꢀC(6’)
HꢀC(7’)
HꢀC(8’)
CH2(9’)
136.4
107.5
148.5
149.4
109.0
120.6
86.9
137.0
107.8
148.3
148.4
109.2
120.8
82.8
6.86 (br. s)
6.94 (d, J ¼ 1.5)
7.15 (d, J ¼ 8.3)
6.82 (d, J ¼ 8.3)
4.68 (d, J ¼ 5.0)
3.08 – 3.02 (m)
4.20 (dd, J ¼ 7.0, 9.0),
3.83 (dd, J ¼ 4.2, 9.0)
5.98 (s)
6.86 (d, J ¼ 8.0 )
6.89 (dd, J ¼ 1.5, 8.0)
4.68 (d, J ¼ 5.6)
3.03 – 2.98 (m)
4.23 (dd, J ¼ 7.0, 9.0),
3.90 (dd, J ¼ 4.0, 9.0)
6.01 (s)
55.4
72.6
55.1
72.4
OCH2O
OCH2O
Glc
102.4
102.6
102.4
5.98 (s)
HꢀC(1’’)
HꢀC(2’’)
HꢀC(3’’)
HꢀC(4’’)
HꢀC(5’’)
CH2(6’’)
4.74 (d, J ¼ 7.5)
3.48 – 3.45 (m)
3.46 – 3.44 (m)
3.40 – 3.38 (m)
3.46 – 3.44 (m)
102.5
74.8
78.2
71.4
78.1
62.5
4.90 (d, J ¼ 7.2)
3.40 (t, J ¼ 8.5)
103.1
74.9
78.3
71.3
78.4
62.4
3.44 – 3.42 (m)
3.34 (t, J ¼ 9.5)
3.44 – 3.42 (m)
3.84 (dd, J ¼ 2.0, 11.2),
3.84 (dd, J ¼ 2.0, 12.0),
3.65 (dd, J ¼ 5.0, 11.2)
3.65 (dd, J ¼ 5.5, 12.0)

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HꢀC(5)), and 6.78 (dd, J ¼ 1.3, 8.0, HꢀC(6)); 6.86 (br. s, HꢀC(2’)), 7.15 (d, J ¼ 8.3,
HꢀC(5’)), and 6.82 (d, J ¼ 8.3, HꢀC(6’))), three O-bearing CH2 groups (d(H) 5.98 (s),
4.20 (dd, J ¼ 7.0, 9.0, HꢀC(9a,9’a)), and 3.83 (dd, J ¼ 4.2, 9.0, HꢀC(9b,9’b))), and four
CH groups, including two O-bearing ones (d(H) 4.67 (d, J ¼ 5.5, HꢀC(7)), 4.68 (d, J ¼
5.0, HꢀC(7’))). These NMR data were closely related to those of demethylpiperitol
[21], except for the presence of an additional glucose moiety in 3. Signals arising from
this additional glucosyl moiety (anomeric H-atom signal at d(H) 4.74 (d, J ¼ 7.5,
HꢀC(1’’))) were also observed. Enzymatic hydrolysis of compound 3 yielded d-glucose
([a]D ¼ þ53.8 (H2O)) as sugar residue, and (ꢀ)-demethylpiperitol ([a]D ¼ ꢀ61.1
(CHCl3), FAB-MS m/z 341 ([M ꢀ H]ꢀ)) as aglycone. In the HMBC spectrum of 3, the
glucosyl anomeric H-atom at d(H) 4.74 correlated with the C(4) (d(C) 146.3)
determined the glucosylation position at C(4) of the demethylpiperitol unit. Thus,
compound 3 was deduced to be demethylpiperitol-4-O-b-d-glucopyranoside.
Compound 4, a pale amorphous powder, had a molecular formula C26H28O12, as
deduced from the HR-ESI-MS (m/z 567.1270 ([M þ Cl]ꢀ), calc. 567.1269). The
1H-NMR spectrum of 4 showed the presence of one 1,3,4-trisubstituted and one 1,2,4,5-
tetrasubstituted benzene ring each (d(H) 6.94 (d, J ¼ 1.5, HꢀC(2’)), 6.86 (d, J ¼ 8.0,
HꢀC(5’)), 6.89 (dd, J ¼ 1.5, 8.0, HꢀC(6’)), and 6.87, 6.90 (s, HꢀC(3), HꢀC(6))), four
O-bearing CH2 groups (d(H) 6.01, 5.98 (2s, 2 OCH2O), 4.37 (dd, J ¼ 7.5, 9.0,
HꢀC(9a)) 4.02 (dd, J ¼ 5.0, 9.0, HꢀC(9b)), 4.23 (dd, J ¼ 7.0, 9.0, HꢀC(9’a)), and
3.90 (dd, J ¼ 4.0, 9.0, HꢀC(9’b)), and four CH groups, including two O-bearing ones
(d(H) 5.16 (d, J ¼ 4.7, HꢀC(7)) and 4.68 (d, J ¼ 5.6, HꢀC(7’))). These NMR data
(Table 3) closely resemble those of 2-episesaminol [22]. In addition, a set of signals due
to a glucosyl unit was observed in the 1H- and 13C-NMR spectra of 4. The HMBCs of
the glucosyl anomeric H-atom at d(H) 4.90 (d, J ¼ 7.2) and HꢀC(7) (d(H) 5.16) with
C(2) (d(C) 150.5) indicated the glucosylated position at C(2) of the 2-episesaminol
unit. In the NOESY spectrum of compound 4, both HꢀC(8) (d(H) 3.14 – 3.09, m) and
HꢀC(8’) (d(H) 3.03 – 2.98, m) showed correlations with HꢀC(7) (d(H) 5.16),
indicating that the two aryl groups in 4 were located on the opposite sites of the
furo[3,4-c]furan moiety, as in 2-episesaminol. Accordingly, compound 4 was deter-
mined as 2-episesaminol 2-O-b-d-glucopyranoside.
According to [22], the aglycone of compound 4, 2-episesaminol, was easily
converted to its epimer, sesaminol, in a CHCl3 solution at room temperature. However,
we did not find any conversion for compound 4 during the isolation and purification
1
process, and even re-recording the H-NMR spectrum after two-month keeping in
CD3OD at room temperature, suggesting that the glycosidation of 2-episesaminol on
HOꢀC(2) may increase the stability of its aglycone, 2-episesaminol.
In this study, besides the new methylcatechin glucoside 1, and lignans 3 and 4, six
hydrolyzable tannins, 2 and 5 – 9, occurring as anomeric mixtures, were isolated from
the fresh leaves of Eucalyptus maideni, in addition to phloroglucinol glycosides,
monoterpenoids, and simple phenolics. They may arise from the hydrolysis of complex
hydrolyzable tannins, such as eucalbanins. On the basis of these results, it can be stated
that E. maideni may provide a good source for further new biologically active natural
products.

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Experimental Part
General. Coloumn chromatography (CC): Diaion HP-20SS (Mitsubishi Chemical Co.), MCI-gel
CHP-20P (75 – 150 mm; Mitsubishi Chemical Co.), Sephadex LH-20 (25 – 100 mm; Pharmacia Fine
Chemical Co. Ltd.), Toyopearl HW-40F (TOSOH, Japan), and silica gel (SiO2; 200 – 300 mesh, Qingdao
Haiyang Chemical Co. Ltd.). TLC: SiO2 plates; detection by spraying with 2% FeCl3 in EtOH or 10%
H2SO4 reagents. Optical rotations: JASCO-20 polarimeter. UV Spectra: Shimadzu UV-2401A
spectrometer; MeOH solns.; lmax (log e) in nm. IR Spectra: Bio-Rad-FTS-135 spectrometer; KBr
pellets; ˜n in cmꢀ1. 1D- and 2D-NMR Spectra: Bruker-AM-400 and -DRX-500 spectrometers; d in ppm
rel. to Me4Si as internal standard, J in Hz. MS: VG-Auto-Spec-3000 spectrometer with matrix as glycerol
for FAB-MS; API-QSTAR-Pulsar-1 spectrometer for ESI-MS and HR-ESI-MS; in m/z.
Plant Material. The fresh leaves of E. maideni were collected in the Botanical Garden of Kunming
Institute of Botany, Chinese Academy of Sciences, Yunnan, P. R. China, in May 2007. A voucher
specimen (KIB-ZL-200701) has been deposited with the State Key Laboratory of Phytochemistry and
Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences.
Extraction and Isolation. The fresh leaves of E. maideni (3.5 kg) were extracted with 80% aq.
acetone at r.t. (3 ꢁ 10 l, each 1 week). After removal of the org. solvent under reduced pressure and of
precipitate by filtration, the concentrated H2O portion was partitioned with CHCl3 (6 ꢁ 2 l). As
described in [3], the H2O layer was then subjected to CC (Diaion HP-20SS; H2O/MeOH 1:0 – 0 :1) to
give seven fractions. Fr. 1 (38 g) was applied to CC (Sephadex LH-20; H2O/MeOH 1:0 – 0 :1), to give
fractions 1A – 1E. Frs. 1B, 1C, and 1D were subjected to CC (MCI-gel CHP-20P, H2O/MeOH 1:0 – 7:3;
and Sephadex LH-20, H2O/MeOH 1:0 – 4 :6) to yield 8 (18 mg), 9 (48 mg), 10 (68 mg), and 14 (30 mg),
resp. Fr. 2 (38 g) was applied to CC (Sephadex LH-20, H2O/MeOH 1:0 – 1:0), to give Frs. 2A – 2C. Fr. 2B
was subjected to CC (Sephadex LH-20; H2O/MeOH 1:0 – 6 :4; MCI-gel CHP-20P, H2O/MeOH 1 :0 –
3 :7) to yield 5 (6 mg), 6 (8 mg), and 7 (57 mg). Fr. 3 (40 g) was subjected to CC (Sephadex LH-20,
H2O/MeOH 1:0 – 1:0), to give Frs. 3A – 3D. Fr. 3A was subjected to CC (MCI-gel CHP-20P, H2O/
MeOH 7:3 – 0 :1; Sephadex LH-20, H2O/MeOH 1:0 – 6 :4; and SiO2, CHCl3/MeOH 9 :1 – 8 :2) to yield
15 (238 mg) and 16 (6 mg). Similarly, Fr. 3B was subjected to CC (MCI-gel CHP-20P, H2O/MeOH 1:0 –
3 :7; Sephadex LH-20, H2O/MeOH 1:0 – 4 :6; and SiO2, CHCl3/MeOH 8.5 :1.5 – 7:3) to yield 2 (30 mg),
12 (18 mg), and 11 (30 mg). Fr. 3C was subjected to CC (MCI-gel CHP-20P, H2O/MeOH 1:0 – 3 :7;
Toyopearl HW-40F, H2O/MeOH 1:0 – 2 :8; and SiO2, CHCl3/MeOH 8 :2 – 7:3) to yield 1 (3 mg) and 13
(4 mg). Fr. 6 (1.92 g) was applied to CC (SiO2, CHCl3/MeOH 9 :1 – 8 :2; MCI-gel CHP-20P, H2O/MeOH
6 :4 – 3 :7) to yield 3 (9 mg). Fr. 7 was applied to CC (Sephadex LH-20, H2O/MeOH 3 :7 – 0 :1; MCI gel
CHP-20P, H2O/MeOH 6 :4 – 0 :1) to yield 4 (16 mg).
7-O-Methylcatechin 5-O-b-d-Glucopyranoside (¼(2R,3S)-3,4-Dihydro-2-(3,4-dihydroxyphenyl)-3-
hydroxy-7-methoxy-2H-chromen-5-yl b-d-Glucopyranoside; 1). Pale amorphous powder. [a]2D7 ¼ ꢀ19.8
(c ¼ 0.15, MeOH). UV: 205 (4.7), 280 (3.97). IR: 3422, 2922, 2851, 1621, 1597, 1515, 1442, 1074, 1047. 1H-
and 13C-NMR: Table 1. ESI-MS (neg.): 465 ([M ꢀ H]ꢀ). HR-ESI-MS (neg.): 465.1410 ([M ꢀ H]ꢀ,
C22H25Oꢀ11 ; calc. 465.1396).
6-O-Feruloyl-d-glucopyranose (¼6-O-[(2E)-3-(4-hydroxy-3-methoxyphenyl)prop-2-enoyl]-d-gluco-
pyranose; 2). Pale amorphous powder. [a]2D7 ¼ 22.7 (c ¼ 0.58, MeOH). UV: 238 (4.07), 327 (4.20). IR:
1
3404, 2923, 2844, 1696, 1600, 1516, 1284, 1028. H- and 13C-NMR: Table 2. ESI-MS (neg.): 355 ([M ꢀ
H]ꢀ). HR-ESI-MS (neg.): 391.0795 ([M þ Cl]ꢀ, C16H20ClOꢀ9 ; calc. 391.0795).
Demethylpiperitol 4-O-b-d-glucopyranoside (¼4-[(1R,3aS,4R,6aS)-4-(1,3-benzodioxol-5-yl)tetrahy-
dro-1H,3H-furo[3,4-c]furan-1-yl]-2-hydroxyphenyl b-d-Glucopyranoside; 3). Pale amorphous powder.
[a]2D8 ¼ ꢀ72.9 (c ¼ 0.50, MeOH). UV: 204 (4.75), 282 (3.89), 376 (3.34). IR: 3397, 2925, 2874, 1710, 1596,
1506, 1443, 1247, 1038. 1H- and 13C-NMR: Table 3. FAB-MS (neg.): 503 ([M ꢀ H]ꢀ), 341 ([M ꢀ Glc]ꢀ).
HR-ESI-MS (neg.): 503.1566 ([M ꢀ H]ꢀ, C25H27O1ꢀ1 ; calc. 503.1553).
2-Episesaminol 2-O-b-d-glucopyranoside (¼6-[(1R,3aR,4S,6aR)-4-(1,3-Benzodioxol-5-yl)tetrahy-
dro-1H,3H-furo[3,4-c]furan-1-yl]-1,3-benzodioxol-5-yl b-d-Glucopyranoside; 4). Pale amorphous.
[a]2D7 ¼ ꢀ37.3 (c ¼ 0.30, MeOH). UV: 203 (4.66), 236(3.98), 290 (3.91). IR: 3407, 2918, 2880, 1631,
1
1504, 1485, 1250, 1073, 1037. H- and 13C-NMR: Table 3. FAB-MS (neg.): 531 ([M ꢀ H]ꢀ), 369 ([M ꢀ
Glc]ꢀ). HR-ESI-MS (neg.): 567.1270 ([M þ Cl]ꢀ, C26H28ClO1ꢀ2 ; calc. 567.1269).

Helvetica Chimica Acta – Vol. 93 (2010)
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Acid Hydrolysis of Compound 2. Compound 2 (4.0 mg) were hydrolyzed with 2n HCl/1,4-dioxane
1:1 (4 ml) at 808 for 3 h. The mixture was passed through a MCI-gel CHP-20P column (1.5 ꢁ 14 cm),
developing with H2O. The H2O eluate was neutralized with NaOH (1n) and was evaporated to dryness.
The dry powder was dissolved in pyridine (2.0 ml), and then l-cysteine methyl ester hydrochloride
(1.5 mg) was added. After heating at 608 for 1 h, 1-(trimethylsilyl)-1H-imidazole (1.5 ml) was added. The
mixture was heated at 608 for another 30 min. An aliquot (4 ml) of the supernatant was removed and
directly subjected to GC analysis: column temp., 180 – 2808 at 3 deg/min; carrier gas, N2 (1 ml/min);
injector and detector temp., 2508; split ratio, 1:50. The configurations of d-glucose moieties of 2 were
determined by comparison of the retentions times (tR) of the corresponding derivatives with those of
standard d/l-glucose. The tR values of the standard d- and l-derivatives were 19.450 and 19.943 min, resp.
Enzymatic Hydrolysis of 3. A mixture of 3 (8.0 mg) and b-glucosidase (6.0 mg, sigma) in H2O
(1.5 ml) was kept in a H2O bath at 378 for 5 d. The mixture was subjected CC (MCI-gel CHP-20P; H2O,
and 70 and 100% MeOH). The H2O eluates were concentrated to give d-glucose (2.0 mg) ([a]D ¼ þ50.8
(c ¼ 0.1, H2O)). The 100% MeOH eluates were dried under reduced pressured to give an aglycone,
demethylpiperitol (3a; 3.0 mg). Pale amorphous powder. [a]D ¼ ꢀ61.1 (c ¼ 0.3, CHCl3). 1H-NMR
(CDCl3): 3.06 (m, HꢀC(8), HꢀC(8’)); 3.86 (m, HꢀC(9a), HꢀC(9’a)); 4.23 (m, HꢀC(9b), HꢀC(9’b));
4.68 (d, J ¼ 5.2, HꢀC(7)); 4.71 (d, J ¼ 5.2, HꢀC(7’)); 5.96 (s, OCH2O); 6.75 (dd, J ¼ 7.8, 1.5, HꢀC(6),
HꢀC(6’)), 6.77 (s, HꢀC(2’)); 6.80 (d, J ¼ 7.8, HꢀC(5), HꢀC(5’)); 6.82 (s, HꢀC(2)). 13C-NMR (CDCl3):
147.9 (C(3’)); 147.1 (C(4’)); 143.8 (C(3)); 143.4 (C(4)); 134.8 (C(1’)); 133.5 (C(1)); 119.4 (C(5’)); 118.6
(C(6)); 115.3 (C(5)); 113.3 (C(2)); 108.2 (C(6’)); 106.5 (C(2’)); 101.1 (OCH2O); 85.8 (C(7’)); 85.6 (C(7));
71.7 (C(9’)); 71.6 (C(9)); 54.1 (C(8’)); 53.9 (C(8)). FAB-MS (neg.): 341 ([M ꢀ H]ꢀ).
We are grateful to the members of the Analytical Group in the State Key Laboratory of
Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, for recording the
spectra. This work was supported by the NSFC (U0632010 and 2008ZX09401-004) and the State Key
Laboratory of Phytochemistry and Plant Resources in West China, Kuming Institute of Botany, Chinese
Academy of Sciences (P2008-ZZ08).
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Received February 15, 2010