Phenolic glycosides from Eriosema tuberosum

Article abstract of DOI:10.1016/S0031-9422(99)00180-6

Three new phenolic glycosides named eriosemasides A-C, one novel (named eriosematin F) and four known phenolic constituents were isolated from the n- BuOH-soluble fraction of the roots of Eriosema tuberosum. Their structures were established by spectroscopic analyses and chemical methods. All the phenolic compounds were fungitoxic except the phenolic glycosides.

Full text of DOI:10.1016/S0031-9422(99)00180-6

Phytochemistry 51 (1999) 1087±1093
Phenolic glycosides from Eriosema tuberosum
Wei Guang Maa, b, Yukiharu Fukushia, b, Bertrand Ducreyc, Kurt Hostettmannd,
Satoshi Taharaa, b,
*
aDepartment of Applied Bioscience, Faculty of Agriculture, Hokkaido University, Kita-ku, Sapporo, 060-8589, Japan
bCREST, Japan Science and Technology Corporation, 4-1-8 Honmachi, Kawaguchi 332-0012, Saitama, Japan
cDebio Recherche Pharmaceutique SA, Case postale 368 Route du Levant 146, CH-1920, Martigny, Switzerland
dInstitut de Pharmacognosie et Phytochimie, Universite de Lausanne, BEP, CH-1015, Lausanne, Switzerland
Received 11 September 1998; received in revised form 31 December 1998; accepted 31 December 1998
Abstract
Three new phenolic glycosides named eriosemasides A±C, one novel (named eriosematin F) and four known phenolic
constituents were isolated from the n-BuOH-soluble fraction of the roots of Eriosema tuberosum. Their structures were
established by spectroscopic analyses and chemical methods. All the phenolic compounds were fungitoxic except the phenolic
glycosides. # 1999 Elsevier Science Ltd. All rights reserved.
Keywords: Eriosema tuberosum; Leguminosae; Chromone glycoside; Phenolics; Fungitoxic activity
1. Introduction
2. Results and discussion
The roots of Eriosema tuberosum (Leguminosae)
have been used as an ethnic medicinal agent in
Yunnan province (P.R. China) since ancient times.
Their medical uses and the isolation of less polar anti-
fungal phenolic compounds were reported in our pre-
vious papers (Ma et al., 1995; Ma, Fuzzati, Xue,
Yang, & Hostettmann, 1996; Ma, Fuzzati, Lu, Gu, &
Hostettmann, 1996). Recently, the polar iso¯avonoid
constituents, have been reported in the literature (Ma,
Fukushi, Hostettman, & Tahara, 1998). However, anti-
fungal compounds in the methanolic extracts were not
identi®ed. This paper deals with the isolation and
structure elucidation of four phenolic glycosides and
four fungitoxic phenolic compounds from the metha-
nolic extract.
Repeated chromatographic puri®cation of the n-
BuOH-soluble fraction of the methanolic extract of E.
tuberosum a€orded three new phenolic glycosides (1±3)
and, one novel (4) and four known non-glycosidic phe-
nolic constituents (5±8). The structures of new com-
pounds were established by spectroscopic analyses and
chemical methods as 5,7-dihydroxy-8-g, g-dimethylal-
lylchromone 7-O-rutinoside (1), 4-hydroxyphenyl b-D-
apiofuranosyl-(1 4 2)-O-b-D-glucopyranoside (2), 5-O-
methylgenistein 7-O-b-D-apiofuranosyl-(1 4 2)-O-b-D-
glucopyranoside (3) and 3,4 dihydro-4-methoxy-
naphthalene-2-carboxylic acid (4). The known com-
pounds were found to be arbutin (5), hydroquinone
(6), 4-hydroxybenzoic acid (7) and vanillic acid (8).
Antifungal activity of all the isolates was tested on
silica gel TLC plates against Cladosporium herbarum.
The results revealed that only phenolic constituents
(6±8) were fungitoxic.
Compound 1 was obtained as a colourless amor-
phous powder after freeze drying. Its molecular for-
mula was deduced as C26H34O13 from the FD mass
* Corresponding author.
0031-9422/99/$ - see front matter # 1999 Elsevier Science Ltd. All rights reserved.
PII: S0031-9422(99)00180-6

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W.G. Ma et al. / Phytochemistry 51 (1999) 1087±1093
Table 1
Proton NMR spectral data for compounds 1, 1a, 2±4 (500 MHz in CD3OD)a
1
1a
2
3
4
Aglycone
1
7.18 s
2
8.09 d (6.4)
6.22 d (6.4)
7.75 d (6.4)
6.18 d (6.4)
6.93 d (8.4)
6.85 d (8.4)
8.06 s
3
3.31±3.44 m
3.88 dd (7.09; 6.3)
7.33 d (7.9)
7.08 t (7.8)
4
5
6.85 d (8.4)
6.93 d (8.4)
6
6.62 s
6.23 s
6.66 d (1.5)
6.71 d (1.5)
7
7.04 t (7.8)
7.62 d (7.9)
8
9
10
1'
2'
3.32 d (6.4)
5.21 t (6.4)
7.35 d (8.8)
6.82 d (8.8)
3'
4'
5'
6'
OMe
1.81 s
1.65 s
1.84 t (6.2)
2.72 t (6.2)
1.36 s Â2
6.82 d (8.8)
7.35 d (8.8)
3.91 s
3.25 s
Sugar moieties
Glucose
1
4.95 d (8.1)
3.54b
4.78 d (8.2)
3.75b
4.79 d (8.4)
3.72b
2
3
3.63b
3.37b
3.29b
4
3.35b
3.51b
3.35b
3.56b
3.34b
3.64b
5
6a
3.59 dd (12.4; 1.1)
4.03 dd (12.4; 0.8)
3.65 dd (12.2; 6.1)
3.86 dd (12.2; 1.4)
3.61 dd (12.2; 5.4)
3.85 dd (12.2; 1.2)
6b
Apiose
1
5.45 d (1.2)
3.92 d (1.2)
5.44 d (1.2)
3.92 d (2.1)
2
3
4a
3.77 d (12.2)
4.07 d (12.2)
3.54 s
3.75 d (12.6)
4.04 d (12.6)
3.54 s
4b
5
Rhamnose
1
2
3
4
5
6
4.68 d (0.8)
3.92 dd (9.4; 1.0)
3.75 dd (9.4; 2.5)
3.34b
3.62b
1.17 d (7.4)
a Chemical shifts d in ppm relative to TMS; J values (in Hz) in parenthesis.
b Signal pattern unclear due to overlapping.
([M]+ m/z 554), negative FAB mass ([M H] m/z
553), and 1H and 13C NMR spectral data (Tables 1
and 2). The UV spectrum of this compound in MeOH
was characteristic of chromone type compounds pre-
viously isolated from this plant (Ma et al., 1996a). The
1H NMR spectrum of 1 revealed clearly the presence
of a preny group [d 1.65, 1.81 (2 Â Me); 3.32 (1 Â CH2)
and 5.21 (1 Â CH)], a trisubstituted chromone moiety
[two doublets at d 8.09 and 6.22, J=6.4 Hz for two
protons, a single at 6.62 for one proton] and two
disaccharide glycoside of eriosematin A. Acid hydroly-
sis of 1 with 1 N HCl a€orded glucose and rhamnose
as sugar moieties. Further cleavage of the molecule
deserved from mass spectral (m/z 408 [M-rha]+ and m/
z 246 [M-rha-glc]+ from FD mass spectrum; m/z 407
[M H-rha] and m/z 245 [M H-rha-glc] from FAB
mass spectrum) suggested that the disaccharide unit
may be rutinose. Enzymatic hydrolysis of 1 with b-glu-
cosidase provided the aglycone which was identi®ed as
eriosematin A by comparing its NMR data with those
reported (Ma et al., 1996b). A pseudo aglycone (1a)
was obtained from the lipophilic residue after strong
acid hydrolysis with HCl, and identi®ed through the
hexoses [anomeric protons appeared at
d
4.95
(J=8.1 Hz) and 4.86 (J=0.8 Hz)]. Comparing its 13C
NMR spectral data with those of the known eriosema-
tin A (Ma et al., 1996a) suggested compound 1 to be a
1
analysis of its FD mass ([M]+ m/z 246), H and 13C

W.G. Ma et al. / Phytochemistry 51 (1999) 1087±1093
1089
Table 2
13C NMR spectral data for compounds 1, 1a, 2±4 (125 MHz; in
CD3OD)
simple phenolic disaccharide glycoside from the mol-
ecular ion at m/z 404 [M]+, and, successive loss of
sugar moiety fragments at m/z 295 [M+Na-pentose]+,
272 [M pentose]+, 133 [M+Na-pentose-hexose]+ and
110 [M pentose-hexose]+. It was clear that the pen-
tose was the terminal sugar moiety of the disaccharide
unit. The molecular formula of C17H25O11 was
1
1a
2
3
4
Aglycone
1
152.4
119.2
116.7
153.7
116.7
119.2
125.1
109.0
24.7
2
158.6
111.6
184.1
161.2
100.0
162.2
111.0
156.2
108.2
22.7
155.1
111.5
181.3
159.8
101.2
160.4
108.5
155.6
107.5
153.0
127.3
178.1
163.6
98.6
1
deduced from its FD mass and from the H and 13C
3
1
NMR spectral data (Tables 1 and 2). The H NMR
4
80.6
5
112.5
122.5
120.1
119.1
128.3
138.1
spectrum of 2 demonstrated a hydroquinone as its
aglycone through the A2B2 coupling system of the ben-
zene ring (d 6.93, J=8.4 for H-2, 4; 6.85, J=8.4 for
H-3, 5). The other proton signals belonged to the
sugar moieties were similar to the known compound
(5-O-methylgenistein 7-O-b-D-apiofuranosyl-(1 4 6)-O-
b-D-glucopyranoside) previously isolated from the
same source, named here as eriosemaside (Ma et al.,
1998). This might suggest that apiose and glucose were
the components of sugar units of 2. Indeed acid hy-
drolysis of 2 with 0.1 N H2SO4 and 1 N HCl (same
treatment as eriosemaside) proved the sugar com-
ponents were apiose and glucose. Careful comparison
of its 1H and 13C NMR spectral data with those of
eriosemaside revealed that the con®gurations of apiose
and glucose of compound 2 were the same as eriose-
maside. The glycosylation position of the aglycone and
the location of the terminal apiose unit to the inner
glucose were clearly determined by the relevant corre-
lation between the protons and the carbons observed
from its HMBC experiment (Fig. 1). Thus, based on
the above analysis, compound 2 was established as 4-
hydroxyphenyl b-D-apiofuranosyl-(1 4 2)-O-b-D-gluco-
pyranoside, named eriosemaside B.
6
7
162.6
97.5
8
9
10
161.1
111.5
124.4
131.6
116.1
158.6
116.1
131.6
56.8
1'
2'
3'
4'
5'
6'
OMe
123.2
132.7
18.1
16.1
31.6
76.1
26.6
26.6
25.9
52.8
171.2
COOH
Sugar moieties
Glucose
1
102.0
74.9
77.3
71.5
78.4
67.8
102.3
75.5
78.1
71.5
78.7
62.6
102.3
75.5
78.1
71.5
78.7
62.6
2
3
4
5
6
Apiose
1
110.8
78.1
80.8
75.5
66.1
110.8
78.2
80.8
75.3
66.1
2
3
4
5
Rhamnose
Compound 3 was obtained from the same fraction
from which eriosemaside had been isolated and deter-
mined (Ma et al., 1998). Its molecular formula as
C27H30O4 was determined from the combination
1
2
3
4
5
6
102.3
72.1
72.4
74.1
69.9
18.9
1
analysis of its FD mass, and H and 13C NMR spec-
tral data (Tables 1 and 2). The UV spectrum and the
1
characteristics of its FD mass, H and 13C NMR spec-
NMR spectral data (Tables 1 and 2). The carbon data
of C-7 of 1, compared with eriosematin A, showed a
large down-®eld shift (+10 ppm) which indicated that
the sugar chain was located at C-7 of the aglycone.
The results of the HMBC experiment of 1 (Fig. 1) con-
®rmed that the glycosylation position was at C-7, and
also that the disaccharide unit was rutinose (terminal
rhamnose linked to the C-6 of glucose). Therefore,
compound 1 was established as 5,7-dihydroxy-8-g-g-
dimethylallychromone-7-O-rutinoside (eriosemaside A).
Compound 2 was obtained as a colourless amor-
phous powder after freeze drying. The UV spectrum in
MeOH was similar to compound 5 (arbutin), and
suggested compound 2 may be a derivative of arbutin.
This hypothesis was supported ®rstly by its FD mass
spectrum, which readily demonstrated that it was a
tra were similar to eriosemaside. Careful comparison
of its 13C NMR spectral data with those of eriosema-
side revealed that the terminal apiose unit of 3 was not
connected to C-6 of the inner glucose moiety. The
terminal apiose located at the C-2 of the inner glucose
in compound 3 was suggested by an obvious glycosyla-
tion shift (d ab. 2 ppm) in its 13C NMR spectrum. In
order to con®rm this suspicion, an HMBC experiment
of 3 was next carried out. The HMBC correlation
between anomeric proton of apiose and C-2 of glucose,
as well as H-2 of glucose to anomeric carbon of apiose
con®rmed that the apiose was located at the C-2 pos-
ition of the glucose (Fig. 1). Therefore, compound 3
was established as 5-O-methylgenistein 7-O-b-D-apio-
furanosyl-(1 4 2)-O-b-D-glucopyranoside, named erio-
semaside C.

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W.G. Ma et al. / Phytochemistry 51 (1999) 1087±1093
Compound 4 was isolated from the less polar sub-
the methine proton (H-4) directly correlated with the
oxygenated carbon (C-4). The signal resonated at d
171.2 ppm in 13C NMR spectrum, together with the
absorptions observed from its IR spectrum (3387±
2750 cm 1, O-H, stretching absorption; 1710 and
1680 cm 1, carbonyl stretching absorption) indicated
that the presence of a carboxyl group in the molecule
of 4. The key correlations between the relevant protons
and the carbons observed from its HMBC experiment
(Fig. 1) ®nally established the structure of compound 4
as 3,4 dihydro-4-methoxylnaphthalene-2-carboxylic
acid, named eriosematin F.
All the isolates (1, 1a, 2±8) were tested for their anti-
fungal activity against the growth of Cladosporium her-
barum using silica gel TLC plate bioassay technique
(Homans & Fuchs, 1970). Compounds 1a, 4 and 6±8
were found to be active compounds. The minimum in-
hibitory dose needed to inhibit fungal growth on TLC
fraction of the n-BuOH soluble fraction. After freezing
dry it presented as a pale yellow powder. From its FD
mass (quasi-molecular ion at m/z 205 [M+H]+), 1H
and 13C NMR spectral data (Tables 1 and 2), a mol-
ecular formula as C12H12O3 was given to the com-
1
pound 4. In the H NMR spectrum, a set of signals
coming from a 1,2-disubstituted aromatic ring were
observed. A singlet signal resonating at d 7.18 was
apparently coming from the conjugated system. A
methylene proton signal (d 3.31, m for H-3), a methine
proton signal (d 3.88, dd, J=7.1, 6.3 for H-4), as well
as a methoxyl group signal (d 3.25, s) were also
1
observed from its H NMR spectrum. The COSY ex-
periment of 4 con®rmed the ortho substitution pattern
of the benzene ring and the adjacent relationship
between C-3 and C-4. HMBC experiment of 4 revealed
that the methoxyl group was located at C-4 through

W.G. Ma et al. / Phytochemistry 51 (1999) 1087±1093
1091
Fig. 1. Key HMBC correlations for establishing sugar sequence and positions of attachments on the aglycone of compounds 1±3. Locations of
carboxyl and methoxyl groups of compound 4 were determined through application of the HMBC technique. Each arrow indicates a correlation
from the relevant proton to carbon.
was 1 mg for 1a, 2 mg for 4 and 3 mg in each for com-
pounds 6±8, respectively. As reported previously, the
aglycone of compound 1 (eriosematin A) was also an
antifungal constituent (Ma et al., 1996a). Its minimum
inhibitory dose was 3 mg. Simple phenolic constituents
were found to be responsible for the fungitoxic activity
of the MeOH extract. However, their corresponding
glycosides i.e. compounds 1, 2 and 5, were not active
against the fungus used in our experiment. It is reason-
able to propose that simple fungitoxic phenolic com-
pounds are released from the corresponding glycosides
through the enzymatic hydrolysis caused by microbial
invasion or herbivore attack on foliage (Harborne,
1988), or due to the isolation procedures. The glyco-
side form of these components are present in the plant
as precursors of `post-inhibitin'. Although there were
some cases that demonstrated that, if the sugar moiety
of arbutin were esteri®ed by butyric acid, it will
become an antimicrobial and cytotoxic compound.
However, the active toxins are also released from such
esteri®ed simple phenolic glycoside by the glycoside
hydrolysis (Perry & Brennan, 1997). From the root of
E. tuberosum ¯avonoids, iso¯avonoids and chromones,
as well as simple phenolics, together with their corre-
sponding glycosides were isolated and determined. It is
clear that simple phenolic compounds are major fungi-
toxic components. The other types of constituents
should be responsible for its medicinal uses as many
cases of leguminous medicinal plants (Southon et al.,
1994).
3. Experimental
3.1. General
Mps: uncorr. NMR: Bruker-AM 500 spectrometer;
Mass spectra: JEOL JMS-SX 102 A instrument; UV:
Hitachi U-3210 instrument; Optical rotation: JASCO
DIP-370 polarimeter (in MeOH); IR: KBr; TLC:
Merck HPTLC RP-18 WF254 plates; Detection: UV
254 and 366 nm and by spraying with Godin reagent
followed 5% H2SO4 in MeOH; Saccharide identi®-
cation was carried out on Merck silica gel TLC plates.
The information on the plant material studied has
been reported previously (Ma et al., 1995).
3.2. Extraction and isolation
Subsequent to the procedure previously described in
Ma et al. (1998), sub-fr. 5 was passed through Lobar
Diol CC with CHCl3±MeOH (9:1), followed by separ-

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W.G. Ma et al. / Phytochemistry 51 (1999) 1087±1093
ation on Lobar RP-18 CC MeOH±H2O (8:2) and then
repeated gel ®ltration on Sephadex LH-20 with MeOH
to give compound 1 (10 mg). Sub fr. 1 was separated
on Lobar Diol CC with CHCl3±MeOH (9:1±7:3)
a€ording pure compound 2 (15 mg) and sub fr. 1a±e.
Sub fr. 1a was puri®ed on silica gel CC with CHCl3±
MeOH (8:2) followed by gel ®ltration on Sephadex
LH-20 with MeOH to provide compound 5 (20 mg).
Sub fr. 1b was chromatographed on Lobar RP-18 CC
MeOH±H2O (1:1) and then subjected to repeated gel
®ltration on Sephadex LH-20 with MeOH to give com-
pound 4 (3 mg). Sub fr. 1c was repuri®ed by gel ®l-
tration on Sephadex LH-20 with MeOH to give
compound 8 (5 mg). Sub fr. 1 d was repuri®ed by gel
®ltration on Sephadex LH-20 with MeOH to give com-
pound 6 (8 mg). Sub fr 1e was repuri®ed by silica gel
CC with CHCl3±MeOH (9:1) to a€ord compound 7
(7 mg). Sub fr. 2a was passed through a Lobar RP-18
CC with MeOH±H2O (3:7), followed by separation on
Lobar Diol CC (CHCl3±MeOH, 8:2) and repeated gel
®ltration on Sephadex LH-20 with MeOH to give com-
pound 3 (3 mg).
3.6. Acid hydrolysis of compound 2
2 (5 mg) was dissolved in 10 ml 0.1 N H2SO4, with
the solution heated until re¯ux began, this being main-
tained for 20 min. The mixture was then cooled and
H2O (10 ml) was added. The aqueous layer was
extracted with EtOAc, then neutralized with NaHCO3
followed by freeze drying. The water soluble residue
was dissolved in 1 ml MeOH, ®ltered and concentrated
to 0.5 ml. Comparison on TLC with an authentic
sample gave apiose (CHCl3±MeOH±H2O, 70:30:5; Rf:
0.38). From the EtOAc extract, arbutin (5) was com-
pared with an authentic sample, as determined by
TLC plate chromatography (CHCl3±MeOH±H2O,
70:30:5; Rf: 0.25).
3.7. Hydrolysis of 2 with 1 N HCl
Compound 2 (2 mg) was hydrolyzed as described in
Ma et al. (1998).
3.8. Acid hydrolysis of compound 3
Compound 3 (2 mg) was hydrolyzed as described in
Ma et al. (1998).
3.3. Bioassay
Bioautography with C. herbarum for evaluation of
antifungal activity of the samples was performed by
TLC bioautography (Homans & Fuchs, 1970).
3.9. Compound 1 (5,7-dihydroxy-8-g,g-
dimethylallylchromone 7-O-rutinoside, eriosemaside A)
Colourless amorphous powder, mp 119±1228.
HPTLC RP-18 (MeOH±H2O, 7:3) Rf 0.65; [a ]D21
65.08 (c 0.20, MeOH); UV lmax (MeOH) nm (log E):
3.4. Acid hydrolysis of compound 1
1
261 (4.25), 314 (3.47), 326 (3.50); IR (KBr) nmax cm
1 (3 mg) was re¯uxed in 1 N HCl (10 ml) for 2 h.
The mixture was cooled and then extracted with
EtOAc. The organic layer was evaporated to dryness
in vacuo. The residue was dissolved in CHCl3 and
repuri®ed on a preparative Si-gel TLC plate develop-
ing with CHCl3±MeOH (95:5) to a€ord an aglycone
derivative (1a, 1 mg). The aqueous layer was neutral-
ized with NaHCO3 followed by freeze drying. The resi-
due was dissolved in 1 ml MeOH, ®ltered and
concentrated to 0.5 ml. Comparison on TLC with
standard sugars indicated those to be glucose and
rhamnose (two times development with CHCl3±
MeOH±H2O, 70:30:5, Rfs. 0.18 for glucose and 0.33
for rhamnose).
3510, 2954, 1670, 1410, 1280, 1108, 830; FD-MS m/z:
554 [M]+, 408 [M-rha]+ 246 [M-rha-glc]+; negative
FAB-MS m/z: 553 [M H] , 407 [M H-rha] , 245
1
[M H-rha-glc] ; H and 13C NMR spectra: see Tables
1 and 2.
3.10. Compound 1a (5-hydroxy-6'-dimethyl-6'-
dihydropyrano (2,3:7,8) chromone)
Pale yellowish needles from MeOH, mp 193±1958.
Silica gel TLC (Hexane±EtOAc, 6:4) Rf 0.55; FD-MS
1
m/z: 246 [M]+; H and 13C NMR spectra: see Tables 1
and 2.
3.11. Compound 2 (4-hydroxyphenyl b-D-apiofuranosyl-
(1 42)-O-b-D-glucopyranoside, eriosemaside B)
3.5. Enzymatic hydrolysis of compound 1
1 (4 mg) was dissolved in 5 ml acetate bu€er
(pH 5.0) to which 5 mg b-glucosidase (Toyobo Co.,
Ltd) was added. The soln was then incubated at 328C
for 20 h. Extraction with EtOAc provided the aglycone
which was found to be the known eriosematin A (Ma
et al., 1996a).
Yellowish amorphous powder, mp 152±1568. Silica
gel HPTLC (CHCl3±MeOH±H2O, 7:3:0.5) Rf 0.25;
[a]2D1 76.88 (c 0.40, MeOH); UV lmax (MeOH) nm
(log E ): 223 (4.54), 287 (3.15); IR (KBr) nmax cm
3334, 1628, 1517, 1455, 1252, 1050, 972; FD-MS m/z:
427 [M+Na]+, 404 [M]+, 295 [M+Na-apiose]+, 272
1

W.G. Ma et al. / Phytochemistry 51 (1999) 1087±1093
1093
[M-apiose]+, 133 [M+Na-apiose-glucose]+, 110 [M-
Acknowledgements
apiose-glucose]+; 1H and 13C NMR spectra: see
Tables 1 and 2.
The authors are grateful to Mr Kenji Watanabe and
Dr Eri Fukushi (GC-MS and NMR Laboratory,
Faculty of Agriculture, Hokkaido University) for
measuring 2-D NMR and mass spectra.
3.12. Compound 3 (5-O-methylgenistein 7-O-b-D-
apiofuranosyl-(1 42)-O-b-D-glucopyranoside,
eriosemaside C)
Yellowish amorphous powder, mp 159±1618.
HPTLC RP-18 (MeOH±H2O, 1:1) Rf 0.56; [a]D21
72.58 (c 0.22, MeOH); UV lmax (MeOH) nm (log E):
258 (4.34), 282 sh (3.52), 310 sh (3.33); IR (KBr) nmax
References
Ma, W. G., Fuzzati, N., Li, Q. S., Yang, C. R., Stooeckli-Evans, H.,
& Hostettmann, K. (1995). Phytochemistry, 39, 1049.
Ma, W. G., Fuzzati, N., Xue, Y., Yang, C. R., & Hostettmann, K.
(1996a). Phytochemistry, 41, 1287.
1
cm 3335, 1640, 1520, 1465, 1275, 1112, 945; FD-MS
m/z: 579 [M+H]+, 446 [M-apiose]+, 284 [M-apiose-
1
glucose]+; H and 13C NMR spectra: see Tables 1 and
Ma, W. G., Fuzzati, N., Lu, S. L., Gu, D. S., & Hostettmann, K.
(1996b). Phytochemistry, 43, 1339.
2.
Ma, W. G., Fukishi, Y., Hostettmann, K., & Tahara, S. (1998).
Phytochemistry, 49, 251.
3.13. Compound 4 (3,4-dihydro-4-methoxylnaphthalene-
2-carboxylic acid, eriosematin F)
Homans, A. L., & Fuchs, A. (1970). J. Chromatogr., 51, 327.
Harborne, J. B. (1988). In Introduction to Ecological Biochemistry
(3rd ed.) (p. 312). London: Academic.
Yellowish amorphous powder, mp 169±1738.
HPTLC RP-18 (MeOH±H2O, 1:1) Rf 0.44; [a]D21
Perry, N. B., & Brennan, N. J. (1997). J. Nat. Prod., 60, 623.
1
Southon, I. W., Bisby, F. A., Buckingham, J., Harborne, J. B.,
Zarucchi, J. L., Polhill, R. M., Adams, B. R., Lock, J. M.,
34.28 (c 0.038, MeOH); IR (KBr) nmax cm 3387,
1710, 1680, 1625, 1459, 748; FD-MS m/z: 205
White, R. J., Bowes, I., Hollis, S., & Heald, J. (1994).
Phytochemical Dictionary of the Leguminosae, vol. 1 and 2.
1
[M+H]+; H and 13C NMR spectra: see Tables 1 and
2.
London: Chapman and Hall.