Two new alkaloids from Corydalis humosa

Article abstract of DOI:10.1080/10286020.2013.822369

Two new alkaloids, named 1,1-dimethyl-6-methoxy-7-hydroxyl-1,2,3,4- tetrahydroisoquinoline (1) and (1R)-(4-hydroxybenzyl)-7-hydroxyl-8-O-β-d- glucopyranosyl-1,2,3,4-tetrahydroisoquinoline (2), together with 11 known compounds (3-13), were isolated from th

Full text of DOI:10.1080/10286020.2013.822369

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Two new alkaloids from Corydalis
humosa
a
a
a
a
a
Xiao-Ke Zheng , Dan-Dan Li , Hui Yan , Meng Li , Jin-Li He & Wei-
a
Sheng Feng
a
School of Pharmacy, Henan University of Traditional Chinese
Medicine, Zhengzhou, 450046, China
Published online: 06 Aug 2013.
To cite this article: Xiao-Ke Zheng, Dan-Dan Li, Hui Yan, Meng Li, Jin-Li He & Wei-Sheng Feng
(2013) Two new alkaloids from Corydalis humosa, Journal of Asian Natural Products Research,
15:11, 1158-1162, DOI: 10.1080/10286020.2013.822369
To link to this article: http://dx.doi.org/10.1080/10286020.2013.822369
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Journal of Asian Natural Products Research, 2013
Vol. 15, No. 11, 1158–1162, http://dx.doi.org/10.1080/10286020.2013.822369
Two new alkaloids from Corydalis humosa
Xiao-Ke Zheng, Dan-Dan Li, Hui Yan, Meng Li, Jin-Li He and Wei-Sheng Feng*
School of Pharmacy, Henan University of Traditional Chinese Medicine, Zhengzhou 450046, China
(Received 13 March 2013; final version received 2 July 2013)
Two new alkaloids, named 1,1-dimethyl-6-methoxy-7-hydroxyl-1,2,3,4-tetrahydroi-
soquinoline (1) and (1R)-(4-hydroxybenzyl)-7-hydroxyl-8-O-b-D-glucopyranosyl-
1,2,3,4-tetrahydroisoquinoline (2), together with 11 known compounds (3–13), were
isolated from the tubers of Corydalis humosa. Their structures were elucidated on the
basis of their spectroscopic and chemical evidence.
Keywords: Papaveraceae; Corydalis humosa; alkaloids; structure elucidation
1
.
Introduction
N-methylcheilanthifolinium (3) [7],
N-methyltetrahydropalmatine (4) [8], pal-
lidine (5) [9], isocorydine (6) [10],
izmirine (7) [11], thalifaurine (8) [12],
jatrorubine (9) [13], choline (10) [14], 6-
acetonyl-5,6-dihydrosanguinarine (11)
Corydalis humosa belongs to Papavera-
ceae family. The family consists of about
5
00 species in the world, of which 270
species are found in China. Most herbs of
this family have obvious biological activi-
ties, such as antibiosis, antiarrhythmic, and
antitumor activities [1–3]. The tubers of
C. humosa has been used to treat digestive
system disease, gynecological pain, and
cephalalgia in the folk. However, a few
studies on chemical composition of C.
humosa have been reported by now, and
the pharmacological study is rare. In 1989,
phytochemical investigations of this plant
have yielded protopine, l-tetrahydrocopti-
sine, bicuculline, dl-tetrahydrocoptisine,
hydroprotopine, noroxyhydrastinine, cryp-
topine, coptisine, palmatine, dl-tetrahy-
droberberine, dehydrocheilanthifoline, and
coryhymolide, of which the first three were
isolated in 1966 [4,5]. And in 2005,
tetrahydropalmatine, berberine, and jatror-
rhizine were obtained [6]. In this study,
two new alkaloids, named 1,1-dimethyl-6-
methoxy-7-hydroxyl-1,2,3,4-tetrahydroi-
soquinoline (1) and (1R)-(4-hydroxyben-
zyl)-7-hydroxyl-8-O-b-D-glucopyranosyl-
[
(
15], pancorine (12) [16], b-sitosterol
13) [17]; compounds 3–13 were obtained
from this plant for the first time.
2.
Results and discussion
Compound 1 (Figure 1) was isolated as a
yellow amorphous powder (MeOH). Its
molecular formula was assigned as
C H NO by the molecular ion peak at
1
2
17
2
þ
m/z 208.1332 [M þ H] in the HR-ESI-
MS. Its IR spectrum indicated the presence
2
of hydroxyl groups at 3421 cm , aromatic
1
2
1
rings at 1615 and 1520 cm , and methyl
2
groups at 1396 and 1377 cm . The
1
1
H NMR spectrum showed the presence
of two aromatic proton signals at d 6.84
H
(1H, s) and 6.59 (1H, s), one methoxyl
signal at d 3.84 (3H, s), and two methyl
H
1
1
groups at dH 1.71 (6H, s). Its H– H
COSY spectrum indicated the presence of
CH CH signals at dH 2.95 (2H, t,
2
2
1,2,3,4-tetrahydroisoquinoline (2), were
isolated, along with 11 known compounds
J ¼ 6.0 Hz) and 3.44 (2H, t, J ¼ 6.0 Hz).
1
The C NMR spectrum exhibited six
3
*Corresponding author. Email: fwsh@hactcm.edu.cn
q 2013 Taylor & Francis

Journal of Asian Natural Products Research
1159
at dH 7.18 (2H, d, J ¼ 8.0 Hz) and 6.84
2H, d, J ¼ 8.0 Hz); two adjacent aromatic
protons at dH 6.74 (1H, d, J ¼ 8.0 Hz),
H
(
5
8
4
1
H CO
6
7
H CO
3
3
3
6
.69 (1H, d, J ¼ 8.0 Hz); and the anomeric
NH
NH
HO
HO
proton at dH 4.69 (1H, d, J ¼ 8.0 Hz).
Finally, six proton signals were found in
the range of dH 3.40–4.00, which
suggested the existence of a sugar moiety.
H C CH3
H C
3
3
CH3
H
Figure 1. Structure and key HMBC
correlations of compound 1.
1
1
The H– H COSY spectrum showed the
presence of CH CH signal in the range of
2
2
1
3
dH 2.50–3.40. The C NMR spectrum
indicated 12 aromatic carbons. In the
HMBC spectrum, the cross-peak between
aromatic carbons and one methoxyl carbon
at d 56.6. In the HMBC spectrum, two
C
methyl groups at d H 1.71 showed long-
range correlation with the quaternary
carbon at dC 58.2 (C-1), suggesting the
attachment of two methyl groups at C-1.
The aromatic proton at dH 6.59 (H-5)
indicated interaction with the carbon at dC
the aromatic proton at d
the carbon at d 29.1 (C-4), as well as the
6.74 (H-5) and
H
C
HMBC correlations of H-3 with C-4a and
of H-4 with C-5, suggested that the
CH
aromatic protons of AA BB system at d
7.18 indicated long-range correlation with
the carbon at d 38.0 (C-9), suggesting the
attachment of the aromatic ring at C-9. The
proton at d
CH unit was linked to C-4a. The
2
2
0
0
2
6.1 (C-4), as well as the HMBC
H
correlations of H-3 with C-4a and of H-4
with C-5, confirming that the CH CH unit
2
2
C
was attached at C-4a. Consequently, the
structure of 1 was determined as 1,1-
dimethyl-6-methoxy-7-hydroxyl-1,2,3,4-
tetrahydroisoquinoline.
4.72 (1H, dd, J ¼ 8.4, 2.0 Hz)
H
indicated a correlation with the carbon at
0
d
133.7 (C-1 ), suggesting the attachment
C
Compound 2 (Figure 2) was isolated as
a light yellow powder (MeOH). The
positive-ion HR-ESI-MS showed the mol-
of the CH unit at C-9. The anomeric proton
at d 4.69 showed a HMBC correlation
with the carbon at d 144.0 (C-8),
confirming that the glucosyl moiety was
linked to C-8. The laws of benzylisoquino-
line alkaloids in the CD spectrum are as
follows: when the absolute configuration
of H-1 is R and no substituent on benzene
ring, there will be two negative Cotton
effects in the short wavelength region
H
C
þ
ecular ion at m/z 434.1818 [M þ H] ,
corresponding to the formula C H NO .
2
2
27
8
Its IR spectrum indicated the absorption of
2
the hydroxyls at 3410 cm and aromatic
1
2
1
ring absorptions at 1610 and 1514 cm
1
.
The H NMR spectrum indicated the
0
0
presence of an AA BB system of protons
H
5
4
1
H
3
6
NH
H
NH
H
H
HO
O
7
HO
8
2
'
1
''
1''
H
O
9
O
O
1'
3
'
HO
HO
OH
HO
HO
OH
4
'
6'
OH
OH
HO
H
HO
5'
H
Figure 2. Structure and key HMBC correlations of compound 2.

1
160
X.-K. Zheng et al.
(
210–230 nm) and one negative Cotton
effect in the long wavelength region (280–
90 nm). If the aromatic ring is replaced by
Qingdao Marine Chemical Industry, Qing-
dao, China), alumina gel (100–200 mesh,
Shanghai Wusi Chemical Reagent Indus-
try, Shanghai, China), Toyopearl HW-40
(TOSOH Corporation, Tokyo, Japan), and
Sephadex LH-20 (Pharmacia Biotech AB,
Uppsala, Sweden). Thin-layer chromatog-
raphy was carried out on self-made silica
gel G (Qingdao Marine Chemical Indus-
try) plates. The chemical reagents were
supplied by Beijing Chemical Plant
(Beijing, China) and Tianjin No. 3
Reagent Plant (Tianjin, China).
2
some substituents, greater changes will
appear in the negative Cotton effect in the
long wavelength region or even become
positive Cotton effect, and the negative
Cotton effect in the short wavelength
region will be essentially unchanged.
Conversely, when the absolute configur-
ation of H-1 is S, three positive Cotton
effect peaks will appear in the 200–320 nm
[
18]. The CD spectrum of 2 showed
two negative Cotton effects at 219 nm
D1 20.69) and 284 nm (D1 20.11).
(
3
.2 Plant material
Therefore, the absolute configuration of
H-1 was determined to be R. Thus, the
structure of compound 2 was elucidated as
(1R)-(4-hydroxybenzyl)-7-hydroxyl-8-O-
b-D-glucopyranosyl-1,2,3,4-tetrahydroiso-
quinoline.
The fresh tubers of C. humosa were
collected in June 2011 from Xinzheng
County, Henan Province of China, and
authenticated by Prof. Sui-Qing Chen of
the Henan University of Traditional
Chinese Medicine. A voucher specimen
(No. 20110605) has been deposited in our
laboratory.
3
.
Experimental
3
.1 General experimental procedures
Optical rotations were recorded on a
PerkinElmer 341 polarimeter (Perki-
nElmer Corporation, Waltham, MA,
USA). UV spectra were obtained on a
Shimadzu UV-VIS 2201 spectropho-
tometer (Shimadzu Corporation, Kyoto,
Japan). IR spectra were measured on a
Shimadzu FTIR-8201 PC spectrometer
3
.3 Extraction and isolation
The fresh tubers of C. humosa (35 kg) were
extracted with 70% acetone at room
temperature, and concentrated under
reduced pressure below 458C. The water-
soluble part (320 g) was chromatographed
over Diaion HP-20 with H O containing
2
(Shimadzu Corporation). NMR spectra
were determined on a Bruker AVANCE
increasing amounts of MeOH to afford
H O eluate 63.6 g (A), 20% MeOH eluate
2
1
III 500 spectrometer (500 MHz for
1
H
38.5 g (B), and 40% MeOH eluate 37.2 g
(C). Fraction A was subjected to a silica
gel column with CH Cl :MeOH (80:1 to
3
NMR and 125 MHz for C NMR) with
tetramethylsilane as internal standard
2
2
(
Bruker Corporation, Ettlingen, Germany).
1:1) as eluent to give five fractions.
Fractions 1 (10.6 g) and 3 (17.2 g) were,
respectively, subjected to Toyopearl HW-
40 chromatography and to Sephadex LH-
20 chromatography eluted with MeOH to
yield compounds 1 (13 mg), 2 (10 mg), 5
(15 mg), and 10 (17 mg). Fraction 2
(12.4 g) was chromatographed on alumina
column (CH Cl :MeOH, 20:1 to 10:1) to
HR-ESI-MS was recorded on an APEX II
spectrometer (Bruker Corporation). GC
analysis was carried out on a Shimadzu
GCMS-QP2010E instrument (Shimadzu
Corporation) using a RXI-5 ms capillary
column
(
(30 m £ 0.25 mm £ 0.25 mm)
RESTEK, Bellefonte, USA). Column
chromatography was carried out on Diaion
HP-20 (Mitsubishi Chemical Corporation,
Tokyo, Japan), silica gel (160–200 mesh,
2
2
afford compounds 3 (11 mg) and 6
(10 mg). Fraction B was chromatographed

Journal of Asian Natural Products Research
1161
1 13
Table 1. H NMR (500 MHz) and C NMR
on the alumina column with CH Cl :
2
2
MeOH (100:1 to 1:1) as eluent to give five
fractions. Fraction 2 (13.7 g) of B was
rechromatographed on alumina column
3
(125 MHz) spectral data of 1 in CD OD.
Number
dH (J, Hz)
dC
(CH Cl :MeOH, 50:1 to 30:1) to yield
compounds 4 (12 mg) and 7 (10 mg).
1a
1
3
4
4a
5
6
7
8
129.8
58.2
38.6
2
2
3.44 (t, J ¼ 6.0)
2.95 (t, J ¼ 6.0)
Fraction C was subjected to the alumina
column with CH Cl :MeOH (100:1 to 1:1)
26.1
2
2
124.0
116.1
148.7
147.5
109.4
28.5
as eluent to give five fractions. Fraction 1
18.3 g) of C was rechromatographed on
the alumina column (CH Cl :MeOH,
6.59 (s)
(
2
2
6.84 (s)
1.71 (s)
3.84 (s)
3
0:1) and on Sephadex LH-20 (70%
2 £ CH
ZOCH
3
3
MeOH) to obtain compounds 8 (25 mg)
and 9 (11 mg). The water-insoluble part
56.6
(550 g) was chromatographed on the silica
gel column with CH Cl :MeOH (100:1 to
þ
2
2
HR-ESI-MS: m/z 434.1818 [M þ H]
1
:1) as eluent to give six fractions.
(calcd for C H NO , 434.1815).
2
2
28
8
Fraction 3 (42.2 g) of this part was
subjected to the alumina column
3
.4 Acid hydrolysis of compound 2
(CH Cl :MeOH, 40:1) to yield compounds
2 2
1
1 (28 mg) and 13 (15 mg). Fraction 4
Compound 2 (2 mg) was dissolved in 2 N
aqueous CF COOH (5 ml) at 95.88C
(
36.7 g) of this part was chromatographed
on the silica gel (petroleum ether:EtOAc,
0:1) to afford 14 (13 mg). Through the
3
for 3 h. After extraction with CH Cl
2
2
1
(3 £ 5 ml), the aqueous layer was evapor-
ated to dryness with EtOH until neutral
and then analyzed by TLC over silica gel
crystallization, compound 12 (10 mg) was
obtained from fraction 2 (34.8 g).
(
CHCl :MeOH:H O, 5:1:0.1) by compari-
3 2
son with authentic sample: glucose
Rf 0.36). The residue was dissolved in
3
.3.1 1,1-Dimethyl-6-methoxy-7-
hydroxyl-1,2,3,4-tetrahydroisoquinoline
1)
(
anhydrous pyridine (2 ml) and then
L-cysteine methyl ester hydrochloride
(3 mg) was added. The mixture was stirred
at 608C for 1 h, and then 1.0 ml of
hexamethyldisilazane:trimethylchlorosi-
lane (HMDS:TMCS, 2:1) was added, and
the mixture was stirred at 608C for another
30 min. The precipitate was centrifuged
off, and the supernatant was subjected to
GC analysis to identify the sugar. Con-
ditions for GC were as follows: column
temperature, 1808C; initial temperature
was maintained at 1808C for 5 min and
then raised to 2508C at the rate of 158C/min
and maintained at 2508C for 5 min; injector
temperature, 2508C; and carrier gas, He.
The D-configuration of glucose was con-
firmed by comparing the retention time
(
Amorphous yellow powder. UV (MeOH):
lmax 238.1, 286.7 nm; IR (KBr): nmax
3
1
421, 3262, 2926, 2853, 1615, 1520, 1396,
2
377, and 1268 cm . H and C NMR
1
1
13
spectral data are shown in Table 1. HR-
þ
ESI-MS m/z: 208.1332 [M þ H] (calcd
for C H NO , 208.1338).
1
2
18
2
3
.3.2 (1R)-(4-Hydroxybenzyl)-7-
hydroxyl-8-O-b-D-glucopyranosyl-
,2,3,4-tetrahydroisoquinoline (2)
1
20
Amorphous yellow powder. ½aꢀ þ 7.0
D
(
c ¼ 0.20, MeOH); UV (MeOH): l
max
2
2
1
77.5, 321.9 nm; IR (KBr): n 3410,
925, 2855, 1610, 1514, 1416, 1384, 1301,
max
2
1
261, 1070, and 812 cm . H and
1
13
C
with standard sample [t (min): D-glucose
R
NMR spectral data are shown in Table 2.
(8.24)].

1
162
X.-K. Zheng et al.
1 13
Table 2. H NMR (500 MHz) and C NMR (125 MHz) spectral data of 2 in CD OD.
3
Number
d
H
(J, Hz)
d
C
1
1
3
4
4
5
6
7
8
9
1
2
3
4
1
2
3
4
5
6
a
131.5
54.1
38.8
4.72 (dd, J ¼ 8.4 and 2.0)
3.16 (m), 2.74 (m)
2.79 (m), 2.60 (m)
29.1
a
125.7
127.0
117.1
150.2
144.0
38.0
133.7
131.4
116.5
157.3
107.3
75.9
6.74 (d, J ¼ 8.0)
6.69 (d, J ¼ 8.0)
3.18 (m), 2.85 (m)
0
0
0
0
, 6
, 5
7.18 (d, J ¼ 8.0)
6.84 (d, J ¼ 8.0)
0
0
0
0
0
0
0
0
0
4.69 (d, J ¼ 8.0)
0
0
0
0
0
3.55 (m)
3.46 (m)
78.3
71.5
79.0
63.0
3.37 (m)
3.21 (m)
3.87 (dd, J ¼ 11.8 and 2.0), 3.68 (m)
Acknowledgments
[
8] D.B. da Silva, E.C.O. Tulli, W.S. Garcez,
E.A. Nascimento, and J.M. de Siqueira,
J. Braz. Chem. Soc. 8, 1560 (2007).
The authors are grateful to Prof. Sui-Qing Chen
(
Henan University of Traditional Chinese
Medicine, China) for collecting and identifying
the plant material, and thank Dr Yan-Li Zhang
[9] F.C. Ohiri, R. Verpoorte, and A.B.
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(
Henan University of Traditional Chinese
[
[
Medicine, China) for recording the NMR
spectra.
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