A new cerebrogalactoside from juglans mandshurica

Article abstract of DOI:10.1007/s10600-011-9895-3

A new cerebrogalactoside, Juglans cerebroside A (1), together with five known compounds, quercetin-3-O-β-D-galactopyranoside (2), myricetin-3-O-β-D-galactopyranoside (3), 2''E-quercetin-3-O-β-D- (6''''-O-[3''-(4'''-hydroxyphenyl) propylene acyl]) glucopyranoside (4), gallic acid (5), and 2-methyl-1-hexadecanol (6) were isolated from the leaves of Juglans mandshurica Maxim. The structures of these compounds were determined by 1D, 2D NMR, and MS techniques.

Full text of DOI:10.1007/s10600-011-9895-3

Chemistry of Natural Compounds, Vol. 47, No. 2, May, 2011 [Russian original No. 2, March–April, 2011]
A NEW CEREBROGALACTOSIDE FROM Juglans mandshurica
1
2
1*
Jiaming Sun, Renlong Chang, and Hui Zhang
UDC 547.29+547.917
A new cerebrogalactoside, Juglans cerebroside A (1), together with five known compounds, quercetin-3-O-
ꢀ-D-galactopyranoside (2), myricetin-3-O-ꢀ-D-galactopyranoside (3), 2ꢁꢁE-quercetin-3-O-ꢀ-D-(6ꢁꢁꢁꢁ-O-[3ꢁꢁ-
(4ꢁꢁꢁ-hydroxyphenyl) propylene acyl]) glucopyranoside (4), gallic acid (5), and 2-methyl-1-hexadecanol (6)
were isolated from the leaves of Juglans mandshurica Maxim. The structures of these compounds were
determined by 1D, 2D NMR, and MS techniques.
Keywords: Juglans mandshurica Maxim., cerebrogalactoside, flavonoid.
Plants of the genus Juglans (Juglandaceae) contain mainly naphthoquinones, flavonoids, diaryl heptanes, terpenoids,
and organic acids. Some of them are used in traditional Chinese medicine for the treatment of lithiasis in the urinary system,
chronic bronchitis, dermatitis, cancer, desinsection, and so on [1, 2].
Juglans mandshurica Maxim., a species of the Juglans genus, is widespread in Northeast China, North China, Hebei,
and other regions. It has long been used in folk medicine in China, and modern pharmaceutical investigations have revealed its
antibacterial, anti-inflammatory, and anticancer effects. In our study on the subject, we herein report one new compound (1)
and five (2–6) known compounds isolated from the leaves of the title plant. All of these known compounds were isolated from
J. mandshurica Maxim. for the first time.
O
3'
22'
1'
(CH ) CH
2 18
HN
3
OH
H
H
OH
H
OH
OH
H
H
a
O
O
HO
HO
+
HO
HO
8
5''
OCH
18
3
3
O
(CH ) CH
2 7
3
1''
1
3''H
H
H
OH
H
OH
H
OH
1
H N
2
OH
O
HO
+
+
(CH ) CH
2 18
(CH ) CH
2 7
H CO
3
3
3
OH
OH
7
8
a. 1N HCl, aq. MeOH
Compound 1 was isolated as a white amorphous powder and was assigned the molecular formula C H NO by its
46 89
10
+
+
HR-ESI-MS (838.63350 [M + Na] , calcd 838.6379 [M + Na] ). IR bands at 3351 and 1623 suggested the presence of
hydroxyl and amide groups. It showed one amide group at ꢂ 7.53 (1H, d, J = 9.6 Hz) in its H NMR spectrum and at ꢂ 173.7
in its C NMR spectrum (Table 1). One glucopyranosyl moiety was indicated by comparing the C NMR data (ꢂ 103.4, 73.4,
76.5, 70.1, 76.8 and 61.0) and a doublet (J = 7.6 Hz) at ꢂ 4.15 in the PMR spectrum with those reported in the literature [3].
1
13
13
1) Development Center of Traditional Chinese Medicine and Bioengineering, Changchun University of Chinese
Medicine, 1035 Boshuo Road, Jingyue Economic Development District, Changchun, P. R. China, 130117, fax: +86 0431
86172080, e-mail: zhanghui_8080@163.com; 2) Office of Food and Drug Industry, Yanbian Korean Autonomous Prefecture,
759 Henan Street, Yanji, P. R. China, 133000. Published in Khimiya Prirodnykh Soedinenii, No. 2, pp. 232–234, March–April,
2011. Original article submitted December 10, 2009.
254
0009-3130/11/4702-0254 02011 Springer Science+Business Media, Inc.

13
TABLE 1. PMR and C NMR Spectra of 1 (DMSO-d , ꢂ, ppm, J/Hz)
6
C atom
C atom
ꢂC
ꢂH
ꢂC
ꢂH
1
2
68.9
49.8
74.1
3.81 (1H, m); 3.65 (1H, m)
4.08 (1H, m)
5.57 (1H, d, J = 5.2)
1.58 (1H, m); 1.23–1.29 (1H, br.s)
1.49 (1H, m)
2ꢁ-OH
3ꢁ
34.3
24.4
28.6–29.1
31.3
22.1
13.9
103.4
73.4
3
3-OH
4
4-OH
5
6
7
3.38 (1H, m)
4.92 (1H, d, J =3.6)
3.36 (1H, m)
ꢁ
4
1.23–1.29 (br.s)
1.23–1.29 (br.s)
1.23–1.29 (br.s)
0.86 (3H, t, J = 6.8)
4.15 (1H, d, J = 7.6)
2.94 (1H, m)
4.75 (1H, d, J = 9.6)
3.14 (1H, m)
5ꢁ–19ꢁ
20ꢁ
70.5
4.88 (1H, t, J =2.0)
1.93 (1H, m); 1.49 (1H, m)
1.49 (2H, m)
ꢁ
21
32.3
25.5
31.7
22ꢁ
1ꢁꢁ
2ꢁꢁ
1.93 (2H, m)
8
9
129.7
130.2
32.0
28.6–29.1
31.3
22.1
13.9
173.7
73.4
5.36 (1H,dt, J =15.5, 6.5)
5.35 (1H, dt, J =15.5, 6.5)
1.93 (2H, m)
ꢁꢁ
2 -OH
76.5
70.1
3ꢁꢁ
3ꢁꢁ-OH
10
11–15
16
17
18
1ꢁ
3.31 (1H, m)
3.07 (1H, m)
3.28 (1H, m)
3.11 (1H, m)
1.23–1.29 (br.s)
1.23–1.29 (br.s)
1.23–1.29 (br.s)
0.86 (3H, t, J = 6.8)
–
ꢁꢁ
4
4ꢁꢁ-OH
5ꢁꢁ
6ꢁꢁ
76.8
61.0
3.68 (1H, m); 3.43 (1H, m)
4.50 (1H, t, J = 6.0)
7.53 (1H, d, J = 9.6)
ꢁꢁ
6 -OH
NH
3.86 (1H, m)
ꢁ
2
O
(CH ) CH
2 18
HN
3
OH
OH
8
Glc
D
O
(CH ) CH
2 7
3
OH
1
Fig. 1. Key correlations observed for analysis of the HMBC
spectrum of compound 1.
The PMR exhibited the presence of seven hydroxyl groups at 4.75 (1H, d, J = 9.6 Hz), 3.31 (1H, m), 3.28 (1H, m), 4.50 (1H,
t, J = 6.0 Hz), ꢂ 5.57 (1H, d, J = 5.2 Hz), 4.92 (1H, d, J = 3.6 Hz), and 4.88 (1H, t, J = 2.0 Hz), where the first four data indicated
the presence of a glucopyranosyl moiety, too. Furthermore, a six-proton triplet (J = 6.8 Hz) at ꢂ 0.86 and one pair of olefinic
proton signals at ꢂ 5.36 and 5.35 (Table 1) demonstrated that compound 1 possessed two aliphatic chains containing one
13
double bond, suggesting that it was probably a cerebroside [4]. This deduction was reinforced by analysis of the C NMR
spectrum (Table 1) as well as by methanolysis of 1, which liberated the anticipated methylꢃꢀ-D-glucose and two aliphatic
molecules (7 and 8), all identified by EI mass spectroscopies. The presence of the 1-O-glucopyranosyl, 2-amino and
3,4,2ꢁ-trihydroxy groups as well as the 8,9-double bond in the main chain was elucidated by analysis of the PMR and
13
C NMR spectroscopic data of 1, which was assigned unambiguously by extensive 2D NMR techniques (Table 1) (Fig. 1).
There are 23 carbons in aliphatic molecule 7. This was proven by the EI mass spectra of 7, giving the quasimolecular ion at 370
+
[M + H] . Thus, the aliphatic molecule 8 has 18 carbons, which was calculated along with the molecular formula C H NO
46 89
10
of 1. Regarding the stereochemistry, the formulated absolute configuration of compound 1 was based on the carbon chemical
shifts at ꢂ 7.53 (1H, d, J = 9.5 Hz), 68.9 (C-1), 49.8 (C-2), 74.1 (C-3), 70.5 (C-4), 173.7 (C-1ꢁ), and 73.4 (C-2ꢁ), which
happened to be fairly close to those previously reported for (2S, 3R, 4S, 2ꢁR) sphingosine moieties [3]. In conclusion, compound
1 is assigned as 1-O-ꢀ-D-glucopyranosyl-(2S,3R,4S,8E)-2-(2ꢁR-hydroxyheneicosenoylamino)-8-octadecene-1,3,4-triol, a
hitherto undescribed cerebroside. We have named compound 1 Juglans cerebroside A.
255

EXPERIMENTAL
General Comments. Melting points were determined on a Fisher-Johns apparatus and are uncorrected. IR spectra
were recorded on a Perkin–Elmer 983G spectrometer. NMR spectra were measured in DMSO-d on a Bruker AM-500
6
spectrometer using TMS as an internal standard. NMR experiments included the HMQC and HMBC pulse sequences. Coupling
constants (J values) are given in Hz. An Autospec-Ultima ETOF spectrometer was used to record the ESI-MS and HR-ESI-MS.
Column chromatography was performed on silica gel H (10–40 ꢄm) (both from Qingdao Haiyang Chemical Group Co.,
Qingdao, Shandong Province, Peopleꢁs Republic of China) and Sephadex LH-20 (Amersham Biosciences, Piscataway,
NJ, U.S.A.)
Plant Material and Extraction and Isolation. The leaves of J. mandshurica Maxim. were collected in the outskirts
of Jiaohe City, Jilin Province of the Peopleꢁs Republic of China, in August 2008 and authenticated by Prof. Ming-Lu Deng of
Changchun University of Chinese Medicine. The leaves (4.5 kg) of J. mandshurica Maxim. were shade-dried, ground, and
extracted with refluxing 95% EtOH successively (45 L, 2 h, 2 times). The EtOH extract was evaporated in vacuo to yield a
semisolid (1400 g), 600 g of which was suspended in H O (3000 mL) and partitioned successively with petroleum ether
2
(3 ꢅ 3 L), CHCl (3 ꢅ 3 L), EtOAc (3 ꢅ 3 L), and n-BuOH (3 ꢅ 3 L) to yield 185 g, 23 g, 42 g, and 102 g, respectively. The
3
CHCl extracts (18 g) were column chromatographed over silica gel using petroleum ether and EtOAc step gradient as eluents.
3
The petroleum ether and EtOAc (9:1, 8:2) eluates were purified individually by repeated column chromatography over silica
gel to yield 6 (8 mg). The EtOAc extract (35 g) was subjected to column chromatography over silica gel eluted with CHCl –MeOH
3
(100:0, 95:5, 90:10, 80:20, 70:30, 60:40, 1:1) and MeOH to yield fractions 1–8. Fraction 5 (5.65 g) was purified successively
with MeOH over Sephadex LH-20 to afford 1 (11 mg), 2 (14 mg), 3 (21 mg), 4 (10 mg), and 5 (17 mg).
Methanolysis of Compound 1.A solution of 1 (9.2 mg) in a mixture of MeOH (2 mL), water (0.2 mL), and 12 N HCl
(0.2 mL) was refluxed for 7 h [5]. The reaction mixture was immediately cooled and dried by a stream of N , then subjected to
2
gel filtration over Sephadex LH-20 with MeOH, which afforded the fatty acid methyl ester 7, long-chain base 8, and methyl
glucopyranoside.
Juglans Cerebroside A (1). C H NO , white amorphous powder (MeOH), mp 221–223ꢆC (MeOH). IR (KBr, ꢇ,
46 89
10
–1
+
cm ): 3351, 2955, 2920, 2851, 1623, 1538, 1468, 1371, 1083, 1037, 963 and 721. HR-ESI-MS m/z 838.63350 [M + Na]
+
13
(calcd 838.6379 [M + Na] ). Table 1 lists the PMR and C NMR spectrum.
–
Quercetin-3-O-ꢀ-D-galactopyranoside (2). Yellow powder (MeOH), mp 182–184ꢆC. ESI-MS m/z: 463 [M – H] [6].
–
Myricetin-3-O-ꢀ-D-galactopyranoside (3). Yellow powder (MeOH), mp 193–194ꢆC. ESI-MS m/z: 479 [M – H] [7].
2ꢁꢁE-Quercetin-3-O-ꢀ-D-(6ꢁꢁꢁꢁ-O-[3ꢁꢁ-(4ꢁꢁꢁ-hydroxyphenyl)propylene acyl]) glucopyranoside (4). Yellow powder
(MeOH). The physicochemical constants and spectral (NMR and MS) data of 4 indicate that it is identical to 2ꢁꢁE-quercetin-3-
O-ꢀ-D-(6ꢁꢁꢁꢁ-O-[3ꢁꢁ-(4ꢁꢁꢁ-hydroxyphenyl)propylene acyl]) glucopyranoside [8].
–
Gallic Acid (5). Colorless crystalline needles (MeOH). ESI-MS m/z: 169 [M – H] [9].
+
2-Methyl-1-hexadecanol (6). White amorphous powder. EI-MS (70 eV), m/z (I , %): 256 (M , 2), 238 (5), 125
rel
(10), 111 (21), 97 (32), 83 (43), 69 (54), 57 (100), 43 (90), 29 (20).
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