Isoflavone glycosides from aerial parts of Artemisia absinthium

Article abstract of DOI:10.1007/s10600-014-0807-1

Two new isoflavone glycosides, designated as artemisia bis-isoflavonyl dirhamnoside and artemisia isoflavonyl glucosyl diester, have been isolated from the aerial parts of A. absinthium and their structures established as 7a,7b-bis-[(5a-hydroxy-3′a,4′a-dimethoxyisoflavonyl) (5b,4′b-dihydroxy-3′b-methoxyisoflavonyl)]-4′b-α- Drhamnopyranosyl-(4 → 1)-α-D-rhamnopyranoside and 7,4′-dihydroxyisoflavonyl-7-β-D-glucopyranosyl-(2 → 1)-β-D-glucopyranosyl-(2 → 1)-β-D-glucopyranosyl-(2 → 1)-β-D-glucopyranosyl-6d-(octadec-9′″-enoate)-2d-7″, 11″,15″-trimethylpentadecan-3″,15″-dioic acid-1″-oate on the basis of chemical reactions and spectral data analysis.

Full text of DOI:10.1007/s10600-014-0807-1

Chemistry of Natural Compounds, Vol. 49, No. 6, January, 2014 [Russian original No. 6, November–December, 2013]
ISOFLAVONE GLYCOSIDES FROM AERIAL PARTS
OF Artemisia absinthium
J. Ahamad, K. J. Naquvi, M. Ali, and S. R. Mir*
UDC 547.972
Two new isoflavone glycosides, designated as artemisia bis-isoflavonyl dirhamnoside and artemisia isoflavonyl
glucosyl diester, have been isolated from the aerial parts of A. absinthium and their structures established as
7a,7b-bis-[(5a-hydroxy-3ꢀa,4ꢀa-dimethoxyisoflavonyl) (5b,4ꢀb-dihydroxy-3ꢀb-methoxyisoflavonyl)]-4ꢀb-ꢁ-D-
rhamnopyranosyl-(4ꢂ1)-ꢁ-D-rhamnopyranoside and 7,4ꢀ-dihydroxyisoflavonyl-7-ꢃ-D-glucopyranosyl-
(2ꢂ1)-ꢃ-D-glucopyranosyl-(2ꢂ1)-ꢃ-D-glucopyranosyl-(2ꢂ1)-ꢃ-D-glucopyranosyl-6d-(octadec-
9ꢀꢀꢀ-enoate)-2d-7ꢀꢀ,11ꢀꢀ,15ꢀꢀ-trimethylpentadecan-3ꢀꢀ,15ꢀꢀ-dioic acid-1ꢀꢀ-oate on the basis of chemical reactions
and spectral data analysis.
Keywords: Artemisia absinthium, Asteraceae, isoflavone glycosides.
Artemisia absinthium L. (Asteraceae), commonly known as wormwood, is a shrubby plant having hairy and ribbed
stem. It is found in Kashmir, up to an altitude of 2100 m [1]. Traditionally it is used to treat epilepsy, gastric problems,
enlargement of the spleen, urinary disorders, and for wound healing [2, 3]. The flowers are prescribed to cure stomach diseases
and as a vermifuge [4]. The plant is reported to have antimicrobial, antioxidant [5], hepatoprotective [6, 7], anthelmintic [8],
and neuroprotective activities [9]. The characteristic bitterness of the plant is due to the presence of sesquiterpene lactones
such as absinthin, anabsin, ketopelenolide b, and anabsinthin. Lignans, polyphenols, and flavonoids have also been reported
from A. absinthium [10, 11]. Among the major components reported in the essential oil of aerial parts are ꢁ- and ꢃ-thujene
[12], (Z)-epoxyocimene and chrysanthenyl acetate [13], and sabinyl acetate [14], depending on the origin of the plant. The
essential oil from aerial parts was found to contain ꢁ-thujene, ꢁ-pinene, camphene, p-cymene, 1,8-cineole, methyl heptenone,
ꢃ-phelandrene, caryophyllene oxide, ꢁ-terpineol, thujyl alcohol, geraniol, thujyl acetate, caryophyllene, ꢁ-himachalene,
ꢁ-cadinene, and elemol [15]. As part of our ongoing research on Artemisia [16, 17], the present paper describes the isolation
and characterization of two new isoflavone glycosides from the aerial parts of A. absinthium.
6a
5a
HO
O
1
O
O
7
9
HO
6b
5b
OH
3'
5'
3a
O
1a
1'
HO
O
OH
3
5
OH
3b
HO
O
OCH
8a
3
1b
6c
9a
O
HO
3'a
7a
6a
O
2a
1'a
3a
O
5c
OH
OCH
HO
3
4a
5a
1c
O
6d
5d
O 3c
O
O
5'a
OH
O
O
OH
8b
HO
OCH
3
9b
6''
CH
1d
3
2b
3b
16''
7b
6b
3d
O
6'
CH
1''
C
11''
O
3''
5''
3
O
OH
7''
9''
COOH
5''
3''
O
O
15''
13''
4b
5b
OH
5'
3'
1''
COOH
O
20''
18''
19''
O
1'
17''
OH
OH
CO(CH )
2 7
CH CH (CH ) CH
2 7
OH OH
3
1
2
9'''
10 '''
1'''
18'''
Phytochemistry Research Laboratory, Department of Pharmacognosy & Phytochemistry, Faculty of Pharmacy, Jamia
Hamdard, PO Hamdard Nagar, 110 062, New Delhi, India, e-mail: showkatrmir@gmail.com. Published in Khimiya Prirodnykh
Soedinenii, No. 6, November–December, 2013, pp. 855–858. Original article submitted June 4, 2012.
996
0009-3130/14/4906-0996 02014 Springer Science+Business Media New York

13
TABLE 1. C NMR Spectral Values of Artemisia Bis-isoflavonyl Dirhamnoside (1)
C atom
C atom
ꢄC
ꢄC
2a
3a
4a
5a
6a
7a
8a
9a
10a
151.26
122.51
178.33
152.23
100.80
158.37
102.98
152.81
107.55
122.51
136.60
138.29
148.54
111.41
131.97
103.35
83.51
2b
3b
4b
5b
6b
7b
8b
9b
10b
151.26
121.78
177.86
151.74
100.06
155.27
102.96
152.84
105.88
121.78
137.01
137.49
143.12
110.85
134.25
90.10
1 a
1 b
ꢀ
ꢀ
2ꢀa
2ꢀb
3 a
3 b
ꢀ
ꢀ
4 a
4 b
ꢀ
ꢀ
5 a
5 b
ꢀ
ꢀ
6 a
6 b
ꢀ
ꢀ
1ꢀ
1ꢀꢀ
83.49
68.25
70.63
85.07
2
3
2
3
ꢀ
ꢀ
ꢀꢀ
ꢀꢀ
69.70
81.67
87.22
29.03
4ꢀ
5ꢀ
4ꢀꢀ
5ꢀꢀ
6
ꢀꢀ
29.10
6
ꢀ
OMe
60.13, 55.73, 54.01
Compound 1, designated as artemisia bis-isoflavonyl dirhamnoside, was obtained as a light brown mass from
chloroform–methanol (99:1) eluats. Its IR spectrum exhibited characteristic absorption bands for the hydroxyl group (3450,
–1
–1
–1
3360, 3210 cm ), carbonyl groups (1707 cm ), and the aromatic moiety (1590, 1506 cm ). Its molecular weight was
+
13
determined at m/z 889 [M + H] on the basis of mass and C NMR spectra, which corresponded to the molecular formula
of a bis-isoflavonyl diglycoside, C H O . The ion peaks at m/z 313 [C H O ] , 309 [C H O ] , 579 [M – 309] , 564
[579 – Me] , 549 [564 – Me] , and 147 [C H O ] supported the presence of a flavonoid and two rhamnose units. The
+
+
+
45 45 19
17 13
6
12 21 9
+
+
+
6
11 4
PMR spectrum of 1 exhibited two one-proton broad signals at ꢄ 7.69 and 7.66, ascribed correspondingly to H-2a and H-2b
methines bonded to oxygen and indicating the presence of the isoflavone nucleis. Two two-proton doublets at 6.52 and 6.47
(J = 2.6 Hz, each) were assigned to meta-coupled H-6a, H-6b, H-8a, and H-8b aromatic protons, respectively. Three doublets
at 7.29 (1H, J = 2.3 Hz), 7.27 (1H, J = 2.8 Hz), and 6.60 (2H, J = 8.7 Hz) and two one-proton multiplets at ꢄ 7.01 and 6.98
were attributed to B-ring protons H-2ꢀa, H-2ꢀb, H-5ꢀa, H-5ꢀb, H-6ꢀa, and H-6ꢀb, respectively. Two one-proton doublets at
4.85 (J = 5.1 Hz) and 4.81 (J = 4.5 Hz) were attributed correspondingly to ꢁ-oriented anomeric protons H-1ꢀ and H-1ꢀꢀ. Two
one-proton doublet of doublets at 3.71 (J = 5.1, 9.0 Hz) and 3.68 (J = 4.5, 8.7 Hz) were ascribed to H-2ꢀ and H-2ꢀꢀ carbinol
protons. The other carbinol protons resonated between ꢄ 3.30–4.07. Two three-proton doublets at ꢄ 1.19 (J = 4.5 Hz) and
1.17 (J = 6.0 Hz) were attributed to methyl protons Me-6ꢀ and Me-6ꢀꢀ, respectively. The methoxy protons resonated as
13
three-proton broad signals at ꢄ 3.83, 3.59, and 3.51. The C NMR spectrum of compound 1 displayed important signals for
carbonyl carbons at ꢄ 178.33 (C-4a) and 177.86 (C-4b), anomeric carbons at ꢄ 103.35 (C-1ꢀ) and 90.10 (C-1ꢀꢀ), and aromatic
carbons from 158.81–100.06. The methyl carbons appeared at 29.03 (C-6ꢀ) and 29.10 (C-6ꢀꢀ), while the methoxy carbons
resonated at ꢄ 54.01, 55.73, and 60.13. The presence of C-2ꢀ, C-5ꢀ, C-2ꢀꢀ, and C-5ꢀꢀ at ꢄ 83.51, 87.22, 83.49, and 85.07,
1
1
respectively, indicated the pyranose form of the sugar units. The H– H COSY spectrum of 1 showed correlations of H-6a/
H-6b with H-8a/H-8b; H-2ꢀa/H-2ꢀb with H-6ꢀa/H-6ꢀb; and H-4ꢀ with H-3ꢀ and H-1ꢀꢀ. The HMBC spectrum of 1 exhibited
interactions of C-1ꢀa/C-1ꢀb with C-2ꢀa/C-2ꢀb; H-2ꢀa/H-2ꢀb and H-6ꢀa/H-6ꢀb; C-7a/C-7b with H-8a/H-8b and H-6a/H-6b; C-4ꢀb
with H-5ꢀb, H-6ꢀb, and H-1ꢀ; and C-1ꢀ/C-1ꢀꢀ with H-2ꢀ/H-2ꢀꢀ and H-3ꢀ/H-3ꢀꢀ. On the basis of the above discussion, the structure
of compound 1 was elucidated as 7a,7b-bis-[(5a-hydroxy-3aꢀ,4aꢀ-dimethoxyisoflavonyl) (5b,4ꢀb-dihydroxy-3ꢀb-
methoxyisoflavonyl)]-4ꢀb-ꢁ-D-rhamnopyranosyl-(4ꢂ1)-ꢁ-D-rhamnopyranoside. This is a new bis-isoflavonyl dirhamnoside.
Compound 2, designated as artemisia isoflavonyl glucosyl diester, was obtained as a light brown mass from
–1
chloroform–methanol (17:5) eluates. Its IR spectrum exhibited characteristic absorption bands for hydroxyl groups (3373, 3280 cm ),
–1
–1
–1
–1
ester groups (1721, 1730 cm ), carboxylic groups (1690 cm ), unsaturation (1640 cm ), and aromatic moiety (1520, 1070 cm ).
997

13
TABLE 2. C NMR Spectral Values of Artemisia Isoflavonyl Glucosyl Diester (2)
C atom
C atom
C atom
C atom
ꢄC
ꢄC
ꢄC
ꢄC
2
3
4
5
6
7
8
9
10
152.36
125.04
178.48
128.81
115.78
162.59
102.51
153.34
110.39
127.41
130.11
146.12
147.99
115.47
128.20
Glc-1
1a
2a
3a
4a
5a
6a
Glc-2
1b
2b
3b
4b
5b
6b
Glc-3
1c
2c
3c
4c
171.08
56.37
55.74
34.30
33.42
32.13
47.69
33.42
32.13
31.67
47.69
31.67
31.11
29.92
49.38
177.76
178.48
16.37
16.82
18.10
173.16
52.45
29.92
29.92
29.92
29.92
29.92
33.40
129.96
128.17
32.15
29.92
27.31
25.80
24.01
22.87
21.50
13.49
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
ꢀꢀ
ꢀꢀ
ꢀꢀ
ꢀꢀ
ꢀꢀ
ꢀꢀ
ꢀꢀ
ꢀꢀ
ꢀꢀ
ꢀꢀ
ꢀꢀ
ꢀꢀ
ꢀꢀ
ꢀꢀ
ꢀꢀ
ꢀꢀ
ꢀꢀ
ꢀꢀ
ꢀꢀ
ꢀꢀ
ꢀꢀꢀ
ꢀꢀꢀ
ꢀꢀꢀ
ꢀꢀꢀ
ꢀꢀꢀ
ꢀꢀꢀ
ꢀꢀꢀ
ꢀꢀꢀ
ꢀꢀꢀ
ꢀꢀꢀ
ꢀꢀꢀ
ꢀꢀꢀ
ꢀꢀꢀ
ꢀꢀꢀ
ꢀꢀꢀ
ꢀꢀꢀ
ꢀꢀꢀ
ꢀꢀꢀ
104.51
79.38
74.51
83.37
71.25
60.56
103.89
77.18
73.94
82.32
70.81
61.66
1
2
3
4
5
6
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
103.83
75.76
72.95
81.85
69.96
62.62
5c
6c
Glc-4
1d
2d
3d
4d
5d
6d
98.62
75.39
72.13
80.63
69.03
63.81
13
On the basis of C NMR and mass spectra, its molecular weight was established at m/z 1520 to be consistent with the
molecular formula C H
O
of a flavonoid tetraglycoside esterified with fatty acids. Its mass spectrum displayed ion peaks
77 116 30
+
at m/z 269, 431, 593, and 755 arising due to glycosidic linkage fission. The important ion peaks at m/z 265 [C H O] , 282
18 33
+
+
+
[C H O ] , 355 [C H O ] , and 372 [C H O ] arising due to ester linkage fission indicated the presence of a terminal
18 34
2
20 35
5
20 36 6
+
oleic acid and a C -tricarboxylic acid esterified at the sugar unit. The other important fragment ion peaks at m/z 115 [C H O ] ,
20
6 11 2
+
+
+
+
+
+
143 [C H O ] , 185 [C H O ] , 255 [C H O ] , 313 [C H O ] , 257 [372 – C H O ] , 229 [372 – C H O ] , and
8
15
2
11 21
2
16 31
2
18 33
4
6
11
2
8 15 2
+
187 [372 – C H O ] supported the location of the carboxylic group at C-3ꢀꢀ and C-15ꢀꢀ of the diterpenic moiety. The PMR
11 21
2
spectrum of compound 2 displayed three one-proton downfield signals as two doublets at ꢄ 7.42 (J = 8.8 Hz) and 6.50 (J = 2.5 Hz),
and a doublet of doublets at ꢄ 6.71 (J = 8.8, 2.5 Hz) assigned correspondingly to H-5, H-8, and H-6 protons. Two two-proton
doublets at ꢄ 7.48 (J = 8.5 Hz) and 6.13 (J = 8.5 Hz) were attributed to H-2ꢀ, H-6ꢀ and H-3ꢀ, H-5ꢀ coupled protons, respectively,
suggesting the AB system of the ring. A one-proton signal at ꢄ 7.92 (H-2) and a corresponding olefinic oxymethine signal
13
in the C NMR at ꢄ 152.36 (C-2) are characteristic of an isoflavone skeleton [18, 19]. The two one-proton multiplets H-9ꢀꢀꢀ
and H-10ꢀꢀꢀ at ꢄ 5.13 and 5.11 were associated with vinylic protons. The four one-proton doublets at ꢄ 5.25 (J =7.2 Hz), 4.99
(J = 7.1 Hz), 4.97 (J = 7.1 Hz), and 4.93 (J = 7.2 Hz), were attributed to anomeric protons H-1a, H-1b, H-1c, and H-1d,
respectively. The four one-proton doublet of doublets at ꢄ 4.09 (J = 7.2, 4.5 Hz), 4.06 (J = 7.1, 4.5 Hz), 4.03 (J = 7.2, 4.5 Hz), and
4.01 (J = 7.2, 6.5 Hz) were ascribed correspondingly to H-2a, H-2b, H-2c, and H-2d carbinol protons. The three signals
appeared slightly deshielded, indicating 2ꢂ1 linkage of the sugar units. The remaining sugar protons appeared from ꢄ 4.31 to
3.12. The presence of H -6d in the deshielded region at ꢄ 3.48 and 3.44 and H-2d at 4.01 indicated the location of the ester
2
linkages at C-6d and C-2d. The relative upfield positions of the anomeric protons of the sugar units would suggest that they are
connected in the molecule through sugar alcoholic groups and not through phenolic hydroxyls. Connection through the latter
would cause these resonances to be shifted relatively downfield [20]. The methylene and methine protons of the diterpenic and
fatty acid chains resonated between ꢄ 1.19–2.69. The three doublets at ꢄ 1.16 (J = 6.6 Hz), 0.76 (J = 6.5 Hz), and 1.08 (J = 7.2 Hz)
and the triplet at ꢄ 0.79 (J = 6.3 Hz), each integrating for three protons, were ascribed to Me-18ꢀꢀ, Me-19ꢀꢀ, and Me-20ꢀꢀ secondary
998

13
methyl protons and Me-18ꢀꢀꢀ primary methyl protons, respectively. The C NMR spectrum of compound 2 displayed important
signals for ester carbons at ꢄ 171.08 (C-1ꢀꢀ), 173.16 (C-1ꢀꢀꢀ); carboxylic carbons at ꢄ 177.76 (C-16ꢀꢀ) and 178.48 (C-17ꢀꢀ); vinylic
carbons at ꢄ 129.96 (C-9ꢀꢀꢀ) and 128.17 (C-10ꢀꢀꢀ); methyl carbons at ꢄ 16.37 (C-18ꢀꢀ), 16.82 (C-19ꢀꢀ), 18.10 (C-20ꢀꢀ), and 13.49
(C-18ꢀꢀꢀ); aromatic carbons between ꢄ 102.51–178.48 and four-anomeric carbons between ꢄ 98.62–104.51, indicating the
presence of four sugar units in the glycosidic chain. The carbinol signals in the deshielded region at ꢄ 79.38 (C-2a), 77.18
(C-2b), 75.76 (C-2c), and 75.39 (C-2d) indicated a 2ꢂ1 linkage between the sugar residues and one of the ester linkages at C-2d.
13
The presence of C-6d at ꢄ 63.81 in the C NMR spectrum suggested the location of another ester linkage at this carbon. The
13
remaining carbinol carbons appeared between ꢄ 69.03–74.51. The C NMR values of the sugar residues were compared with
13
1
1
the C NMR chemical shifts of other sugar [19]. The H– H COSY spectrum of 2 showed correlations of H-6 with H-5 and
H-8; H-6ꢀ with H-2ꢀ and H-5ꢀ; H-2a with H-1a, H-3a, and H-1b; H-1d with H-2d and H-3d; and H-19ꢀꢀ with H-10ꢀꢀ and
H -11ꢀꢀ. The HMBC spectrum of 2 exhibited interactions of C-3 with H-2, H-2ꢀ, and H-6ꢀ; C-7 with H-8, H-6, H-5, and H-1a;
2
C-4a with H-3a, H-5a, and H-6a; C-2b with H-1b, H-3b, and H-1; C-1ꢀꢀ with H-2d and H -2ꢀꢀ; C-16ꢀꢀ with H-15ꢀꢀ and H -20ꢀꢀ;
2
3
and C-1ꢀꢀ with H -6d and H -2ꢀꢀ.
2
2
Acid hydrolysis of compound 2 yielded oleic acid and D-glucose (co-TLC comparable). On the basis of the above
discussion, the structure of compound 2 was elucidated as 7,4ꢀ-dihydroxyisoflavonyl-7-ꢃ-D-glucopyranosyl-(2ꢂ1)-ꢃ-D-
glucopyranosyl-(2ꢂ1)-ꢃ-D-glucopyranosyl-(2ꢂ1)-ꢃ-D-glucopyranosyl-6d-(octadec-9ꢀꢀꢀ-enoate)-2d-7ꢀꢀ,11ꢀꢀ,15ꢀ-
trimethylpentadecan-3ꢀꢀ,15ꢀꢀ-dioic acid 1ꢀꢀ-oate. This is a new isoflavonyl tetraglycosidic diester.
EXPERIMENTAL
Material and Methods. Melting points were determined on a Perfit melting apparatus (India) and are uncorrected.
UV spectra were measured with a Lambda Bio 20 spectrophotometer (PerkinElmer, Switzerland) in methanol. Infrared spectra
were recorded on a Bio-Rad FTIR 5000 (FTS 135, Hong Kong) spectrophotometer using KBr pellets; ꢅ
cm . PMR and C NMR spectra were screened on Advance DRY 300, Bruker spectrospin, Germany, at 300 and 75 MHz,
values are given in
max
–1
13
respectively, in DMSO-d using TMS as an internal standard. Mass spectra were scanned by effecting FAB ionization at 70 eV
6
on a JEOL-JMSDX 303 spectrometer (Japan) equipped with a direct inlet probe system. Column chromatography was performed
on silica gel (60–120 mesh; Qualigen, India). TLC was run on silica gel G (Qualigen). Spots were visualized by exposing to
iodine vapor, UV radiation, and spraying reagents.
The aerial parts of A. absinthium (3 kg) were procured from the local crude drug market, Delhi and identified by
Prof. J. Ahmad, Department of Botany, Faculty of Science, Hamdard University. A voucher specimen (PRL/JH/09/20) was
deposited in the Phytochemistry Research Laboratory, Faculty of Pharmacy, Hamdard University, New Delhi, India. The
air-dried aerial parts were coarsely powdered and extracted with methanol in a Soxhlet apparatus for 72 h. The extract was
concentrated under reduced pressure to obtain a dark viscous mass (375 g, yield 12.5% w/w). It was chromatographed over
silica gel (60–120 mesh) packed in petroleum ether (60–80ꢆC). Gradient elution with chloroform–methanol resulted in the
isolation of compounds 1 and 2.
Artemisia Bis-isoflavonyl Dirhamnoside (1). Elution of the column with chloroform–methanol (99:1) mixture gave
a light brown mass of 1, recrystallized from methanol (0.08% yield); R value: 0.33 (chloroform–methanol, 99:01), mp 55–56ꢆC.
f
–1
UV (MeOH, ꢇ , nm): 273, 340 (log ꢈ 3.1, 2.1). IR (KBr, ꢅ , cm ): 3450, 3360, 3210, 2934, 2845, 1707, 1590, 1506,
max
max
1455, 1361, 1233, 1125, 1035, 1001. PMR (DMSO-d , ꢄ, ppm, J/Hz): 7.69 (1H, br.s, H-2a), 7.66 (1H, br.s, H-2b), 7.29 (1H, d,
6
J = 2.3, H-2ꢀa), 7.27 (1H, d, J = 2.8, H-2ꢀb), 7.01 (1H, m, H-6ꢀa), 6.98 (1H, m, H-6ꢀb), 6.60 (2H, d, J = 8.7, H-5ꢀa, H-5ꢀb), 6.52
(2H, d, J = 2.6, H-6a, H-6b), 6.47 (2H, d, J = 2.6, H-8a, H-8b), 4.85 (1H, d, J = 5.1, H-1ꢀ), 4.81 (1H, d, J = 4.5, H-1ꢀꢀ), 4.07 (1H,
m, H-5ꢀ), 3.90 (1H, m, H-5ꢀꢀ), 3.80 (1H, m, H-4ꢀ), 3.71 (1H, dd, J = 5.1, 9.0, H-2ꢀ), 3.68 (1H, dd, J = 4.5, 8.7, H-2ꢀꢀ), 3.32 (1H,
m, H-4ꢀꢀ), 3.30 (2H, m, H-3ꢀ, H-3ꢀꢀ), 1.19 (3H, d, J = 4.5, Me-6ꢀ), 1.17 (3H, d, J = 6.0, Me-6ꢀꢀ), 3.83, 3.59, 3.51 (each 3H, br.s,
13
+
3 ꢉ OMe). For C NMR (DMSO-d , ꢄ, ppm) data, see Table 1. +ve FAB-MS (m/z, I , %): 889 [M + H] (C H O ) (21.1),
6
rel.
45 45 19
874 (26.3), 579 (22.5), 564 (13.1), 549 (19.7), 313 (12.8), 309 (11.5), 147 (35.6).
Artemisia Isoflavonyl Glucosyl Diester (2). Elution of the column with chloroform–methanol mixture (17:5) furnished
a light brown semi-solid mass of 2, recrystallized from methanol, yield 0.20%; R value: 0.4 (chloroform–methanol, 1:1);
f
–1
mp 54–55ꢆC. UV (MeOH, ꢇ , nm): 271, 310 (log ꢈ 5.1, 1.1). IR (KBr, ꢅ , cm ): 3373, 3280, 2916, 2849, 1730, 1721,
max
max
1690, 1640, 1520, 1462, 1285, 1125, 1070. PMR (DMSO-d , ꢄ, ppm, J/Hz): 7.92 (1H, br.s, H-2), 7.48 (2H, d, J = 8.5, H-2ꢀ, H-6ꢀ),
6
7.46 (1H, d, J = 8.8, H-5), 6.71 (1H, dd, J = 2.5, 8.8, H-6), 6.50 (1H, d, J = 2.5, H-8), 6.13 (1H, d, J = 8.5, H-3ꢀ, H-5ꢀ), 5.25 (1H,
999

d, J = 7.2, H-1a), 4.09 (1H, dd, J = 7.2, 4.5, H-2a), 3.78 (1H, m, H-3a), 3.61 (1H, dd, J = 4.5, 5.4, H-4a), 4.31 (1H, m, H-5a),
3.37 and 3.39 (each 1H, d, J = 6.1, H -6a), 4.99 (1H, d, J = 7.1, H-1b), 4.06 (1H, dd, J = 7.1, 4.5, H-2b), 3.73 (1H, m, H-3b),
2
3.62 (1H, dd, J = 4.5, 5.4, H-4b), 4.27 (1H, m, H-5b), 3.19 and 3.12 (each 1H, d, J = 6.0, H -6b), 4.97 (1H, d, J = 7.1, H-1c),
2
4.03 (1H, dd, J = 7.1, 4.5, H-2c), 3.63 (1H, m, H-3c), 3.60 (1H, dd, J = 5.4, 6.9, H-4c), 4.19 (1H, m, H-5c), 3.39 and 3.37 (each 1H,
d, J = 6.2, H -6c), 4.93 (1H, d, J = 7.2, H-1d), 4.01 (1H, dd, J = 7.2, 6.5, H-2d), 3.63 (1H, m, H-3d), 3.60 (1H, dd, J = 5.4, 6.9,
2
H-4d), 4.19 (H, m, H -5d), 3.48 and 3.44 (1H each, d, J = 6.0, H -6d), 2.69 (2H, t, J = 7.2, H -2ꢀꢀ), 1.16 (3H, d, J = 6.6,
2
2
2
Me-18ꢀꢀ), 0.76 (3H, d, J = 6.5, Me-19ꢀꢀ), 1.08 (3H, d, J = 7.2, Me-20ꢀꢀ), 5.13 (1H, m, H-9ꢀꢀꢀ), 5.11 (1H, m, H-10ꢀꢀꢀ), 2.49 to 1.19
13
(H-3ꢀꢀ, H-7ꢀꢀ, H-11ꢀꢀ, H-15ꢀꢀ, 23 ꢉ CH ), 0.79 (3H, t, J = 6.3, Me-18ꢀꢀꢀ). For C NMR (DMSO-d , ꢄ, ppm) data, see Table 2.
2
6
+
+ve FAB-MS (m/z, I , %): 1520 [M] (C H O ) (not observed), 593 (22.3), 431 (18.3), 372 (12.6), 355 (19.6), 313
rel.
77 116 30
(28.7), 282 (24.0), 257 (21.8), 255 (31.1), 229 (20.6), 187 (19.3), 185 (33.6), 159 (43.2), 145 (74.8), 143 (38.3), 131 (48.2),
117 (38.3), 115 (37.9).
Hydrolysis of Compound 2. Compound 2 (50 mg) was dissolved in ethanol (5 mL), dilute HCl (2 mL) added, and
the reaction mixture heated for 1 h on a steam bath. It was extracted with petroleum ether (3 ꢉ 10 mL). The organic phase was
washed with water (2 ꢉ 10 mL), dried over anhydrous Na SO , and evaporated to get oleic acid, co-TLC comparable. The
2
4
reaction after separation of the acids was dried under reduced pressure, and the residue dissolved in methanol to isolate the
diterpenic acid. The residue was dissolved in water and subjected to TLC with a standard sample of D-glucose using
butanol–acetic acid–water (4:1:5) as a developing solvent, R 0.12.
f
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