Flavonoids from Teucrium orientale

Full text of DOI:10.1007/s10600-013-0520-5

Chemistry of Natural Compounds, Vol. 49, No. 1, March, 2013 [Russian original No. 1, January–February, 2013]
FLAVONOIDS FROM Teucrium orientale
G. B. Oganesyan
UDC 547.972
Teucrium orientale L. (Oriental germander, Lamiaceae) is a grayish-green perennial herb with short protruding hairs
that is indigenous to Armenia [1]. It is known to have hypotensive and antioxidant action [2, 3]. Flavones from Teucrium
species exhibit anticonvulsant, antibacterial, and cytotoxic activity [4, 5].
The flavone eupatorin was isolated previously from the flowering aerial part of T. orientale [6]. Eupatorin was also
isolated from T. pseudochamaepitys L. [4] of the Teucrium section [7]. An isomer of eupatorin, cirsilineol, was found in other
species of this section (T. brevifolium Schreber, T. fruticans L., and T. orientale L. var. orientale) [3, 7, 8].
Herein we communicate results from a study of the flavonoid composition of the flowering aerial part of T. orientale
from four habitats and a more detailed study of a collection in the vicinity of Tatev monastery (Syunik Oblast, RA). Dried
plant (450 g) was extracted with MeOH (80%). The condensed extract was diluted with H O (2:1). The filtrate was extracted
2
with C H (residue mass 2.5 g), CHCl (2.2g), and EtOAc (2.0 g).
6
6
3
Flavonoids with R 0.53 and 0.42 (Silufol UV-254, CHCl :Et O, 17:3, system 1) were detected in the initial fractions
f
3
2
by column chromatography (CC) over silica gel (SG) L (40/100 mesh) of the C H residue using CHCl :Et O (2%). The PMR
6
6
3
2
spectra of these fractions showed polymethoxylated flavonoids with 4ꢀ- and 3ꢀ,4ꢀ-substituted B-rings. This excluded the
possibility that they contained 5-demethylsinensetin, a marker of the section Teucrium [7]. The eluate containing CHCl :Et O
3
2
(
4%) isolated light-yellow crystals of 1 (154 mg), mp 191–192°C, R 0.31 (system 1) and R 0.51 (CHCl :MeOH, 19:1, system
f f 3
2
), which gave a positive test (Mg/HCl) for flavones. It was identified based on physicochemical properties as the native
1
3
compound (IR, UV, PMR, C NMR, 2D NMR, and mass spectra) and the diacetate (PMR, mass spectra) of eupatorin
+
(
5,3ꢀ-dihydroxy-6,7,4ꢀ-trimethoxyflavone), C H O . Mass spectrum m/z 344 (M , 100) [6].
1
8 16 7
Subsequent fractions from CC upon elution by CHCl and CHCl :MeOH (1ꢁ4%) on TLC using systems 1 and 2
3
3
detected for the first time for this species cirsimaritin (2, 5,4ꢀ-dihydroxy-6,7-dimethoxyflavone), cirsiliol (3, 5,3ꢀ,4ꢀ-trihydroxy-
,7-dimethoxyflavone), apigenin (4, 5,7,4ꢀ-trihydroxyflavone), and luteolin (5, 5,7,3ꢀ,4ꢀ-tetrahydroxyflavone). CC fractions
of the C H and CHCl residues eluted by CHCl :MeOH (2%) afforded crystals of 3 (8 mg), mp 275–277°C, R 0.27 (system 2).
6
6
6
3
3
f
+
UV spectrum (MeOH, ꢂmax, nm): 253, 276, 343. It was identified as cirsiliol, C H O . Mass spectrum: m/z 330 (M , 100).
17
14 7
PMR spectrum of 3 (300 MHz, DMSO-d :CCl , 1:3, ꢃ, ppm, J/Hz): 3.78 (3H, s, OMe), 3.94 (3H, s, OMe), 6.52 (1H, s, H-3),
6
4
6
3
.67 (1H, s, H-8), 6.85 (1H, d, J = 8.3, H-5ꢀ), 7.32 (1H, dd, J = 8.3, 2.3, H-6ꢀ), 7.35 (1H, d, J = 2.3, H-2ꢀ), 8.95 (1H, br.s,
ꢀ-OH), 9.41 (1H, br.s, 4ꢀ-OH), 12.81 (1H, br.s, 5-OH). 13C NMR spectrum of 3: (75.46 MHz, ꢃ, ppm): 55.7 (MeO-7), 59.4
(
(
MeO-6), 90.4 (C-8), 102.4 (C-3), 113.1 (C-2ꢀ), 115.5 (C-5ꢀ), 118.2 (C-6ꢀ), 121.4 (C-1ꢀ), 131.8 (C-6), 145.4 (C-3ꢀ), 149.4
C-4ꢀ), 152.4 (C-5 and C-9), 158.1 (C-2), 164.0 (C-7), 181.7 (C-4).
The C H and CHCl residues from T. orientale collected during flowering in the vicinity of Aghveran (Kotayk
6
6
3
Oblast, RA) andArtanish villages (Gegharkunik Oblast, RA) afforded a compound with the same physicochemical and spectral
properties as eupatorin [6]. The qualitative compositions of the residues (TLC using systems 1 and 2) of the aforementioned
collections were also identical.
The EtOAc residue of T. orientale from Tatev monastery contained three glycosides. CC over SG L (40/100 mesh)
using EtOAc:MeOH:H O (98:1.5:0.5) isolated light-yellow crystals (25 mg) of 6 with R 0.46 (EtOAc:MeOH:H O, 9:1:0.5,
2
f
2
2
0
system 3), mp 237–238°C, [ꢄ] –59° (c 0.5, EtOH). UV spectrum (MeOH, ꢂmax, nm): 257, 269sh, 300sh, 360. It was
identified as hyperoside (quercetin-3-O-ꢅ-D-galactopyranoside), C H O . Mass spectrum m/z 302 (M agl, 48) [9]. PMR
D
+
2
1 20 12
spectrum of 6 (300 MHz, DMSO-d , ꢃ, ppm, J/Hz): 3.33 (1H, td, J = 6.0, J5,4 = 0.9, H-5ꢀꢀ), 3.40 (1H, dd, J6a,6b = 11.0,
6
5,6
J = 6.0, H-6bꢆ), 3.41 (1H, dd, J2,3 = 9.5, J3,4 = 3.4, H-3ꢆ), 3.51 (1H, dd, J6a,6b = 11.0, J5,6a = 6.0, H-6aꢆ), 3.66 (1H, dd,
A. L. Mndzhoyan Institute of Fine Organic Chemistry, Scientific Technical Center, Department of Physical Chemistry,
National Academy of Sciences of the Republic of Armenia, 0014, Erevan, Prosp. Azatutyuna, 26, fax: (3741) 28 83 37,
e-mail: Hyrcanamarum@yahoo.com. Translated from Khimiya Prirodnykh Soedinenii, No. 1, January–February, 2013,
pp. 94–95. Original article submitted June 18, 2012.
106
0009-3130/13/4901-0106 ©2013 Springer Science+Business Media New York

J2,3 = 9.5, J1,2 = 7.7, H-2ꢆ), 3.73 (1H, dd, J3,4 = 3.4, J4,5 = 0.9, H-4ꢆ), 5.04 (1H, d, J1,2 = 7.7, H-1ꢆ), 6.14 (1H, d, J = 2.1, H-6),
6
3
5
.42 (1H, d, J = 2.1, H-8), 6.80 (1H, d, J = 8.5, H-5ꢀ), 7.48 (1H, dd, J = 8.5, 2.2, H-6ꢀ), 7.70 (1H, d, J = 2.2, H-2ꢀ), 8.83 (1H, br.s,
ꢀ-OH), 9.09 (1H, br.s, 4ꢀ-OH), 10.34 (1H, br.s, 7-OH), 12.30 (1H, br.s, 5-OH). 13C NMR spectrum of 6 (75.46 MHz, ꢃ, ppm):
9.7 (C-6ꢆ), 67.5 (C-4ꢆ), 71.7 (C-2ꢆ), 73.2 (C-3ꢆ), 75.3 (C-5ꢆ), 93.2 (C-8), 98.5 (C-6), 102.9 (C-1ꢆ), 103.7 (C-10), 114.9
(
1
C-5ꢀ), 116.3 (C-2ꢀ), 121.2 (C-6ꢀ), 133.6 (C-3), 144.3 (C-3ꢀ), 148.2 (C-4ꢀ), 156.2 (C-2), 156.5 (C-9), 161.2 (C-5), 164.0 (C-7),
77.3 (C-4).
Acid hydrolysis of 6 (H SO , 5%) produced quercetin with R 0.63 (system 3), mp 313–316°C. UV spectrum (MeOH,
2
4
f
ꢂmax, nm): 255, 269sh, 300sh, 369. Galactose was detected by PC. CC fractions of the EtOAc residue also contained cinaroside
(
7, luteolin-7-O-ꢅ-D-glucopyranoside) (TLC, system 3).
A study of the short- and long-haired varieties of T. orientale (near Geghard monastery, Kotayk Oblast, RA) detected
eupatorin in the short-haired variety. Hyperoside was absent in the EtOAc residue of the MeOH extract of both varieties, in
contrast with the sample from Tatev monastery (TLC, system 3).
The studies suggested that eupatorin and the flavonol glycoside hyperoside were definitive for the chemotype
T. orientale. Cirsiliol (3) and hyperoside (6) were isolated for the first time from T. orientale.
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