Chemistry of Natural Compounds, Vol. 47, No. 5, November, 2011 [Russian original No. 5, September–October, 2011]
FLAVONOIDS OF Bupleurum plantagineum
1
1
R. Bencheraiet, A. Kabouche,
UDC 547.972
1*
2
Z. Kabouche, and M. Jay
Bupleurum (Apiaceae) species are used in traditional medicine to treat various diseases. Bupleuri Radix (roots of
Bupleurum) is one of the most frequently prescribed crude herbs in the prescriptions of traditional Chinese medicine for the
treatment of inflammatory and autoimmune diseases [1]. It is used in at least 66% of the formulations/prescriptions in traditional
Chinese medicine [2]. Bupleurum species have been reported to possess anti-inflammatory [3], antioxidant, and hepatoprotective
effects [4–8]. Saikosaponins are the principal secondary metabolite of Bupleurum [2, 4–8] in addition to polyacetylenes,
terpenoids, and two flavonoids (tamarixetin 3-robinobioside and tamarixetin 3-galactoside) [9] and polysaccharides [10].
Bupleurum plantagineum (Apiaceae), an endemic species [11], was collected around Cap Carbon at Bejaia (Eastern
Algerian) in may 2004 and authenticated by Prof. Gerard De Belair (Annaba, Algeria). A voucher specimen was deposited in
the Herbarium of the Laboratory of Therapeutic Substances (LOST) at Mentouri University (LOST/Bp/05/04).
Air-dried and powdered aerial parts (1 kg) of Bupleurum plantagineum were macerated in a methanolic solution
(70%). The extract was successively concentrated to dryness (under low pressure); the residue was dissolved in boiling water
and extracted with petroleum ether, dichloromethane, ethyl acetate, and n-butanol, successively.
The butanolic extract was column chromatographed on polyamid SC6, eluting with toluene–methanol with increasing
polarity. Whatman 3MM paper chromatography using 15% AcOH and BAW [n-BuOH–AcOH–H O, 4:1:5 (upper phase)] and
2
TLC on polyamid DC6, eluting with H O–MeOH–methylethylketone–acetylacetone (13:3:3:1), followed by a column flash
2
1
chromatography over Sephadex LH-20 in MeOH, led to three pure flavonoids 1–3, which were identified using UV, H NMR,
13
C NMR, and MS analysis [12–14].
Acid Hydrolysis. The pure compounds were treated with 2 M HCl at 100ꢁC for 1 h. The hydrolysates were extracted
with EtOAc, and the aglycones were identified by their UV spectra in methanol and by comparison of their R with authentic
f
samples.
Sugars were identified in the aqueous residue by comparison with authentic samples on silica gel TLC impregnated
with 0.2 M NaH PO , solvent Me CO–H O (9:1), and revealed with aniline malonate.
2
4
2
2
Compound 1, C H O , yellow needles (acetone), mp >300ꢁC. This compound was characterized as quercetin
15 10
7
[12–14].
Compound 2, C H O , mp 250–254°C. UV (MeOH, ꢂ , nm): 257, 300 sh, 356; +NaOH: 272, 325, 407;
27 30 16
max
+
+
+ AlCl : 275, 290, 350 sh; +HCl: 268, 285 sh, 350, 390; +NaOAc: 271, 385; +H BO : 263, 378. FAB -MS, m/z 611 [M + H] .
H NMR (250 MHz, CD OD, ꢃ, ppm, J/Hz): 7.80 (1H, d, J = 2.0, H-2ꢀ), 7.75 (1H, dd, J = 9.0, J = 2.0, H-6ꢀ), 6.85 (1H, d,
3
3
3
1
3
J = 9.0, H-5ꢀ), 6.30 (1H, d, J = 2.0, H-8), 6.20 (1H, d, J = 2.0, H-6), 5.12 (1H, d, J = 7.0, H-1ꢀꢀ glucose), 4.55 (1H, d,
H-1ꢀꢀꢀrhamnose), 3.20–3.90 (10H, protons of rutinose), 1.1 (3H, d, J = 6.2, H-6ꢀꢀꢀrhamnose). Acid hydrolysis of 2 produced
quercetin, D-glucose, and L-rhamnose. Compound 2 was identified as quercetin-3-O-rutinoside [12–14].
Compound 3, C H O . UV (MeOH, ꢂ , nm): 254, 265 sh, 306 sh, 356; +NaOH: 271, 330, 414; +AlCl : 267,
28 32 16
max
3
+
300 sh, 368, 401 sh; +HCl: 267, 302 sh, 360, 400; +NaOAc: 271, 320, 398; +H BO : 254, 267 sh, 305 sh, 360. FAB -MS,
m/z 625 [M + H] . H NMR (250 MHz, CD OD, ꢃ, ppm, J/Hz): 7.50 (1H, d, J = 2.0 H-2ꢀ), 7.34 (1H, dd, J = 8.5, J = 2.0, H-6ꢀ),
3
3
+ 1
3
6.82 (1H, d, J = 8.5, H-5ꢀ), 6.44 (1H, d, J = 2.0, H-8), 6.15 (1H, d, J = 2.0, H-6), 5.30 (1H, d, J = 7.5, H-1ꢀꢀglucose), 4.35 (1H,
d, J = 2.0, H-1ꢀꢀꢀrhamnose), 3.25–3.85 (10H, protons of rutinose), 3.87 (3H, s, 3ꢀ-OMe), 0.90 (3H, d, J = 6.5, H-6ꢀꢀꢀrhamnose).
1) Laboratoire dꢀObtention de Substances Therapeutiques (L.O.S.T), Faculte des Sciences Exactes, Universite
Mentouri–Constantine, Campus Chaabat Ersas, 25000 Constantine, Algeria, fax: 213 31 81 88 59, e-mail:
zkabouche@yahoo.com; 2) Universite Claude Bernard, Laboratoire de Phytochimie, Lyon I, France. Published in Khimiya
Prirodnykh Soedinenii, No. 5, pp. 713–714, September–October, 2011. Original article submitted May 24, 2010.
814
0009-3130/11/4705-0814 02011 Springer Science+Business Media, Inc.
Bencheraiet
