and co-TLC with an authentic sample. The presence of the 4-hydroxy-3,5-dimethylbenzoyloxy group at C-3 was concluded
1
3
from the downfield shift of C-3 in the C NMR spectrum compared to oblonginine and also by an HMBC experiment
3
3
showing J correlation of H-3 at ꢀ 3.18 with C-7ꢂ (ꢀ 170.2). The anomeric proton at ꢀ 5.86 showed J correlation with C-4ꢂ
ꢀ 160.7) in the HMBC spectrum, confirming the presence of the ꢁ-D-glucopyranosyloxy moiety at C-4ꢂ of the aromatic ring.
(
The downfield shift of the oxymethylene carbon of D-glucose indicated esterification of the primary hydroxyl group. It was
3
confirmed by J correlation of both the oxymethylene protons with the carbonyl carbon of the dodecanoyl moiety. The structure
of compound 1 was therefore deduced as 3ꢁ-O-[4-(6-O-dodecanoyl-ꢁ-D-glucopyranosyloxy)-3,5-dimethylbenzoyl]-oblonginine
[
3
(3ꢁ,17ꢁ)-17-{(1S)-1-[(2R,5S)-5-methylpiperidin-2-yl]ethyl}androst-5-en-3-yl-4-(6-O-dodecanoyl-ꢁ-D-glucopyranosyloxy)-
,5-dimethylbenzoate].
EXPERIMENTAL
General Procedure. Optical rotations were recorded on a JASCO DIP-360 digital polarimeter. IR spectra were
recorded on a JASCO 302-A spectrophotometer in KBr. NMR spectra were measured on a Bruker 500 MHz instrument.
Chemical shifts ꢀ are shown in ppm, and coupling constants J are expressed in Hz. EI and HR-FAB-MS were recorded on
JEOL JMS-HX-110 and JMS-DA-500 mass spectrometers using glycerol as matrix. Silica gel (250–400 mesh; E. Merck,
Darmstadt, Germany) was used for column chromatography (CC); silica gel 60 F254 plates (E. Merck, Darmstadt, Germany)
were used for TLC. Arachidonic acid and sodium citrate were purchased from the Sigma Chemical Co. (St. Louis, Mo. USA).
All other chemicals used were of the highest purity grade available.
Plant Material. The whole plant material of Allium victorialis L. was collected from northern areas of Pakistan in
2
004 and identified by Dr. Surraiya Khatoon, Plant Taxonomist, Department of Botany, University of Karachi, Karachi,
Pakistan, where a voucher specimen has been deposited in the herbarium (voucher specimen No. 202/KUH).
Extraction and Isolation. The freshly collected whole plants of A. victorialis (20 kg) were shade dried, ground, and
extracted with ethanol (3 ꢃ 40 L, 10 days each) at room temperature. The combined ethanolic extract was evaporated under
reduced pressure to yield a residue (800 g), which was suspended in water (1.0 L) and successively extracted with n-hexane
(
80 g), CHCl (170 g), EtOAc (220 g), and BuOH (150 g) soluble fractions. The CHCl soluble fraction (80 g) was subjected
3
3
to column chromatography over silica gel and eluted with n-hexane, n-hexane–CHCl , CHCl and CHCl –MeOH in increasing
3
3
3
order of polarity to obtain 20 subfractions. The subfraction eluted with CHCl –MeOH (9.5:0.5) was rechromatographed and
3
eluted with CHCl –MeOH (8.5:1.5) to provide allumine C (1) (28 mg).
3
2
0
–1
Allumine C (1). Colorless gummy solid; [ꢄ] –53ꢅꢆ(c 0.02, CHCl ). IR (KBr, ꢇ , cm ): 3450–3330, 1700, 1660,
602, 1540, 1500. EI-MS m/z (I , %): 546 [M – sugar residue – H , 11], 398 (21), 126 (28), 98 (100); HR-FAB-MS (neg. mode)
m/z 890.6146 [M – H] (calcd 890.6148 for C H NO ). For the H (500 MHz, CDCl ) and C NMR (125 MHz, CDCl3),
D
3
max
+
1
rel.
–
1
13
5
4
84
9
3
see Table 1.
Basic Hydrolysis of Compound 1. Compound 1 (16 mg) was suspended in a mixture of 4% NaOH (4 mL), MeOH
12 mL), and H O (3 mL). The suspension was warmed until a vigorous exothermic reaction began, and in 10 min the entire
(
2
solid had dissolved. The solution was then heated under reflux for 5 min longer. After dilution with water (6 mL), the MeOH
was removed in vacuo and the resulting aqueous solution was repeatedly extracted with CHCl . The residue recovered from
3
2
3
the organic phase was crystallized from acetone/hexane, mp 220ꢅC, [ꢄ] –40.3ꢅ (c 0.14; CHCl ). Its physical and spectral
D
3
data were in complete agreement with those reported in the literature for oblonginine [7].
The basic solution left over after extraction with CHCl was acidified with 0.1 N HCl to pH 2 and freeze dried. The
3
residue was subjected to column chromatography eluting with chloroform and mixtures of chloroform and methanol in increasing
order of polarity. The fraction eluted with chloroform was crystallized from ethanol, mp 43ꢅC. It was identified as dodecanoic
acid (lauric acid) through comparison of its physical and spectral data with those reported in the literature [9]. The fractions
eluted with chloroform–methanol (99:01 and 98:02) were combined and subjected to acid hydrolysis with 10% aq. HCl for
3
h at 100ꢅC. On cooling, the aqueous fraction was extracted with chloroform. The organic phase was repeatedly washed with
water, dried, and freed of solvent. The residue was crystallized from benzene to furnish 4-hydroxy-3,5-dimethylbenzoic acid
10]. The aqueous phase was neutralized with silver carbonate and concentrated. The sugar was identified as D-glucose
[
2
3
through co-TLC with an authentic sample and through the sign of its optical rotation ([ꢄ] + 51ꢅ).
D
1
136