Phytochemistry 52 (1999) 1319±1322
Bucharioside and buchariol from Salvia bucharica
Viqar Uddin Ahmad a,*, Muhammad Zahid b, Muhammad Shaiq Ali a, Amir
Reza Jassbi a, Muhammad Abbas a, Zul®qar Ali a, Muhammad Zafar Iqbal b
a
International Center for Chemical Sciences, H.E.J. Research Institute of Chemistry, University of Karachi, Karachi 75270, Pakistan
b
Institute of Chemistry, University of the Punjab, Lahore, Pakistan
Received 24 May 1999; accepted 9 July 1999
Abstract
A new monoterpene-glycoside (2-exo-b-D-glucopyranosyl-1,8-cineol) named bucharioside from the methanol-soluble part and
a new sesquiterpenoid (4,10-epoxy-6a±hydroxyguaiane) named buchariol from the hexane-soluble part of Salvia bucharica were
obtained. Their structures were elucidated with the help of NMR spectroscopy including 1D and 2D experiments. # 1999
Elsevier Science Ltd. All rights reserved.
Keywords: Salvia bucharica; Lamiaceae; Bucharioside; Buchariol; Spectroscopy; Structure elucidation
1. Introduction
Salvia is the largest genus of the family Lamiaceae
having about 800 species throughout the world
(Chadha, 1972). Most of the plants of this genus are
well known for their constituents having biological activities, especially anti-tumor activity (Fujita & Node,
1984). The plants of this genus are rich in essential oils
and among their constituents, 1,8-cineol and guaiane
mono and sesquiterpenes are very common
(Rustaiyan, Masoudi & Jassbi, 1997a; Rustaiyan,
Komeilizadeh, Masoudi & Jassbi, 1997; Ahmad &
Jassbi, 1999). Salvia bucharica is a conspicuous aromatic plant that grows in Pakistan, Afghanistan and
central Asia (Hedge, 1990). It is locally called `sursunda' and traditionally used for the treatment of liver
disorders.
2. Results and discussion
The methanolic extract of Salvia bucharica was subjected to repeated column chromatography and then
* Corresponding author.
HPLC to purify 1, which exhibited the molecular ion
peak at m/z 332.1793 (calcd. m/z 332.1821 for
C16H28O7) in HREIMS. The EIMS of 1 showed in addition to the molecular ion peak at m/z 332, a prominent peak at m/z 170 (52%) due to the loss of glucose
moiety from the molecular ion.
The 1 H-NMR spectrum suggested p-menthane
monoterpene type aglycone. The signals at d 1.39, 1.27
and 1.18 having integration of three protons each
assigned to Me-9, Me-10 and Me-7, respectively. The
signals at d 4.05 (dd, J = 9.7, 3.2 Hz, H-2endo), 2.37
(dddd, J = 14.0, 3.1, 3.1, 3.1 Hz, H-3exo) and 1.80
(ddd, J = 14.0, 9.8, 3.1 Hz, H-3endo) were clearly distinguished 1 from its endo-isomer (Orihara & Furuya,
1994). The double-doublet at d 4.05 with coupling constant 9.7 and 3.2 Hz indicated the position of glucose
moiety at C-2. The large vicinal coupling constant (9.8
Hz) in the signal of H-3endo at d 1.80 and H-2endo at d
4.05 clearly explained the orientation of glucose moiety
as exo (Orihara & Furuya, 1994).
The 13 C-NMR of 1 showed sixteen signals due to
aglycone and sugar moiety, which were resolved by
DEPT experiments into three methyl, four methylene,
seven methine and two quaternary carbons. Signals at
d 23.6, 29.1 and 28.4 were due to the Me-7, Me-9 and
Me-10, respectively. The chemical shifts of these three
0031-9422/99/$ - see front matter # 1999 Elsevier Science Ltd. All rights reserved.
PII: S 0 0 3 1 - 9 4 2 2 ( 9 9 ) 0 0 3 8 9 - 1
1320
V.U. Ahmad et al. / Phytochemistry 52 (1999) 1319±1322
Table 1
Decoupling experiments of 1
Number of experiments
Irradiation of 1 H
Collapsed 1 H
1
d 4.05 (H-2endo)
2
d 1.80 (H-3endo)
3
d 1.30 (H-4)
4
d 1.20(H-5endo)
d
d
d
d
d
d
d
d
d
1.80 (ddd, J = 14.0, 9.8 and 3.1 Hz, H-3endo) 4 (dd, J = 12.0 and 3.0 Hz)
2.37(dddd, J = 14.0, 3.1, 3.1 and 3.1 Hz, H-3exo) 4 (ddd, J =14.0, 3.0 and 3.0 Hz)
4.05 (dd, J = 9.7 and 3.2 Hz, H-2endo) 4 (d, J = 4.0 Hz)
2.37(dddd, J = 14.0, 3.1, 3.1 and 3.1 Hz, H-3exo) 4 (br.s. )
1.80 (ddd, J = 14.0, 9.8 and 3.1 Hz, H-3endo) 4 (dd, J = 14.0 and 9.6 Hz)
2.37(dddd, J = 14.0, 3.1, 3.1 and 3.1 Hz, H-3exo) 4 (ddd, J = 14.0, 3.0 and 3.0 Hz)
1.64 (ddd, J = 17.1, 11.8 and 6.1 Hz, H-5exo) 4 (dd, J = 16.0 and 6.0 Hz)
1.64 (ddd, J = 17.1, 11.8 and 6.1 Hz, H-5exo) 4 (dd, J = 12.0 and 8.0)
1.80 (ddd, J = 14.0, 9.8 and 3.1 Hz, H-3endo) 4 (br.dd )
methyls concluded 1 as 1-8-cineol type skeleton
(Formacek & Kubeczka, 1982). The remaining carbon
signals were comparable with the reported data of
endo-isomer of 1 (Orihara & Furuya, 1994).
The relative con®guration of 1 was established
through NOE experiments. The extensive decoupling
experiments (Table 1) and NOE dierence experiments
(Table 2) suggested the structure of 1 as 2-exo-b-D-glucopyranosyl-1,8-cineol and named bucharioside. To
the best of our knowledge this compound has not been
isolated so far from any natural source. However, the
endo-isomer of 1 had already been isolated from Citrus
unshiu peel (Sawabe, Matsubara & Iizuka, 1988).
Compound 2 was puri®ed from hexane soluble part
of the same source. The molecular ion peak was
observed in the HRMS and FDMS at m/z 238.1933
(calcd. m/z 238.1932) suggesting the molecular formula
C15H26O2 showing three degrees of unsaturation. In
addition to molecular ion peak in the EIMS other
peaks at m/z 223 [M-CH3]+, 220 [M-H2O]+, 195 [MC3H7]+, 167, 81 and 71 were also observed. Peaks at
m/z 71(80%), 167(12%) and 81(100%) were due to the
fragments A, B and C (Scheme 1) (Itigaka, Kurokawa,
Moriyama, Sasaki & Watanase, 1985).
The 1 H-NMR spectrum of 2 displayed two secondary methyls due to isopropyl unit at d 0.92 J 6:7
Hz), 0.93 J 6:7 Hz) and two tertiary methyls at d
1.18, 1.42 due to Me-14 and Me-15. The chemical
shifts of these methyls were compatible with guaiane
type skeleton (Bohlmann & Jakupovic, 1979; Bruno,
Torre, Rodriguez & Omar, 1993; Oshima, Iwakawa &
Hikino, 1983). A broad doublet at d 4.00 J 1:5 Hz)
was observed in the spectrum due to hydroxyl bearing
methine-carbon which was attested for C-6 (Bohlmann
& Jakupovic, 1979).
In the broad band spectrum of 2 ®fteen signals were
observed which were resolved into four methyl, four
methylene, ®ve methine and two quaternary carbons.
The assignment of these signals were based on the
reported data of the related compounds (Itigaka et al.,
1985; Bohlmann & Jakupovic, 1979; Bruno et al.,
1993; Ahmed, Ela, Adams & Mabry, 1996; Mahmud,
1997; Oshima et al., 1983; Yoshikawa, Hatakeyama,
Tanak, Fukuda, Murakami & Yamahara, 1992).
The stereochemistry of 2 was established on the
basis of comparative NMR data. A cis-fused-4,10
dihydroxy guaiane-type compound showed the same
chemical shifts for Me-14 and Me-15 as in 2, which
have proved the stereochemistry of Me-14 and Me-15
as cis to each other (Bohlmann & Jakupovic, 1979).
The up®eld shift of C-4 d 74.4) in comparison to
other oxygen-bearing quaternary carbons which normally come at about d 80.0 could be justi®ed due to
the g-eect of the a-hydroxyl function situated at C-6.
Similarly, the down®eld shift of C-5 d 68.2) was due
to b-eect of the same hydroxyl group (Bruno et al.,
1993; Ahmed et al., 1996). The small coupling constant
of H-6 J 1:5 Hz) was due to almost 908 dihedral
Table 2
NOE experiments of 1
Number of experiments
Irradiation of 1 H
% NOE
1
d 1.27 (H-10):
2
d 1.80 (H-3endo):
3
d 2.37 (H-3exo):
7.7% NOE at d 2.37 (H-3exo)
3.5% NOE at d 4.93 (H-1')
3.7% NOE at d 1.10.-1.30 (H-6')
38% NOE at d 4.05 (H-2endo)
61% NOE at d 2.37 (H-3exo)
30.1% NOE at d 1.80 (H-3endo)
23% NOE at d 4.93 (H-1')
V.U. Ahmad et al. / Phytochemistry 52 (1999) 1319±1322
1321
Alisma orientale (Yoshikawa et al., 1992). On the basis
of this suggested biogenetic route (Fig. 1), the hydroxyl
function could be placed at C-6. The compound 2 was
decomposed after spectroscopic techniques, because of
the instability which may be due to the opening of the
ether-bridge across C-4 and C-10. This compound is
also a new addition in the natural products and named
buchariol.
3. Experimental
3.1. General
H- and 13 C-NMR spectra were recorded on Bruker
AM-500 and Bruker AM-300 spectrometers. Mass
spectra were measured on JMSHX-110 (Jeol).The
infra-red (IR) spectra were scanned on JASCO-A 302
spectrophotometer. Optical rotation was carried out
on Schmidt and Haensch polartronic-D polarimeter at
258.
1
3.2. Plant material
Scheme 1. Proposed mass fragmentation pattern of 2.
angle between H-5, H-6 and H-7b (Mahmud, 1997)
which was con®rmed by molecular model. So the
orientation of isopropyl unit at C-7 must be a.
On biogenetic grounds it is proposed that 2 may be
derived from alismoxide isolated from Alisma plantago-aquatic var orientale (Oshima et al., 1983) and
Fig. 1
Salvia bucharica (whole plant) was collected from
Quetta, Baluchistan, (Pakistan) in June, 1998 and was
identi®ed by Dr. Rasool Baksh Tareen, Department of
Botany, Baluchistan University, Quetta, where the
voucher specimen (No. 354) of the plant has been
deposited in the herbarium.
3.3. Extraction and isolation
Shade-dried plant material (6.0 kg) was chopped
into small pieces and soaked in hexane (15 l) and then
in methanol (15 l) for a period of 10 days each. The
solvents were removed at low temperature and pressure to aord gummy masses (hexane part: 92.71 g and
methanolic part: 428.24 g). The methanolic extract was
partitioned between aqueous and ethyl acetate soluble
portions. The ethyl acetate portion (123.439) was subjected to column chromatography using hexane, hexane-chloroform, chloroform, chloroform-methanol and
®nally, pure methanol as mobile phase.
Compound 1 was obtained from column loaded
with ethyl acetate crude extract. The fraction eluted
with 10% methanol in chloroform give 1 as a semipure sample. After repeated column chromatography,
1 was ®nally (10.5 mg) puri®ed by HPLC using
MeOH±H2O (9:1) (RP C-18, bondapak column with
¯ow rate 1.5 ml/min. and pressure uptill 300 psi.).
O
Bucharioside (1): [a]258
D ÿ25.48 (MeOH, c 2.29). IR
ÿ1
nmax (KBr) cm : 3450 (OH). FDMS: m/z 332. EIMS:
m/z 332 [M]+, 170 [M-glucose]+. Peak match: m/z
332.1793 (calcd. m/z 332.1821 for C16H28O7). 1 HNMR (C5D5N, 500 MHz): d 4.05 (1H, dd, J = 9.7,
1322
V.U. Ahmad et al. / Phytochemistry 52 (1999) 1319±1322
3.2 Hz, H-2endo), 1.80 (1H, ddd, J = 14.0, 9.8, 3.1 Hz,
H-3endo), 2.37 (1H, dddd, J = 14.0, 3.1, 3.1, 3.1, 3.1
Hz, H-3exo), 1.30 (1H, m, H-4), 1.64 (1H, ddd, J =
17.1, 11.8, 6.1 Hz, H-5exo), 1.20 (1H, m, H-5endo),
1.10±1.30 (1H, m, H-6exo ), 1.80 (1H, m, H-6endo), 1.18
(3H, s, Me-7), 1.39 (3H, s, Me-9), 1.27 (3H, s, Me-10),
4.93 (1H, d, J = 7.8 Hz, H-1 '), 3.92 (1H, br.t, J = 8.5
Hz, H-2 '), 4.26 (1H, t, J = 9.6 Hz, H-3 '), 4.14 (1H,
br.t, J = 9.7 Hz, H-4 '), 3.97 (1H, ddd, J = 10.0, 5.5,
2.5 Hz, H-5 '), 4.33 (1H, dd, J = 11.7, 5.7 Hz, H-6 'a)
and 4.55 ((1H, dd, J = 11.7, 2.3 Hz, H-6 'b). 13CNMR (C5D5N, 75 MHz): d 71.7 (C-1), 74.5 (C-2), 31.4
(C-3), 33.5 (C-4), 30.5 (C-5), 20.1 (C-6), 23.6 (C-7),
73.4 (C-8), 29.1 (C-9), 28.4 (C-10), 101.4 (C-1 '), 74.4
(C-2 '), 78.5 (C-3 '), 71.8 (C-4 '), 78.4 (C-5 '), 62.9 (C-6 ').
Compound 2 was obtained from hexane soluble part
of Salvia bucharica. It was eluted with 0.5% methanol
in chloroform from silica gel column, which was
further loaded on preparative plates using 2% methanol in chloroform as mobile phase. The UV active
impurities were removed and ®nally, 2 was puri®ed by
repeated preparative layer chromatography as an oil
(12.5 mg).
Buchariol (2): IR nmax (CHCl3) cmÿ1: 3410 (OH).
FDMS: m/z 238. EIMS: m/z 238 [M]+, 223 [MCH3]+, 220 [M-H2O]+, 195 [M-C3H7]+, 169, 81
(100%). Peak match: m/z 238.1933 (calcd. m/z
238.1932 for C15H26O2). 1 H-NMR (CDCl3 300 MHz): d
4.00 (1H, br.dd, J 1:5 Hz, H-6), 2.14 (1H, br.dd, J
9:1,3:1 Hz, H-7), 0.93 (3H, d, J 6:7 Hz, Me-12), 0.92
(3H, d, J 6:7 Hz, Me-13), 1.18 (3H, s, Me-14), 1.42
(3H, s, Me-15). 13 C-NMR (CDCl3 75 MHz): d 53.3 (C1), 23.8 (C-2), 37.5 (C-3), 74.4 (C-4), 68.2 (C-5), 75.9
(C-6), 38.5 (C-7), 20.2 (C-8), 48.2 (C-9), 74.4 (C-10),
32.7 (C-11), 21.1 (C-12), 21.1 (C-13), 21.9 (C-14), 25.8
(C-15).
Acknowledgements
We thank Dr. R.B. Tareen, Department of Botany,
Baluchistan University, Quetta, for the collection and
identi®cation of the plant material.
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