A new furocoumarin glycoside from aerial parts of pleurospermum brunonis

Article abstract of DOI:10.14233/ajchem.2017.20366

From the ethyl acetate extract of aerial parts of Pleurospermum brunonis, a new furocoumarin glycoside 5-O-β-D-glucopyranosyl-6-methoxyangelicin along with ferulic acid and angelicin has been isolated. Structure of isolated compound was elucidated by the analysis of their spectroscopic data and chemical analysis.

Full text of DOI:10.14233/ajchem.2017.20366

Asian Journal of Chemistry; Vol. 29, No. 1 (2017), 233-234
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SIAN
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OURNAL OF HEMISTRY
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http://dx.doi.org/10.14233/ajchem.2017.20366
NOTE
A New Furocoumarin Glycoside from Aerial Parts of Pleurospermum brunonis
*
M.A. RATHER, D.P. PANDEY , R.P. SINGH, Y. SINGH and D.P. NAUTIYAL
Department of Chemistry, Government P.G. College, Uttarkashi-249 193, India
*Corresponding author: E-mail: pandeydp_123@rediffmail.com
Received: 24 October 2016;
Accepted: 10 November 2016;
Published online: 21 November 2016;
AJC-18135
From the ethyl acetate extract of aerial parts of Pleurospermum brunonis, a new furocoumarin glycoside 5-O-β-D-glucopyranosyl-6-
methoxyangelicin along with ferulic acid and angelicin has been isolated. Structure of isolated compound was elucidated by the analysis
of their spectroscopic data and chemical analysis.
Keywords: Pleurospermum brunonis, 5-O-β-D-Glucopyranosyl-6-methoxyangelicin, Ferulic acid, Angelicin.
Pleurospermum (Apiaceae) is a genus of perennial, rarely
biennial herbs. There are about 50 species confined to north
Asia, east Europe and especially diverse in the Himalayan
region and west China [1]. Pleurospermum brunonis is a
perennial herb, 10-15 cm high, found in the temperate regions
of Himachal Pradesh and Kashmir at an altitude of 4500-
5000 m. The powder of the flowering shoot is mixed with cow’s
fresh butter and messaged over the entire body to allay fevers,
stomatitis and small pox. The dried herb or the garland prepared
from the plant is used to protect woolen cloths from the attack
of moths and silver fish [2,3]. Coumarins [4-9], saponins [10],
flavonoid glycosides [11] and terpenoids [12] have been
isolated from various Pleurospermum species. Saponins and
sapogenins isolated from P. kamtschatidium have been reported
to possess anti-inflammatory, analgesic, antinociceptive and
inhibitory effect on NO, PGE2 and TNF-α release [13]. There
is no previous record of chemical investigation on P. brunonis;
therefore, the phytochemical examination of ethyl acetate
extract of aerial parts of this plant was carried out. The present
communication describes the isolation and identification of a
new furocoumarin glycoside; 5-O-β-D-glucopyranosyl-6-
methoxyangelicin (1) along with ferulic acid and angelicin
from aerial parts of P. brunonis. Structure of isolated com-
pound was elucidated by the analysis of their spectroscopic
data and chemical analysis.
HO
6"
O
OH
O
1"
OH
HO
4
H3CO
5
3
1
O
O
O
2'
Structure of 5-O-β-D-glucopyranosyl-6-methoxyangelicin (1)
Department of Botany, Government P.G. College, Uttarkashi,
India.
General procedure and detection method: The air-dried
and powdered plant material of P. brunonis (2 kg) was extracted
with light petroleum ether (60-80 °C). The petroleum free mass
was sequentially extracted with chloroform, ethyl acetate,
acetone and ethanol. Each extract was concentrated under reduced
pressure over vacuum evaporator. The ethyl acetate extract
(8.5 g) was CC over Si-gel using CHCl3-EtOAc (100→0; 1→1)
afforded various fractions. Fraction 1 on repeated CC over Si-gel
using gradient elution n-hexane-EtOAc (1:1) to give angelicin
(89 mg). Fraction 2 on repeated CC over Si-gel on elution
with CHCl3-EtOAc (1:3) yielded ferulic acid (29 mg). Fraction
3 on repeated CC over Si-gel eluted with CHCl3:MeOH (2:1)
to give compound 1 (21 mg).
The plant material P. brunonis was collected from Daggan
Dhar (4200-4300 m asl) Bhalessa, District Doda, India, in July,
2010, The plant species were identified by Dr. Sumer Chand,
Systematic Botany Division, FRI, Dehradun, India. The voucher
specimen (Hr. no. 61) was deposited in the herbarium of

234 Rather et al.
Asian J. Chem.
5-O-β-D-Glucopyranosyl-6-methoxyangelicin (1):
methoxy group at δ 3.88 and an anomeric proton at δ 4.66 (d,
J 7.8 Hz, H-1") along with signals assignable to sugar protons.
The presence of methoxy group and sugar moiety was confir-
med by 13C shifts of methoxy carbon at δ 59.01 and anomeric
carbon at δ 106.49. On acid hydrolysis with HClcompound 1
afforded D-glucose. The β-orientation of sugar was determined
from the value of coupling constant (J 7.8 Hz) of anomeric
Light yellow amorphous powder; UV (λmax, H2O): nm 219,
248, 305; IR (KBr, νmax, cm-1): 2910, 1692, 1619, 1582, 1454,
1
1256, 1061, 1036, etc.; (+) FABMS: m/z: 395.0934 etc.; H
NMR: (400 MHz, CD3OD): 6.38 (1H, d, J 9.9 Hz, H-3), 8.58
(1H, d, J 9.9 Hz, H-4), 7.85 (1H, d, J 2.3 Hz, H-2’) 7.12 (1H,
d, J 2.3 Hz, H-3’) 4.66 (1H, d, J 7.8 Hz H-1") 3.55 (1 H, t, J
7.8, Hz, H-2") 3.46 (1H, d, J 7.8, Hz, H-3"), 3.49 (1H, d, J 7.6
Hz, H-4"), 3.38 (1H, ddd, J 7.6, 5.2, 2.4 Hz, H-5"), 3.76 (1H,
dd, J 5.2, 11.8 Hz, H-6a”), 3.83 (1H, dd, J 2.4, 11.8 Hz, H-
6b”), 3.88 (3H, s, -OCH3); 13C NMR (100 MHz, CD3OD):
162.98 (s, C-2), 113.40 (d, C-3), 141.76 (d, C-4), 143.09 (s,
C-5), 136.73 (s, C-6), 149.54 (s, C-7), 117.41 (s, C-8), 143.38
(s, C-9), 112.80 (s, C-10), 147.85 (d, C-2’), 104.12 (d, C-3’),
106.49 (d, C-1"), 74.76 (d, C-2"), 76.82 (d, C-3"), 70.11 (d,
C-4"), 79.09 (d, C-5"), 61.76 (t, C-6"), 59.01 (q, C6-OCH3).
Acid hydrolysis of compound 1: Compound 1 (5 mg)
was refluxed with 5 % aqueous HCl (5 mL) at 80 °C for 3 h.
After cooling, the reaction mixture was neutralized with
AgNO3. The aqueous layer after concentration under reduced
pressure was subjected to PC using BuOH-AcOH-H2O (5:1:4)
with authentic sugars. The sugar was identified as D-glucose.
The ethyl acetate extract of aerial parts of P. brunonis on
repeated CC over Si-gel afforded a new furanocoumarin
glycoside; 5-O-β-D-glucopyranosyl-6-methoxyangelicin (1)
along with ferulic acid and angelicin. The structure of ferulic
acid and angelicin was determined by direct comparison of
their spectral data with the reported values [14,15].
1
proton. Absence of aromatic protons in H NMR spectrum
suggested that both C-5 and C-6 positions are substituted. The
HMBC spectrum displayed 3JCH correlation of anomeric proton
3
at δ 4.66 with the carbon signal at δ 143.09 (C-5) and JCH
correlation of H-4 proton (δ 8.58) with C-5. The methoxy
protons at δ 3.88 showed 3JCH correlation with C-6 carbon at δ
149.55. These data unambiguously established that the glucose
and methoxy group was attached at C-5 and C-6 position of
furocoumarin nucleus, respectively. Accordingly, the structure
of 1 was deduced as 5-O-β-D-glucopyranosyl-6-methoxy-
angelicin.
ACKNOWLEDGEMENTS
The authors are thankful to the Principal Govt. P.G.
College, Uttarkashi, India for providing necessary facilities
for the present investigation.
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Compound 1 a light yellow amorphous powder, was found
to have molecular ion peak at m/z 395.0942 in the positive
HRFABMS spectrum (calc. for C18H19O10; 395.0978). The IR
spectrum showed characteristic absorption band for carbonyl
group at 1699 cm-1. Its UV absorption maxima at 219, 248 and
305 nm were similar to that of 5,6-dioxygenated angelicin
skeleton [16]. The 1H NMR and 13C NMR spectra of 1 were
similar to those of furanocoumarins. The 13C NMR spectrum
of 1 showed 18 carbon signals out of which carbon signals at
δ 104-163 due to the 11 carbons of the angular furocoumarin
nucleus, one signal for anomeric carbon of the glucose, five
carbon signals at δ 60-80 due to the sugar moiety and one
signal for methoxy carbon at δ59.01. The assignment proton
1
and carbon signals were made by DEPT, H-1H COSY and
HSQC experiments.
The 1H NMR spectrum showed characteristic signals of a
disubstituted furan ring at δ 7.84 (d, J 2.3 Hz, H-2’) and 7.12
(d, J 2.3 Hz, H-3’) and an AX type spin system at δ 6.38 (d, J
9.9 Hz, H-3) and 8.58 (d, J 9.9 Hz, H-4), which was confirmed
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1
these signals H NMR spectra also displayed presence of