Vitexin 7- O -rhamnoside, a New Flavonoid from Pteris vittata

2004·1.8 MB·English

by  Filippo Imperato

SHORTER NOTES
159
"Broken 2"^
along Land
the line rate generally. Lime stone rock along the
ravines"
The
largest concentration of A. ruta-muraria
occurs
at this site in a small,
the
and
east facing bluffs, A. ruta-muraria grows with dominant
the
fern
Mett
whereas on
brake), the small, sheltered northern
face occurs with
Cystopteris
it
bulbifera (L.) Bernh. (bulblet fern]. Other plant species co-inhabiting the
and
shelves
crevices of these bluffs include Arabis
lyrata (rock
cress),
Min
Michx
vanica Muhl. ex
Willd.
(pellitory), Aquilegia canadensis (columbine),
L.
Sporobolus Nash
neglectus (small rush grass) and Schizachyrium scoparium
bluestem).
(little
We
thank Doug
Gart Bishop, Larson, Jim Peck, Tony Reznicek,
Carl Taylor,
and
George Yatskievych
information advice.—Thomas
for or Cady, Iowa
F.
lA and Diana Horton,
City,
Biological Sciences Department, 143 BB,
University of Iowa, Iowa lA 52242.
City,
—
New
Vitexin 7-0-rhamnoside, a Flavonoid from
Pteris vittata. Previous
work
on
the flavonoids of Pteris vittata L. has led to the identification of
luteolinidin 5-0-glucoside by Harborne (Phytochemistry
5:589-600,
1966); in
addition acid hydrolysis of extracts of this fern has led the
to identification of
kaempferol, leucocyanidin and
quercetin, leucodelphinidin by
Voirin
(Ph. D.
thesis, University of Lyon, 151, 1970). More recently 3 p-
p. -C-(6 '"-acetyl-
cellobiosyl)-apigenin (Amer. Fern 89:217-220, and
1999)
6-C-|3-cellobiosyl-
J.
isoscutellarein-8-methyl ether together with quercetin 3-O-glucuronide and
rutin (Amer. Fern 90:42-45, 2000) have been identified by Imperato and
J.
Telesca. In addition three kaempferol glycosides (3-O-glucoside, 3-O-glucuro-
nide and 3-0-(X",X"-di-protocatechuoyl)-glucuronide), two
di-C-glycosylfla-
vones and
(3,8-di-C-arabinosylluteolin 6-C-arabinosyl-8-C-glucosylluteolin)
and
three flavonol glucosides acylated with hydroxycinnamic
acids (kaemp-
and
ferol quercetin 3-0-(2", 3"-di-0-p-coumaroyl)-glucosides together with
kaempferol
3-0-(X"-0-p-coumaroyl-X"-0-feruloyl)-glucoside) have been found
by
Imperato (Amer. Fern 90:141-144, 2000; Amer. Fern 92:244-246,
2002;
J. J.
Amer.
Fern 93:157-160,
2004).
J.
In the present paper two flavonoids and have been from
isolated
aerial
(I II)
Garden
parts of Pteris vittata L. collected in the Botanic of the University of
Naples. The was by Nazzaro
fern identified Dr. R. (University of Naples);
a voucher specimen (149.001.001.01) has been deposited Herbarium
in the
Neapolitanum (NAP)
of the University of Naples.
Flavonoids and were isolated from an ethanolic extract of aerial parts of
(I II)
BAW
BEW
VOLUME NUMBER
AMERICAN FERN JOURNAL:
160 94 3 (2004)
^H-NMR
Table and spectral data [DMSO-de) of flavonoid
1. "^^C- (I).
ppm ppm
Carbon in Hz)
5h
Sc
(J
Apigenin
=
rhamnosyl methyl group)
2 164.6 0.97 (3H, d, 6,
J
+
3 102.7 2.95-4.11 (10 H, m, glucosyl 6 protons rhamnosyl 4 protons)
=
4 182.4 4.52 H, glucosyl H-1)
d,
(1 8.
J
=
161.6 5.51 H, rhamnosyl H-1)
5 (1 d, 2,
J
6 99.1 6.33 H, H-6)
(1 s,
163.2 6.77 H, H-3)
7
(1 s,
=
and
8 104.4 6.91 (2 H, d, 8..6,(??) H-3' H-5')
J
and
9 156.8 7.97 H, d, -= 8.6, H-2' H-6')
(2
J
10 103.2
1' 121.6
2',6' 128.9
3',5' 115.7
4'
160.5
O-Rliamnosyl
1"
99.2
2"
70.4^
3" 70.5^
4" 71.8^
5"
70.8^'
6"
18.2
C-Glucosyl
V"
73.6
2"'
71.5*'
3'"
79.6
4'"
69.9
5'"
82.1
6'"
62.2
a,b may
same
Assignments with the superscripts be interchanged
ethanol-water, Further purification was carried out by Sephadex
4:1:2.2).
LH-20 column chromatography eluting with methanol. Color reactions (brown
yellow in UV+NH3.)» chromatographic behaviour values on Whatman No
to
(Rf
BAW; 15% HOAc)
0.37 and
1 paper: in 0.54 in ultraviolet spectral analysis in
(MeOH)
the presence of usual shift reagents 273, 332; +AICI3 280,
(?Ln,ax(nm)
+NaOAc +NaOMe
+AICI3/HCI
302, 344, 383; 281, 300, 341, 381; 273, 391; 274,
may
391) suggested that flavonoid be a flavonoid glycoside with
free
[I)
hydroxyl groups at positions 5 and 4'. Acid hydrolysis (2N HCl; 1 hr at 100°C)
gave L-rhamnose, and
vitexin (8-C-glucosylapigenin) isovitexin (6-C-gluco-
show may
sylapigenin). These results that flavonoid be a C-glucosylapige-
[1)
FAB
nin 7-O-rhamnoside and was confirmed by mass spectrum which
this the
showed
a quasimolecular ion m/z 579 and an ion m/z 601
at [M+Hl"*" at
NMR
and showed
[(MHrH)+Na]^. ^H- spectral data (Table D-glucose
^'^C- 1) that
is attached at position 8 o f the flavone since H-6 appeared as a singlet at 5 6.33;
showed
in addition C-8 a downfield shift of 10.4 p.p.m., in comparison with
the corresponding carbon atom of apigenin; this shift of glycosylated carbon
SHORTER NOTES
161
7-O-rhamnoside
Vitexin
Fig. 1.
shown
atom an C-glycosylation on the aglycone spectrum as in the
effect of
is
review by Markham and Chari 19-134 in B. Harborne and T. Mabry,
(pp.
J,
J.
Chapman and London,
The Flavonoids: Advances in Research, Hall,
eds.,
among
Hence the presence of isovitexin the products of acid hydrolysis
1982],
The combined
due Wessely-Moser acid isomerization.
of flavonoid to a
is
(I)
new
show 7-O-rhamnoside natural
data that flavonoid vitexin (Fig a
is 1),
(I)
product; and ^^C-NMR spectral data (Table support this structure.
'^H- 1)
A
shown
number C-glycosylflavonoids have been found in ferns as in
large of
review by Markham 427-468 Harborne, The Flavonoids,
the in B. ed,,
(pp.
J.
Chapman and London, and
Advances Research Since 1980, Hall, 1988) in
in
Phytochemistry
review by Tmperato 39
a (pp.
Trivandrum, However C-glycosylflavonoid O-glycosides are rare
Trends, 2000].
A
which hydrolyzable sugar
C-glycosylflavonoid O-glycoside in the
in ferns.
attached to a phenolic hydroxy group was found for the first time in ferns
is
who
by Hiraoka (Bioch. Syst. and Ecol. 6:171-175, 1978] identified vitexin
genus Dryoptens; subsequently 8-C-rhamnosylluteolin
7-O-glucoside the
in
was found (Phytochemistry 37:589-590,
7-O-rhamnoside in Pteris cretica
which hydro-
by C-Glycosylflavonoid-O-glycosides in the
1994) Tmperato.
sugar attached a hydroxy group of a C-glycosyl moiety were found
lysable to
is
Markham 19:415-
by and Wallace (Phytochemistry
the time in ferns
for
first
who found apigenin and luteolin 8-C-glucoside 2"-0-xylosides in
1980]
420,
Trichomanes venosum; two further C-glycosylflavone O-glycosides of this type
who
and
by Imperato Telesca
been found
have subsequently in Pteris vittata
(Amer. Fern
3-C-(6'"-acetyl-cellobiosyl)-apigenin
these flavonoids as
identified
8-methyl
and ether
89:217-220, 1999)
P
J.
(Amer. Fern 90:42-45, 2000).
J.
UV
by
kaempferol 3-O-rutinoside
Flavonoid has been identified as
(II]
H-NMR
niQtomprv
oT^oli7cio P shift reaaents. acid hvdrolvsis.
oi^r^r^fr^oi TAfitVi til
162 FERN
C-NMR
spectrum, spectrum and
co-chromatography
with an
authentic
As shown
sample. Markham
in the review by kaempferol 3-0-
[1988],
mtinoside has previously been Adiantum
identified in
capillus-veneris
(Adiantaceae), another of the 53 species oi Adiantum, Loxsoma cunninghamii,
costaricensis (Loxsomaceae], Bommeria
L. all four species of (Sinopterida-
ceae), four species of Gymnopteris (Sinopteridaceae), two species of Hemi-
onitis [Sinopteridaceae) and the genus Trachypteris more
[Sinopteridaceae);
recently kaempferol
3-O-rutinoside has been
Diplazium
identified in nippo-
nicum
and
(Athyriaceae) Thelypteris palustris (Sinopteridaceae] shown
as in
the review by Imperato
[2000).
The
author thanks Murst [Rome] Mass
for financial support.
spectral data
SESMA
were
provided by
[CNR, Naples).—
Filippo Imperato Dipartimento
di
Chimica,
Universita della 85100
Basilicata, Potenza,
Italy.