A novel acylated flavonoid glycoside from astragalus complanatus

0040.4039/91 $3.00+.00 Porg;imonRessplc

Tctnh&on Letrcrs,Vo1.32,No.43,pp 6135-6138, 199: Printed inGreatBritain

A NOVEL

ACYLATED

FROM

Baoliang

FLAVONOID

ASTRAGALUS

COMPLANATUS

Cui, Junei Kinjo,

Motoyuki

and Tosbihiro

A

flavonoid

novel

was obtained

glycoside

from the seeds

Astragali

Semen,

(Leguminosae),

seeds

paper,*) methanolic

paper

flavonoid

a novel

designated

Complanatin showed

a

absorption

due

peaks

absorptions(cm-1)

a sesquiterpene. R.

complanatus

in the traditional

acylated

dihydrophaseic

BR.

with

an

R.

Chinese

we reported the occurrence extract of the title plant.

BR.

medicine.

of the oleanene We now present a absc::sic acid-type

as complanatin. yellow

needles,

to

[M+l]+

at

m/z

[hmax

267

(log

&

at

with

Astragalus

of

glycoside

(11, pale

peak

862, Japan

complanatus

used as a tonic

In the preceding qlycosides in the of

acylated

of Astragalus

the

has been

sesquiterpene,

Nakamura,

Nohara*

Kumamoto

5-l Oe-honmachi,

acid,

I)

of Pharmaceutical Sciences, Kumamoto University,

Faculty

Abstract:

GLYCOSIDE

3428

(OH),

mp

889 4.88),

1705

the

340

(ester

[01lD +0.50

192-4"C,

in

positive

(log

&

carbonyl),

(MeOH),

FAB-MS,

4.39)1, 1658

and

UV IR

(conjugated

carbonyl) and 1602 (aromatic ring). The lH- and 13C-NMR spectra of 13) displayed that it was constituted with a flavonoid portion, glycosidic parts and a sesquiterpene moiety as listed in Table I. Since the appearance of the ester

linkage

flavonoid

was

suggested,

derivative

(DMSO-d6),

positive

(2), FAB-MS

(3), a resin,

[a]D -72.6"

The

signals

512.2

IH-NMR

Hz),

saponified

yellow

(m/z):

625

(CHC13), EI-MS (in DMSO-d6)

terminal Hz)

(ZH, d, J=8.8

glucosyl and

respectively,

moieties

5.04 by the

(lH,

Hz),

[M+l]+

mp

and

(m/z): 296

c86.38 8.17

with

crystals,

a

alkaline 271-3'C,

to

afford

[a]D

sesquiterpene

a

+28.0c moiety

CM+).

(lH, d, J-2.2

[two anomeric d,

13C-NMR

J-7.3

(2H, d, J=8.8

Hz),

proton

Hz) 1 to

spectrum.4) 6135

Hz),

6.77

(lH, d,

(lH, s) I 3.87 (3H, s) I of 2 could assign its structure to be a 3,5,1,4'tetrahydroxyflavone (kaempferol) derivative. It was furthermore suggested to possess one methoxyl group at C-7 by the NOE experiment and subsequently two J=7.3

7.17

1 was

pale

signals

attach

to

12.56

at 2; 5.50

C-3-OH

and

(lH, d, C-4'-OH,

6136

Table

I

Flavone

13C-NMR

Spectral

Data

for 1, 2, 3, 4 and 5

1

2

156.3 133.9 177.6 160.8 97.5 165.1 92.2 155.6 105.0 124.0 130.6 116.5 158.6 116.5 130.6 56.0

156.4 134.0 177.7 160.9 98.0 165.2 92.4 155.9 105.1 123.6 130.7 115.8 159.3 115.8 130.7 56.2

100.7 74.1 76.3 69.8 17.5 60.8

100.8

5

moiety

c-2 3 4 5 6 I 8 9 10 1' 2' 3' 4' 5' 6' MeO-7 3-u-glc C-l 2 3 4 5 6 4'-o-glc C-l 2 3 4 5 6 Terpene moiety C-l 2 3 4 5 7 a 1' 2' 3' 4' 5' Me-l Me-5 Me-3'

91.8 74.0 72.6 69.7 77.1 60.3

assignments

1, 2 and 5 were

146.1 136.6 176.2 160.3 97.4 165.0 92.0 156.1 104.0 124.7 129.2 116.1 157.9 116.1 129.2 56.0

14.2 76.5 69.9 77.6 60.9 99.9

97.6 74.0 72.6 69.8 77.2 60.3

73.2 16.4 69.6 77.1 60.1

48.1 43.8 63.8 45.4 81.5 75.3 as.7 136.1 116.5 151.2 129.3 163.9 16.1 19.4 20.7

MeO-5 f These

4

3

48.4 43.5 65.3 45.0 82.4 76.3 86.0 133.3 116.5 149.9 130.5 166.6 16.0 19.1 21.2 51.2

48.3 52.5 208.1 52.8 82.3 77.6 85.8 131.8 118.8 149.0 131.2 166.5 15.7 18.9 21.1 51.3

were made by lH-13C COSY experiment. measured

in DMSO-d6;

3 and 4 were

in CDC13.

48.1 43.7 63.8 45.4 81.5 75.2 85.7 136.1 116.5 151.2 129.2 163.9 16.1 19.4 20.7

6137

On the

other

hand,

due to two methyl Jz1.5

Hz),

groups

(6 0.89,

one methoxyl group 6.36 (111, d, ~=16.1

(lH, s), group bearing 2.2 Hz)], J=10.6,

'H-NMR

the

oxygen

methine

10.3,

atom

group

7.0,

of 3 s.howed signals

1.11, each s), one vinyl

[6 3.69 and

Hz),

(in CDCl3)

methyl

(61.99,

d,

[6 5.69 (6 3.65, s), three olefinic protons Hz), 7.95 (lH, d, J=16.1 Hz)], a methylene

adjacent

7.0

spectrum

(lH, d, 5~7.7 to the

hydroxyl

other

methylene

Hz),

3.14

group

(lH, dd,

[8 4.22

[6 1.60

signals

J=l.7,

(lH, dddd, (lH, dd,

J=13.6, 10.6 Hz), 1.67 (lH, dd, J=13.6, 10.3 Hz), 1.84 (lH, ddd, J=13.6, to a (lH, ddd, JE13.6, 7.0, 1.5 Hz), 2.10 7.0, 1.5 Hz)] attrjbutable which was der:ved from (-)sesquiterpene moiety, methyl dihydrophaseate,5) phaseate 6*7) by

methyl

acid yielded

a product

methyl phaseate Meanwhile, which m/z

was

estimated

the acylated sesquiterpene (-3.8)],10) due

to H-l

NaBH4.

(4),8)

spectrum. moiety linked

3 with

chromic

with

(-)-

the

of 1 by the FAB-MS 13C-NMR

spectrum

{ [M+ll+ at

revealed

that

attached to the C-4'-OH and furthermore the to the C-2 hydroxyl group of gl-ucosyl moiety

(ppm):

C-l,

whose

lH-NMR

spectrum

appeared

of

ident:cal

rotation, IH- and 13C-NMR spectra. 1 provided a sole product (5),g)

compound

Moreover,

shifts H-2

Oxidation

[@ID -26.7" (CHC13), being

as a deglucosyl

glucosyl residue

and

with

in respects with specific enzymatic hydrolysis of

727) and 13C-NMR

[acylation

reduction

6 97.6(-2.3); also

at 65.83

C-2,

supported

6 74.0(+0.8); by

the

fact

(lH, d, J=8.1

Hz)

and

C-3, that 5.94

6 72.6 signals

(lH, dd,

Jz8.1, 9.5 Hz), respectively, being substantiated by the lH-lH COSY. Consequently, the structure of complanatin (1) was determined as shown in the firstly

formula.

A novel

flavonoi~d glycosj_de acylated

with

sesquiterpene

reported.

-OH

Structure

of 1

is

6138

REFERENCES 1. Part 2.

AND

25

in

the

series

of

studies

Y.; Cui, B. IA.; Sakai, Pharm. Bull., submitted.

3. The lH-NMR

spectrum

on

of 1

(6 ppm,

constituens

the

Takeshita,

T.;

of leguminous

Kinjo,

plants Chem.

J.;

Nohara,

T.

in DMSO-d6) : flavone

moiety,

3.86

(3H,

s, MeO-7), 6.37 (lH, d, J=2.2 Hz, H-6), 6.73 (1H, d, J=2.2 Hz, H-8), 7.12(2H, d, 5~8.8 Hz, H-3', 5'), 8.15 (211, d, J=8.8 Hz, H-:?I, 6'), 12.54 (lH, s, HO-5); sugar anomeric protons, 5.52 H-l), 5.35 (lH, d, J=7.3 Hz, 4'-O-glc H-l); s, Me-l), 1.03 (3H, s, Me-5), 1.57 (lH, br t,

(lH, d,

J=7.'7 Hz,

3-O-glc

terpene moiety, 0.87 (3H, Ha-2), 1.64 (lH, br t, Ha-

4) r 1.74 (lH, dd, J=13.2, 6.6 Hz, Hb-2), 1.90 (lH, dd, J--13.2, 6.2 Hz, Hb-4), 2.07 (3H, s, Me-3'), 3.55 (lH, d, J=8.1 Hz, Ha-71, 3.77 (lH, d, J-8.1 Hz, Hb-7), 3.93 (1~1, m, H-3), 5.78 (lH, s, H-4'), 6.53 (IH, d, J=15.8

Hz, H-2'),

4. Markham,

7.98

(lH, d, J=15.4

K. R.; Ternai,

B; Stanley,

Hz, H-l').

R.; Geiger,

Tetrahedron, 1978, 34, 1389-1396. 5. Milborrow, B. V. Phytochemistry, 1975, 6. MacMillan,

J.; Pryce,

I.

T.;

Kitahara, 45, 6387.

8. The

'H-NMR

R. J. Chem.

Touhara,

spectrum

of

K.; 4

(6 ppm,

T. J.

14, 1045.

Sot.,

Watanabe,

H.; Mabry,

Chem. H.;

Commun.,

Mori,

in CDC13):

K.

1.04

1968,

124.

Tetra'Tedron, (3H, s, Me-l),

1989, 1.25

(3H, s, Me-5), 2.02 (3H, s, Me-3'), 2.48 (lH, d, 5~18.5 Hz, Ha-2), 2.55 (lH, dd, J=18.5, 2.6 Hz, Hb-2), 2.64 (ZH, br t, H-4), 3.73 (3H, s, MeO5'), 5.80

3.78 (lH, d, J=8.1 Hz, Ha-7), 3.98 (lH, s, H-4'), 6.23 (lH, d, J~16.1

9. yh/e ";Y'. H NMR

spectrum

of 5

(6 ppm,

(lH, dd, J=8.1, Hz, H-2'), 8.15

in pyridine-d6)

2.6 Hz, Hb-71, (:H, d, J=15.8

: flavone

moiety,

3.80

(3H, s, MeO-7), 6.60 (lH, d, 5x2.2 Hz, H-6), 6.70 (lH, d, J=2.2 Hz, H8.43 (2H, d, J-9.2 Hz, H-2',6'); E), 7.47 (2H, d, J=9.2 Hz, H-3',5'), sugar

moiety,

4.23

(IH, overlapped

with

other

signal,

H-5),

4.37

(lH,

dd, J=8.8, 9.2 Hz, H-4), 4.38 (lH, d, J=lZ.l Hz, Hb-61, 4.48 (lH, dd, J=8.8, 9.5 Hz, H-3), 4.59 (lH, br d, 5=12-l Hz, Ha-6), 5.83 (IH, d, J=8.1 Hz, H-l), 5.94 (lH, dd, J=8.1, 9.5 Hz, H-Z); terpene moiety, 1.22 (3H, s, Me-l), 1.51 (3H, s, Me-5), 1.88 (3H, d, J-l.1 Hz, Me-3'), 2.19 7.3 Hz, Ha-2), 2.27 (lH, dd (1H, br t, Ha-4), 2.20 (lH, dd, J=13.2, J=13.6, 10.3 Hz, Hb-4), 2.53 (lH, ddd, J=13.2, 7.0, 1.8 Hz, Hb-2), 3.94 (IH, d, J=7.3 Hz, Ha-7), 4.24 (lH, d, J=7.3 Hz, Hb-7), 4.71 (lH, tdd, J=10.3, 7.3, 7.0 Hz, H-3), 5.92 (lH, s, H-4'), 6.93 (lH, d, J=15.8 Hz, H-2'), 8.86 (la, d, J-15.8 Hz, H-l').

10. Dorman,

D. E.; Roberts,

(Received inJapan 20 June 1991)

J. D. J. Am. Chem.

Sot.,

1971,

93, 4463.