Phenylpropanoid and iridoid glycosides from Pedicularis striata

Short Reports

1341 REFERENCES

the mixt. refluxed for 2 hr. After cooling, the mixt. was filtered and treated as described above. A further part of the above sample (7 g) was incubated in H,O (200 ml) for 3 days at room temp. before the mixt. was filtered, the insoluble material dried and extracted with CHCI,, as described above. Chlorogenone was synthesized from diosgenin by the method of Marker et al. [ 1 I]. ‘HNMR (270 MHz) and ‘%NMR (68 MHz) spectra were obtained in CDCI,, EIMS (probe.) were recorded at 70eV and IR spectra were measured as KBr discs. Chlorogenone. Mp 234-235.5”; ‘H NMR: 60.78 (3H, d, 5=6 Hz; H,-27). 0.80 (3H, s; H,-18), 0.98 (3H, s; H,-19), 0.98 (3H, d, .I=6 Hq H,-21), 2.65-2.23 (7H. m; 2H-2, H,-l, H-5, 3.36 (IH, t, J= 11, 11 Hz; H-26ax). 3.45 H,-7). (lH,dd,J=3, 11 Hq H-26eq),4,42(1H, q,J=7, 7, 7Hr H-16).

1. Carabot Cuervo, A. and Usubillaga, A. (1981) Rea. Lrrtinoam. Quim. 12, 132. 2. Perer, N., Matteo, C., Marcos M., M., Carabot Cuervo, A. and Blunden, G. (1989) Rev. futinoum. Quim. 20, 102. 3. Faul, W. H. and Djerassi, C. (1970) Org. Mass Spectrom. 3, 1187. 4. Agrawal, P. K., Jain, D. C., Gupta, R. K. and Thakur. R. S. (1985) Phytochemistry 24, 2479. 5. Blunden, G., Jaffer, J. A., Jewers, K. and Griffin, W. J. (1981) J. Nat. Prod. 44, 44. 6. Blunt, J. W. and Stothers, J. B. (1977) Org. Magn. Reson. 9. 439. 7. Dapke, W., Nogueiras, C. and Hess, U. (1975) Pharmazie 30, 755. 8. Fayez. M. B. E. and Saleh, A. A. (1967) Planta Med. 15,430. 9. Morales Menda, A., Cazares, R. and Romo, J. (1971) Rev. Lutinoam. Quim. 1, 1. 10. Blunden, G.. Hardman, R. and Wensley, W. R. (1965) J. Pharm. Pharmacol. 17,274. I I. Marker, R. E., Jones, E. M., Turner, D. L. and Rohrmann, E. (1940) J. Am. Chem. Sot. 62, 3006.

Acknowledgements----We thank Mr C. H. Turner for the NMR spectra, Mr N. J. Armstrong for the EIMS, Professor C. E. Benitez de Rojas for identification of the Solanum specie-s and Mr J. Dugarte for help in the collection of the plant material.

Phyrochemistry, Vol. 30, No. 4, pp. 1341-1344.1991 Pnntcd in Great Lintain.

8

PHENYLPROPANOID AND IRIDOID GLYCOSIDES PEDICULARIS STRIATA IXJ Institute

of Organic

Chemistry,

Z~M~N and

Lanzhou

CKI31-9422,‘91 $3.00+000 1991Pergamon Press plc

FROM

JIA ZHONGJIAN*

University,

Lanzhou

730000, Peoples’ Republic

of China

(Received 15 August 1990) Key Word Index-Pedicularis ioside A.

striata; Scrophulariaccae;

phenylpropanoid

glycosides

iridoid glycoside; pedicular-

Abstract-A new phenylpropanoid glycoside, pedicularioside A, and five known glycosides, acteoside, isoacteoside, decaffeoylacteoside, echinacoside and 8-acetylharpagide, were isolated from whole plants of Pedicularis striata. On the basis of spectral and chemical evidence, pedicularioside A was shown to be 1’-O-/I-D-(3,4-dihydroxy-/?-phenyl)-ethyl4’-O-CaffeOy~-~-D-apiOSyl-(l+3’)-r-L-rhamnosyl-(l -6’~glucopyranoside.

INTRODUClION China, there are many species of Pedicularis (Scrophulariaceae). They are used as folk medicines as cardiac tonics for the treatment of collapse, exhaustion

In northwestern

and senility [ 11, and are usually called ‘pseduo-ginseng’ by local inhabitants. We report the isolation and structural elucidation of a new phenylpropanoid glycoside, pedicularioside A (3), as well as the isolation of five known compounds, from whole plants of P. striata. *Author

to whom correspondence

should be addressed.

RESULTS AND Dl!XUSlON

Dried whole plants were extracted with 95% ethanol

under reflux. The water-soluble part of the ethanolic extract was partitioned with petrol, ethyl acetate and nbutanol. The n-butanol extract was repeatedly chromatographed over silica gel to give acteoside (I), isoacteoside (2), decaffeoylacteoside (4), echinacoside (S), 8-acetylharpagide (6) and a new compound (3). Compound 3 was obtained as an amorphous powder, [or]k2 -58.4” (MeOH; c 1.2). Its UV spectrum (MeOH) showed AR:” at 330,291,217,206 nm. The IR spectrum

I342

(KBr)

Short Reports

Rho

I

R’.H

R2’03f

A’-

2

R1.Cof

R*.H

R’- Rha

3

R’=Rh.

R2’ Cat

R’s API

4

R’=H

R2.H

R’- Rho

3

R’.Glc

R2. cat

R3* Rho

showed

conjugated (1631 cm-‘)

absorptions for hydroxyl (3377 cm-‘), ester (1700 cn- ‘), Q-unsaturated acid and aromatic rings (1604 and 1523cm-‘).

The FAB mass spectrum gave peaks at m/z 763 [M + Li] + and 779 [M + Na] +, which correspond to the molecular formula C3.,H4.,01 9. On methanolysis with 5% acetyl chloride in methanol, methyl caffeate and 3,4dihydroxyphenethyl alcohol were detected by TLC. Acid hydrolysis of 3 in refluxing aqueous 1 M H,SO,methanol (1: 1) afforded D-glucose, L-rhamnose and Dapiose. Mild hydrolysis in 0.1 M HCI yielded rhamnose and apiose, indicating their positions as terminal sugars. Acylation at the C-4’ hydroxyl of glucose was deduced from the downfield shift of H-4’ of glucose (6,4.67, r, J = 9.7 Hz, 1H). Comparison of ‘H and 13C NMR data of 3 with those reported in the literature [2,3] showed that it has a similar structure to forsythoside B, except for differences in the linkage of rhamnose and apiose with glucose. The linkage was determined by a NOE difference spectrum. If the rhamnose and apiose were linked with C6’ and C-3’ of glucose, there would be enhancement of H6’ and H-3’ on irradiation of the anomeric protons of rhamnose and apiose, respectively. The experimental findings clearly indicated that rhamnose and apiose are linked to C-6’ and C-3’ of the glucose moiety. Their coupling constants confirmed the configurations of sugar linkages to be the /&D-form for glucose, the z-L-form for rhamnose and the /?-D-form for apiose. Thus, the structure of 3 is I’-O-B-D-(3,4-dihydroxy-/I-phenyl)-ethyl-4’-0caffeoyl-B-D-apiosyi-( 1 -+3’)-r-I_-rhamnosyl-(l +6’)-glucopyranoside. EXPERIMENTAL General. ‘H and “CNMR were recorded 100 MHz, respectively. in the FT mode.

at 400 and

Plant material. Pedicularis striata Pall (Jueyehesen) was collected in Zhang County, Gansu Province in August 1988. It was identified by Prof. Zhao Runeng and a voucher specimen is deposited in the Herbarium of the Pharmacognosy Department, Lanzhou Medical College. Extraction and prepurijication. Dried whole plants (4.6 kg) were extd with 95% EtOH under reflux (3 x I I). After concn of the combined extracts nearly to dryness under red. pres., hot H,O (500 ml) was added and the water-insol. material removed

by filtration through Celite. The filtrate wasextracted with petrol (60~90”), EtOAc and n-BuOH. The n-BuOH portion was evapd to obtain a crude syrup, which was chromatographed over silica gel (400 g) eluting with CHCI,-MeOH (19: I) followed by increasing concns of MeOH; 5 frs were collected. isolation ofpedudarioside A (3). Fr. 5 was chromatographed over silica gel eluting with CHCI,-MeOH (4: I) lo give pure 3 (80 mg). UV 1:::” (nm): 206 (4.34). 217 (4.25), 291 (4.00). 330 (4.15). IR v::; (cm _ ‘): 3377 (OH), 2933,2888 (C-H), 1700 (conj. ester) 1631 (C=C). 1604,1523 (aromatic ring). ‘H NMR (DMSOd,. TMS) Gppm: 0.96 (d, J=6.2 Hz, 3H, Me of Rha), 2.69 (r, J = 7 Hz, 2H, Ar-CH,CH,), 3.61.3.83 (m. ZH, H-6 ofGlc). 4.37 (d, J=7.7 Hz, IH, H-l of Glc), 4.67 (f, J=9.7 Hz, IH, H-4 of Glc). 5.02(d.J=l.5H~,IH,H-lofRha).5.59(d,J=5.9Hz,lH,H-lof Api), 6.15 (d, J= 15.9 Hz. IH, Ar-CH=CH), 6.48-7.03 (6H, aromatic H), 7.47 (d, J- 15.9 Hz. 11~. Ar-CH=CH). 8.63, 8.71, 9.18, Y.61 (4 x OH). ‘“C NMR: see Table I. Total hydrolysis ofpedicularios~de A (3). Compound 3 (IO mg) was dissolved in 2 ml of aq. I M H,SO,MeOH (I : I) and refluxed for 3 hr. After neutralization and removal by filtration of the ppt., the soln was coned. u-Glucose. L-rhamnose and o-aplose were identified by TLC on silica gel [CHCI,-MeOH-H,O. (15:6:2) lower phase-HOAc (Y:l)] and PC [n-BuOH-HOAc-H,O (4: 1:5) upper phase]. Parfml hydrolysis ojprdicularroside A (3). Mild acid hydrolysis of 3 (IO mg) in 2 ml of refluxmg aq. 0 I M HCI-MeOH (I : I) for I hr gave I.-rhamnose and D-apiose as the only detectable sugars by TLC and PC. Methanolysis ojpedicularioside A (3). Compound 3 (2 mg) was refluxed with methanolic 5”/0 AcCl (2 ml) for 30 min and the reagents evapd under red pres. The presence of 3.4-dihydroxyphenethyl alcohol and Me cafeate was detected by TLC on silica gel [CHCI,-MeOH, 12: I, the former R, 0.1; the latter, R, 0.25]. Compound 1. Amorphous powder (100 mg), [a]? -41.5’ (MeOH; c 1.1). UV I::$ (nm): 208 (4.30), 217 (4.45). 2Y2 (4.10), 329 (4.25). IR $;: (cm _ ‘)’ 3400 (OH), 2932 (C-H), 1701 (conj, ester), 1631 (C=C). 1604. 1521 (aromatic rmg). ‘HNMR (DMSO-d,, TMS) dppm: O.Y7 (d. J = 6 Hz, 3H. Me of Rha). 2.70 (1. J = 7 Hz, ZH, Ar --CFt2 -CH,), 4.36 (d, J = 7.2 Hz, I H. H-l of Glc), 4.72 (t, J=9.6 Hz, 1H. H-4 of Glc), 5.03 (d, J= 1.1 Hz, IH, H-l of Rha), 6.21 (d, J = I5 8 Hr. IH, Ar-CH=C&, 6.49-7.01 (6H, aromatic H), 7.47 (d. J = 15.4 Hz, IH, Ar-CH=CH). 8.69, 8.75, 9.19, 9.62 (4 x OH). ‘-‘CNMR: see Table I. FABMS (m/z): 631 [M+Li]‘, 647 [M +Na] ‘. Analytical data of I were identical lo those published for acteoside [4]. Compound 2. Amorphous powder (100 mg), [z]:,’ -31.7” (MeOH, c 1.2). UV ;.i:z” (nm): 208 (4.28). 219 (4.40). 291 (4.05), 329 (4.20). IR v::; (cm-‘): 3324 (OH), 2931 (C-H). 1690 (conj. ester), 1632 (C=C), 1605, 1516 (aromatic ring). ‘H NMR (DMSO-I,, TMS) dppm: 1.15 (d, J=5.8 Hz, 3H, Me of Rha). 2.72 (br, ZH, Ar-W--CH,), 3.24 (r. J -9 Hz. IH, H-4 of Glc). 4.33(d, J=7.2 Hz, IH, H-l ofGlc).4.26(m. IH. H-6ofGlc),4.43 (d,J= IO.9 Hz, lH,H-6ofGlc),5.11 (s, lH,H-I ofRha),6.35(d.J = 15.9 Hc I H. Ar CH=Cf$6.49-7. I7 (6H. aromanc H). 7.53 (d, J= 15.9 Hr. IH, ArCB=CH), 8.70, 8.76, 9.21. 9.64 (4x OH). ‘%INMR: see Table I. FABMS (miz): 631 [M + Li]+, 647 [M + Na] ’ Analytical data of 2 were identical to those reported for isoacteoside [5]. Compound 4. Amorphous white powder (IO mg). UV ,J.z$” (nm): 206(4.40), 285 (3.10). ‘jC NMR: see Table I. FABMS (m/z): 469 [M + LI] +, 485 [M + Na] ‘. Spectral data of 4 were identical to those published for decaffeoylacteoside [6]. Compound 5. Amorphous powder (120 mg). [a]:’ -39.6” (MeOH; c 1.1). UV ~~~‘” (nm): 205 (4.21). 218 (4.17). 289 (3.95), 331 (4.12). IR vE;(cm -‘): 3391 (OH), 2932 (C---H), I699 (conj. ester). 1630 (CH=CH), 1604. 1522 (aromatic ring). ‘H NMR

Short Reports Table

1. r3C NMR chemical

C

shifts of compounds

I’

2’

125.5 114.7 145.5 148.4 113.6 121.4 145.5 115.5 165.7

125.8 114.1 145.5 148.6 115.0 121.7 145.7 115.7 166.7

129.1 116.3 145.0 143.5 115.8 119.5 35.0 70.2

129.5 116.5 145.1 143.6 116.0 119.8 35.3 70.5

GIG 1’ 2’ 3’ 4 5’ 6

102.3 74.5 79.1 69. I 74.5 60.7

Rha 1 2 3 4 5 6

101.2 70.5 70.4 71.7 68.7 18.1

4t

1343 l-5 (100 MHz, 6 in ppm from TMS) 5*

3*

DEPT

125.5 114.7 145.5 148.5 113.3 121.4 145.8 115.4 166.0

125.4 114.7 145.5 148.4 113.3 121.4 145.7 115.4 165.7

C CH C C CH CH CH CH C

131.5 117.1 146.0 144.6 116.3 121.2 36.5 72.1

129.2 116.3 144.9 143.4 115.7 119.5 35.0 70.2

129.1 116.3 144.9 143.4 115.7 119.5 35.0 70.0

C CH C C CH CH

102.8 74.3 81.3 68.4 73.9 63.6

104.1 77.7 84.5 70.0 75.5 62.6

102.2 74.4 78.9 69.1 74.4 68.0

102.2 74.3 78.7 69.4 72.8 67.0

CH CH CH CH CH

100.8 70.8 70.8 72.4 68.8 18.0

102.7 72.2 72.2 73.9 70.0 17.9

101.2 70.4 70.2 71.6 68.7 18.1

101.1 70.4 70.3 71.6 68.7 18.1

CH CH CH CH CH

103.3 73.4 76.8 69.9 76.5 61.0

109.1 75.9 78.7 73.4 63.2

CH CH C

Caffeic acid

I 2 3 4 5 ;* :Q Aglycone 1 2 3 4 5 ; a

Api (Glc for 5) 1 2 3 4 5 6

-

__

-

-

CH, CHz

CH,

CH,

CHz CHz

*In DMSO-I,. tin methanol-d,.

(DMSO-dn, TMS) Gppm: 0.96 (d, J =6.0 Hz, 3H, Me of Rha), 2.70(r,.l=6.8 Hz, 2H,Ar-CH,CH,),4.15(d,J=7.6 Hz, lH, H1 of Glc), 4.36 (d, J = 7.6 HG lH, H-l of Glc), 5.02 (s, lH, H-l of Rha), 6.20 (d, J= 15.6 Hz, IH, Ar-CH=CY), 6.49-7.14 (6H, aromatic H), 7.47 (d, J= 15.6 Ht IH, Ar-C&CH), 8.65, 8.71, 9.16, 9.62 (4 x OH). ‘%NMR: see Table 1. FABMS (m/z): 793 [M + Li] +, 809 [M + Na] +. Analytical data of 5 were identical to those reported for echinacoside [4]_ Compound 6. Yellowish jelly-like solid (70 mg). ‘HNMR (DMSO-d,, TMS) dppm: 1.37 (s. 3H, H-lo), 1.78 (dd, J= 14.8, 4.4 H7, lH, H,-7). 1.94(s, 3H, AC), 2.07(d.J= 14.8 Hz, tH, H,-7), 2.66(d,J=1.3Hz,1H,H-9),4.39(d,J=7.8Hz,IH,H-l’ofGlc~ 4.87(dd, J=6.3. 1.2Hz. IH, H-4). 59O(d, J=1.3Hz, lH,H-1). 6.34 (d, J = 6.3 Hz, IH, H-3). “C NMR (DMSO-I,, TMS) dppm:

92.6 (C-l), 141.4 (C-3), 107.4 (C-4), 71.3 (C-5), 75.8 (C-6). 44.7 (C7), 86.5 (C-8), 54.4 (C-9). 170.4 (MeCO). 21.2 (MeCO), 97.5 (C-l’), 73.2 (C-2’), 77.2 (C-3’). 70.3 (C-4’), 76.3 (C-5’), 61.3 (C-6’). FABMS (m/z): 413 [M + Li]+, 429 [M + Na]+. Spectral data of 5 were identical to those published for 8-acetyl harpagide [7] [8]. Totol hydrolysis of compounds 1, 2, 46. Acid hydrolysis (co 5 mg) in 2 ml refluxing aq. I M H,SO,-MeOH (1: I) for 3 hr yielded their respective sugars which were identified by TLC and PC.

Acknowledgements-The authors are indebted to Yang Li, Zhu Qixiu and Cheng Jihong for NMR measurements and to Cheng Nengyu, Z.ai Jianjun, Li Haiquan and Zhao Fanzhi for FABMS.

1344

Short Reports

We are grateful to Prof. Zhao Runeng for identification

4. Kobayashi, H.. Karasawa, H.. Miyasc. T. and Fukushima, S. (1984) Chem. Pharnr. Bull. 32, 3009. 5. Kobayashl, H.. Oguchi. H. and Takizawa, N. (1987) Chem. Pharm. Bull. 35. 3309. 6. Burger, J. F. W., Brand{. E. V. and Ferreira, D. (1987) Ph~roc%emisrr~ 26. 1453. 7. Scarpati. M. L.. Guiso. M. and Panizzi. L. (196%. Tefrahedron Letfers 39. 3439. 8. Belofsky. G.. Bowers. %I. D., Janren. S. and Stermitc F. (1989) Plt~roc+femi.~rr~28. 160I

of plant

material. REFERENCES I. Jiangsu New Medical College (1977) The Chinese medicine Dicrionar). Shanghai People’s Publishing House. 2. Endo, K.. Takahashl, K., Abe, T. and Hikino. H. (1982) Hrrcwcples 19, 26 I. 3. Cooper. R., Solomon, P. H., Kubo. 1.and Nakanishi, K.(1980) J. Am. (‘hem. Sot. 102. 7953.

Ph,uodwmwr~.

Vol.

30.

No

4. pp.

1344

1345.

1991

Pruned In (ircat Hrnaln

(

QUERCETIN

3’-SULPHATE

FROM H YPERICUM

003 I 94?2:91 $3.00 + 0.00 1991 Pergamon Prerr plc

ELODES

ROSA M. SEABRA and A. CORRFIA ALVFS Centro

de Estudos de Quimica

Orginlca.

Fitoquimica

e Farmawlogia,

Anibal Cunha. 4000 Porte.

(Rewwd

Key Word Index

de Farmricla

sulphak:

INTRODllCTION

RESULTS AND DISCUSSION

The yellow colour on a cellulose plate (366 nm) and the UV spectral data (methanol) of compound 1 suggest that it is a flavonoid with a free C-3 hydroxyl [3]. Besides, its arrow-shaped spot on TLC and its electrophoretic mobility (0.7) suggest the presence of a sulphate group. Etfectively, upon acid hydrolysis, 1 gave quercetin, and sulphate (BaCI, ppt), but no sugar was present. The IJV spectral data obtained with the usual reagent shifts [3] support the conclusion that in the quercetin molecule only the C-3’ hydroxyl is occupied, once the following results were observed: (i) a bathochromic shift of 65 nm was observed in band I when the spectrum was

do Porte.

Rua

qucrcctin 3’-sulphate.

from Hypericum e/odes has been identified

Recently we have described the characterization of three quercetin glycosides [l] and quercetin 3-glucuronide-3’sulphate [2] in Hypericum e/odes. We now report the identification of another flavonoid sulphate (1) in the same plant material, which. as far as we know, is a new natutal compound.

da L’niversidade

Portugal

IO July 1990)

Hypericum e/odes: Guttiferae: llavonoid

Abstract---A new flavonol sulphate isolated graphic data as quercetin 3’-sulphate.

Faculdade

by spectral

and chromato-

recorded in the presence of AICI, + HCI (free C-5 hydroxyl); (ii) a bathochromic shift of I5 nm was observed in band II in the presence of NaOAc (free C-7 hydroxyl); (iii) a bathochromic shift of 60 nm was observed in band I, with no decrease in its intensity. after addition of NaOMe (free C-4’ hydroxyl) and (iv) the CJV spectrum recorded in the presence of AICI, was superimposable with that recorded after addition of HCI (occupied C-3’ hydroxyl). These conclusions were also supported by the yellow fluorescence (AICI,) and yellow-green colour (NA) obtained on cellulose plates [4]. The FAB mass spectrum of the compound showed peaks at 405, 383 and 303 consistent. respectively, with the presence of [R--O SO,Na+ H] I, [R--O-SO,H + H] + and [R--OH + H] ’ fragments. The final confirmation of the structure of I as quercetin 3’-sulphate was made by “C NMR spectroscopy, which is in good agreement with that published fqr the synthetic compound [5], and by ‘H NMT: which shows the characteristic shifts of the (5 values of ring B protons. It is not an artifact of the isolation procedure. as it could be detected after macerating the plant in methanol for IO min at room temperature.