Perseapicroside A, hexanorcucurbitacin-type glucopyranoside from Persea mexicana

Perseapicroside A, hexanorcucurbitacin-type glucopyranoside from Persea mexicana

Phytochemistry, Vol. 29, No. 4, pp. 1330 1332, 19YO Printed in Great Britain. Oil31 9422/90$3.00+ 0.00 (” 1990 Pergamon Pressptc PERSEAPICROSIDE A, ...

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Phytochemistry, Vol. 29, No. 4, pp. 1330 1332, 19YO Printed in Great Britain.

Oil31 9422/90$3.00+ 0.00 (” 1990 Pergamon Pressptc

PERSEAPICROSIDE A, HEXANORCUCURBITACIN-TYPE GLUCOPYRANOSIDE FROM PERSEA MEXICANA AYUMI OHSAKI. Department

of Chemistry.

Key Word Index- Persea principle,

perseapicrosidc

School

TAKASHI

of Medicine,

KUBOTA

Kinki University,

and

YUKIHIRO

Ohnohigashi,

INTRODUCTION

The bitter bark of Persea mexicanu, known in the Monterrey area in Mexico as ‘Palta de Apetito’. is a medicinal plant used in the form of a tea as an aperitive. In our continuing search for bitter principles from plant sources, we here report the isolation and structure of a new hexanorcucurbitacin-type glucopyranoside. perseapicroside A, the bitter principle of Persea mrxicann. RESULTS AND DISCUSSIOR

The bitter ethyl acetate fraction was obtained from the methanol extract of dried bark of ‘Palta de Apetito’. Droplet counter current chromatography with chloroform-methanol--water (13 : 7 : 4) of the bitter fraction resulted in the isolation of perseapicroside A. Perseapicroside A (I) had mp 204-206 (MeOH); [cz]n + 100’ (MeOH; c 0.1); elemental analysis, C, 59.99%, H, 8.07%, C,,H,,O,, .2H,O requires C, 59.78%, H, 8.36%; FAB mass spectrum (70 eV), m/z 567 [M + H] -; UV 208.5 (log E 4.59. EtOH) nm. It exhibited hydroxy and carbonyl absorption bands at 3400 and 1680 cm -’ in its IR spectrum. The ‘H and 13C NMR spectra of 1 (Tables 1,2) indicated the presence of five tertiary methyl groups, one acetyl group, five methylene groups, 11 methine groups, one carbonyl group, four sp” quarternary carbons and one trisubstituted carboncarbon double bond. Analysis of the ‘H and 13C NMR data of 1 suggested the presence of a glucose moiety. Hydrolysis of 1 with emulsin afforded glucose and aglycone 2, mp 237.55238 (EtOH); HRMS: (70 eV) m/z 404.2559 [Ml’. C,,H,,O, requires 404.2563. On the basis of overall unsaturation data, 1 was concluded to be a hexanortriterpenoid molecule posessing four rings. The ‘H, 13C, ‘H-{rH) COSY, ‘3C?(1H) COSY NMR spectra and detailed spin decoupled experiments of 2 revealed it to possess seven partial structural units as in a-f (Fig. 1).

to whom correspondence

Osaka-sayama.

mexicana, Lauraceac, avocado, hexanorcucurbitacin-type A; 2,3,16-trihydroxy-4,4,9,14-tetramethy1-19-norpregn-5-ene-1

Abstract--Perseapicroside A. a new bitter hexanorcucurbitacin-type glucoside been assigned the structure 2,3,16-trihydroxy-4.4,9,14-tetramethyl-l9-norpregn-5-ene-l detailed spectrsocopic analysis.

*Author

ASAKA*

should

Osaka,

glucopyranoside, 1.20-dionc.

isolated

589, Japan

bitter

from Persea mexicana, has 1,20-dione on the basis of

The NOESY NMR analysis of 2 revealed NOE between the following protons, namely. H-6jH-10, H-6/H30, H-16/H-21. H-12x/H-28, H-17/H-28, H-17/H-21, H3/H-30, H-3/H-l/{. H-lO’H-28, H-l’aiH-18, H-8/H-19 and H-8/H-18. These results fully assigned the structure 2 as 2,3,16trihydroxy-4,4,9,14-tetramethyl-19-norpregn-5-ene-l1,20dione(hexa-norcucurbitacin F, lit. mp 128-130’), which was isolated previously from Elaeocurpus dolichostyhs (Elaeocarpaceae) Cl]. The physical properties of 2 were very similar to those described for hexanorcucurbitacin F except for the mp. The ‘H and 13CNMR spectra of 2 (Tables 1,2) were very similar to those of 1 except for the chemical shifts of H-2 (64.05. Lidd, J= 13, 10. 4 Hz). C-2 (fi71.42) and C-3 (681.35). Therefore, perseapicroside A was deduced to have the structure 1 as a result of comparison between the chemical shifts of 1, 2 and the published data for some cucurbitacins [l--5]. Although various 16a-glucosyloxycucurbitacins and some hexanorcucurbitacins were found in the family Cucurbitaceae and Cruciferae [6] and Scrophularaceae [2], Cucurbitaceae [4] and Begoniaceae [7], respectively, this report represents the first example of a 2/1-glucosyloxyhexanorcucurbitacin in nature and the first isolation from the family Lauraceae. EXPERIMENTAL

‘Palta de Apetito’ was purchased in Monterrey, Mexico in August 1978. It was identified by Dr X. A. Dominguez. I.sdution ~$1.Extraction ofdried pulverized ‘Palta de Apetito’ (400g) with MeOH and the partition of the concentrated aq.

be addressed.

2R=H 1330

Short Reports Table H

1

la

2.36 1.46 4.25 3.40 5.72 2.38 1.96 1.88 2.70 3.34 2.58 1.81 1.90 5.32

18 2 3 6 7u 7P 8 10 12a ‘2P 15a ‘5s 16

1. ‘H NMR*

(ddd, 13, 4, 4) (m) (ddd, 13, 10, 4) (d, 10) (d, 6) (ddd, 20, 9, 6) (dd, 20, 6) (d, 9) (hr d, 14) (d, 14) (d, 14) (d, 14) (d, 14) (ddd, 8, 8, 2)

chemical

2. 13C NMR chemical

1

2.36 (ddd, 13, 4, 4) 1.48(m) 4.05 (ddd, 13, 10, 4) 3.38 (d, 10) 5.72 (d, 6) 2.38 (ddd, 20, 9, 6) 1.96 (dd, 20, 6) 1.88 (d, 9) 2.72 (hr d, 14) 3.32 (d, 14) 2.58 (d, 14) 1.81 (d, 14) 1.90 (d, 14) 5.32 (ddd, 8, 8, 2)

17 18 19 21 28 29 30 1’ 2 3’ 4 5’ 6’a 6’b

3.48 0.79 1.22 2.17 1.54 1.21 1.46 5.18 4.12 4.22 4.27 3.94 4.42 4.54

shifts of compounds

2

C

1

2

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

33.80 78.68 93.76 42.50 141.86 119.18 24.22 43.34 50.39 34.02 211.86 47.39 48.99 49.15 46.00

34.37 71.42 81.35 42.77 142.40 118.54 24.19 43.46 50.44 34.56 211.99 47.42 49.02 49.23 46.03

16 17 18 19 20 21 28 29 30 1’ 2 3’ 4 5’ 6

71.61 67.88 19.87 20.30 208.55 31.64 25.26 23.32 19.16 107.14 76.23 78.68 71.37 78.50 62.80

70.90 67.85 19.86 20.30 208.61 31.64 25.41 22.30 19.20

2 (d, 6) (s) (s) (s) (s) (s) (s) (d, 8) (dd, 10, 8) (dd, 10, 8) (dd, 8, 8) (ddd, 8, 6, 2) (dd, 12, 2) (dd, 12, 6)

3.48 0.79 1.29 2.17 1.53 1.21 1.46

(d, 6) (s) (s) (s) (s) (s) (s)

&values are given in ppm relative to TMS, multiplicity

1 and 2

1

and J-

methanolic soln with EtOAc afforded an amorphous bitter material (47 g). The ascending method of DCCC with CHCl,-MeOH-H,O (13 : 7 :4) successfully resulted in the isolation of 1 (4 ml/hr, fr. 3545, 165 mg) from the bitter fraction (1 g). Treatment of 1 with emulsin. To a soln of emulsin (100 mg) in Na acetate buffer (pH 5.3, 20 ml), 1 (100 mg) was added. After 24 hr (25 “C), the soln was extracted with CHCI,. The extract was dried (Na,SO,) and the solvent removed under red. pres. leaving crude crystalline aglycone 2 (46.3 mg). Acknowledgements-We wish to thank Dr X. A. Dominguez (Instituto Tecnologico y de estudios superores de Monterrey, Mexico) for identification of Pet-sea mexicana. This study was supported by a grant from SUNBOR.

REFERENCES 1. Fang, X., Phoebe, Jr., Pezzuto, J. M., Fong, H. H. S. and Farnsworth, N. R. (1984) J. Nat. Prod. 47, 988.

*The spectra were measured at 100 MHz in pyridine-d,; values are given in ppm relative to TMS.

=CH-CH,-CH-

1 and 2

H

C

-c

shifts of compounds

2

*The spectra were measured at 400 MHz in pyridine-d,; values (in Hz) are in parentheses.

Table

1331

6-

Me-C-

(4

x2

Ac-

Me-C-Me

I

I

@I

(cl

W

I

I

I

-CO-CH,-C(Me)-CH-CHOH-CH~-

-CH--HI-CHOH-CHOH-

(f)

(e) Fig. 1. Structural

components

of aglycone

2.

1332

Short Reports

2. Che, C., Fang, X., Phoebe, C. H. Jr., Kinghorn, A. D., Farnsworth, N. R., Yellin, B. and Hecht, S. M. (1985) J. Nar. Prod. 48, 429. 3. Laurie, W. A., McHale and D. and Sheriden. J. B. (1985) Phytochemistry 24, 2659. 4. Sasamori, H., Raddy, K. S., Kirkup, M. P., Shabanowitz, J., Lynn, D. G., Hecht, S. M., Woode, K. A., Bryan, R. F., Campbell, J., Lynn, W. S., Egret, E. and Sheldrick. G. M.

(1983) J. Chem. Sot. Perkin Tums I 1333. 5. Rao, M. H., Meschulan, H. and Lavie, D. (1974) J. Chem. Sot. Perkin Truns I 2552. 6. Lavie, D. and Glotter, E. (1971) Proqr. Chem. Org. Nat. Prod. 29, 387. 7. Doskotch, R. W. and Hufford. c’. D. (1970) CN~. J. Chem. 48, 1787.

Phyrochemistry, Vol. 29,No. 4,pp.1332 1334,lY90 Printed in Great Britain.

TWO FUROSTANE

0031 9422;YO$3.00+0.00 'f'1990Pergamon Press plc

SAPOGENINS

FROM

CORDYLZNE

RUBRA

MING-HE YANG, GERALD BLUNDEN, ASMITA PATEL, TREVOR A. CRABB,* KEITH BRAIN? and

WILLIAM J. GRIFFIN: School of Pharmacy and Biomedical Sciences; Portsmouth,

*Department of Chemistry, Portsmouth Polytechnic, King Henry I Street, PO1 2DZ, U.K.; tWelsh School of Pharmacy, UWCC, PO Box 13, Cardiff CFI 3XF, U.K.: ZDepartment of Pharmacy, University of Queensland, St Lucia, Queensland 4067, Australia (Received

Key Word Index

Cordyline

in recised form 12 September

ruhra; Agavaceae;

steroidal

sapogenins;

1989)

lg,3z-dihydroxy-furost-5-ene;

lB,3%,26-tri-

hydroxy-5r-furostane.

Abstract--From the leaves of Cordyline spectroscopic and mass spectrometric lb,3a,26-trihydroxy-Sr-furostane.

rubra

data

two new steroidal sapogenins have been isolated. NMR prove the compounds to be l/I,3r-dihydroxy-furost-5-ene

INTRODUCTION In previous studies of the steroidal sapogenins produced after acid hydrolysis of the saponins extracted from the leaves of Cordyline rubra, several mono-, di- and trihydroxy compounds have been isolated [ 1, 21. In this report we record the isolation and identification of a further two sapogenins, both of which are novel compounds.

RESULTSAND

and IR and

DECUSSION

Cordyline rubru leaves were extracted with ethanol and the saponins present acid hydrolysed. The sapogenins liberated were separated and isolated by column chromatography and preparative TLC. In addition to the sapogenins reported earlier [2], two further compounds were isolated. Compound 1, C,,H,,O, (M’, rnjz 416.6411; cal-

CH,OH