Lignans in flower buds of Magnolia saulangiana

Lignans in flower buds of Magnolia saulangiana

Phytochemistry, Vol. 34, No. 4, pp. 1185-l 187, 1993 Printed in Great Britain. 0 003 1 9422/93 $6.00 + 0.00 1993 Pergamon Press Ltd LIGNANS IN FLOW...

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Phytochemistry, Vol. 34, No. 4, pp. 1185-l 187, 1993 Printed in Great Britain.

0

003 1 9422/93 $6.00 + 0.00 1993 Pergamon Press Ltd

LIGNANS IN FLOWER BUDS OF MAGNOLlA SAULANGIANA 0.

Department

of Pharmacognosy,

Faculty of Pharmacy,

(Received in

Key Word Index-Magnolia

M. ABDALLAH

revised form

29

saulangiana; Magnoliaceae;

Assiut University,

Assiut, Egypt

April 1993)

flower buds; lignans.

Abstract-From the flower buds of Magnolia saulangiana, seven lignans were isolated and characterized. One was a new lignan for which the name saulangianin and structure (3S,3aR)-3a-allyl-$methoxy-3-methyl-2-(3’,5’ methylene dioxybenzyl)-2,3,3a,4,5,6 hexahydro-6-oxobenzofuran, are proposed

INTRODUCTION The genus Magnolia has many folkloric uses e.g. an antipyretic Cl], antibacterial [Z], antifungal [2] and recently as an anticancer agent [33. This genus contains diverse groups of active constituents, including alkaloids [4-61, volatile oils [7], sesquiterpene lactones [8-111, flavonoids [12] and lignans [13-153. Magnolia saulangiana was introduced into Egypt for ornamental purposes for its showy, large and fragrant flowers. In the present investigation of M. saulangiana we have isolated a new hexahydrobenzofuranoid, saulangianin (1). In addition, six other known lignans were isolated, viz., denudatin A (2) [ 133, denudatin B (3) [ 133, cyclohexadienone (4) [14], aurein (5) [15], pinoresinol dimethylether (6) [16] and verguansin (7) [17, 181.

solvent systems. Spots were detected on TLC in UV (254 nm), after spraying with Dragendorff’s reagent or H,SO, (10%) and heating to 100” for 5 min. Plant material. Magnolia saulangiana was collected from flowering plants growing in a private garden near El-Minia during May 1987. Authentication of the species was carried out by Dr N. El-Hadidi, Cairo University. Isolation of constituents. Flower buds (2 kg) were defatted with petrol (60-80”) and then extracted with MeOH. The MeOH extract was coned (residue 12 g) and

Table 1. ‘%NMR* data saulangianin 1 and denudatin measured at 22 MHz C

1

2

87.3 42.8 50.2 32.1 46.6 196.4 100.2 183.1 39.3 132.1 119.4 128.9 108.1 148.5t 148.3t 110.1 117.9 58.3 101.4 44.1 11.6

91.3 50.0 17.7 131.1 143.0 187.0 102.8 174.5 33.5 135.1 117.2 131.2 106.7 148.3t 148.2t 108.2 120.9 51.1 101.3

for A 2

RESULTS AND DISCUSSION

The 5-p-methoxybenzofuranoid neolignan, saulangianin I, of molecular formula CalH1,Os was determined by high resolution mass spectrometry and 13C and ‘H NMR. The ‘HNMR spectrum revealed the presence of the moiety Me-CH-C -R, where R = -CH,-piperonyl, 8 with the R and Me groups in a trans-relationship. The additional C,-C, unit must be represented by a cyclohexaenone. A comparative 13CNMR study (Table 1) of saulangianin I with denudatin A [ 131 led to the formula 1.

EXPERIMENTAL MPS are uncorr. ‘H (90 MHz) and 13CNMR (22 MHz) in CDCl, with TMS as int. standard (70 eV), direct insertion. [a];‘: CHCl,. UV: MeOH. CD: MeOH. IR: KBr, CHCl,. Chromatographic sepns were carried out on silica gel (Merck). TLC was performed on silica gel G using petrol-EtOAc (9:l) Sl and CHCl,-MeOH (19: 1) as

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2 3 3a 4 5 6 7 8 z B Y 1’ 2 3’ 4’ 5 6 OMe OCH,O Ar-CH, Me

6.7

‘CLXl,. tValues may be interchangeable.

Short Reports

1186

2

R --a&--

3

-0Me

0 R

-Ii 0

R

6 R=

chromatographed on a silica gel column (5 x 40 cm) using Sl to give frs A-D. Each fr. was rechromatographed on a silica gel column, fr. A giving l(20 mg) and 2 (100 mg), fr. B, 3 (200 mg) and fr. C, 4 (30 mg) and 5 (60 mg). Fr. D yielded 6 and 7 in quantities sufficient for analysis. The new compound 1 was submitted to complete analysis; known compounds were identified by direct comparison of mp, [a&, and spectral data with published data. Saulang~anin f, (3S,3aR~3a-allyl-5-~thoxy-3-~thyl2~~,S-~@t~yle~ dioxybe~y~-2,3,3a,4,5,~~xahydro-6oxo-benzofwan) 1. Colourless oil, [LX];‘+ 2.5 (CHCI,;

e 0.5). IR vEtF13cm - *: 3050, 1660, 1620, 1170. UV Lgz’” nm: 207,235,294. MS m/z (rel. int.) 356. 1617 (5) [calcd for Cz1Ha405, 356.16201 340 (lOO), C,,Hzo05, 310 (12), C,,H,,O,, 299 (7% C~$IJ%r 271 (ll), C&I,@, 267 (2% G&izO* 239 (2% G,H,,O,, 237 (1% C,,H,O~. ‘H NMR (90 MHz, CDCI,, 6): 1.25 (d, J = 7 Hz, Me), 2.40 (mC!gJ, 2.54 (m, Ar-CH,), 3.72 (s, OMe), 3.95 (m, H-5), 5.1-5.2 (m, CH&, 5.42 (m, H-2), 5.80 (s, H-7), 5.82-6.00 (m,

B-CH), 5.97 (s, OCH*O) and 6.65-6.88 (m, Ar-H). 13C NMR data in Table 1. Denudatin A 2 (2S,3R,3aR)-5-allyl-3a-mPthoxy-2~i~ronyl-3-~thyl

2,3,3a,6 tetrahydro-6-oxobenzo~an.

Colourless needles, mp 105-107”. HRMS (rel. int.) m/z 340.1313 (33) [C,,H,,O, requires 340.13103. 13CNMR data in Table 1. Other spectral data similar to those reported in ref. [13]. Denudatin B 3 (2S,3R,3aR)-3a-allyl-bmethoxy-2pipercmyl-3-methyl-~3,346-tetrahydro-6-oxobenzofur~n. Oil. HRMS (rel. int.) m/z 356.1624 (62) [C,,H2,0,

requires 356.1624-J. Other data coincidental reported in ref. [13].

with those

Cyclohexadienone 4 (2S,3S,5S)-S-allyl-5-methoxy-3methyl-2-piperonyl-2,3,5,6-tetrahydro-&benzofiran. Oil.

HRMS (ret. int.) m/z 340.1311 (C2,H,,0,) requires 340.1310. Other spectra1 data the same as those reported in ref. [14]. Aurein 5 2-(4-aflyloxy-3,5-methoxyphenyl)-l-(3,4,5-trimethoxyphenyl)-propane. Mp 80-84”. HRMS m/z (rel.

Short Reports int.) 402.2047 (17) [CzJHJoOL requires 402.2043). Other spectroscopic data similar to those reported in ref. [15]. Pinoresinol dimethyl ether 6. Colourless crystals, mp 106”. [Cz2Hz606, requires 386.17291. Other spectral data similar to those reported in ref. [16]. Veraguensin 7. Colourless crystals, mp 121”. HRMS (rel. int.) m/z 372.194 (28) [Cz2H2s05, requires 372.1937-J. Other spectral data as reported in refs [17, 18-j. Acknowledgements-Thanks are due to Prof. Dr W. Steglich, Bonn University, F.R.G. for the measurements of high resolution spectra. BEFERF,NCES

1. Koppaka, V. R. (1975) Planta Medica 27, 31. 2. Shakla, P. and Misra, S. P. (1979) in An Introduction to Taxonomy of Angiosperms p. 213. Vikas Publishing House, New Delhi. 3. Lewis, H. W. (1977) in Medical Botany, Plants A$ecsing Man’s Health, pp. 86, 131, 135. John Wiley, New York. 4. Hegnauer, R. (1965) in Chemotaxonomie Der Pjlanzen Vol. 5, Birkhauser, Basell. 5. Shamma, M. (1972) in 7’he Isoquinoline Alkaloids, Vol. 25, pp. 44, 115, 194, 221, 245, 247. Academic Press, New York.

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6. Manske, R. H. F. (1970) in The Alkaloids, Vol. 12, p. 489. Academic Press, New York. 7. Guenther, E. (1975) in The Essential Oils Vol. 5, p. 381. Robert, E. Kriegger Publishing Company, Huntington, New York. 8. EI-Feraly, F. S. and Chan, Y. M. (1978) J. Pharm. Sci. 67, 347.

9. Wiedhopf, R. M., Yoimy, M., Binachi, E. and Cole, J. R. (1973) J. Pharm. Sci. 62, 345. 10. El-Feraly, F. S., Chan, Y. M., Fairchild, E. l’t and Doskotch, R. W. (1977) Tetrahedron Letters 1973. 11. Fujita, S., Ichimatsu, Y. and Fujita, Y. (1977) Yakugaku Zasshi 97, 1216. 12. Francis, F. J. and Harborne, J. B. (1966) Proc. Am. Horticulture

89, 657.

13. Lida, T., Ichino, K. and Ito, K. (1982) Phytochemistry 21, 2939.

14. Gottlieb, 0. R., da Silva, M. L. and Ferreira, Z. S. (1975) Phytochemistry 14, 1825. 15. Gottlieb, 0. R., Maia, J. G. S. and Mourao, J. C. (1976) Phytochemistry 15, 1289. 16. Kakisawa, H., Chen, Y. P. and Hsii, H. Y. (1972) Phytochemistry 11, 2289. 17. Crossely, N. S. and Djerassi, C. (1962) J. Chem. Sot. 1459. 18. Ahmed, R., Schreiber, F. G., Stevenson, R., Williams, J. R. and Yeo, H. M. (1976) Tetrahedron 32, 1339.