Butyraceol, a triterpenoidal sapogenin from Madhuca butyracea

Phyfocht-mistry, Vol. 30, No. 6, pp. 2087-2088, Printed in Great Britain.

BUTYRACEOL,

C&I-9422/91 S3.00+0.00 f$ 1991 Pergamoo Press plc

1991

A TRITERPENOIDAL SAPOGENIN MADHUCA BUTYRACEA G. MISRA, R. BANERJIand

FROM

S. K. NIGAM

National Botanical Research Institute, Lucknow 226 001, India (Received 9 October 1990)

Key Word ImIex--Mod&a

butyracea; Sapotaceae; seed kernel; sapogenin.

Abstract-The structure of a new triterpenoidal sapogenin, butyraceol, from the seed saponin of Madhuca butyracea has been elucidated as olean-5,12-dien-2/3,3B,23-triol by spectral data and comparison with a synthesized sample. ‘-./

INTRODUCTION

The saponins from the seeds of plants of the genera Madhuca and Mimusops [l-3], on conventional acid hydrolysis, yield bassic acid as the major sapogenin, an artifact, of protobassic acid [2, 43. In the present study, using mild acidic conditions, a further sapogenin, butyraceol, from the seed kernel saponin of Mudhuca butyracea Macbride has been isolated and its structure elucidated. RESULTS

RO

AND DISCUSSION

The saponins from the seed kernel of Madhuca butyraon mild acid hydrolysis, yielded a mixture of polyoxygenated sapogenins. Chromatography of the sapogenins yielded, beside bassic acid, a triterpene of the oleanane series, provisionally named butyraceol (I), C3,,Ha803, ([Ml’ at m/z 456), mp 278-280”. It gave a violet colour in the Liebermann-Burchard test and the IR spectrum showed a broad band at 3460 cm- ‘. The 13C NMR spectrum showed three signals at 667.37,68.40 and 71.21 assignable to three carbons bearing hydroxyl -a..rc “J. L-l Tl..P c:n”olr 4L o* ”S ‘7-v.L”) 1AA7L ,“I3 70 a1.u 0.4 pJl”ql’J L-‘, 111G X~i’LcuJ IN. 72 I-‘, 11 ‘1 ‘I1.&Z 115.59 revealed the presence of two double bonds. The presence. of three acylable hydroxyl groups was further confirmed by treatment with acetic anhydride and pyridine, which resulted in the formation of an amorphous triacetate, C,,H,,Os ([Ml’ at m/z 582) exhibiting three singlets at 6 1.96, 1.97 and 2.20 in the ‘H NMR spectrum and signals at 6169.95 (2 x OAc) and 170.81 in the 13C NMR spectrum. In the mass spectrum of 1 and la, the strong peaks at m/z 218 and 203 indicate the presence of a double bond at C-12, but the absence of substituents in the rings C, D and E. The fragment ion at m/z 258 (a), arising by retroDiels-Alder fragmentation, confirms another double band at C-5 143. The fragment ions at m/z 238 (b) in 1 and m/z 364 in la prove that all the hydroxyl groups are confined exclusively to ring A. The chemical shifts in the ‘H NMR spectrum (Table 1) for C-2, C-3, C-6, C-23 are found to be in close agreement with those of the reported values for triacetoxy methyl bassate [4]. Consequently the structure of butyraceol was elucidated as olean-5,12&en-2R.3R.21-~jo! Ill charac-r,-I-,-\-I- All --- the ---- nhvsico-chemica! r--J---teristics of butyraceol are comparable with those of the trio1 synthesized from bassic acid. tea,

(a)

m/z 258

(b)

m/z238

EXPERIMENTAL

Plant material. The seeds were collected from the Pithoragarh district of Uttar Pradesh and a voucher specimen is deposited in the herbarium section of the Institute. Isolation o/ suponin. The decorticated and powdered seed material (5 kg) was defatted with petrol (bp 40-60”) and then extracted with EtOH. After removal of EtOH in uacuo the syrupy concentrate was pptd in a large excess of Me,CO to afford crude saponin, purified by repeated precipitations, as a light brown amorphous powder (500 g). Acid hydrolysis ofthe saponin. The saponin (50 g) was hydrolysed with ethanolic 2% H,SO, under reflux for 4 hr and the reaction product extracted with ether (3 x 200 ml). The sapogenin mixt. was subjected to chromatography over silica gel and eluted with CHCl,-MeOH mixts of increasing polarity. The CHCl,-MeOH (9: 1) eluate gave needles of butyraceol(1) @OOmg) mp 278-280”: IR YE; cm-‘: (OH) 3460, 1362, 1068, 1048,1030,1014; MS, m/t (rel.int.): C,,H,sO, 456(S) [Ml’, 438 (19)[M-H,O]+,420(5)[M-2H,O]+,258(18)(a),238(100)(b),

2087

Short

2088

Table Methyl C-Me OCOMe C,,,,H,-OAc CWH C,,,H-/?-OAc C;,,H-/?-OAc C,,lIH

Reports

I. ‘H NMR spectral

triacetoxy

bassate

data Triacetoxy

butyraceol

0.94 (6H). 0.95, 1.05, 1.26. 1.36 (3H each) (all s) 1.99, 2.04. 2.08 (3H each. s) 3.81, 4.22 (ZH, ABq. J = 12 Hz) 5.50-5.70 (I H, m) 5.02 (IH, d, J=4 Hz)

0.85, 0.90, 0.94, 0.95, 1.27 1.25, 1.38 (3H each) (all 5) 1.96, 1.97. 2.02 (3H each. s) 3.82, 4.22 (ZH, ABy. J .= 12 Hz) 5.W5.60 (IH, m) 4.95 (IH, d. J=4 Hz)

5.4X--5.52’

5.3.-5.4 (2H)’

1

*Signal pattern

unclear

due IO overlapping.

218 (74). 203 (28); ‘H NMR: 60.65 (3H, s). 0.72 (3 x 3H, s), 1.10 (3H,s), 1.51 (3H,s), 1.60(3H,s), 3.90(2H.q, J= 12 Hz),4.25(lH. d, J =4 Hz), 5.24, 5.57 and 5.82 (I H, all, signal pattern unclear); ‘“C NMR, 41.67 (C-l, t), 67.37 (C-2, d), 68.40 (c-3, d). 40.33 (C-4,s). 140.75(C-5,s). 115.59(C-6.d),34.55(C-7.f),40.54(C-8,~). 47.61 (C-9, d), 41.39 (C-IO, d), 20.94 (C-l I, I). 117.59 (C-12. d), 144.40 (C-13, s), 41.92 (C-14, s), 28.20 (C-15, I), 21.53 (C-16, f), 35.77 (C-17, a). 42.77 (C-18, d), 43.07 (C-19, 1). 31.79 (C-20, s), 34.75 (C-21, f), 36.31 (C-22, 1). 71.21 (C-23, t), 16.80 (C-24, 4). 16.80 (C-25, q). 19.47 (C-26, y), 22.31 (C-27, 9). 22.31 (C-28. q), 3 I.00 (C-29.4). 2 I .33 (C-30. &Further eluates iiclded bassic acid (500 mg), mp 288-290” [4]. Acetylation of hufyraceoL Compound ! (!@I me) 01 in nvridine r, (2 ml) with Ac,O (2 ml) was left overnight at room temp. to afford la, vi:: LZ- ‘: 1735, 1256; MS m/z (rel. int.): C 36H 540 6 582 [M]’ (3). 522 [M -MeCO,H]’ (49). 364 (2) (h), 258 (18) (a), 218 (70); ‘H NMR: see Table 1: “C NMR: 66.13 (C-2). 69.10 (C-3), 142.26 (C-5), 121.53 (C-6), 117.53 (C-12), 142.59 (C-13). 70.97 (C-23). 170.81, 169.95, 169.95 (-OCOMe), 20.57, 20.64. 24.5 1 (--0COMe). ComersIon of hassic acid to butyruceol. Bassic acid (IO0 mg) in MeOH was treated with excess of ethereal CH,N, to afford needles of methyl bassate. mp 215-216’. A soln of the ester I.tiw mgj in pyridine (2 mij was refluxed with benzyi chioride (2 ml) at 130” for 4 hr to afford the benzyl derivative of methyl bassate (80 mg). The product, thus obtained, was reduced with

LiAIH, (50 mg) in THF (2.5 ml) and finally left overnight in pyridine (2 ml) with p-toluene sulphonyl chloride to afford the tosyl derivative. The tosyl derivative (50 mg) in THF (2 ml) was again reduced with LiAIH, (50 mg) for 3 hr and the product was finally treated with Pd charcoal to give butyraceol, mp 278-280”. mmp no depression. Acknowled+menr

D. K. Kulshrestha suggestions.

are grateful to Dr -The authors (C.D.R.I.. Lucknow, India) for his helpful

REFERENCFS

I. Banerji, R., Misra, G. and Nigam, S. K. (1985) Plonra Med. 280. 2. Banerji, R. (1978) Ph.D. Thesis. University of Lucknow, Lucknow, India. 3. Banerji, R., Misra. G. and Nigam, S. K. (1979) Fitoterapla 50. 53. 4. Kitagawa, I., Inada, A., Yosioka, I., Somanathan, R. and Sultanbava, M. U. S. (1972) C/tern. Pharm. Bull 20, 630. 5. Doddrell, D. M., Khong, P. W. and Lewis, K. G. (1974) Fe(rairedron ierlers 238 i. 6. Ton, K., Seo, S., Shimaoka. A. and Tomita, Y. (1974) Tetrohedron

Lerlers

4227.