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Diterpenoid acids from Mulinum spinosum
Pergamon
Phytochemistry, Vol. 43, No. 5, pp. 1065-1067, 1996 Copyright © 1996 Elsevier Science Ltd Printed in Great Britain. All rights reserved 0031-9422/96 $15.00 + 0.00
PII: S0031-9422(96)00403-7
DITERPENOID ACIDS FROM MULINUM SPINOSUM MARCELLONICOLETTI,* ANTONELLADl FABIO, ARMANDOD'ANDREA,t GIUSEPPESALVATORE,:~CATALINAVAN BAREN§ and JORGE D. Cousslo§ Dipartimento di Biologia Vegetale, Universith La Sapienza, P.le A. Moro 5, 1-00185, Rome, Italy tE.N.E.A.C.R. Casaccia INN-BIOAG, Rome, Italy :~Istituto Superiore di Sanith, Rome, Italy §Facultad de Farmacia y Biochimica, Universidad de Buenos Aires, IQUIMEFA-CONICET, Buenos Aires, Argentina
(Received in revisedform 29 May 1996) Key Word Index--Mulinum spinosum; Umbelliferae; diterpenoid acid; mulinane.
A b s t r a c t - - T w o new diterpenoid acids were isolated from Mulinum spinosum. Their structures determined by NMR data are related to the mulinane skeleton, but lack the endoperoxide ring system. Copyright © 1996 Elsevier Science Ltd
INTRODUCTION
Mulinum spinosum (Cav.) Pers. is a shrub of the Patagonia steppe in Argentina and Chile, where it is known as 'neneo' and is used as a medicinal plant to treat dental neuralgias, hepatic diseases and altitude sickness [1-4]. A previous study reported on the presence in this plant of resinic acids and some components (a- and /3-pinene, limonene) of its essential oil [5]. In 1990 M. crassifolium was reported to contain two diterpenoids with a novel carbon skeleton, named mulinane, the structure of which was determined by X-ray analyses [6]. This was followed by reports of other products of the same type [7, 8]. In this paper, we report on the isolation and structural determination of two new mulinane diterpenoid acids, 1 and 2 from M. spinosum.
arrangement of a labdane precursor into its 5(4--~ 3)abeo derivative, which in turn gives a further intermediate, whose oxidation finally generates mulinic acid. The structure of the last intermediate exactly corresponds to that of 1. 16
i
//~ 18
15
(~O2H 19
RESULTS AND DISCUSSION Terpenoid 1, C2oH3oO 2, [M] + at m/z 302, gave rise to IH and ~C NMR data (Tables 1 and 2) which were easily assigned by comparison with those of mulinic acid. In particular, the chemical shift values of the carbon atoms of the cyclopentane and cyclohexane tings were practically identical, confirming, in accord with the t H NMR data, the substitution and the configuration of the stereogenic centres. The remaining data were consistent with the presence of an additional double bond in the seven-membered ring and with the consequent absence of the endoperoxide ring of mulinic acid (3). Assignment of a double bond system between H - l l and H-14 was possible from the 2D COSY spectrum of 1. Loyola et al. [6] proposed a biogenetic scheme for mulinane diterpenoids based on the re*Author to whom correspondence should be addressed. 1065
1
R = CH 3
2
R = CH2OH
H
M. NICOLETTIet al.
1066
Table 1.1H NMR data of compounds 1 and 2 H
1
2
H
1
2
la
1.94, m
ov.
12
5.63
lb
ov.
ov.
14
2a
2.02, m
2.01, m
15a
2b 3 4
1.45, m 1.50, m 1.52, m
1.46, m 1.50, m 1.51, m
15b 16 17a
5.62, dd J = 12.5 and 1.5 5.48, br d J=7.5 2.69, br d J = 14.0 ov. 0.87, s 0.87, s
6a
1.60, m
17b
6b
1.40, m
7a
2.42, dt J = 13.2 and 3.7 ov. 2.20, dd J = 10.5 and 6.0 1.78, m 5.59, dd J = 12.5 and 6.0
1.53, dt J = 12.0 and 3.0 1.38, dt J = 12.0 and 3.0 2.48
7b 9 10 11
19
0.87, d J = 8.0 1.03, d J=8.0
2.69 1.95, m 0.87 3.92, d J = 10.5 3.51, d J = 10.5 0.87 1.04
1.71, m 2.40 ov. 5.52
The second diterpenoid, 2, C2oH3oO3, gave 1H and N M R data in accordance with the substitution of the methyl group at C-8 in 1 by a primary alcohol group. In particular, besides the change to C-17, the deshielding fl-effect on C-8 and the shielding "y-effects on C-7 and C-15 were evident. Therefore, the two acids isolated from M. spinosum confirm the specific occurrence of mulinane terpenoids in the genus and also by analogy of 2 with 17-acetoxymulinic acid in the substitution at C-17 [7]. 13C
EXPERIMENTAL
~H and 13C NMR: Bruker AM-500 Spectrometer in CDC13 soln with TMS as int. standard. EI-MS: LBK 2091 spectrometer. Plant material. Aerial parts of Mulinum spinosum were collected in Rio Negro (locality Cipolletti), Argentina by Dr I. Mizrahi and identified by R. Fortunato. A voucher sample is deposited at the Facultad de Farmacia, Universidad de Buenos Aires.
Table 2. ~3C NMR data of compounds 1 and 2 C
1
2
C
1
2
1 2 3 4 5 6 7 8 9 10
24.6 28.7 57.6 31.7 58.5 32.6 41.4 34.8 55.0 50.3
24.5 28.7 57.6 31.7 58.1 32.1 38.4 35.1 54.2 45.0
11 12 13 14 15 16 17 18 19 20
132.7 127.8 131.7 125.3 36.3 25.6 27.9 22.6 a 22.4 a 181.0
132.7 128.3 131.9 124.0 32.6 25.4 70.3 22.7 a 22.4 a 179.8
~Assignments may be interchanged.
18
5.43
Extraction and sepn. This study is part of a bilateral project (VESA) devoted to the exploitation of essential oils of Argentinian plants, including the use of different methods of extraction. For this reason, the dried plant material (10 g) was milled and subjected to supercritical fluid extraction in a Dionex SFE-703 multiple cell supercritical Fluid Extractor, using supercritical CO 2 with addition of MeOH (2 ml) as entralner. CO 2 conditions were as follows: pressure = 230 bar, temp = 40°; density = 0 . 8 7 g m l - t ; flow r a t e = 5 2 0 ml; total CO 2 used = 80.5 g. The extract obtained (0.74 g) was sepd by CC on silica-gel in OAcEt-petrol (1:9), followed by further sepn in n-hexane-OAcEt, to give terpenoids 1 (80 mg, eluted with n - h e x a n e - O A c E t 4: 1) and 2 (50 mg eluted with n - h e x a n e - O A c E t 7:3). Terpenoid 1. Oily material, [ ~ ] 2 o = - 3 6 . 4 (CHCI 3, KBr -- I c = l . 1 ) . IR ureax cm : 3 3 0 0 - 2 7 0 0 br, 1695, 1460, 1200; El-MS, mlz (relative intensity): 302 [M] ÷ (43), 287 (27), 257 (31), 213 (29), 163 (52), 120 (99), 119 (100); ~H and 13C NMR: Tables 1 and 2. Terpenoid 2. Oily material, [a] 2°= - 6 . 9 (CHCI a, c = 0 . 1 ) . IR Urea xKBr cm-m: 3 3 0 0 - 2 7 0 0 br, 1695, 1460, 1200; El-MS, m/z (relative intensity): 287 (17), 257 (42), 255 (43), 227 (69), 175 (66), 131 (100), 119 (98); IH and t3C NMR: see Tables 1 and 2.
REFERENCES
1. Boelcke, O. (1992) in Plantas vasculares de la Argentina, nativas y exbticas, 2nd edn, p. 215. Hemisferio Sur., Buenos Aires, Argentina. 2. Montes, M. and Wilkormirsky, T. (1985) in Medicina Tradicinal Chilena, Universidad de Concepcibn, Santiago, Chile. 3. Wilhelm de Mosbach, E. (1992) in Botanica
Diterpenoid acids from Mulinum spinosum lndigena de Chile (A. Belo, ed.), p. 99. Fundacion Andes, Villarica, Chile. 4. San Martin, J. A. (1983) Economic Botany 37, 216, 5. Rivieros, R., Morales, G. and Loyola L. (1982) Bol. Soc. Chil. Quim. 27, 244. 6. Loyola, L. A., Morales, G., Rodriguez, B., Jimenez-Barbero, J., de la Torte, M. C., Perales, A.
1067
and Torres, M. C. (1990) Tetrahedron 46, 5413. 7. Loyola, L. A., Morales, G., de la Torre, M. C., Pedreros S. and Rodriguez, B. (1990) Phytochemist ~ 29, 3950. 8. Loyola, L. A., Morales, G., Rodriguez, B., Jimenez-Barbero, J., de la Torre, M. C., Pedreros, S. and Tortes, M. C. (1991) J. Nat. Prod. 54, 1404.
Phytochemistry, Vol. 43, No. 5, pp. 1065-1067, 1996 Copyright © 1996 Elsevier Science Ltd Printed in Great Britain. All rights reserved 0031-9422/96 $15.00 + 0.00
PII: S0031-9422(96)00403-7
DITERPENOID ACIDS FROM MULINUM SPINOSUM MARCELLONICOLETTI,* ANTONELLADl FABIO, ARMANDOD'ANDREA,t GIUSEPPESALVATORE,:~CATALINAVAN BAREN§ and JORGE D. Cousslo§ Dipartimento di Biologia Vegetale, Universith La Sapienza, P.le A. Moro 5, 1-00185, Rome, Italy tE.N.E.A.C.R. Casaccia INN-BIOAG, Rome, Italy :~Istituto Superiore di Sanith, Rome, Italy §Facultad de Farmacia y Biochimica, Universidad de Buenos Aires, IQUIMEFA-CONICET, Buenos Aires, Argentina
(Received in revisedform 29 May 1996) Key Word Index--Mulinum spinosum; Umbelliferae; diterpenoid acid; mulinane.
A b s t r a c t - - T w o new diterpenoid acids were isolated from Mulinum spinosum. Their structures determined by NMR data are related to the mulinane skeleton, but lack the endoperoxide ring system. Copyright © 1996 Elsevier Science Ltd
INTRODUCTION
Mulinum spinosum (Cav.) Pers. is a shrub of the Patagonia steppe in Argentina and Chile, where it is known as 'neneo' and is used as a medicinal plant to treat dental neuralgias, hepatic diseases and altitude sickness [1-4]. A previous study reported on the presence in this plant of resinic acids and some components (a- and /3-pinene, limonene) of its essential oil [5]. In 1990 M. crassifolium was reported to contain two diterpenoids with a novel carbon skeleton, named mulinane, the structure of which was determined by X-ray analyses [6]. This was followed by reports of other products of the same type [7, 8]. In this paper, we report on the isolation and structural determination of two new mulinane diterpenoid acids, 1 and 2 from M. spinosum.
arrangement of a labdane precursor into its 5(4--~ 3)abeo derivative, which in turn gives a further intermediate, whose oxidation finally generates mulinic acid. The structure of the last intermediate exactly corresponds to that of 1. 16
i
//~ 18
15
(~O2H 19
RESULTS AND DISCUSSION Terpenoid 1, C2oH3oO 2, [M] + at m/z 302, gave rise to IH and ~C NMR data (Tables 1 and 2) which were easily assigned by comparison with those of mulinic acid. In particular, the chemical shift values of the carbon atoms of the cyclopentane and cyclohexane tings were practically identical, confirming, in accord with the t H NMR data, the substitution and the configuration of the stereogenic centres. The remaining data were consistent with the presence of an additional double bond in the seven-membered ring and with the consequent absence of the endoperoxide ring of mulinic acid (3). Assignment of a double bond system between H - l l and H-14 was possible from the 2D COSY spectrum of 1. Loyola et al. [6] proposed a biogenetic scheme for mulinane diterpenoids based on the re*Author to whom correspondence should be addressed. 1065
1
R = CH 3
2
R = CH2OH
H
M. NICOLETTIet al.
1066
Table 1.1H NMR data of compounds 1 and 2 H
1
2
H
1
2
la
1.94, m
ov.
12
5.63
lb
ov.
ov.
14
2a
2.02, m
2.01, m
15a
2b 3 4
1.45, m 1.50, m 1.52, m
1.46, m 1.50, m 1.51, m
15b 16 17a
5.62, dd J = 12.5 and 1.5 5.48, br d J=7.5 2.69, br d J = 14.0 ov. 0.87, s 0.87, s
6a
1.60, m
17b
6b
1.40, m
7a
2.42, dt J = 13.2 and 3.7 ov. 2.20, dd J = 10.5 and 6.0 1.78, m 5.59, dd J = 12.5 and 6.0
1.53, dt J = 12.0 and 3.0 1.38, dt J = 12.0 and 3.0 2.48
7b 9 10 11
19
0.87, d J = 8.0 1.03, d J=8.0
2.69 1.95, m 0.87 3.92, d J = 10.5 3.51, d J = 10.5 0.87 1.04
1.71, m 2.40 ov. 5.52
The second diterpenoid, 2, C2oH3oO3, gave 1H and N M R data in accordance with the substitution of the methyl group at C-8 in 1 by a primary alcohol group. In particular, besides the change to C-17, the deshielding fl-effect on C-8 and the shielding "y-effects on C-7 and C-15 were evident. Therefore, the two acids isolated from M. spinosum confirm the specific occurrence of mulinane terpenoids in the genus and also by analogy of 2 with 17-acetoxymulinic acid in the substitution at C-17 [7]. 13C
EXPERIMENTAL
~H and 13C NMR: Bruker AM-500 Spectrometer in CDC13 soln with TMS as int. standard. EI-MS: LBK 2091 spectrometer. Plant material. Aerial parts of Mulinum spinosum were collected in Rio Negro (locality Cipolletti), Argentina by Dr I. Mizrahi and identified by R. Fortunato. A voucher sample is deposited at the Facultad de Farmacia, Universidad de Buenos Aires.
Table 2. ~3C NMR data of compounds 1 and 2 C
1
2
C
1
2
1 2 3 4 5 6 7 8 9 10
24.6 28.7 57.6 31.7 58.5 32.6 41.4 34.8 55.0 50.3
24.5 28.7 57.6 31.7 58.1 32.1 38.4 35.1 54.2 45.0
11 12 13 14 15 16 17 18 19 20
132.7 127.8 131.7 125.3 36.3 25.6 27.9 22.6 a 22.4 a 181.0
132.7 128.3 131.9 124.0 32.6 25.4 70.3 22.7 a 22.4 a 179.8
~Assignments may be interchanged.
18
5.43
Extraction and sepn. This study is part of a bilateral project (VESA) devoted to the exploitation of essential oils of Argentinian plants, including the use of different methods of extraction. For this reason, the dried plant material (10 g) was milled and subjected to supercritical fluid extraction in a Dionex SFE-703 multiple cell supercritical Fluid Extractor, using supercritical CO 2 with addition of MeOH (2 ml) as entralner. CO 2 conditions were as follows: pressure = 230 bar, temp = 40°; density = 0 . 8 7 g m l - t ; flow r a t e = 5 2 0 ml; total CO 2 used = 80.5 g. The extract obtained (0.74 g) was sepd by CC on silica-gel in OAcEt-petrol (1:9), followed by further sepn in n-hexane-OAcEt, to give terpenoids 1 (80 mg, eluted with n - h e x a n e - O A c E t 4: 1) and 2 (50 mg eluted with n - h e x a n e - O A c E t 7:3). Terpenoid 1. Oily material, [ ~ ] 2 o = - 3 6 . 4 (CHCI 3, KBr -- I c = l . 1 ) . IR ureax cm : 3 3 0 0 - 2 7 0 0 br, 1695, 1460, 1200; El-MS, mlz (relative intensity): 302 [M] ÷ (43), 287 (27), 257 (31), 213 (29), 163 (52), 120 (99), 119 (100); ~H and 13C NMR: Tables 1 and 2. Terpenoid 2. Oily material, [a] 2°= - 6 . 9 (CHCI a, c = 0 . 1 ) . IR Urea xKBr cm-m: 3 3 0 0 - 2 7 0 0 br, 1695, 1460, 1200; El-MS, m/z (relative intensity): 287 (17), 257 (42), 255 (43), 227 (69), 175 (66), 131 (100), 119 (98); IH and t3C NMR: see Tables 1 and 2.
REFERENCES
1. Boelcke, O. (1992) in Plantas vasculares de la Argentina, nativas y exbticas, 2nd edn, p. 215. Hemisferio Sur., Buenos Aires, Argentina. 2. Montes, M. and Wilkormirsky, T. (1985) in Medicina Tradicinal Chilena, Universidad de Concepcibn, Santiago, Chile. 3. Wilhelm de Mosbach, E. (1992) in Botanica
Diterpenoid acids from Mulinum spinosum lndigena de Chile (A. Belo, ed.), p. 99. Fundacion Andes, Villarica, Chile. 4. San Martin, J. A. (1983) Economic Botany 37, 216, 5. Rivieros, R., Morales, G. and Loyola L. (1982) Bol. Soc. Chil. Quim. 27, 244. 6. Loyola, L. A., Morales, G., Rodriguez, B., Jimenez-Barbero, J., de la Torte, M. C., Perales, A.
1067
and Torres, M. C. (1990) Tetrahedron 46, 5413. 7. Loyola, L. A., Morales, G., de la Torre, M. C., Pedreros S. and Rodriguez, B. (1990) Phytochemist ~ 29, 3950. 8. Loyola, L. A., Morales, G., Rodriguez, B., Jimenez-Barbero, J., de la Torre, M. C., Pedreros, S. and Tortes, M. C. (1991) J. Nat. Prod. 54, 1404.