- Email: [email protected]
Triterpenoids from Dittrichia viscosa
Phytochemistry,Vol. 31, No. 5, pp. 1X26-1828, 1992
0031.9422!‘92 SS.OO+O.oO Q 1992 PergamonPress plc
Printedin Great Bntain.
TRITERPENOIDS FROM DITTRICHIA VISCOSA MANUEL
Departamento
de Quimica
GRANDE,*
PASCLJAL TORRES,~ FRANCISCO PIERAt
Organica, Fact&ad de C. Quimicas, Facultad de Crencias, Apartado
and IN& S.
E-37008 Salamanca, Spain; 99, E-03080 Alicante. Spain
BELLIDO
tDivisi6n
de Quimica
Organica,
(Received in revised form 29 October 1991) Key Word Index-Dittrichia r;iscosa; lnula viscosa; Compositae; triterpenoids fatty esters; 3/Gacetoxydammara20,25-diene-24-01; 3/?-acetoxydammara-20,23-diene-25-01; fatty esters of 2-(4’-hydroxyphenyh-ethanol.
Abstract-A phytochemical study of the aerial parts of Dittrichia viscosa resulted in the isolation of 10 triterpenoids as free alcohols, acetates or fatty esters. One of the esters, 3p-acetoxydammara-20,25-diene-24-01, has been isolated for the first time as a natural compound. This substance, as well as the 20,23-diene-25-01 isomer, was synthesized by photooxidation of dammaradienyl acetate. Fatty esters of 2-(4’-hydroxyphenyl)-ethanol were also isolated.
INTRODUCTION Dittrichia
uiscosa (L.) W. Greuter
[sin. Ida viscosa (L.) Aiton, Tribus Inuleae] is a herbaceous perennial plant which is widespread in the Spanish Comunidad Valenciana, and which has been used for years in folk medicine in the Mediterranean area [l-3]. Previous chemical studies on D. viscosa led to the isolation of 3-methoxy-p-cymene-7-yl isobutyrate and isovalerate [4], pseudotaraxasterol acetate [S], dammaradienyl acetate, nerolidol, eudesma-3,11(13)-diene-12-oic acid and related derivatives [6, 71, the sesquiterpene lactones 2-deacetoxyxanthinin and inuviscolide [6] and six flavonoids [S, 6, 81. In a previous paper, we reported the isolation of 16 flavonoids [9] from the aerial parts of D. viscosa, and we now describe the isolation of 10 triterpenoids (free and esterified) as well as fatty esters of 2-(4’-hydroxyphenyl)ethanol. RESL’LTS AND DISCUSSION
The dewaxed acetone extract from the aerial parts of D. viscosa yielded dammaradienyl acetate (1) [ 10,111, taraxasteryl acetate (2) [12], pseudotaraxasteryl acetate (3) [S], friedelin (4) [ll, 131, 3_epifriedelinol(5) [ll], a mixture of fatty esters of faradiol (6) [14], pseudotaraxasterol (7) [12], taraxasterol (8) [12], fatty esters of 20(29)-lupene3/I,16/&diol(9) [15-171, the 3/I-monoacetate of the triterpene diol 10 and fatty esters of 2-(4’-hydroxyphenyl)ethanol (11) [18]. Compounds 1-5, 7 and 8 were identified by comparison of their spectral and physical properties with those of authentic samples and/or literature data. Three chromatography fractions, each of which seemed to be homogeneous on TLC, were in fact fatty acid mixtures which gave on saponification the triterpene alcohols 6 and 9, and 2-(4’-hydroxyphenyl)-ethanol (ll), respectively, also identified by comparison with authentic samples.
*Author
to whom correspondence
should
be addressed.
10 The fatty acids bonded to the C-3 hydroxyl group of 6 and 9 were identified as palmitic (main component), myristic and stearic acids and those esterified to 11 were identified as behenic, lignoceric (main component), cerotic and montanic acids (GC of the methyl esters). Compound 10was the monoacetate of a triterpene diol ([Ml’ 484, C,,H,,O,), whose IR spectrum was very similar to that of dammaradienyl acetate, except for the presence of an additional free hydroxyl group (3420, 1025 cm ‘) and the absence of the trisubstituted double bond. The ‘H NMR spectrum also showed a signal at 64.08 (1 H, t, J = 6.3 Hz) characteristic of a geminal proton to a hydroxyl group as well as signals of four C=CH, olefinic protons at 64.86,4.95,4.73 and 4.76. A singlet at 6 1.74 of an Me -C = group was also outstanding and was confirmed by the ‘YYNMR spectrum (Table 1). These data allowed us to propose for 10 the structure of 38-acetoxydammara-20,25-diene-24-01, which was confirmed by photo-oxidation of dammaradienyl acetate with ‘0, and Bengal rose as a sensitizer [19]. Reduction in situ of the hydroperoxide mixture with NaBH, gave two diols that were isolated by chromatography. One of them was identical to 10.and the other was identified by spectral methods as 3/&acetoxydammara-20,23-diene-2501 (see Experimental). The related diols dammara-20,25diene-3/3,24-diol and dammara-20,23-diene-3/j,25-diol
1826
1827
Short Reports Table
were
recently described, [20].
1. ‘sC NMR data for dammaradienyl acetoxydammara-20,25-diene-24-01
C
1
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
38.8 23.0 80.9 37.9 55.9 18.2 35.4 40.5 50.9 37.2 21.4 25.0 47.8 49.4 31.4 29.0
the last one from
10
C
39.1 23.9 81.2 38.1 56.3 18.4 35.6 40.8 51.2 37.4 21.6 25.2 47.9 49.7 31.6 29.5
17 18 19 20 21 22 23 24 25 26 27 28 29 30 CH,COO CH,COO
Santolina
oblongifolia
EXPERIMENTAL
General. Mps: uncorrected; ‘H NMR (60 and 200 MHz) and “CNMR (50.3 MHz): CDCI, using TMS as int. standard, values are reported in 6 units; MS: 70 eV; GC of Me esters of 6 and 9 were run on a 15% DEGS column, N, as carrier gas, at 27 ml min-‘, 190” isothermal, dual FID detector; the esters of compound 11 were analysed on a 10% SE-30 column, the oven temp. was programmed at 250” for 6 mitt, then increased to 300” at 2” mm’. Material, extraction and isolation. The plant material (Ditrrichia uiscosa, L. = Inula oiscosa, Ait.) was collected at the end of October at the Peti de las Aguilas (Elche, Alicante, Spain). The air-dried and finely ground aerial parts of the plant (7185 g) were extracted with hot Me&O and the crude extract (345 g, 4.8% of the dried plant weight) was fractionated as previously reported [9]. The hexanesoluble fraction of the Me&O extract (125 g, 36.2%) was chromatographed on silica gel with hexane-EtOAc mixtures. After repeated chromatographies and/or crystallization the following components were isolated: 1 (400 mg), 2 (40 mg), 3 (20 mg), 4 (75 mg), 5 (50 mg), fatty esters of 6 (350 mg), 7 (60 mg), 8 (40 mg), fatty esters of 9 (200 mg), 10 (100 mg) and fatty esters of 11 (150 mg). Saponification of the fatty ester mixtures with 5% KOH-MeOH gave 6 (50 mg), 9 (35 mg) and 11(19 mg), respectively. The fatty acids linked to the triterpenes were esterified with CH,Nz-Et20 and identified by GC as methyl myristate (lO-12%). methyl palmitate (81-82%) and methyl stearate (5-7%). The fatty acids bonded to 11 were identified (GC of methyl esters), as behenic (CZ2, 7.3%), lignoceric (C,,, 47.1%), cerotic (CZ6, 34.5%) and montanic acids (C,,, 3.4%). 3/I-Acetoxydammara-20,25-diene-24-o/ (10). Purified by CC on silica gel, with CH,Cl,-EtOH (99:l). Mp 135-136” (MeOH), [u]o+ 50.9” (MeGH; c 1.5). IR v:;; cm-‘: 3420,3060,1720,1635, 1440, 1385, 1370, 1245, 1025, 1010, 980, 895, 880; ‘HNMR (200 MHz, CDCI,): 64.95 (lH, m, H-26), 4.86 (lH, m, H-26), 4.76 (lH,brs,H-21),4.73(1H,d,J= 1.2 Hz, H-21),4.48(1H,m,Xpart of ABX, JAX+ax=16.2Hz, H-31x), 4.08 (lH, t, J=6.3 Hz, H-24),
acetate (1) and 3/I(10) 1
10
45.3 16.3 15.7 152.6 107.5 34.2 27.1 124.5 131.3 25.7 17.7 15.9 28.0 16.5 21.3 171.0
45.9 16.4 16.2 152.9 107.8 30.8 34.0 75.9 147.9 111.1 17.8 15.9 28.2 16.7 21.4 171.0
2.05 (3H, s, OAc-3/I), 1.74 (3H, s, Me-27), 0.98 (3H, s, Me), 0.87 (6H, s, Me-2), 0.86 (6H, s, Me-2k i3CNMR: see Table 1; EIMS (probe) 70 eV, m/z (rel. int.): 484 [M]’ (3), 469 (7), 466 (13), 357 (5), 249 (7), 203 (IS), 191(23), 189 (46) 175 (12), 161(13), 147 (13), 135 (28), 125 (19), 121 (27). 107 (31) 105 (18), 95 (36), 93 (31), 85 (33), 69 (33), 55 (27) 43 (100). Photo-oxidation ofdammaradienyl acetate. A soln of l(360 mg) in isopropanol (37 ml) was photo-oxidized in the presence of Bengal rose (7 mg). After 1.5 hr exposure to sunlight, the solvent was evapd and diluted with MeOH. NaBH, (370 mg) was added to the mixture, which was then stirred for 1 hr. Afterwards, aq. 10% KIO, (20 ml) and H,O (20 ml) were added. The reaction mixture was left for 15 mitt and then extracted with Et,O. The ethereal extract was washed with 2 M HCl and H,O, dried on Na,SO, and evapd, to give a residue (350 mg) which was chromatographed on silica gel to afford compounds 10 (29 mg) and 38-acetoxydammara-20,23diene-25-01: mp 154-155” (MeOH); [a&+54.4” (MeOH; c 1.7). IR v=i cn-‘: 3400,3060, 1720, 1630, 1435, 1370, 1250, 1140, 1020, 980, 890; ‘HNMR (60 MHz, CDCI,): 65.41(2H, m, H-23 and H-24), 4.71(2H, m, H21), 4.46 (lH, m, X part of ABX, H-3=), 2.68 (2H, m, H-22), 2.02 (3H, s, OAc-3h 1.30 (6H, s, Me-26 and Me-27), 0.94 (3H, s, Me), 0.83 (12H, br s, Me-4); EIMS (probe) 70 eV, m/z (rel. int.): 484 [M]’ (49), 469 (7), 466 (100) 451 (lo), 424 (9) 409 (16), 391 (15) 355 (7), 342 (7). 289 (82), 276 (7), 249 (25), 229 (24), 203 (lo), 189 (36), 187 (16), 175 (6), 43 (16).
REFERENCES
1. Font Quer, P. (1973) Plantas Medicinales. El Dioscdrides Renooado, p. 785, Labor, Barcelona. 2. Lopez Soria, L. (1980) Mediterrhnen 4, 115. 3. Rigual Magallon, A. (1972) Flora y Vegetacidn de la Provincia de Alicante. I.E.A. Excma. Diputacion Provincial de Alicante, Alicante. 4. Shtacher, G. and Kashman, Y. (1971) Tetrahedron 27, 1343. 5. Okstiz, S. (1977) Plunta Med. 31, 270. 6. Bohlmann, F., Czerson, H. and Schiineweiss, S. (1977) Chem. Ber. 110, 1330. 7. Ceccherelli, P., Curini, M., Marcotullio, M. C. (1988) J. Nat. Prod. 51. 1006.
1828
Short Reports
8. Taillade, C., Susplugas, P. and Balansard, G. (1980) Plantes Med. Phytoterapie 14, 26. 9. Grande. M., Piera, F., Cuenca, A., Torres, P. and Bellido, I. S. (1985) Planta Med. 5, 414. 10. Talapatra, S. K., Bhar, D. S. and Talapatra, B. (1974) Aust. J. Chem. 27, 1137. 11. De Pascual Teresa, J., San Feliciano, A., Barrero, A. F. and Medarde, M. (1979) An. Quim. 75,422. 12. Ames, T. R., Beton, J. L., Bowers, A., Halsall, T. G. and Jones, E. R. M. (1954) J. Chem. Sot. 1905. 13. De Pascual Teresa, J., Bellido, I. S., Salado, V. J. R., Moliner, F. and Alberdi, M. R. (1980) Riu. Ital. E.P.O.S. 62, 236. 14. Jizba, J., Budesinsky, M , Vanek, T., Boeva, A., Dimitrova,
15. 16. 17. 18. 19. 20.
K., Santavy, F. and Novotny, L. (.1982) CoUect. Czech. Chem Commun. 47,664. Oksiiz, S. and Topcu. G. (1987) Phyrochemisrry 26, 3082. Dominguez, X. A., Rojas, P., Dueiias Wiarco, M. C. and Escarria, S. (1973) Phytochemistry 12, 224. Baddeley, G. V., Bealing, A. J., Jefferies, P. R. and Retallack, R. W. (1964) Aust. J. Chem. 17, 908. Isbiguro, T., Koga, N., Takamura, K. and Maruyana. T. (1955) .I. Pharm. Sot. Japan 75, 781. Ikekawa, N., Ohta. A., Seki, M. and Takahasln, A. (1972) Phytochemistry 11, 3037. De Pascual Teresa, J., Gonzalez, M. S., Vicente, S. and Bellido, I. S. (1986) Phyrochemistrp 25, 185.
0031.9422!‘92 SS.OO+O.oO Q 1992 PergamonPress plc
Printedin Great Bntain.
TRITERPENOIDS FROM DITTRICHIA VISCOSA MANUEL
Departamento
de Quimica
GRANDE,*
PASCLJAL TORRES,~ FRANCISCO PIERAt
Organica, Fact&ad de C. Quimicas, Facultad de Crencias, Apartado
and IN& S.
E-37008 Salamanca, Spain; 99, E-03080 Alicante. Spain
BELLIDO
tDivisi6n
de Quimica
Organica,
(Received in revised form 29 October 1991) Key Word Index-Dittrichia r;iscosa; lnula viscosa; Compositae; triterpenoids fatty esters; 3/Gacetoxydammara20,25-diene-24-01; 3/?-acetoxydammara-20,23-diene-25-01; fatty esters of 2-(4’-hydroxyphenyh-ethanol.
Abstract-A phytochemical study of the aerial parts of Dittrichia viscosa resulted in the isolation of 10 triterpenoids as free alcohols, acetates or fatty esters. One of the esters, 3p-acetoxydammara-20,25-diene-24-01, has been isolated for the first time as a natural compound. This substance, as well as the 20,23-diene-25-01 isomer, was synthesized by photooxidation of dammaradienyl acetate. Fatty esters of 2-(4’-hydroxyphenyl)-ethanol were also isolated.
INTRODUCTION Dittrichia
uiscosa (L.) W. Greuter
[sin. Ida viscosa (L.) Aiton, Tribus Inuleae] is a herbaceous perennial plant which is widespread in the Spanish Comunidad Valenciana, and which has been used for years in folk medicine in the Mediterranean area [l-3]. Previous chemical studies on D. viscosa led to the isolation of 3-methoxy-p-cymene-7-yl isobutyrate and isovalerate [4], pseudotaraxasterol acetate [S], dammaradienyl acetate, nerolidol, eudesma-3,11(13)-diene-12-oic acid and related derivatives [6, 71, the sesquiterpene lactones 2-deacetoxyxanthinin and inuviscolide [6] and six flavonoids [S, 6, 81. In a previous paper, we reported the isolation of 16 flavonoids [9] from the aerial parts of D. viscosa, and we now describe the isolation of 10 triterpenoids (free and esterified) as well as fatty esters of 2-(4’-hydroxyphenyl)ethanol. RESL’LTS AND DISCUSSION
The dewaxed acetone extract from the aerial parts of D. viscosa yielded dammaradienyl acetate (1) [ 10,111, taraxasteryl acetate (2) [12], pseudotaraxasteryl acetate (3) [S], friedelin (4) [ll, 131, 3_epifriedelinol(5) [ll], a mixture of fatty esters of faradiol (6) [14], pseudotaraxasterol (7) [12], taraxasterol (8) [12], fatty esters of 20(29)-lupene3/I,16/&diol(9) [15-171, the 3/I-monoacetate of the triterpene diol 10 and fatty esters of 2-(4’-hydroxyphenyl)ethanol (11) [18]. Compounds 1-5, 7 and 8 were identified by comparison of their spectral and physical properties with those of authentic samples and/or literature data. Three chromatography fractions, each of which seemed to be homogeneous on TLC, were in fact fatty acid mixtures which gave on saponification the triterpene alcohols 6 and 9, and 2-(4’-hydroxyphenyl)-ethanol (ll), respectively, also identified by comparison with authentic samples.
*Author
to whom correspondence
should
be addressed.
10 The fatty acids bonded to the C-3 hydroxyl group of 6 and 9 were identified as palmitic (main component), myristic and stearic acids and those esterified to 11 were identified as behenic, lignoceric (main component), cerotic and montanic acids (GC of the methyl esters). Compound 10was the monoacetate of a triterpene diol ([Ml’ 484, C,,H,,O,), whose IR spectrum was very similar to that of dammaradienyl acetate, except for the presence of an additional free hydroxyl group (3420, 1025 cm ‘) and the absence of the trisubstituted double bond. The ‘H NMR spectrum also showed a signal at 64.08 (1 H, t, J = 6.3 Hz) characteristic of a geminal proton to a hydroxyl group as well as signals of four C=CH, olefinic protons at 64.86,4.95,4.73 and 4.76. A singlet at 6 1.74 of an Me -C = group was also outstanding and was confirmed by the ‘YYNMR spectrum (Table 1). These data allowed us to propose for 10 the structure of 38-acetoxydammara-20,25-diene-24-01, which was confirmed by photo-oxidation of dammaradienyl acetate with ‘0, and Bengal rose as a sensitizer [19]. Reduction in situ of the hydroperoxide mixture with NaBH, gave two diols that were isolated by chromatography. One of them was identical to 10.and the other was identified by spectral methods as 3/&acetoxydammara-20,23-diene-2501 (see Experimental). The related diols dammara-20,25diene-3/3,24-diol and dammara-20,23-diene-3/j,25-diol
1826
1827
Short Reports Table
were
recently described, [20].
1. ‘sC NMR data for dammaradienyl acetoxydammara-20,25-diene-24-01
C
1
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
38.8 23.0 80.9 37.9 55.9 18.2 35.4 40.5 50.9 37.2 21.4 25.0 47.8 49.4 31.4 29.0
the last one from
10
C
39.1 23.9 81.2 38.1 56.3 18.4 35.6 40.8 51.2 37.4 21.6 25.2 47.9 49.7 31.6 29.5
17 18 19 20 21 22 23 24 25 26 27 28 29 30 CH,COO CH,COO
Santolina
oblongifolia
EXPERIMENTAL
General. Mps: uncorrected; ‘H NMR (60 and 200 MHz) and “CNMR (50.3 MHz): CDCI, using TMS as int. standard, values are reported in 6 units; MS: 70 eV; GC of Me esters of 6 and 9 were run on a 15% DEGS column, N, as carrier gas, at 27 ml min-‘, 190” isothermal, dual FID detector; the esters of compound 11 were analysed on a 10% SE-30 column, the oven temp. was programmed at 250” for 6 mitt, then increased to 300” at 2” mm’. Material, extraction and isolation. The plant material (Ditrrichia uiscosa, L. = Inula oiscosa, Ait.) was collected at the end of October at the Peti de las Aguilas (Elche, Alicante, Spain). The air-dried and finely ground aerial parts of the plant (7185 g) were extracted with hot Me&O and the crude extract (345 g, 4.8% of the dried plant weight) was fractionated as previously reported [9]. The hexanesoluble fraction of the Me&O extract (125 g, 36.2%) was chromatographed on silica gel with hexane-EtOAc mixtures. After repeated chromatographies and/or crystallization the following components were isolated: 1 (400 mg), 2 (40 mg), 3 (20 mg), 4 (75 mg), 5 (50 mg), fatty esters of 6 (350 mg), 7 (60 mg), 8 (40 mg), fatty esters of 9 (200 mg), 10 (100 mg) and fatty esters of 11 (150 mg). Saponification of the fatty ester mixtures with 5% KOH-MeOH gave 6 (50 mg), 9 (35 mg) and 11(19 mg), respectively. The fatty acids linked to the triterpenes were esterified with CH,Nz-Et20 and identified by GC as methyl myristate (lO-12%). methyl palmitate (81-82%) and methyl stearate (5-7%). The fatty acids bonded to 11 were identified (GC of methyl esters), as behenic (CZ2, 7.3%), lignoceric (C,,, 47.1%), cerotic (CZ6, 34.5%) and montanic acids (C,,, 3.4%). 3/I-Acetoxydammara-20,25-diene-24-o/ (10). Purified by CC on silica gel, with CH,Cl,-EtOH (99:l). Mp 135-136” (MeOH), [u]o+ 50.9” (MeGH; c 1.5). IR v:;; cm-‘: 3420,3060,1720,1635, 1440, 1385, 1370, 1245, 1025, 1010, 980, 895, 880; ‘HNMR (200 MHz, CDCI,): 64.95 (lH, m, H-26), 4.86 (lH, m, H-26), 4.76 (lH,brs,H-21),4.73(1H,d,J= 1.2 Hz, H-21),4.48(1H,m,Xpart of ABX, JAX+ax=16.2Hz, H-31x), 4.08 (lH, t, J=6.3 Hz, H-24),
acetate (1) and 3/I(10) 1
10
45.3 16.3 15.7 152.6 107.5 34.2 27.1 124.5 131.3 25.7 17.7 15.9 28.0 16.5 21.3 171.0
45.9 16.4 16.2 152.9 107.8 30.8 34.0 75.9 147.9 111.1 17.8 15.9 28.2 16.7 21.4 171.0
2.05 (3H, s, OAc-3/I), 1.74 (3H, s, Me-27), 0.98 (3H, s, Me), 0.87 (6H, s, Me-2), 0.86 (6H, s, Me-2k i3CNMR: see Table 1; EIMS (probe) 70 eV, m/z (rel. int.): 484 [M]’ (3), 469 (7), 466 (13), 357 (5), 249 (7), 203 (IS), 191(23), 189 (46) 175 (12), 161(13), 147 (13), 135 (28), 125 (19), 121 (27). 107 (31) 105 (18), 95 (36), 93 (31), 85 (33), 69 (33), 55 (27) 43 (100). Photo-oxidation ofdammaradienyl acetate. A soln of l(360 mg) in isopropanol (37 ml) was photo-oxidized in the presence of Bengal rose (7 mg). After 1.5 hr exposure to sunlight, the solvent was evapd and diluted with MeOH. NaBH, (370 mg) was added to the mixture, which was then stirred for 1 hr. Afterwards, aq. 10% KIO, (20 ml) and H,O (20 ml) were added. The reaction mixture was left for 15 mitt and then extracted with Et,O. The ethereal extract was washed with 2 M HCl and H,O, dried on Na,SO, and evapd, to give a residue (350 mg) which was chromatographed on silica gel to afford compounds 10 (29 mg) and 38-acetoxydammara-20,23diene-25-01: mp 154-155” (MeOH); [a&+54.4” (MeOH; c 1.7). IR v=i cn-‘: 3400,3060, 1720, 1630, 1435, 1370, 1250, 1140, 1020, 980, 890; ‘HNMR (60 MHz, CDCI,): 65.41(2H, m, H-23 and H-24), 4.71(2H, m, H21), 4.46 (lH, m, X part of ABX, H-3=), 2.68 (2H, m, H-22), 2.02 (3H, s, OAc-3h 1.30 (6H, s, Me-26 and Me-27), 0.94 (3H, s, Me), 0.83 (12H, br s, Me-4); EIMS (probe) 70 eV, m/z (rel. int.): 484 [M]’ (49), 469 (7), 466 (100) 451 (lo), 424 (9) 409 (16), 391 (15) 355 (7), 342 (7). 289 (82), 276 (7), 249 (25), 229 (24), 203 (lo), 189 (36), 187 (16), 175 (6), 43 (16).
REFERENCES
1. Font Quer, P. (1973) Plantas Medicinales. El Dioscdrides Renooado, p. 785, Labor, Barcelona. 2. Lopez Soria, L. (1980) Mediterrhnen 4, 115. 3. Rigual Magallon, A. (1972) Flora y Vegetacidn de la Provincia de Alicante. I.E.A. Excma. Diputacion Provincial de Alicante, Alicante. 4. Shtacher, G. and Kashman, Y. (1971) Tetrahedron 27, 1343. 5. Okstiz, S. (1977) Plunta Med. 31, 270. 6. Bohlmann, F., Czerson, H. and Schiineweiss, S. (1977) Chem. Ber. 110, 1330. 7. Ceccherelli, P., Curini, M., Marcotullio, M. C. (1988) J. Nat. Prod. 51. 1006.
1828
Short Reports
8. Taillade, C., Susplugas, P. and Balansard, G. (1980) Plantes Med. Phytoterapie 14, 26. 9. Grande. M., Piera, F., Cuenca, A., Torres, P. and Bellido, I. S. (1985) Planta Med. 5, 414. 10. Talapatra, S. K., Bhar, D. S. and Talapatra, B. (1974) Aust. J. Chem. 27, 1137. 11. De Pascual Teresa, J., San Feliciano, A., Barrero, A. F. and Medarde, M. (1979) An. Quim. 75,422. 12. Ames, T. R., Beton, J. L., Bowers, A., Halsall, T. G. and Jones, E. R. M. (1954) J. Chem. Sot. 1905. 13. De Pascual Teresa, J., Bellido, I. S., Salado, V. J. R., Moliner, F. and Alberdi, M. R. (1980) Riu. Ital. E.P.O.S. 62, 236. 14. Jizba, J., Budesinsky, M , Vanek, T., Boeva, A., Dimitrova,
15. 16. 17. 18. 19. 20.
K., Santavy, F. and Novotny, L. (.1982) CoUect. Czech. Chem Commun. 47,664. Oksiiz, S. and Topcu. G. (1987) Phyrochemisrry 26, 3082. Dominguez, X. A., Rojas, P., Dueiias Wiarco, M. C. and Escarria, S. (1973) Phytochemistry 12, 224. Baddeley, G. V., Bealing, A. J., Jefferies, P. R. and Retallack, R. W. (1964) Aust. J. Chem. 17, 908. Isbiguro, T., Koga, N., Takamura, K. and Maruyana. T. (1955) .I. Pharm. Sot. Japan 75, 781. Ikekawa, N., Ohta. A., Seki, M. and Takahasln, A. (1972) Phytochemistry 11, 3037. De Pascual Teresa, J., Gonzalez, M. S., Vicente, S. and Bellido, I. S. (1986) Phyrochemistrp 25, 185.