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Phenolic lignans from flower buds of Magnolia fargesii
P~ytochemlscry, Vol. 31, No. 10, pp. 36663468, 1992 Printedin Great Britain.
PHENOLIC
LIGNANS MITSUO
003 l-9422,92 $5.00 + 0.00 Q 1992 PergamonPress Ltd
FROM
MIYAZAWA,
FLOWER
BUDS OF MAGNOLIA
HKROYUKI KASAHARA
and
HIROMU
FARGESIl
KAMEOKA
Department of Applied Chemistry, Faculty of Science and Engineering, Kinki University, Kowakae, Higashiosaka-shi, Osaka 577,
Japan (Received in revise~~r~ fargesii; Magnoliaceae; phi11ygenin; ( + I_pinoresinol; ( + )-magnolin.
Key Word In~x-~ag~f~~
31 March 1992)
flower buds; lignans; ( + ~-de-~-me~ylma~oli~
(+ )-
Abstract-Three phenolic lignans were isolated from flower buds of Magnolia fargesii. One was a new lignan named (+)-de-0-methylmagnolin and the other two were the newly found lignans from this plant, (+)-phillygenin and (+)pinoresinol. The structures of these lignans were determined by spectroscopic studies. The structure of (+)-magnolin isolated from this plant was also investigated in detail by spectral data.
The flower buds of ~agno~ia~ff~gesi~ have been used as the source of a Chinese drug, Shin-i in Japanese, and have been used for the treatment of nasal congestion with headache, sinusitis, and allergic rhinitis. In previous reports on chemical investigations of this plant, Kimura et al. [l] found a-pinene, cineol, chavicol methyl ether and citral in the essential oil of M. fargesii and an alkaloid with empirical formula C,,H,,O,N was isolated [2]. Kakisawa et al. [3] found pinoresinol dimethyl ether, lirioresinol dimethyl ether, fargesin and magnolin, and Chen et at. [4] found fargeson A, fargeson B, fargeson C and denudatin B from this plant as lignans. Recently, pha~acolo~c~ activities of these lignans from Shin-i, Ca2+ antagonistic activity [4] and PAF antagonistic activity [S] were revealed. But, so far, the lignans which contain phenolic hydroxyl groups have never been isolated from M. fargesii. In this paper, we report the isolation and spectral elucidation of a new phenolic lignan named (+)-de-0-methylmagnolin (2), and the identification of (+)-phillygenin (1) and (+)-pinoresinol (3) from Shin-i.
*Me
Me0
MeO
5’
I
RESULTS AND DLSCUSSION
Flower buds of M.~urges~i were extracted with methylene chloride and the extracted part was chromatographed on silica gel eluting with n-hexane containing increasing concentrations of ethyl acetate (20, 40 and 70%) and with methanol. Fraction 5 (212 g) was se.parated into neutral and phenolic fractions by aqueous sodium hydroxide extraction. From the phenolic fraction, compounds 1-3 were isolated, and from the neutral fraction, 4 was isolated by chromatography on silica gel. The lignans isolated were identified as (+)-phillygenin (1) [6, 71, (+)-pinoresinol (3) [S] and (+)-magnolin (4). Compound 2 was isolated as an oil. Its ‘HNMR spectral data were very similar to those of magnolin [3], with eight aliphatic protons present at 63.11, 3.91, 4.28
I
OR,
5 R,=Obe, R,=R =H R,=Me m/z 137 6 m/z 181
3666
I 0% 7 %=R.,=H m/t 8 R,=OMe,&=Me
151 m/z 195
3667
Short Reports Table 1. ‘HNMR
spectral data of hgnans having a 2,6-diaryl-3,7-dioxabicyclo[3,3,0]octane skehon
1
H
2.91 br aV 4.43 d (7.2) 3.33 m 3.84 m 3.33 m 4.87 d (5.5) 4.13 d (9.6) 3.84 m 5.72 ca 6.85 m ca 6.91 m 6.94 s OMe 3.88 s 3.91 s
1 2 4*X 4CL! 5 6 8SX 8 & Ar
2
3
4
3.11 m 4.75 d (4) 3.91 dd (9, 4) 4.28 m 3.11 m 4.75 d (4) 3.91 dd (9, 4)
3.10m 4.74 d (5) 3.87 dd (9, 4)
3.11 m 4.77 d (5) 3.92 dd (9, 4) 4.29 m 3.11 m 4.75 d (5) 3.92 dd (9, 4) 4.29 m 6.57 s ca 6.85 m
4.28 m 5.75 6.58 m ca 6.85 m 3.84 s 3.88 s 3.90 s
4.24 dd (9, 7)
3.10m 4.74 d (5) 3.87 dd 4.24 dd 5.70 ca 6.82 ca 6.88 3.90 s
(9, 4) (9, 7) m m
3.84 s 3.88 s 3.90 s
All values were recorded in CDCI, at 270 MHq chemical shifts in ppm from TMS; coupling constants in Hz
Table 2. t3CNMR spectral data of lignans from flower buds of Magnolia fargesii C
1
2
3
4
1
54.4 50.1 87.7 82.0 69.6 71.0 133.0 130.9 109.0 108.5 146.7 148.8 145.3 148.0 114.2 111.0 119.1 117.7 55.9
54.0 54.3 85.7 86.0 71.6 71.9 132.8 136.8 108.6 102.8 146.7 153.4 145.2 137.4 114.3 153.4 118.9 102.8 55.9 56.1 56.1 60.8
54.1 54.1 85.8 85.8 71.6 71.6 132.9 132.9 108.6 108.6 146.7 146.7 145.2 145.2 114.3 114.3 118.9 118.9 55.9
54.1 54.4 85.7 86.0 71.8 71.9 133.5 136.8 109.2 102.8 148.7 153.4 149.2 137.5 111.1 153.4 118.2 102.8 55.9 56.2 56.2 60.8
5 2 6 4 8 1’ 1” 2 2” 3 3” 4 4” 5 5” 6 6” OMe
All values were recorded in CDCl, at 270 MHz; chemical shifts in ppm from TMS.
and 4.74, and five aromatic protons present at 66.58 and cu 6.85, respectively. But, 12 protons were present at 63.84, 3.88 and 3.89, corresponding to four methoxyl groups, and a phenolic hydroxyl proton was evident at 65.75. From a comparison of the chemical shifts of the eight aliphatic protons of 2 with those of magnolin and
phillygenin, the stereochemistries of the two aromatic rings were of the diequatorial type. The 13C NMR spectral data of 2 confirmed that the stereochemistries of the two aromatic rings were diequatorial, because six aliphatic carbon signals were in agreement with those of magnolin. The mass spectral data showed [M]’ at m/z 402. The peaks at m/z 137 and 151 were attributable to cleavage of fragments containing a guaiacyl group (5,7), and the peaks at m/z 181 and 195 were also attributable to cleavage of fragments containing 3,4,5-trimethoxyl group (6, 8), respectively. Methylation of 2 with diazomethane gave 4’-0-methylated 2, and its ‘H NMR and 13C NMR spectral data were clearly consistent with those of magnolin. Therefore, the structure of 2 named (+)-de-Omethylmagnolin is assigned as rel. (2S, 6S)-2-(4-hydroxy3-methoxyphenyl)-6-(3,4,5-rrimethoxyphenyl)-3,7-~oxabicyclo[3,3,0]octane. EXPERIMENTAL Isolation of lignans. Dried and pulverized flower buds of Magnolia fargesii Cheng (6.86 kg) were extracted with CH,Cl, for several hr. Solvent was removed under red. pres., when a brown residue was obtained. This residue was chromatographed on Kieselgel, and eluted with a n-hexane-EtOAc system. Fr. 5 (212 g, R,=ca 0.52; n-hexane-EtOAc, 1: 1) was sepd. Fr. 5 was dissolved in CH,Cl, and transferred to a separatory funnel. A 5% NaOH aq. soln was added to the funnel and the contents shaken until the compounds which contained phenolic hydroxyl groups were removed from the CH,Cl, layer completely. After that, the CH,Cl, layer was removed and fractionated further by CC to isolate 4 (68.03 g, R, =0.64, Me,CO-CHCl,, 1:9). A 1 N
HCl soln was ad&d, to acidify the extract. Et,0 was added, the contents mixed and the Et,0 layer sepd. The acid part was also shaken with CH,Cl, and the CH,Cl, layer was added to the Et,0 layer. This treatment was repeated several times. The Et,0 layer was chromatographed with n-hexane-Me,CO-CHCl,, to give l(229 mg, R,=0.52), 2 (482 mg, R,=0.46) and 3 (214 mg, R,=0.34), respectively. These R, values were measured in Me,CGCHCl, 1: 9.
3668
Short Reports
~et~y~at~on of ( +)~e-O-met~y~m~nolin. Compound 2 (40 mg) was methylated with CH,N, in the usual way, and 4-Qmethylated 2 (39 mg) was obtained. (+ )-Phillygenin (1). Repeated purification by silica gel CC and evapn with CHCI, resulted in amorphous phillygenin. [elk3 +93.2” (CHCI,; c 0.6) (ht. [4] +95.7”, MeOH; c 2.0). EIMS (probe, 70 eV) m/z (rel. int.): 372 ([Ml’, 3i%), 205 (23), 177 (33), 165(44), 151 (IGO),137(40). IRv,,,,,cm-‘: 3414(OH), H&9,1593, 1517, 1465, 1270. NMR see Tables 1 and 2. ( C )-De-O-methylmagnolin (2). Repeated purification by silica gel CC and evapn with CHCI, resulted in oily de-O-methylmagnolin. [alis + 58.1” (CHCI,; c 2.75). EIMS (probe, 70 eV) m/z (rel. mt.): 402 ([Ml’, 83%), 207 (33), 195 (44), 182 (SO), 181 (75), I51 (fOO), 137 (68). TR v,, cm-‘: 3419 (OH), 1593, 1515, 1464, 1272, 1216. NMR see Tables 1 and 2. (+)-Pinoresinol(3). Repeated purification by silica gel CC and evapn with CHCI, resulted in amorphous pinoresinol. [@Ii3 + 35” (CHCl,; c 0.7). IR Y,.. cm-i: 3410 (OH), 1604,1517,1465, 1434, 1367, 1160. NMR see Tables 1 and 2. (+)-Magnolin (4). Repeated purification by silica gel CC and evapn with CHCl, resulted in oily magnolin. [u]~s+49.9” (CHCI,; c 0.9). IR Y,,, cm- I: 1592,1515,1463, 1265,1235,1128,
1028. EIMS (probe, 70 eV) m/z (rel. int.): 416 ([Ml’, 46%). 207 (38), 195 (48), 181 (71), 177 (69), 165 (lOO), 151 (85). NMR see Tables 1 and 2. REFERENCES
1. Kimura, K., Hata, K. and Yoshizaki, M. (1962) Jupa~ J. Pha~o~. l&18. 2. Kimura, M., Yoshizaki, M., Muro, I. and Shiho, D. (1965) J. Pharm. Sot. Japan 85,18. 3. Kakisawa, H., Chen, Y. P. and Hsu, H. Y. (i972) Phytoc~em~stry 11, 2289.
4. Chen, C, C., Huang, Y. L., Chen, H. T., Chen, Y. P. and Hsu, H. Y. (1988) Pfantu Med. 438. 5. Pan, J.-X., Hensens, 0. D., Zink, D. L., Chan, M. N. and Hwang, S.-B. (1987) Phytochemistry 26, 1377. 6. Rahman, M. M. A., Dewick, P. M., Jackson, D. E. and Lucas, J. A. (1990) P~yt~hemistry 29, 1971. 7. Iida, T., Nakano, M. and Ito, K. (1982) P~yruchemistry 21, 673. 8. Vermes, B., Sehgmann, 0. and Wargner, H. (1991) Phytochemistry 30, 3087.
PHENOLIC
LIGNANS MITSUO
003 l-9422,92 $5.00 + 0.00 Q 1992 PergamonPress Ltd
FROM
MIYAZAWA,
FLOWER
BUDS OF MAGNOLIA
HKROYUKI KASAHARA
and
HIROMU
FARGESIl
KAMEOKA
Department of Applied Chemistry, Faculty of Science and Engineering, Kinki University, Kowakae, Higashiosaka-shi, Osaka 577,
Japan (Received in revise~~r~ fargesii; Magnoliaceae; phi11ygenin; ( + I_pinoresinol; ( + )-magnolin.
Key Word In~x-~ag~f~~
31 March 1992)
flower buds; lignans; ( + ~-de-~-me~ylma~oli~
(+ )-
Abstract-Three phenolic lignans were isolated from flower buds of Magnolia fargesii. One was a new lignan named (+)-de-0-methylmagnolin and the other two were the newly found lignans from this plant, (+)-phillygenin and (+)pinoresinol. The structures of these lignans were determined by spectroscopic studies. The structure of (+)-magnolin isolated from this plant was also investigated in detail by spectral data.
The flower buds of ~agno~ia~ff~gesi~ have been used as the source of a Chinese drug, Shin-i in Japanese, and have been used for the treatment of nasal congestion with headache, sinusitis, and allergic rhinitis. In previous reports on chemical investigations of this plant, Kimura et al. [l] found a-pinene, cineol, chavicol methyl ether and citral in the essential oil of M. fargesii and an alkaloid with empirical formula C,,H,,O,N was isolated [2]. Kakisawa et al. [3] found pinoresinol dimethyl ether, lirioresinol dimethyl ether, fargesin and magnolin, and Chen et at. [4] found fargeson A, fargeson B, fargeson C and denudatin B from this plant as lignans. Recently, pha~acolo~c~ activities of these lignans from Shin-i, Ca2+ antagonistic activity [4] and PAF antagonistic activity [S] were revealed. But, so far, the lignans which contain phenolic hydroxyl groups have never been isolated from M. fargesii. In this paper, we report the isolation and spectral elucidation of a new phenolic lignan named (+)-de-0-methylmagnolin (2), and the identification of (+)-phillygenin (1) and (+)-pinoresinol (3) from Shin-i.
*Me
Me0
MeO
5’
I
RESULTS AND DLSCUSSION
Flower buds of M.~urges~i were extracted with methylene chloride and the extracted part was chromatographed on silica gel eluting with n-hexane containing increasing concentrations of ethyl acetate (20, 40 and 70%) and with methanol. Fraction 5 (212 g) was se.parated into neutral and phenolic fractions by aqueous sodium hydroxide extraction. From the phenolic fraction, compounds 1-3 were isolated, and from the neutral fraction, 4 was isolated by chromatography on silica gel. The lignans isolated were identified as (+)-phillygenin (1) [6, 71, (+)-pinoresinol (3) [S] and (+)-magnolin (4). Compound 2 was isolated as an oil. Its ‘HNMR spectral data were very similar to those of magnolin [3], with eight aliphatic protons present at 63.11, 3.91, 4.28
I
OR,
5 R,=Obe, R,=R =H R,=Me m/z 137 6 m/z 181
3666
I 0% 7 %=R.,=H m/t 8 R,=OMe,&=Me
151 m/z 195
3667
Short Reports Table 1. ‘HNMR
spectral data of hgnans having a 2,6-diaryl-3,7-dioxabicyclo[3,3,0]octane skehon
1
H
2.91 br aV 4.43 d (7.2) 3.33 m 3.84 m 3.33 m 4.87 d (5.5) 4.13 d (9.6) 3.84 m 5.72 ca 6.85 m ca 6.91 m 6.94 s OMe 3.88 s 3.91 s
1 2 4*X 4CL! 5 6 8SX 8 & Ar
2
3
4
3.11 m 4.75 d (4) 3.91 dd (9, 4) 4.28 m 3.11 m 4.75 d (4) 3.91 dd (9, 4)
3.10m 4.74 d (5) 3.87 dd (9, 4)
3.11 m 4.77 d (5) 3.92 dd (9, 4) 4.29 m 3.11 m 4.75 d (5) 3.92 dd (9, 4) 4.29 m 6.57 s ca 6.85 m
4.28 m 5.75 6.58 m ca 6.85 m 3.84 s 3.88 s 3.90 s
4.24 dd (9, 7)
3.10m 4.74 d (5) 3.87 dd 4.24 dd 5.70 ca 6.82 ca 6.88 3.90 s
(9, 4) (9, 7) m m
3.84 s 3.88 s 3.90 s
All values were recorded in CDCI, at 270 MHq chemical shifts in ppm from TMS; coupling constants in Hz
Table 2. t3CNMR spectral data of lignans from flower buds of Magnolia fargesii C
1
2
3
4
1
54.4 50.1 87.7 82.0 69.6 71.0 133.0 130.9 109.0 108.5 146.7 148.8 145.3 148.0 114.2 111.0 119.1 117.7 55.9
54.0 54.3 85.7 86.0 71.6 71.9 132.8 136.8 108.6 102.8 146.7 153.4 145.2 137.4 114.3 153.4 118.9 102.8 55.9 56.1 56.1 60.8
54.1 54.1 85.8 85.8 71.6 71.6 132.9 132.9 108.6 108.6 146.7 146.7 145.2 145.2 114.3 114.3 118.9 118.9 55.9
54.1 54.4 85.7 86.0 71.8 71.9 133.5 136.8 109.2 102.8 148.7 153.4 149.2 137.5 111.1 153.4 118.2 102.8 55.9 56.2 56.2 60.8
5 2 6 4 8 1’ 1” 2 2” 3 3” 4 4” 5 5” 6 6” OMe
All values were recorded in CDCl, at 270 MHz; chemical shifts in ppm from TMS.
and 4.74, and five aromatic protons present at 66.58 and cu 6.85, respectively. But, 12 protons were present at 63.84, 3.88 and 3.89, corresponding to four methoxyl groups, and a phenolic hydroxyl proton was evident at 65.75. From a comparison of the chemical shifts of the eight aliphatic protons of 2 with those of magnolin and
phillygenin, the stereochemistries of the two aromatic rings were of the diequatorial type. The 13C NMR spectral data of 2 confirmed that the stereochemistries of the two aromatic rings were diequatorial, because six aliphatic carbon signals were in agreement with those of magnolin. The mass spectral data showed [M]’ at m/z 402. The peaks at m/z 137 and 151 were attributable to cleavage of fragments containing a guaiacyl group (5,7), and the peaks at m/z 181 and 195 were also attributable to cleavage of fragments containing 3,4,5-trimethoxyl group (6, 8), respectively. Methylation of 2 with diazomethane gave 4’-0-methylated 2, and its ‘H NMR and 13C NMR spectral data were clearly consistent with those of magnolin. Therefore, the structure of 2 named (+)-de-Omethylmagnolin is assigned as rel. (2S, 6S)-2-(4-hydroxy3-methoxyphenyl)-6-(3,4,5-rrimethoxyphenyl)-3,7-~oxabicyclo[3,3,0]octane. EXPERIMENTAL Isolation of lignans. Dried and pulverized flower buds of Magnolia fargesii Cheng (6.86 kg) were extracted with CH,Cl, for several hr. Solvent was removed under red. pres., when a brown residue was obtained. This residue was chromatographed on Kieselgel, and eluted with a n-hexane-EtOAc system. Fr. 5 (212 g, R,=ca 0.52; n-hexane-EtOAc, 1: 1) was sepd. Fr. 5 was dissolved in CH,Cl, and transferred to a separatory funnel. A 5% NaOH aq. soln was added to the funnel and the contents shaken until the compounds which contained phenolic hydroxyl groups were removed from the CH,Cl, layer completely. After that, the CH,Cl, layer was removed and fractionated further by CC to isolate 4 (68.03 g, R, =0.64, Me,CO-CHCl,, 1:9). A 1 N
HCl soln was ad&d, to acidify the extract. Et,0 was added, the contents mixed and the Et,0 layer sepd. The acid part was also shaken with CH,Cl, and the CH,Cl, layer was added to the Et,0 layer. This treatment was repeated several times. The Et,0 layer was chromatographed with n-hexane-Me,CO-CHCl,, to give l(229 mg, R,=0.52), 2 (482 mg, R,=0.46) and 3 (214 mg, R,=0.34), respectively. These R, values were measured in Me,CGCHCl, 1: 9.
3668
Short Reports
~et~y~at~on of ( +)~e-O-met~y~m~nolin. Compound 2 (40 mg) was methylated with CH,N, in the usual way, and 4-Qmethylated 2 (39 mg) was obtained. (+ )-Phillygenin (1). Repeated purification by silica gel CC and evapn with CHCI, resulted in amorphous phillygenin. [elk3 +93.2” (CHCI,; c 0.6) (ht. [4] +95.7”, MeOH; c 2.0). EIMS (probe, 70 eV) m/z (rel. int.): 372 ([Ml’, 3i%), 205 (23), 177 (33), 165(44), 151 (IGO),137(40). IRv,,,,,cm-‘: 3414(OH), H&9,1593, 1517, 1465, 1270. NMR see Tables 1 and 2. ( C )-De-O-methylmagnolin (2). Repeated purification by silica gel CC and evapn with CHCI, resulted in oily de-O-methylmagnolin. [alis + 58.1” (CHCI,; c 2.75). EIMS (probe, 70 eV) m/z (rel. mt.): 402 ([Ml’, 83%), 207 (33), 195 (44), 182 (SO), 181 (75), I51 (fOO), 137 (68). TR v,, cm-‘: 3419 (OH), 1593, 1515, 1464, 1272, 1216. NMR see Tables 1 and 2. (+)-Pinoresinol(3). Repeated purification by silica gel CC and evapn with CHCI, resulted in amorphous pinoresinol. [@Ii3 + 35” (CHCl,; c 0.7). IR Y,.. cm-i: 3410 (OH), 1604,1517,1465, 1434, 1367, 1160. NMR see Tables 1 and 2. (+)-Magnolin (4). Repeated purification by silica gel CC and evapn with CHCl, resulted in oily magnolin. [u]~s+49.9” (CHCI,; c 0.9). IR Y,,, cm- I: 1592,1515,1463, 1265,1235,1128,
1028. EIMS (probe, 70 eV) m/z (rel. int.): 416 ([Ml’, 46%). 207 (38), 195 (48), 181 (71), 177 (69), 165 (lOO), 151 (85). NMR see Tables 1 and 2. REFERENCES
1. Kimura, K., Hata, K. and Yoshizaki, M. (1962) Jupa~ J. Pha~o~. l&18. 2. Kimura, M., Yoshizaki, M., Muro, I. and Shiho, D. (1965) J. Pharm. Sot. Japan 85,18. 3. Kakisawa, H., Chen, Y. P. and Hsu, H. Y. (i972) Phytoc~em~stry 11, 2289.
4. Chen, C, C., Huang, Y. L., Chen, H. T., Chen, Y. P. and Hsu, H. Y. (1988) Pfantu Med. 438. 5. Pan, J.-X., Hensens, 0. D., Zink, D. L., Chan, M. N. and Hwang, S.-B. (1987) Phytochemistry 26, 1377. 6. Rahman, M. M. A., Dewick, P. M., Jackson, D. E. and Lucas, J. A. (1990) P~yt~hemistry 29, 1971. 7. Iida, T., Nakano, M. and Ito, K. (1982) P~yruchemistry 21, 673. 8. Vermes, B., Sehgmann, 0. and Wargner, H. (1991) Phytochemistry 30, 3087.