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Phytochemical Constituents of the Leaves of Hosta longipes
Phytochemical Constituents of the Leaves of Hosta longipes
Natural Product Sciences. 2014. Jun, 20(2): 86-90
Copyright © 2014, The Korean Society of Pharmacognosy
  • Received : May 02, 2014
  • Accepted : June 06, 2014
  • Published : June 30, 2014
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About the Authors
Chung Sub Kim
Ki Hyun Kim
Kang Ro Lee
krlee@skku.edu

Abstract
Phytochemical investigation of the 80% MeOH extract from the leaves of Hosta longipes resulted in the isolation of sixteen compounds ( 1 - 16 ). The structures of the compounds were elucidated by spectroscopic methods to be methyl 10,10-dimethoxydecanoate ( 1 ), methyl 10-hydroxy-8 E ,12 Z -octadecadienoate ( 2 ), methyl coriolate ( 3 ), trans -phytol ( 4 ), phytene-1,2-diol ( 5 ), phyton ( 6 ), (3 S ,5 R ,6 S ,7 E ,9 R )-7-megastigmene-3,6,9-triol ( 7 ), (3 S ,5 R ,6 S ,9 R )-3,6,9-trihydroxymegastigman-7-ene ( 8 ), shikimic acid ( 9 ), p -coumaramide ( 10 ), trans-N-p -coumaroyltyramine ( 11 ), cis-N -coumaroyltyramine ( 12 ), tryptophan ( 13 ), thymidine ( 14 ), adenosine ( 15 ), and deoxyadenosine ( 16 ). Compound 1 was synthesized, but not yet isolated from natural source, and compounds 2-16 were isolated for the first time from this plant source.
Keywords
Introduction
Hosta longipes (Fr. et Sav.) Matsumura (Liliaceae), widely distributed throughout Korea, China, and Japan, is an edible vegetable in Korea. It has long been used as a traditional Korean medicine for treating cough, sputum, laryngopharyngitis, burns, swelling, snake bites and inflammation. 1 , 2 Previous phytochemical investigations of this plant led to the isolation of steroidal saponins. 3 , 4 In the course of our continuing search for biologically active components from Korean medicinal plants, we investigated the constituents of the leaves of H. longipes and reported the isolation of steroidal saponins and flavonoids and their anti-inflammatory effects. 5 , 6 In our continuing study on this source, we further isolated sixteen compounds ( 1 - 16 ). Their structures were elucidated by physicochemical and spectroscopic methods. Compound 1 was isolated for the first time from nature and compounds 2 - 16 were isolated for the first time from this plant source.
Experimental
General experimental procedures – Optical rotations were measured on a Jasco P-1020 polarimeter in MeOH. IR spectra were recorded on a Bruker IFS-66/S FT-IR spectrometer. HRFABMS were obtained on a JEOL JMS700 mass spectrometer. NMR spectra were recorded on a Varian UNITY INOVA 500 NMR spectrometer operating at 500 MHz ( 1 H) and 125 MHz ( 13 C) with chemical shifts given in ppm (δ). Preparative HPLC was conducted using a Gilson 306 pump with Shodex refractive index detector and Apollo Silica 5 μ column (250 × 22 mm i.d.). Silica gel 60 (Merck, 70 - 230 mesh and 230 - 400 mesh) was used for column chromatography. The packing material for molecular sieve column chromatography was Sephadex LH-20 (Pharmacia Co.). TLC was performed using Merck precoated silica gel F 254 plates. Spots were detected on TLC under UV light or by heating after spraying with 10% H 2 SO 4 in C 2 H 5 OH (v/v).
Plant materials – Leaves of H. longipes were collected in Taebaek City, Korea, in June 2010. The plant was identified by one of the authors (K. R. Lee). A voucher specimen (SKKU-NPL 1103) of the plant has been deposited at the herbarium of the School of Pharmacy, Sungkyunkwan University, Suwon, Korea.
Extraction and isolation – Leaves of H. longipes (2.5 kg) were extracted with 80% MeOH at room temperature and filtered. The filtrate was evaporated under reduced pressure to give a MeOH extract (190 g), which was suspended in water (800 mL) and solvent-partitioned to give n -hexane (3 g), CHCl 3 (14 g), EtOAc (3 g), and n -BuOH (24 g) layers. The n -hexane (3 g) layer was separated over a silica gel column ( n -hexane: EtOAc = 7 : 1 – 1 : 1) to yield nine fractions (H1 – H9). Fraction H2 (370 mg) was chromatographed on an RP-C 18 silica gel column (90% MeOH) to give three subfractions (H21 – H23). Subfraction H21 (100 mg) was purified over a silica gel semi-prep. HPLC (hexane : CHCl 3 : EtOAc = 9 : 2 : 1) to afford compounds 2 (10 mg, Rt = 13.1 min) and 3 (3 mg, Rt = 16.0 min). Subfraction H22 (20 mg) was purified by an RP-C 18 semi-prep. HPLC (95% MeCN) to afford compound 4 (8 mg, Rt = 18.7 min). Fraction H7 (150 mg) was purified with an RP-C 18 silica Lobar A ® -column (80% MeOH) and silica gel semi-prep. HPLC (hexane : EtOAc = 3 : 1) to afford compound 5 (6 mg, Rt = 11.0 min). The CHCl 3 (14 g) layer was separated over a silica gel column ( n -hexane : EtOAc = 7 : 1 – 1 : 1) to yield seven fractions (C1 – C7). Fraction C1 (1.0 g) was separated over an RP-C 18 silica gel column (90% MeOH) and purified by a silica gel semiprep. HPLC (hexane : EtOAc = 2 : 1) to afford compound 1 (11 mg, Rt = 13.4 min). Fraction C2 (200 mg) was purified with an RP-C 18 silica Lobar A ® -column (90% MeOH) and silica gel semi-prep. HPLC (hexane : EtOAc = 7 : 1) to afford compound 6 (4 mg, Rt = 17.0 min). The EtOAc (3 g) layer was chromatographed over a Sephadex LH-20 column (90% MeOH) to yield nine fractions (E1 – E9). Fraction E2 (800 mg) separated over a silica gel column (CHCl 3 :MeOH = 12 : 1) and further purified with RP-C 18 semi-prep. HPLC (50% MeOH) to afford compounds 7 (2 mg, Rt = 11.8 min) and 8 (3 mg, Rt = 12.9 min). Fraction E3 (700 mg) was separated over an RP-C 18 silica gel column (90% MeOH) to give six subfractions (E31 – E36). Subfraction E31 (200 mg) was purified with an RP-C 18 silica Lobar A ® -column (80% MeOH) and silica gel semi-prep. HPLC (CHCl 3 :MeOH= 2 : 1) to afford compounds 9 (7 mg, Rt = 16.7 min), 14 (6 mg, Rt = 18.7 min), 15 (3 mg, Rt = 20.3 min), and 16 (3mg Rt = 25.3min). Subfraction E33 (80mg) was purified by an RP-C 18 semi-prep. HPLC (30% MeCN) to afford compounds 11 (3 mg, Rt = 11.8 min) and 12 (3 mg, Rt = 10.4 min). Compound 10 (3 mg) was obtained by purification of subfraction E4 (210 mg) using a silica gel semiprep. HPLC (CHCl 3 : MeOH :H 2 O = 9 : 2 : 0.2). Fraction E9 (100 mg) was purified with a silica gel semi-prep. HPLC (CHCl 3 :MeOH:H 2 O= 2 : 1 : 0.2) to yield compound 13 (7 mg, Rt = 15.0 min).
Methyl 10,10-dimethoxydecanoate (1) − Colorless gum. IR (KBr) ν max cm −1 : 2951 (C-H), 1723 (C = O), 1284, 1032; 1 H and 13 C NMR: see Table 1 ; HRFABMS m/z 269.1733 [M+ Na] + ; (calcd for C 13 H 26 O 4 Na, 269.1729).
1H (500 MHz) and13C NMR (125 MHz) data of1in CDCl3
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aThe assignments were based on HMQC and HMBC experiments.
Methyl 10-hydroxy-8E,12Z-octadecadienoate (2) − Colorless gum.
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: −3.0 ( c 0.25, CHCl 3 ); 1 H NMR (CDCl 3 , 500 MHz): δ 5.67 (1H, dt, J = 15.5, 6.5 Hz, H- 12), 5.54 (1H, m, H-9), 5.48 (1H, m, H-13), 5.37 (1H, m, H-8), 4.08 (1H, m, H-10), 3.67 (3H, s, OCH 3 ), 2.30 (2H, t, J = 7.5 Hz, H-2), 2.25 (2H, m, H-11), 2.04 (4H, m, H-7 and 14), 1.62 (2H, m, H-17), 1.31 - 1.40 (12H, m, H-3 to H-6, H-15, H-16), 0.90 (3H, t, J = 7.0 Hz, H-18); 13 C NMR (CDCl 3 , 125 MHz): δ 174.5 (C-1), 133.4 (C-8), 132.5 (C-9), 132.4 (C-13), 125.0 (C-12), 72.7 (C-10), 51.6 (OCH 3 ), 35.7 (C-11), 34.3 (C-7), 32.1 (C-2), 31.5 (C-16), 29.8 (C-4), 29.3 (C-5, C-6, C-15), 27.6 (C-14), 25.2 (C-3), 22.4 (C-17), 14.1 (C-18). FABMS m/z : 311.3 [M + H] + .
Methyl coriolate (3) − Colorless gum.
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: +10.2 ( c 0.30, CHCl 3 ); 1 H NMR (CDCl 3 , 500 MHz): δ 6.49 (1H, dd, J = 15.0, 10.5 Hz, H-11), 5.97 (1H, t, J = 10.5 Hz, H-10), 5.66 (1H, dd, J = 15.0, 7.0 Hz, H-12), 5.45 (1H, dt, J = 10.5, 8.0 Hz, H-9), 4.16 (1H, q, J = 7.0, H-13), 3.67 (3H, s, H-OCH 3 ) 2.30 (2H, t, J = 7.5 Hz, H-2), 2.18 (2H, m, H-8), 1.26 - 1.62 (18H, m, H-3 to H-7, H-14 to H-17), 0.89 (3H, t, J = 7.5 Hz, H-18). FABMS m/z : 311.3 [M+H] + .
trans-Phytol (4) − Coloress oil. 1 H NMR (500 MHz, CD 3 OD): δ 5.35 (1H, t, J = 7.0 Hz, H-2), 4.07 (2H, d, J = 6.5 Hz, H-1), 2.00 (2H, t, J = 6.5 Hz, H-4), 1.65 (3H, s, H-20), 1.52 - 1.05 (19H, m), 0.87 (9H, d, J = 6.5 Hz, H-16, 18, 19), 0.88 (3H, d, J = 6.5 Hz, H-17); 13 C NMR (125 MHz, CD 3 OD): δ 138.4 (C-3), 123.6 (C-2), 58.2 (C- 1), 39.8 (C-4), 39.4 (C-14), 37.4 (C-8), 37.3 (C-10), 37.2 (C-12), 36.6 (C-6), 32.8 (C-7), 32.7 (C-11), 27.9 (C-15), 25.1 (C-5), 24.7 (C-13), 24.3 (C-9), 22.0 (C-17), 21.9 (C- 16), 19.1 (C-19), 19.0 (C-18), 15.0 (C-20). FABMS m/z : 319.3 [M + Na] +
Phytene-1,2-diol (5) − Coloress gum. 1 H NMR (500 MHz, CD 3 OD): δ 5.07 (1H, s, H-20a), 4.89 (1H, s, H- 20b), 4.07 (1H, dd, J = 7.0, 3.5 Hz, H-2), 3.58 (1H, dd, J = 6.5, 4.0 Hz, H-1a), 3.44 (1H, dd, J = 6.5, 2.5 Hz, H-1b), 2.09 - 1.97 (2H, m, H-4), 1.57 - 1.06 (19H, m), 0.88 (9H, d, J = 7.0 Hz, H-16, 18, 20), 0.86 (3H, d, J = 7.0 Hz, H-19); 13 C NMR (125 MHz, CD 3 OD): δ 149.6 (C-3), 109.6 (C-17), 75.4 (C-2), 65.3 (C-1), 39.3 (C-14), 37.3 (C-8), 37.2 (C-10, 12), 36.8 (C-6), 32.7 (C-4), 32.5 (C-7, 11), 27.9 (C-15), 25.5 (C-5), 24.6 (C-13), 24.3 (C-9), 21.9 (C-20), 21.8 (C-16), 19.0 (C-19), 18.9 (C-18). EIMS m/z : 312.3 [M] + .
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The structures of 1 - 16 isolated from H. longipes.
Phyton (6) − Colorless gum.
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: +2.1 ( c 0.15, CHCl 3 ); 1 H NMR (500 MHz, CDCl 3 ): δ 2.40 (2H, t, J = 7.5 Hz, H-3), 2.12 (3H, s, H-1), 1.03 - 1.58 (17H, m, H-4 to H-14), 0.85 (12H, d, J = 7.0 Hz, H-15 to H-18); 13 C NMR (125 MHz, CDCl 3 ): 209.5 (C-2), 44.4 (C-3), 39.6 (C-13), 37.6, 37.5, 37.5 and 36.7 (C-5, C-7, C-9, C-11) 33.0 and 32.9 (C-6, C-10), 30.0 (C-1), 28.2 (C-4), 25.0 (C-14), 24.6 (C-12), 22.9 (C-8), 22.8 and 21.7 (C-15, C- 18), 20.0 and 19.8 (C-16, C-17). FABMS m/z : 269.3 [M + H] + .
(3S,5R,6S,7E,9R)-7-Megastigmene-3,6,9-triol (7) − Amorphous powder.
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: −11.9 ( c 0.15, CH 3 OH); 1 H NMR (500 MHz, CD 3 OD): δ 5.72 (1H, dd, J = 16.0, 6.0 Hz, H-8), 5.55 (1H, dd, J = 16.0, 1.0 Hz, H-7), 4.29 (1H, m, H-9), 3.80 (1H, m, H-3), 1.93 (1H, m, H-5), 1.67 (1H, m, H-4a), 1.66 (1H, m, H-2a), 1.40 (1H, m, H-2b), 1.39 (1H, m, H-4b), 1.24 (3H, d, J = 6.0 Hz, H-10), 0.98 (3H, s, H-11),0.89 (3H, s, H-12), 0.81 (3H, d, J = 6.0 Hz, H-13); 13 C NMR (125 MHz, CD 3 OD): δ 135.7 (C-8), 134.0 (C-7), 78.3 (C-6), 69.4 (C-9), 67.6 (C-3), 46.1 (C-2), 40.6 (C-1), 40.1 (C-4), 35.6 (C-5), 25.9 (C-11), 25.3 (C-12), 24.3 (C-10), 16.6 (C-13). FABMS m/z : 229.2 [M + H] + .
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Key HMBC (→) and 1H-1H COSY () correlations of 1.
(3S,5R,6S,9R)-3,6,9-Trihydroxymegastigman-7-ene (8) − Amorphous powder.
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: −15.9 ( c 0.20, CH 3 OH). 1 H-NMR (500 MHz, CD 3 OD): 5.73 (1H, dd, J = 16.0, 6.0 Hz, H-8), 5.55 (1H, dd, J = 16.0, 1.0 Hz, H-7), 4.29 (1H, m, H-9), 3.80 (1H, m, H-3), 1.94 (1H, m, H-5), 1.68 (1H, m, H-4a), 1.66 (1H, t, J = 12.0 Hz, H-2a), 1.40 (1H, ddd, J = 12.0, 4.0, 2.0 Hz, H-2b), 1.39 (1H, q, J = 12.0 Hz, H- 4b), 1.24 (3H, d, J = 6.0 Hz, H-10), 0.96 (3H, s, H-11), 0.86 (3H, s, H-12), 0.84 (3H, d, J = 7.0 Hz, H-13); 13 C NMR (125 MHz, CD 3 OD): δ 135.6 (C-8), 133.9 (C-7), 78.1 (C-6), 69.3 (C-9), 67.5 (C-3), 40.5 (C-1), 40.0 (C-4), 35.5 (C-5), 25.9 (C-12), 25.2 (C-11), 24.2 (C-10), 16.5 (C-13). FABMS m/z : 229.2 [M + H] + .
Shikimic acid (9) − Amorphous powder.
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: −12.1 ( c 0.20, CH 3 OH). 1 H-NMR (500 MHz, CD 3 OD): δ 6.48 (1H, m, H-6), 4.28 (1H, t, J = 4.0 Hz, H-5), 3.90 (1H, m, H-4), 3.53 (1H, m, H-3), 2.81 (1H, dd, J = 18.0, 5.5 Hz, H-2a), 2.16 (1H, dd, J = 18.0, 4.0 Hz, H-2b); 13 C-NMR (125 MHz, CD 3 OD): δ 174.2 (C-7), 136.7 (C-1), 130.4 (C-6), 73.2 (C-5), 67.4 (C-4), 66.8 (C-3), 33.4 (C-2). FABMS m/z : 175.1 [M + H] + .
p-Coumaramide (10) − Amorphous powder. 1 H-NMR (500 MHz, CD 3 OD): δ 7.35 (2H, d, J = 8.0 Hz, H-2, H-6), 7.32 (1H, d, J = 16.0 Hz, H-7), 6.75 (2H, d, J = 8.0 Hz, H-3, H-5), 6.33 (1H, d, J = 16.0 Hz, H-8). FABMS m/z : 164.1 [M + H] + .
trans-N-p-Coumaroyltyramine (11) −Amorphous powder. 1 H-NMR (500 MHz, CD 3 OD): δ 7.33 (1H, d, J = 15.5 Hz, H-7), 7.02 (1H, d, J = 1.5 Hz, H-2), 7.00 (2H, d, J = 8.5 Hz, H-2', H-6'), 6.95 (1H, dd, J = 8.5, 1.5 Hz, H-6), 6.69 (1H, d, J = 8.5 Hz, H-5), 6.62 (2H, d, J = 8.5 Hz, H-3', H-5'), 6.30 (1H, d, J = 15.5 Hz, H-8), 3.38 (2H, t, J = 7.5 Hz, H-8), 2.66 (2H, t, J = 7.5 Hz, H-7); 13 C-NMR (125 MHz, CD 3 OD): δ 167.2 (C-9), 155.6 (C-4'), 147.5 (C-4), 145.5 (C-3), 141.0 (C-7), 131.0 (C-1), 130.7 (C-2', C-6'), 127.1 (C-1), 121.0 (C-6), 117.3 (C-8), 116.3 (C-5), 116.0 (C-3', C-5'), 114.1 (C-2), 42.0 (C-8'), 34.0 (C-7'). FABMS m/z : 284.2 [M + H] + .
cis-N-Coumaroyltyramine (12) − Amorphous powder. 1 H-NMR (500 MHz, CD 3 OD): δ 7.26 (2H, d, J = 8.5 Hz, H-2', H-6'), 6.91 (2H, d, J = 8.5 Hz, H-2, H-6), 6.65 (2H, d, J = 8.5 Hz, H-3', H-5'), 6.62 (2H, d, J = 8.5 Hz, H-3, H-5), 6.51 (1H, d, J = 12.5 Hz, H-8), 5.69 (1H, d, J = 12.5 Hz, H-7), 3.29 (2H, t, J = 7.5 Hz, H-8'), 2.59 (2H, t, J = 7.5 Hz, H-7'); 13 C-NMR (125 MHz, CD 3 OD): δ 170.4 (C-9), 159.4 (C-4), 156.9 (C-4'), 138.1 (C-7), 132.3 (C-2', C-6'), 131.2 (C-1'), 130.7 (C-2, C-6), 127.9 (C-1), 121.4 (C-8), 116.2 (C-3, C-5), 116.0 (C-3', C-5'), 42.3 (C-8'), 35.5 (C-7'). FABMS m/z : 284.2 [M + H] + .
Tryptophan (13) − Amorphous powder. 1 H-NMR (500 MHz, DMSO- d6 ): δ 10.95 (1H, s, H-NH), 7.55 (1H, d, J = 7.5 Hz, H-4), 7.34 (1H, d, J = 7.5 Hz, H-7), 7.22 (1H, s, H-2), 7.05 (1H, t, J = 7.5 Hz, H-5), 6.96 (1H, t, J = 7.5 Hz, H-6), 3.53 (1H, m, H-12), 3.33 (1H, m, H-10a), 3.03 (1H, m, H-10b); 13 C-NMR (125 MHz, DMSO- d6 ): δ 171.0 (C-12), 137.1 (C-8), 127.9 (C-9), 124.8 (C-2), 121.6 (C-4), 119.1 (C-5), 118.9 (C-6), 112.0 (C-7), 110.3 (C-3), 55.5 (C-11), 27.9 (C-10).
Thymidine (14) − Amorphous powder. 1 H-NMR (500 MHz, CD 3 OD): δ 7.81 (1H, s, H-6), 6.28 (1H, t, J = 7.0 Hz, H-1'), 4.40 (1H, m, H-3'), 3.90 (1H, dd, J = 6.5, 3.5 Hz, H-4'), 3.79 (1H, dd, J = 12.0, 3.5 Hz, H-5'a), 3.72 (1H, dd, J = 12.0, 3.5 Hz, H-5'b), 2.20 (2H, m, H-2'), 1.88 (3H, s, H-7).
Adenosine (15) − Amorphous powder. 1 H-NMR (500 MHz, CD 3 OD): δ 8.30 (1H, s, H-2), 8.18 (1H, s, H-8), 5.96 (1H, d, J = 6.0 Hz, H-1'), 4.74 (1H, t, J = 6.0 Hz, H-2'), 4.33 (1H, dd, J = 6.0, 2.0 Hz, H-3'), 4.17 (1H, m, H- 4'), 3.88 (1H, dd, J = 12.5, 2.5 Hz, H-5'a), 3.74 (1H, dd, J = 12.5, 3.0 Hz, H-5'b)
Deoxyadenosine (16) − Amorphous powder. 1 H-NMR (500 MHz, CD 3 OD): δ 8.32 (1H, s, H-2), 8.18 (1H, s, H-8), 6.43 (1H, d, J = 7.0 Hz, H-1'), 4.58 (1H, m, H-3'), 4.07 (1H, m, H-4'), 3.84 (1H, dd, J = 12.5, 2.5 Hz, H-5'a), 3.74 (1H, dd, J = 12.5, 3.0 Hz, H-5'b), 2.80 (1H, m, H-2'a), 2.41 (1H, m, H-2'b)
Result and Discussion
Column chromatographic separation of the 80% MeOH extract from the leaves of H. longipes led to the isolation of known compounds 2 - 16 , which were identified as methyl 10-hydroxy-8 E ,12 Z -octadecadienoate ( 2 ), 7 methyl coriolate ( 3 ), 8 trans -phytol ( 4 ), 9 phytene-1,2-diol ( 5 ), 10 phyton ( 6 ), 11 (3 S ,5 R ,6 S ,7 E ,9 R )-7-megastigmene-3,6,9-triol ( 7 ), 12 (3 S ,5 R ,6 S ,9 R )-3,6,9-trihydroxymegastigman-7-ene ( 8 ), 13 shikimic acid ( 9 ), 14 p -coumaramide ( 10 ), 15 trans-N-p -coumaroyltyramine ( 11 ), 16 cis-N -coumaroyltyramine ( 12 ), 16 tryptophan ( 13 ), 17 thymidine ( 14 ), 17 adenosine ( 15 ), 17 and deoxyadenosine ( 16 ) 17 by comparing the spectroscopic data. All compounds were isolated for the first time from this plant source. The following describes the structure elucidation of compound 1 , which was synthesized 18 but was not yet isolated from natural source. 269.1733 [M+ Na] + ; (calcd for C 13 H 26 O 4 Na, 269.1729).
Compound 1 was obtained as a colorless oil and had a molecular formula of C 13 H 26 O 4 , as determined from the ion peak [M+ Na] + at m/z 269.1733 [M + Na] + ; (calcd for C 13 H 26 O 4 Na, 269.1729) in positive ion HRFABMS. The IR spectrum indicated that 1 possessed C-H bond (2951 cm −1 ) and carbonyl (1723 cm −1 ) groups. The 1 H NMR spectrum showed an oxygenated methine [δ H 4.34 (1H, t, J = 5.5 Hz, H-10)], three methoxy groups [δ H 3.66 (3H, s, 1-OCH 3 ), 3.30 (6H, s, 10-OCH 3 )], a methylene adjacent to carbonyl group [δ H 2.29 (2H, t, J = 7.5 Hz, H-2)], and seven methylenes [δ H 1.61 (2H, m, H-9), 1.59 (2H, m, H-3), 1.30-1.34 (10H, m, H-4 to H-8)]. The 13 C NMR spectrum contained 13 signals, including a carboxylic carbon [δ C 174.5 (C-1)], an acetal carbon [δ C 104.8 (C-10)], three methoxy carbons [δ C 52.8 (×2) (10-OCH 3 ), 51.6 (1-OCH 3 )], and eight methylene carbons [δ C 34.3 (C-2), 32.7 (C-9), 29.5 (C-7), 29.4 (C-4), 29.2 (C-6), 29.1 (C-5), 25.1 (C-8), and 24.7 (C-3)]. This spectroscopic data were very similar to those of methyl 8,8- dimethoxyoctanoate 19 except that the presence of additional two methylene groups [δ H 1.30-1.34; δ C 29.2, 29.5]. The HMBC cross-peaks of 1-OCH 3 /C-1 and 10 OCH 3 /C-10 confirmed the location of three methoxy groups. Analyses of 1 H- 1 H COSY, HMQC and HMBC spectra corroborated the gross structure of 1 , which was elucidated as methyl 10,10-dimethoxydecanoate. Compound 1 was previously reported as a synthetic 18 without NMR assignment. We isolated compound 1 from natural source and performed full NMR assignment of 1 for the first time. But we suggest that compound 1 could be an artifact because MeOH was used as solvent during purification.
Acknowledgements
This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2012R1A5A2A 28671860). We are thankful to the Korea Basic Science Institute (KBSI) for the measurements of NMR and MS spectra.
References
Cho J. Y. , Heo B. G. , Yang S. Y. 2005 Korean J. Org. Agric. 13 389 - 400
Han H. Y. , Kim Y. B. , Chang K. J. , Park C. H. , Lee K. C. 2000 Korean J. Plant Res. 13 62 -
Mimaki Y. , Kanmoto T. , Kuroda M. , Sashida Y. , Nishino A. , Satomi Y. , Nishino H. 1995 Chem. Pharm. Bull. 43 1190 - 1196    DOI : 10.1248/cpb.43.1190
Mimaki Y. , Kanmoto T. , Kuroda M. , Sashida Y. , Satomi Y. , Nishino A. , Nishino H. 1996 Phytochemistry 42 1065 - 1070    DOI : 10.1016/0031-9422(96)00030-1
Kim C. S. , Kim S. Y. , Moon E. , Lee M. K. , Lee K. R. 2013 Bioorg. Med. Chem. Lett. 23 1771 - 1775    DOI : 10.1016/j.bmcl.2013.01.050
Kim C. S. , Kwon O.W. , Kim S.Y. , Lee K.R. 2014 J. Braz. Chem. Soc. 25 907 - 912
Koshino H. , Togiya S. , Yoshihara T. , Sakamura S. 1987 Tetrahedron Lett. 28 73 - 76    DOI : 10.1016/S0040-4039(00)95652-1
Nor bin Omar M. , Nor N. N. M. , Moynihan H. , Hamilton R. 2007 Biotechnol. 6 283 - 287    DOI : 10.3923/biotech.2007.283.287
Kim K. H. , Lee K. H. , Choi S. U. , Kim Y. H. , Lee K. R. 2008 Arch. Pharm. Res. 31 983 - 988    DOI : 10.1007/s12272-001-1256-8
Woo K. W. , Lee K. R. 2013 Nat. Prod. Sci. 19 221 - 226
Odinokov V. N. , Mallyabaeva M. I. , Spivak Y. Yu. , Emel’yanova G. A. , Dzhemilev U. M. 2001 Dokl. Chem. 380 255 - 257    DOI : 10.1023/A:1011998504137
Kawakami S. , Matsunami K. , Otsuka H. , Shinzato T. , Takeda Y. 2011 Phytochemistry 72 147 - 153    DOI : 10.1016/j.phytochem.2010.10.003
Yu Q. , Otsuka H. , Hirata E. , Shinzato T. , Taketa Y. 2002 Chem. Pharm. Bull. 50 640 - 644    DOI : 10.1248/cpb.50.640
Kwon J. H. , Kim J. H. , Choi S. E. , Park K. H. , Lee M. W. 2010 Arch. Pharm. Res. 33 2011 - 2016    DOI : 10.1007/s12272-010-1217-y
Nishioka T. , Watanabe J. , Kawabata J. , Niki R. 1997 Biosci. Biotech. Biochem. 61 1138 - 1141    DOI : 10.1271/bbb.61.1138
Kim D. K. , Lim J. P. , Kim J. W. , Park H. W. , Eun J. S. 2005 Arch. Pharm. Res. 28 39 - 43    DOI : 10.1007/BF02975133
Pretsch E. , Bühlmann P. , Affolter C. 2000 Structure Determination of Organic Compounds Springer Berlin 238 - 239
Cardinale G. , Laan J. A. M. , Ward J. P. 1985 Tetrahedron 41 2899 - 2902    DOI : 10.1016/S0040-4020(01)96613-X
Ji S. J. , Horiuchi C. A. 2000 Bull. Chem. Soc. Jpn. 73 1645 - 1652    DOI : 10.1246/bcsj.73.1645