Phenolic Constituents of the Stems of Dipterocarpus intricatus
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PHENOLIC CONSTITUENTS OF THE STEMS OF Dipterocarpus intricatus
Changon Seo,1 Eun-Kyung Ahn,1 Jung A Lee,1 Jae-Shin Kang,2 Hye-Woo Byun,2 and Seong Su Hong1*
Dipterocarpus is the third largest and most diverse genus among Dipterocarpaceae, consisting of about 75 species distributed mainly in the tropical regions (South-East Asia) [1, 2]. They are well known for timber but less known for its medicinal importance. This family of plant is known to contain resveratrol oligomers, saponins, sesquiterpenes, and terpenoids [3–9], and pharmacological studies have shown anti-inflammatory, antihyperuricemic, antifilarial, anticholinesterase, and cytotoxic activity [4–7]. As part of our ongoing project in search for biologically active small molecules from Cambodian medicinal plants, Dipterocarpus intricatus was selected for phytochemical investigation of its EtOH extract. D. intricatus is a deciduous tree, with a usual height of 15–30 m, which grows in clear forests in low regions and is widely distributed in countries such as Cambodia, Laos, Vietnam, and Thailand [10]. To our knowledge, there has been no report of phytochemical and pharmacological investigations of D. intricatus so far. In continuation of our studies on chemical constituents from the stems of D. intricatus, eight compounds were isolated and elucidated: (Z)-ε -viniferin (1), (–)-4′-O-methylepigallocatechin 3-gallate (2), 11-O-galloylbergenin (3), bergenin (4), 4-hydroxybenzaldehyde (5), vanillin (6), vanillic acid (7), and syringic acid (8). To the best our knowledge, compounds 1–3 were obtained from the genus Dipterocarpus for the first time. General. Melting points were obtained in open capillary tubes with a Buchi melting point B-540 apparatus and are uncorrected (Buchi, Switzerland). NMR spectra were measured on a Bruker Ascend III 700 spectrometer (Bruker, Germany) with tetramethylsilane as internal standard, and chemical shifts are expressed in δ values. Electrospray ionization (ESI) mass spectra were obtained on a LTQ Orbitrap XL (Thermo Scientific, USA) mass spectrometer. MPLC (Combi Flash RF, Teledyne ISCO) separations were performed on a RediSep® Rf revesed-phase silica column. Preparative HPLC was performed on a Shimadzu (LC-8A pump and SPD-20A UV/VIS detector) instrument, a Kromasil column (250 × 21.2 mm I.D.), and a YMC-Pack ODS A column (250 × 20 mm I.D.) using a mixed solvent system of ACN-water at a flow rate of 8 mL/min. Semipreparative HPLC was carried out using an LC-Acme 9000 instrument (Young-rin, Korea). LC-ESI-MS were obtained on a Triple TOF 5600+ instrument (AB SCIX, USA). Column chromatography was performed using ODS-A (12 nm S-7 μm, YMC GEL, Japan). All chemicals and solvents were of analytical grade and used without further purification. OH HO
12
OCH3 1a
4a
O
11b
HO
OH
7a 9a
6
8b 1b 7b
12a
9
O
2
4b
OH
OH
1'
13b
8a
HO
O
4
OH
OH
1'' 4''
OH 2
2
9
10
OH
HO
O 4
OH
OH
10a
4'
10b
7''
O
HO
OR 11
10
OH 1
OCH3
4'
4a
OH
6a
O
6
O
3: R =
1'
OH
O
OH 3, 4
7'
4: R = H
1) Bio-Center, Gyeo
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