Chien-Kuang Chen
National Taiwan University
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Publication
Featured researches published by Chien-Kuang Chen.
Phytochemistry | 2012
Yi-Chun Lai; Chien-Kuang Chen; Wan-Wan Lin; Shoei-Sheng Lee
This study was aimed to investigate thoroughly the diarylheptanoids in the n-BuOH soluble fraction of leaves of Alnus formosana in order to examine their anti-inflammatory activities. The application of HPLC-SPE-NMR as a preliminary chemical screening led to characterization of eleven compounds. Further separation resulted in isolation of 28 compounds, of which 10 diarylheptanoids and 2-coumaroylxyloside are new natural products. Compound 1 and alnuside A (27) were found to possess good activities against LPS-induced NO production with respective IC(50) values of 7.99 and 8.08 μM, and which were devoid of significant cytotoxicity.
Journal of Natural Products | 2011
Chien-Kuang Chen; Feng-Hsu Lin; Li-Hong Tseng; Chia-Ling Jiang; Shoei-Sheng Lee
A comprehensive study of the alkaloids presentin the leaves of Crinum asiaticum var. sinicum, assisted by HPLC-SPE-NMR, led to the characterization of 21 compounds of similar polarity on an analytical scale. Thirteen of these were isolated for further structural confirmation. Seven are proved to be new, namely, (+)-siculine (4), 1-epijosephinine (11), 7-methoxycrinamabine (10), 2-O-acetylcrinamabine (16), 3-O-acetyl-8-O-demethylmaritidine (17), 2-O-acetylbulbisine (18), and 1-O-acetylbulbisine (19). In addition, dihydrovittatine (6) and 8-O-demethyloxomaritidine (21) were isolated for the first time from Nature, although they have been prepared previously as synthetic products. Their structures were established by spectroscopic analysis.
Journal of Chromatography A | 1997
Shao-Wen Sun; Shoei-Sheng Lee; Li-Yun Chen; Chien-Kuang Chen
The separation of nine aporphine alkaloids, lindcarpine, laurolitsine, N-methyllindcarpine, boldine, norpredicentrine, isocorydine, laurotetanine, N-methyllaurotetanine and isoboldine, was investigated by micellar electrokinetic chromatography. Optimization of separation was realized with the univariate approach by studying the effects of five factors relevant to run buffer on migration times. Quantitative analysis on a Lauraceous plant showed a similar result to that obtained with HPLC previously performed.
Journal of Natural Products | 2009
Shoei-Sheng Lee; Yi-Shan Lin; Chien-Kuang Chen
Chemical investigation of the EtOH extract of the leaves of Machilus japonica var. kusanoi resulted in the isolation of three compounds with a unique skeleton, i.e., apigenosylides A-C (4-6), together with five known flavonoid glycosides. Some of these compounds possess moderate inhibitory activity against alpha-glucosidase. The structures of the new compounds were elucidated on the basis of spectrometric analyses. They possess an unprecedented skeleton comprising the adduct of a butenolide moiety and apigenin glycoside linked via a 1,2-dioxane moiety.
Journal of Chromatography A | 1998
Shao-Wen Sun; Ching-Hua Kuo; Shoei-Sheng Lee; Chien-Kuang Chen
After the earlier analysis of nine bisbenzylisoquinoline alkaloids with ion pair chromatography, seven other bisbenzylisoquinoline alkaloids were analyzed using gradient elution with an acetonitrile-phosphate buffer (pH 8.0) mixture, and UV detection. Four alkaloids were detected in the stem woods of a Lauraceous plant, Dehaasia triandra Merr. and their contents determined. LC-MS suggested that a major unknown compound in the plant was also a bisbenzylisoquinoline alkaloid.
Drug Metabolism and Disposition | 2012
Yung-Ping Lee; Feng-Lin Hsu; Jaw-Jou Kang; Chien-Kuang Chen; Shoei-Sheng Lee
The metabolic profile of the potent hypoglycemic agent, (2S)-pterosin A (1), in rat urine via intragastrical oral administration was investigated. In total, 19 metabolites (M1–M19) were identified. Among these, 16 metabolites were characterized by high-performance liquid chromatography solid-phase extraction-tube transfer-NMR, and seven metabolites were further isolated from the treated urine to enable further structural determination. Twelve of these are new compounds. The phase I metabolites of 1 were formed via various oxidations at positions C-3, C-10, C-12, C-13, or C-1 followed by decarboxylation of C-10 or C-14, and lactonization at C-12/C-14 or C-14/C-12. The phase II metabolites were glucuronide conjugates from the parent compound or phase I metabolites. The major metabolites were found to be (2S)-14-O-glucuronylpterosin A (M9), (2S)-2-hydroxymethylpterosin E (M14), and (±)-pterosin B (M19). Quantitative HPLC analysis of metabolites, based on similar UV absorption and use of the regression equation of 1, indicated that ∼71% 1 was excreted as metabolites in rat urine.
Fitoterapia | 2011
Xiao-Ling Wang; Bing-Rui Liu; Chien-Kuang Chen; Jun-Ru Wang; Shoei-Sheng Lee
Four new fluorenone alkaloids, caulophylline A-D (1-4), and one new dihydroazafluoranthene alkaloid, caulophylline E (5) were isolated from the roots of Caulophyllum robustum Maxim. Their structures were elucidated by spectroscopic analysis. Among the isolated alkaloids, Caulophylline E showed good scavenging effects against DPPH radical with IC(50) of 39 μM.
Drug Metabolism and Disposition | 2010
Yi-Chun Lai; Tzong-Fu Kuo; Chien-Kuang Chen; Han-Ju Tsai; Shoei-Sheng Lee
The metabolic profile of dicentrine, a selective α1-adrenoceptor antagonist with potent antiarrhythmic and antihypertensive activities, in miniature pig urine via oral administration was investigated for the first time. The urine, collected after a single oral administration of dicentrine, was pretreated using solvent extraction and column chromatographic methods to identify the metabolites containing fractions. Twenty-four metabolites (MI-1–9 and MII-1-15), of which 21 compounds are new, were identified by mass spectrometry and high-performance liquid chromatography-diode array detector solid-phase extraction-NMR techniques. Of these, 14 metabolites (MI-5, MII-1 and 2, and MII-5-15) were further isolated for structure confirmation. The phase I metabolic transformations of dicentrine were found to be N-demethylation, N-oxidation, O-demethylation (9,10-OMe), O,O-demethylenation (1-OCH2O-2), and hydroxylation at the benzylic (C-4) and the aromatic (C-3) positions, whereas those for the phase II were O-glucuronidation and O-glucosylation of the phenolic group of the phase I metabolites.
Journal of Asian Natural Products Research | 2011
Xiao-Ling Wang; Bing-Rui Liu; Jun-Ru Wang; Chien-Kuang Chen; Guo-Wei Qin; Shoei-Sheng Lee
Two new morphinane alkaloids, 1-hydroxy-10-oxo-sinomenine (1) and 4,5-epoxy-14-hydroxy sinomenine N-oxide (2), have been isolated from the stems of Sinomenium acutum. Their structures were established by various spectral analyses, especially 2D NMR experiments. The structure of 2 was confirmed by single crystal X-ray diffraction. The absolute configurations of 1 and 2 were deduced by comparison of CD spectra with the known alkaloid sinomenine (3). Compound 1 was tested for DPPH inhibition and gave IC50 of 27.9 μM. Compound 2 was tested for neuroprotective effect and showed significant activity against β-amyloid25–35-induced oxidative injury (*P < 0.05) at 10 μM in PC-12 cells.
Journal of Natural Products | 2014
Chien-Kuang Chen; Jaw-Jou Kang; Wu-Che Wen; Hui-Fen Chiang; Shoei-Sheng Lee
Four metabolites (1-4) of antroquinonol from rat urine, collected within 24 h after oral administration of antroquinonol, were characterized by HPLC-SPE-NMR. Compounds 1-4 were further isolated by semipreparative HPLC for structure confirmation. Their structures were elucidated on the basis of 1D and 2D NMR spectroscopic analyses and HRESIMS data.