Sang Zin Choi

Sungkyunkwan University, Sŏul, Seoul, South Korea

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Publications (24)51.43 Total impact

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    ABSTRACT: The purpose of this study was to investigate the therapeutic effects of DA-9801, an optimized extract of Dioscorea species, on diabetic peripheral neuropathy in a type 2 diabetic animal model. In this study, db/db mice were treated with DA-9801 (30 and 100 mg/kg, daily, p.o.) for 12 weeks. DA-9801 reduced the blood glucose levels and increased the withdrawal latencies in hot plate tests. Moreover, it prevented nerve damage based on increased nerve conduction velocity and ultrastructural changes. Decrease of nerve growth factor (NGF) may have a detrimental effect on diabetic neuropathy. We previously reported NGF regulatory properties of the Dioscorea genus. In this study, DA-9801 induced NGF production in rat primary astrocytes. In addition, it increased NGF levels in the sciatic nerve and the plasma of type 2 diabetic animals. DA-9801 also increased neurite outgrowth and mRNA expression of Tieg1/Klf10, an NGF target gene, in PC12 cells. These results demonstrated the attenuation of diabetic peripheral neuropathy by oral treatment with DA-9801 via NGF regulation. DA-9801 is currently being evaluated in a phase II clinical study.
    Biomolecules and Therapeutics 09/2014; 22(5):445-452. DOI:10.4062/biomolther.2014.051 · 0.84 Impact Factor
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    ABSTRACT: In the search for antitumor compounds from Korean natural resources, activity-guided fractionation and purification processes were used on seeds of Morning glory (Pharbitis nil). Air-dried P. nil seeds were extracted with ethanol and separated into n-hexane, chloroform, ethyl acetate, and n-butanol. Four new lignans, pharbilignans A-D (1-4) were isolated from the most active ethyl acetate fraction of the ethanol extract. Their structures were characterized on the basis of spectroscopic methods, including one- and two-dimensional nuclear magnetic resonance (NMR) techniques, high resolution mass spectrometry (HRMS), and circular dichroism (CD) spectroscopy. The cytotoxic activities of the isolates (1-4) were evaluated by determining their inhibitory effects on four human tumor cell lines (A549, SK-OV-3, SK-MEL-2, and HCT15) using a sulforhodamine B (SRB) bioassay. Pharbilignan C (3) showed potent cytotoxicity against A549, SK-OV-3, SK-MEL-2, and HCT-15 cell lines with IC50 values of 1.42, 0.16, 0.20, and 0.14 μM, respectively. On the basis of the expanded understanding that inflammation is a crucial cause in tumor progress, we also evaluated anti-inflammatory activity of the isolates (1-4). Pharbilignan C (3) strongly inhibited nitric oxide (NO) production in lipopolysaccharide (LPS)-activated BV-2 microglia cell line with an IC50 value of 12.8 μM.
    Journal of Agricultural and Food Chemistry 07/2014; 62(31). DOI:10.1021/jf501470k · 3.11 Impact Factor
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    ABSTRACT: Ethnopharmacological relevance: Dioscorea nipponica (Dioscoreaceae) have been used as traditional medicines for diabetes, inflammatory and neurodegenerative diseases in Korea. The aim of the study was to isolate the bioactive components from the rhizomes of Dioscorea nipponica and to evaluate their anti-neuroinfalmmatory and neuroprotective activities. Material and methods: The phytochemical investigation of 50% EtOH extract of Dioscorea nipponica using successive column chromatography over silica gel, Sephadex LH-20, and preparative high performance liquid chromatography (HPLC) resulted in the isolation and identification of 17 phenolic derivatives, including four new phenolic compounds (1-4). The structural elucidation of these compounds was based on spectroscopic methods, including 1D and 2D nuclear magnetic resonance (NMR) spectroscopy techniques, mass spectrometry, and optical rotation. All isolated compounds were evaluated for their effects on nerve growth factor (NGF) secretion in a C6 rat glioma cell line and nitric oxide (NO) production in lipopolysaccharide (LPS)-activated BV2 cells. The neurite outgrowth of compound 16 was further evaluated by using mouse neuroblastoma N2a cell lines. Results: Three new stilbene derivatives, diosniponol C (1), D (2) and diosniposide A (3) and one new phenanthrene glycoside, diosniposide B (4), together with 13 known compounds were isolated from the rhizomes of Dioscorea nipponica. Of the tested compounds (1-17), phenanthrene, 3,7-dihydroxy-2,4,6-trimethoxy-phenanthrene (16) was the most potent NGF inducer, with 162.35 +/- 16.18% stimulation, and strongly reduced NO levels with an IC50 value of 19.56 mu M in BV2 microglial cells. Also, it significantly increased neurite outgrowth in N2a cells. Conclusions: This study supports the ethnopharmacological use of Dioscorea nipponica rhizomes as traditional medicine.
    Journal of Ethnopharmacology 06/2014; 155(2). DOI:10.1016/j.jep.2014.06.043 · 3.00 Impact Factor
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    ABSTRACT: A phytochemical investigation on the essential oil of Thuja orientalis resulted in the isolation and identification of three new sesquiterpenes, 3α-methoxy-4α-epoxythujopsane (1), Δ3,15-4β-epoxythujopsene (2), and Δ3,4-thujopsen-2,15-diol (3), together with eight known sesquiterpenoids (4-11). The structures of these new compounds were elucidated based on spectroscopic data analyses including extensive 2D-NMR data and HR-ESIMS. The full assignments of 1H and 13C NMR chemical shifts for thujopsadiene (4) were obtained by 2D-NMR for the first time. All compounds (1-11) showed antiproliferative activities against the SK-OV-3 and SK-MEL-2 cell lines with IC50 values of 5.85-28.64 µM. In addition, compounds 1, 3, 4, 7, 8, and 9 significantly inhibited nitric oxide production in lipopolysaccharide-activated BV-2 cells with IC50 values of 3.93-17.85 µM without cell toxicity.
    Planta Medica 10/2013; 79(17). DOI:10.1055/s-0033-1350952 · 2.34 Impact Factor
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    ABSTRACT: Pharbinilic acid (1), the first naturally occurring allogibberic acid, was isolated from ethanol extracts of morning glory (Pharbitis nil) seeds. Its absolute configuration was determined by NOESY NMR and ECD experiments. Compound 1 showed weak cytotoxicity against A549, SK-OV-3, SK-MEL-2, and HCT-15 cells and weakly inhibited nitric oxide production in lipopolysaccharide-activated BV-2 microglia cells.
    Journal of Natural Products 07/2013; 76(7). DOI:10.1021/np400326e · 3.95 Impact Factor
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    ABSTRACT: In a continuing search for bioactive constituents from Dioscoreaceae medicinal plants, two new cyclic diarylheptanoids, diosniponol A (1) and B (2), together with 10 known compounds (3-12) were isolated from the rhizomes of Dioscorea nipponica. The structures of these new compounds were determined by spectroscopic analyses, including extensive two-dimensional nuclear magnetic resonance, high-resolution mass spectrometry, and optical rotation. All isolated compounds 1-12 were evaluated for their effects on nitric oxide (NO) production in murine microglia cell line BV-2. Compounds 8 and 11 showed potent inhibitory activities on NO production (IC50 13.36 and 14.36μM, respectively) without cell toxicity in lipopolysaccharide-activated BV-2 cells.
    Bioorganic & medicinal chemistry letters 05/2013; 23(13). DOI:10.1016/j.bmcl.2013.04.073 · 2.33 Impact Factor
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    ABSTRACT: Diabetic neuropathy is characterized by axonal degeneration, demyelination, and atrophy in association with failed axonal regeneration, remyelination, and synaptogenesis. Recent reports suggest that reduced levels of nerve growth factor (NGF) may play a significant role in the pathogenesis of diabetic polyneuropathy. In this study, we investigated the regulation of NGF by steroid diosgenin (DG) in a diabetic neuropathy rodent model. We found that DG, the primary spirostane-type steroid in several Dioscorea species, increased NGF levels in the sciatic nerve of diabetic rats. Additionally, DG increased neurite outgrowth in PC12 cells and enhanced nerve conduction velocities in the diabetic neuropathy mouse model. DG-treated diabetic mice showed reduced disarrangement of the myelin sheath and increased area of myelinated axons by electron microscope studies and exhibited improvement in the damaged axons. Our data further suggest that DG increased the nerve conduction velocity through induction of NGF. Thus, our findings indicate that DG, a major sapogenin obtained from Dioscorea nipponica, reverses functional and ultrastructural changes and induces neural regeneration in a diabetic neuropathy model.
    Biological & Pharmaceutical Bulletin 09/2011; 34(9):1493-8. DOI:10.1248/bpb.34.1493 · 1.78 Impact Factor
  • Ki Hyun Kim · Sang Un Choi · Sang Zin Choi · Mi Won Son · Kang Ro Lee
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    ABSTRACT: Edible yams are tropical crops that serve as important staple foods in many parts of the world. The rhizome of Dioscorea japonica , well-known as "Japanese yam", is a food and medicinal source known as "San Yak" in Korea. Bioassay-guided fractionation and chemical investigation of the extract of this yam resulted in the identification of two new withanolides, named dioscorolide A (1) and dioscorolide B (2). The structures of these new compounds were determined by spectroscopic methods, including 1D and 2D nuclear magnetic resonance (NMR) techniques, high-resolution mass spectrometry (HRMS), and chemical methods. The cytotoxic activities of the isolates (1 and 2) were evaluated by determining their inhibitory effects on four human tumor cell lines (A549, SK-OV-3, SK-MEL-2, and HCT15) and a human normal cell line (HUVEC) using a sulforhodamine B (SRB) bioassay. Compounds 1 and 2 showed cytotoxicity against tumor cell lines (A549, SK-OV-3, SK-MEL-2, and HCT15) with IC(50) values ranging from 6.3 to 26.9 μM and exhibited lower activity against the normal cell line (HUVEC) with IC(50) values ranging from 27.1 to 28.8 μM, suggesting selective toxicity among tumor and normal cells.
    Journal of Agricultural and Food Chemistry 06/2011; 59(13):6980-4. DOI:10.1021/jf2006535 · 3.11 Impact Factor
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    ABSTRACT: The rhizome of Dioscorea japonica is a food and medicinal source known as 'San Yak' in Korea. Two new furostanol saponins, coreajaponins A (1) and B (2), together with 10 known compounds (3-12) were isolated from the rhizomes of D. japonica. Their structures were determined by spectroscopic methods, including 1D and 2D NMR techniques, HRMS, and chemical methods. Nerve growth factor (NGF), a crucial factor for neuronal survival and differentiation, can potentially improve neurodegenerative diseases and diabetic polyneuropathy. We evaluated the effects of isolates (1-12) on NGF induction in a C6 rat glioma cell line. Coreajaponin B (2) upregulated NGF content without significant cell toxicity, as did 6, 8, 9, and 11.
    Bioorganic & medicinal chemistry letters 02/2011; 21(7):2075-8. DOI:10.1016/j.bmcl.2011.02.003 · 2.33 Impact Factor
  • Ki Hyun Kim · Mi Rim Jin · Sang Zin Choi · Mi Won Son · Kang Ro Lee
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    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    ChemInform 10/2008; 39(42). DOI:10.1002/chin.200842179
  • Kang Ro Lee · Ki Hyun Kim · Mi Rim Jin · Sang Zin Choi · Mi Won Son
    Heterocycles 01/2008; 75(6). DOI:10.3987/COM-07-11291 · 0.91 Impact Factor
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    ABSTRACT: Three new sesquiterpene hydroperoxides, 1-[3-(2-hydroperoxy-3-methylbut-3-en)-4-hydroxyphenyl]ethanone (2), 7beta-hydroperoxy-eudesma-11-en-4-ol (3), and 7alpha-hydroperoxymanool (4), together with three known compounds, germacrone (1), ent-germacra-4(15),5,10(14)-trien-1alpha-ol (5) and teucdiol A (6) were isolated from the aerial parts of Aster spathulifolius (Compositae). Their structures were characterized using chemical and spectroscopic methods. The isolated compounds were tested for their cytotoxicity against five human tumor cell lines in vitro using a SRB method. The two new compounds, 3 and 4, showed moderate cytotoxicity against human cancer cells with ED50 values ranging from 0.24 to 13.27 microg/mL.
    Archives of Pharmacal Research 11/2006; 29(10):845-8. DOI:10.1007/BF02973904 · 1.75 Impact Factor
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    Sang Zin Choi · Min Cheol Yang · Sang Un Choi · Kang Ro Lee
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    ABSTRACT: The chromatographic separation of the MeOH extract of the roots of Ainsliaea acerifolia (Compositae) led to the isolation of six known terpenes and two known lignans. Their structures were identified by spectroscopic methods as mokko lactone (1), betulonic acid (2), betulinic acid (3), zaluzanin C (4), 1beta-hydroperoxygermacra-4(15),5,10(14)-triene (5), pluviatilol (6), (+)-syringaresinol (7), and glucozaluzanin C (8). Compounds 1 approximately 4 and 8 showed non-specific significant cytotoxicity against five human tumor cell lines with ED50 values ranging from 0.36 approximately 5.54 microg/mL.
    Archives of Pharmacal Research 04/2006; 29(3):203-8. DOI:10.1007/BF02969394 · 1.75 Impact Factor
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    ABSTRACT: Three new labdane diterpenes (1-3), together with eight known diterpenoids, were isolated from a methanol extract of the aerial parts of Aster spathulifolius. The structures of 1-3 were determined as (13R)-labda-7,14-diene 13-O-beta-d-(4'-O-acetyl)fucopyranoside (1), (13R)-labda-7,14-diene 13-O-beta-d-(3'-O-acetyl)fucopyranoside (2), and (13R)-labda-14(15)-en-8,13-diol 13-O-beta-d-fucopyranoside (3), on the basis of spectroscopic and chemical methods. Compounds 1, 2, and four of the known compounds exhibited generally nonspecific cytotoxicity against human A549, SK-OV-3, SK-MEL-2, XF498, and HCT15 tumor cells.
    Journal of Natural Products 11/2005; 68(10):1471-4. DOI:10.1021/np058044e · 3.95 Impact Factor
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    Sang Zin Choi · Sang Un Choi · Kang Ro Lee
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    ABSTRACT: Seven sesquiterpene lactones were isolated by the chromatographic separation of the MeOH extract of the aerial parts of Saussurea calcicola (Compositae). Their structures were determined spectroscopically to be cynaropicrin (1), arguerin B (2), cebellin F (3), 8alpha-hydroxy-11alpha, 13-dihydrozaluzanin C (4), desacylcynaropicrin (5), 3beta-hydroxy-8alpha-epoxymethylacriloiloxy-4(15),10(14),11(13)-trien-guaian-6,12-olide (6), and kandavanolide (7). Compounds 1 and 2 showed significant cytotoxicity against five cultured human tumor cell lines with ED50 values ranging from 0.23-1.72 microg/mL.
    Archives of Pharmacal Research 11/2005; 28(10):1142-6. DOI:10.1007/BF02972976 · 1.75 Impact Factor
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    ABSTRACT: The antidiabetic-activity-guided fractionation and isolation of the 80% EtOH extracts obtained from cultivated Korean Rhubarb rhizomes (Rheum undulatum, Polygonaceae) led to the isolation and characterization of one stilbene, desoxyrhapontigenin (1) and two anthraquinones, emodin (2) and chrysophanol (3). Their structures were established by chemical and spectroscopic methods. Compounds 1, 2, and 3 inhibited postprandial hyperglycemia by 35.8, 29.5, 42.3%, respectively.
    Archives of Pharmacal Research 10/2005; 28(9):1027-30. DOI:10.1007/BF02977396 · 1.75 Impact Factor
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    ABSTRACT: The chromatographic separation of the hexane soluble fraction of the methanol extract of the aerial parts of Solidago virga-aurea var. gigantea M(IQ*) (Compositae) led to the isolation of a new benzylbenzoate (1) together with four known benzylbenzoates (2-5). Their structures were determined as 2-methoxybenzyl-2-hydroxybenzoate (1), benzyl-2-hydroxy-6-methoxybenzoate (2), 2-methoxybenzyl-2,6-dimethoxybenzoate (3), 2-methoxybenzyl-2-methoxy-6-hydroxybenzoate (4), and benzyl-2,6-dimethoxybenzoate (5). Their structures were established by spectroscopic methods. Biological effects of compounds, 1 and 2, were investigated in vitro using mouse peritoneal macrophages. The benzylbenzoates (1 and 2) could serve as immunotherapeutic agents by stimulating macrophage functions, with potential use in the treatment of infectious diseases.
    Archives of Pharmacal Research 02/2005; 28(1):49-54. · 1.75 Impact Factor
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    ABSTRACT: The chromatographic separation of the hexane soluble fraction of the methanol extract of the aerial parts ofSolidago virga-aurea var.gigantea MIQ. (Compositae) led to the isolation of a new benzylbenzoate (1) together with four known benzylbenzoates (2~5). Their structures were determined as 2-methoxybenzyl-2-hydroxybenzoate (1), benzyl-2-hydroxy-6-methoxy-benzoate (2), 2-methoxybenzyl-2,6-dimethoxybenzoate (3), 2-methoxybenzyl-2-methoxy-6-hydroxybenzoate (4), and benzyl-2,6-dimethoxybenzoate (5). Their structures were established by spectroscopic methods. Biological effects of compounds,1 and2, were investigatedin vitro using mouse peritoneal macrophages. The benzylbenzoates (1 and2) could serve as immunotherapeutic agents by stimulating macrophage functions, with potential use in the treatment of infectious diseases.
    Archives of Pharmacal Research 01/2005; 28(1):49-54. DOI:10.1007/BF02975135 · 1.75 Impact Factor
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    ABSTRACT: The antidiabetic activity-guided fractionation and isolation of the 80% EtOH extracts from Peucedani Radix (Peucedanum japonicum, Umbelliferae) led to the isolation and characterization of a coumarin and a cyclitol as active principles, that is, peucedanol 7-O-beta-D-glucopyranoside (1) and myo-inositol (2). Their structures were identified by spectroscopic methods. Compound 1 showed 39% inhibition of postprandial hyperglycemia at 5.8 mg/kg dose, and compound 2 also significantly inhibited postprandial hyperglycemia by 34% (P<0.05).
    Archives of Pharmacal Research 12/2004; 27(12):1207-10. DOI:10.1007/BF02975882 · 1.75 Impact Factor
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    ABSTRACT: The chromatographic separation of a methylene chloride extract of Artemisia rubripes led to the isolation of a new sesquiterpene lactone (3), together with four known compounds, a coumarin (2) and three terpenes (1, 4, and 5). Their structures were characterized to be 1beta,6alpha-dihydroxy-4(15)-eudesmene (1), scopoletin (2), 1alpha,4beta-dihydroxy-8alpha-acetoxy-guaia-2,10(14), 11(13)-triene-6,12-olide (3), 1alpha,4beta-dihydroxy-8alpha-acetoxy-guaia-2,9,11(13)-triene-6,12-olide (4), and beta-sitosterol-3-O-beta-D-glycoside (5) by spectroscopic means.
    Archives of Pharmacal Research 11/2004; 27(10):1016-9. DOI:10.1007/BF02975423 · 1.75 Impact Factor