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Moon E.,Gachon University | Kang T.H.,Kyung Hee University | Kim H.J.,Dong A Pharm Institute | Choi S.Z.,Dong A Pharm Institute | And 3 more authors.
Biomolecules and Therapeutics | Year: 2014

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. © 2014 The Korean Society of Applied Pharmacology.


Kim K.H.,Sungkyunkwan University | Piao C.J.,Sungkyunkwan University | Choi S.U.,Korea Research Institute of Chemical Technology | Son M.W.,Dong A Pharm Institute | Lee K.R.,Sungkyunkwan University
Planta Medica | Year: 2010

Two new tetrahydroprotoberberine-aporphine dimeric alkaloids, corydaturtschines A (1) and B (2), and a new aporphine derivative, ethyl glausuccinate (3), together with 13 known protoberberine (416) and nine known aporphine alkaloids (1725), were isolated from the tubers of Corydalis turtschaninovii. The structures of these new compounds were determined through spectral analyses, including extensive 2DNMR data. The absolute configurations of the compounds were clarified by CD spectroscopic studies. The isolated compounds were tested for their cytotoxicity against four human cancer cell lines in vitro using a sulforhodamine B bioassay. © Georg Thieme Verlag KG Stuttgart - New York.


Kim K.H.,Sungkyunkwan University | Choi S.U.,Korea Research Institute of Chemical Technology | Son M.W.,Dong A Pharm Institute | Lee K.R.,Sungkyunkwan University
Chemical and Pharmaceutical Bulletin | Year: 2010

Two new phenolic amides, pharnilatins A (1) and B (2), were isolated from the seeds of Pharbitis nil. These new compounds possess a p-coumaroyl unit with a structurally unique side chain, (2S,3S)-2,3-dihydroxyputrescine. The chemical structures and absolute stereochemistries of the new compounds were determined on the basis of spectroscopic analyses including 1D- and 2D-NMR experiments and chemical reactions. Compounds 1 and 2 exhibited cytotoxicity against A549, SK-OV-3, SK-MEL-2, and HCT-15 human tumor cells. However, none of the compounds inhibited nitric oxide (NO) production in lipopolysaccharide (LPS)-activated microglia cells. © 2010 Pharmaceutical Society of Japan.


Kim K.H.,Harvard University | Kim K.H.,Sungkyunkwan University | Choi S.U.,Korea Research Institute of Chemical Technology | Son M.W.,Dong A Pharm Institute | And 3 more authors.
Journal of Natural Products | Year: 2013

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. © 2013 The American Chemical Society and American Society of Pharmacognosy.


Kim K.H.,Sungkyunkwan University | Choi S.U.,Korea Research Institute of Chemical Technology | Choi S.Z.,Dong A Pharm Institute | Son M.W.,Dong A Pharm Institute | Lee K.R.,Sungkyunkwan University
Journal of Agricultural and Food Chemistry | Year: 2011

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 IC50 values ranging from 27.1 to 28.8 μM, suggesting selective toxicity among tumor and normal cells. © 2011 American Chemical Society.


Kim K.H.,Sungkyunkwan University | Kim M.A.,Sungkyunkwan University | Moon E.,Kyung Hee University | Kim S.Y.,Kyung Hee University | And 3 more authors.
Bioorganic and Medicinal Chemistry Letters | Year: 2011

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. © 2011 Elsevier Ltd. All rights reserved.


Woo K.W.,Sungkyunkwan University | Moon E.,Gachon University | Kwon O.W.,Kyung Hee University | Lee S.O.,Kyung Hee University | And 4 more authors.
Bioorganic and Medicinal Chemistry Letters | Year: 2013

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 14.36 μM, respectively) without cell toxicity in lipopolysaccharide-activated BV-2 cells. © 2013 Elsevier Ltd. All rights reserved.


Kim K.H.,Sungkyunkwan University | Woo K.W.,Sungkyunkwan University | Moon E.,Gachon University | Choi S.U.,Korea Research Institute of Chemical Technology | And 4 more authors.
Journal of Agricultural and Food Chemistry | Year: 2014

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 the lipopolysaccharide (LPS)-activated BV-2 microglia cell line with an IC 50 value of 12.8 μM. © 2014 American Chemical Society.


PubMed | Sungkyunkwan University, Gachon University, Dong A Pharm Institute and Kyung Hee University
Type: Journal Article | Journal: Journal of ethnopharmacology | Year: 2014

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.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.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 162.3516.18% stimulation, and strongly reduced NO levels with an IC50 value of 19.56 M in BV2 microglial cells. Also, it significantly increased neurite outgrowth in N2a cells.This study supports the ethnopharmacological use of Dioscorea nipponica rhizomes as traditional medicine.


PubMed | Dong A Pharm Institute, Gachon University, Kyung Hee University and Incheon National University
Type: Journal Article | Journal: Biomolecules & therapeutics | Year: 2014

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.

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