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An Efficient Stereospecific Synthesis of 1-α-C-glycosylphosphonic Acid
남길수 한국키틴키토산학회 2006 한국키틴키토산학회지 Vol.11 No.1
The convenient stereospecific synthesis of the isosteric phosphono analogue of N-acetylglucosamine was described.Especially the α analogue of N-acetyl-D-glucosamine 1-phosphoric acid 1 has been synthesized starting from N-acetyl-D-glucosamine through the following reaction: Stereoselective radical α-1-C-allylation of 1-chloro-N-acetyl-D-glucosamine,catalytic double bond isomerization, Lemieux-Johnson oxidation, addition reaction of dialkylphosphonates, radicaldehydroxylation, and removal of protecting group. Final compound was fully characterized by NMR (1H, 13C, 19F and 31P) andHRMS experiments.
Evaluation of the Chemical Reporter Analog PNP-6AzGlcNAc as an O-GlcNAcase Substrate
김은주,Michelle R. Bond,남길수,John A. Hanover 대한화학회 2017 Bulletin of the Korean Chemical Society Vol.38 No.2
6-Azido-6-deoxy-N-acetylglucosamine (6AzGlcNAc) was recently introduced as a new selective metabolic chemical reporter (MCR) for labeling O-GlcNAc-modified proteins in cells. To investigate whether O-6AzGlcNAc is readily cleaved by O-GlcNAcase (OGA), the enzyme responsible for removing the O-GlcNAc modification, we synthesized PNP-6AzGlcNAc. This analog mimics O-GlcNAc and can be used in vitro to define the kinetic parameters for OGA thereby defining whether O-6AzGlcNAc can be employed as an appropriate tool to monitor O-GlcNAc dynamics in cells. Both PNP-6AzGlcNAc and PNP-GlcNAc were efficiently hydrolyzed by OGA with similar kinetics suggesting that an azido-modification at the GlcNAc C6 position does not significantly interfere with the β-hexosaminidase activity of OGA.
Synthesis and Nrf2 Activating Ability of Thiourea and Vinyl Sulfoxide Derivatives
Young Sun Shim,황현숙,남길수,최경일 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.8
Thiourea and vinyl sulfoxide derivatives were designed based on the structures of sulforaphane and gallic acid, prepared and tested for HO-1 inducing activity as a measure of Nrf2 activation, and inhibitory effect on NO production as a measure of anti-inflammatory activity. Both series of compounds showed moderate activity on HO-1 induction, and no inhibitory effect on NO production. Interestingly the thiourea compound 6d showed better HO-1 induction (71% SFN) than the corresponding isothiocyanate compound 6a (55% SFN). Overall, it seemed that more efficient electrophile is needed to get more effective Nrf2 activator.
오명석,나란투야 난딘셋세그,박찬주,남길수,조식제,문자영 한국생명과학회 2023 생명과학회지 Vol.33 No.2
This study compared and analyzed the antioxidant activities of various organic solvent fractions from the leaves and roots of Peucedanum insolens Kitagawa. For this study, the dried leaves and roots of P. insolens Kitagawa were first extracted using 70% ethanol. The extracts were sequentially sub-fractionated in the order of hexane, chloroform, ethyl acetate, n-butanol, and water. The results revealed that the distribution of total phenolic contents by organic solvent fractions showed the same pattern in both the leaves and roots, with the highest in the ethyl acetate fraction (101.1±1.0 mg vs 71.2±3.4 mg of GAE/mg), but the lowest content in the hexane fraction (9.5±0.2 mg vs 7.5±2.1 mg of GAE/mg). The distribution of total flavonoid content in the organic solvent fractions showed the same pattern as that of total phenolic content. The results of DPPH, ABTS, and FRAP assays showed that the leaf and root extracts exhibited free radical scavenging activity in the same pattern, particularly, the ethyl acetate fraction had the highest activity. These results indicate that not only the roots of P. insolens Kitagawa but also the leaves possess potential substances that exhibit strong antioxidant activity. Significant correlations (R=0.903, p<0.0001, DPPH radical; R=0.891, p<0.001, ABTS radical; R=0.745, p<0.05, FRAP radical) between total phenolics and radical scavenging activities, but also significant correlations (R=0.867, p<0.001, DPPH vs. ABTS radicals; R=0.882, p<0.0001, DPPH vs. FRAP radicals; R=0.973, p<0.0001, ABTS vs. FRAP radicals) between radical scavenging activities were found in the organic solvent fractions. Therefore, as in the roots of P. insolens Kitagawa, the leaves possess strong antioxidant capacity and can be used as the main antioxidant material.
김희숙,오광석,이병호,추현아,배애님,노은주,남길수 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.11
In a search for novel molecules to treat inflammatory disorders, we identified several compounds with inhibitory action against the IKK2 enzyme using in silico methods. Based on the virtual hit of compounds 1 and 2, a novel series of 2-phenylimino-5((5-phenylfuran-2-yl)methylene)thiazolidin-4-one derivatives was designed, synthesized, and evaluated for IKK2 inhibitory activity. Among the synthesized derivatives, compounds 17f and 19f showed good IKK2 inhibitory potency, which have 4-carboxaminophenyl on the 2-furan ring and a methoxy group on the phenylimino moiety at the 2-position of the core structure. The most potent compound was 2-(2,4-dimethoxyphenyl)imino-5((5(4-carboxaminophenyl)furan-2-yl)methylene)thiazolidin-4-one (19f, IC50 = 0.94 μM), which represents a synergic effect of the two virtual hit compounds against IKK2. We also identified compounds showing inhibitory activities against interleukin (IL)-17, CCK-8, and tumor necrosis factor-alpha (TNF-α), which are NF-κB-dependent pro-inflammatory cytokine mediators.
심영선,이예용,왕현정,태진성,박종현,추현아,임혜원,남길수 대한화학회 2023 Bulletin of the Korean Chemical Society Vol.44 No.7
A novel series of 4-arylthio- or 4-arylsulfonyl-substituted 2-amino-5,6,7,8- tetrahydroquiazolines was synthesized and evaluated for serotonin receptor subtype 6 (5-HT6R) antagonistic effects in vitro. The structure activity relationships (SAR) of this series were discussed on the basis of in vitro activity. Among the derivatives synthesized in the present study, the lead compound, 7a, having sulfonyl functionality at the 4-position and N-methylpiperazine at the 2-position of the core structure showed the most potent 5-HT6 receptor inhibitory activity in vitro and good metabolic stability without CYP liability.
Isoxazoline, Isoxazole, and Oxadiazole Derivatives as M1 Muscarinic Acetylcholine Receptor Agonists
Selvaraj Muthusamy,이수민,Minghua Huang,Nam-Chul Cho,남길수,Ae Nim Pae,Hyewhon Rhim,금교창,최경일 대한화학회 2016 Bulletin of the Korean Chemical Society Vol.37 No.7
Insertion of a methylene linker between the 2-pyrrolidinone substituent and the isoxazoline core of the lead compound 1 previously reported resulted in the loss of its agonistic activity. One exception was the compound 6f having oxadiazole core and 2-azabicyclo[2.2.1]heptane substituent. Of the two isomers of 6f, exo-isomer (EC50 0.013 μM) was five- to six-fold more effective than endo-isomer (EC50 0.30 μM), and ca. two-fold active than the mother compound 1 (EC50 0.031 μM) in stimulating the M1 mAChR. Both isomers were moderately selective agonists for M1 mAChR over the rest four subtypes, and it could be explained by docking study on active conformation allosteric binding sites of M1–M5 mAChRs and calculating their binding energies.
A Role for the Carbohydrate Portion of Ginsenoside Rg3 in Na+ Channel Inhibition
나승열,Sang Min Jeong,이병환,Sang-Mok Lee,Jong-Hoon Kim,Yoon-Hee Hong,Jun-Ho Lee,김동현,남길수 한국분자세포생물학회 2005 Molecules and cells Vol.19 No.1
We showed recently that ginsenosides inhibit the activ-ity of various types of ion channel. Here we have inves-tigated the role of the carbohydrate component of gin-senoside Rg3 in the inhibition of Na+ channels. The channels were expressed in Xenopus oocytes by inject-ing cRNAs encoding rat brain Nav1.2 and 1 sub-units, and analyzed by the two-electrode voltage clamp technique. Treatment with Rg3 reversibly inhibited the inward Na+ peak current (INa) with an IC50 of 32.2 4.5 M, and the inhibition was voltage-dependent. To examine the role of the sugar moiety, we prepared a straight chain form of the second glucose and a conju-gate of this glucose with 3-(4-hydroxyphenyl) propi-onic acid hydrazide (HPPH). Neither derivative inhib-ited INa. Treatment with the carbohydrate portion of ginsenoside Rg3, sophorose [-D-glucopyranosyl (1→2)- -glucopyranoside], or the aglycone (protopanaxadiol), on their own or in combination had no effect on INa. These observations indicate that the carbohydrate portion of ginsenoside Rg3 plays an important role in its effect on the Na+ channel.