• Bulletin of the Korean Chemical Society
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• v.24 no.8
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• pp.1053-1054
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• 2003

• Natural Product Sciences
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• v.29 no.1
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• pp.10-16
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• 2023

We previously reported that dried Lysimachia christinae whole plant extract exerted significant neuroprotective activity. In this study, we tried to isolate neuroprotective compounds of L. christinae. We evaluated the neuroprotective activity of the four fractions (hexane, chloroform, ethyl acetate, and n-butanol fractions) of methanol extract. Among them, ethyl acetate and n-butanol fractions showed most potent neuroprotective activity against glutamate excitotoxicity. Nine compounds were isolated from ethyl acetate and n-butanol fractions of L. christinae extract and identified as cynaroside (1), (3,4,5,6-tetrahydroxytetrahydro-2H-pyran-2-yl)methyl-3-hydroxy-2-octyldopentaconta-23,33-dienoate (2), androst-16-ene-3,6-diol (3), 2-hydroxy-24-propoxytetracos-4-enoic acid (4), 2-hydroxy-24-methoxytetracos-4-enoic acid (5), 12-(stearoyloxy)octadec-9-enoic acid (6), β-sitosterol (7), (E)-4-(3,4-dimethoxyphenyl)but-3-en-1-yl palmitate (8) and (1S,2S,3R,4R)-4-(((2S,3R,4R,5R,6S)-2-(((2R,3R,4S,5R,6R)-2-(3,4-dimethoxyphenethoxy)-3,5-dihydroxy-6-(hydroxymethyl) tetrahydro-2H-pyran-4-yl)oxy)-4,5-dihydroxy-6-methyltetrahydro-2H-pyran-3-yl)oxy)cyclohexane-1,2,3-triol (9) by spectroscopic data such as UV, IR, NMR, Mass spectroscopy. Their neuroprotective activity was evaluated by MTT assay. Cynaroside (1) and androst-16-ene-3,6-diol (3) had significant neuroprotective activity against glutamate-injured HT22 cells. The neuroprotective efficacy of cynaroside (1) and androst-16-ene-3,6-diol (3) was related to their anti-oxidative activity.

• Applied Chemistry for Engineering
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• v.31 no.2
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• pp.187-192
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• 2020

(2S,3R)-3-hydroxyhomoserine lactone (HSL) has been used as a key intermediate for the synthesis of various biologically active compounds. In this study, we demonstrated an efficient synthesis of HSL via anti selective dihydroxylation of a protected vinyl glycine analog with an oxabicyclo[2.2.2]octyl orthoester (OBO) ester group. Because the acyclic conformation of the substrate was efficiently controlled by the bulky OBO ester group, a diastereoselectivity of > 10 : 1 was obtained in the dihydroxylation reaction without the use of a chiral reagent. By using this result, the target compound 1 can be obtained from commercially available N-Cbz-L-serine 2 in seven steps with an overall yeid of 34%. This result could be applied to the stereoselective synthesis of biologically active molecules containing a vicinal amino diol moiety.

• Mass Spectrometry Letters
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• v.8 no.4
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• pp.90-97
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• 2017

Androgenic anabolic steroids (AASs) are synthetic derivatives of testosterone with a common structure containing cyclopentanoperhydrophenanthrene nucleus. Their use enhances the muscle building capacity and is beneficial during performance. The AASs are one of the most abused group of substances in horse doping. Liquid chromatography tandem mass spectrometry ($LC/MS^n$) has been successfully applied to the detection of anabolic steroids in biological samples. However, the saturated hydroxysteroids viz: nandrolone, $5{\alpha}-estrane-3{\beta}$, $17{\alpha}-diol$ exhibit lower detection responses in electrospray ionisation (ESI) because of their poor ionisation efficiency. To overcome this limitation pre-column chemical derivatization has been introduced to enhance their detection responses in $LC-ESI-MS^n$ analysis. The aim of present study was to develop a sensitive method for identification and confirmation of nandrolone and its metabolite in horse urine incorporating pre-column derivatization using picolinic acid. The method consists of extraction of targeted steroid conjugates by solid phase extraction (SPE). The eluted steroid conjugates were hydrolysed by methanolysis and free steroids were recovered with liquid-liquid extraction. The resulting steroids were derivatized to form picolinoyl esters and identification was done using LC-ESI-MS/MS in positive ionization mode. The picolinated steroid adduct enhanced the detection levels in comparison to underivatized steroids.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2689-2694
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• 2011

Novel 5'-norcarbocyclic adenine and guanine phosphonic acid analogues with 6'-electronegative moiety such as unsaturated C-C bond were designed and synthesized from commercially available 2-methylene-propane-1,3-diol (4). Regioselective Mitsunobu reaction successfully proceeded from an allylic functional group (${\pm}$)-12b at low reaction temperature in polar cosolvent (DMF/1,4-dioxane) to give purine phosphonate analogues (${\pm}$)-13 and (${\pm}$)-20. The purine nucleoside phosphonate and phosphonic acid analogues were subjected to antiviral screening against HIV-1. Guanine analogue (${\pm}$)-23 shows significant anti-HIV activity in PBM cell lines ($EC_{50}=8.1\;{\mu}M$).

• Bulletin of the Korean Chemical Society
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• v.18 no.8
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• pp.856-860
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• 1997

The arene epoxides from naphthalene, 1β,2α-dihydroxy-3α,4α-epoxy- (1) and 1β,2α-dihydroxy-3β,4β-epoxy-1,2,3,4-tetrahydronaphthalene (2) (anti- and syn-diol epoxide), 1,2-epoxy-1,2,3,4-tetrahydronaphthalene (3), and 1,2-epoxy-l,2-dihydronaphthalene (4), are model compounds of the ultimate carcinogenic metabolites of polycyclic aromatic hydrocarbons, ubiquitous environmental pollutants which may be causal in several human cancers. The product distribution in the hydrolysis of 1-4 have been studied by HPLC analysis of reaction mixtures. The yields of the trans product from the hydronium-ion-catalyzed and pH-independent hydrolysis in 9 : 1 (v/v) 20 mM buffer-dioxane at 25 ℃, respectively, were; 1: 98, 100; 2: 74, 87, 3: 95, 97, 4:100, 100. The results were rationalized by conformational equilibria of the epoxides and the carbocationic and zwitterionic intermediates from the epoxides.

• Mycobiology
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• v.51 no.4
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• pp.246-255
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• 2023

Genus Penicillium comprising the most important and extensively studied fungi has been well-known as a rich source of secondary metabolites. Our study aimed to analyze and investigate biological activities, including in vitro anti-cancer, anti-inflammatory and anti-diabetic properties, of metabolites from a marine-derived fungus belonging to P. levitum. The chemical compounds in the culture broth of P. levitum strain N33.2 were extracted with ethyl acetate. Followingly, chemical analysis of the extract leaded to the isolation of three ergostane-type steroid components, namely cerevisterol (1), ergosterol peroxide (2), and (3β,5α,22E)-ergosta-6,8(14),22-triene-3,5-diol (3). Among these, (3) was the most potent cytotoxic against human cancer cell lines Hep-G2, A549 and MCF-7 with IC₅₀ values of 2.89, 18.51, and 16.47 ㎍/mL, respectively, while the compound (1) showed no significant effect against tested cancer cells. Anti-inflammatory properties of purified compounds were evaluated based on NO-production in LPS-induced murine RAW264.7 macrophages. As a result, tested compounds performed diverse inhibitory effects on NO production by the macrophages, with the most significant inhibition rate of 81.37±1.35% at 25 ㎍/mL by the compound (2). Interestingly, compounds (2) and (3) exhibited inhibitory activities against pancreatic lipase and α-glucosidase enzymes in vitro assays. Our study brought out new data concerning the chemical properties and biological activities of isolated steroids from a P. levitum fungus.

• Applied Chemistry for Engineering
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• v.29 no.4
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• pp.405-412
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• 2018

Three types of bis[3-(dialkyloxylphosphorothionyl) thio-2-methylpropanyloxy]alkane (BAPA) drived from alkane diol were synthesized. The principal chain of each BAPA had a different carbon number, i.e., 6, 9, and 11. The three types of synthesized BAPA were compared to zinc dialkyl dithiophosphates (ZDDPs) in terms of abrasion resistance. A four-ball test was conducted to evaluate the anti-abrasion performance of the synthesized BAPA according to the length of the principal carbon chain. Each product was added to an additive at a concentration of 1% of the base oil weight, and the wear scar diameter (WSD) was measured as 0.472, 0.459, and 0.480 mm, respectively. Among the BAPA compounds, dialkyl dithiophosphoric acid (DDP), which is the side chain of bis[methacryloyloxy] nonane (BMOO9), was synthesized by varying the carbon number, i.e., 4, 8, and 12, and subsequently the 4-ball test was carried out. The WSD was determined as 0.537, 0.459, and 0.531 mm, respectively. As a result, it was found that when a side chain is short, a thin film is formed. In contrast, a long side chain hindered the formation of a film, and hence the best result was achieved when the carbon number was 8. As for the ZDDPs, the WSD was determined to be 0.563 mm, when measured under the same conditions. The measurements confirm that the synthesized BAPA compounds are superior to the ZDDPs as abrasion resistance additives.

• Journal of the Korean Wood Science and Technology
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• v.48 no.6
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• pp.888-895
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• 2020

Ulmus genus has excellent various physiological activities, including anti-ulcer, antioxidant, antibacterial, anti-cancer, immunity, and homeostasis maintenance effects, and it is known to have many additional drug effects And one of reasons for these excellentbiological activities is a flavan-3-ol chemical group in Ulmus genus. In this study a new flavan-3-ol compound was identified in Ulmus davidiana var. japonica. A flavan-3-ol,(2R,3S)-7-[(2S,3R,4R)-3,4-dihydroxy-4-(hydroxymethyl)oxolan-2-yl]oxy-2-(3,4-dihydroxyphenyl)-3,4-dihydro-2H-chromene-3,5-diol, named as catechin 7-O-beta-D apiofuranoside, was isolated from the stems and barks of Ulmus davidiana var. japonica for. suberosa, which is a species belonging to the genus Ulmus, growing throughout the Korea peninsula. The structure was elucidated by various spectroscopic methods including high-resolution TOF mass spectrometry, ¹H-NMR and ¹³C-NMR spectrometry and comparison with chemical structures of defined compounds.

• Korean Chemical Engineering Research
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• v.52 no.4
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• pp.451-458
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• 2014

Waterborne polyurethane dispersion (WPUD) was prepared from polycarbonate diol (PCD), isophorone diisocyanate (IPDI) and dimethylol propionic acid (DMPA) as starting materials. Then, waterborne acrylic polyurethane dispersion (AUD) was synthesized by reacting the WPUD with different types of acrylate monomers, such as methyl methacrylate (MMA), 2-hydroxyethyl methacrylate (HEMA) and butyl acrylate (BA). Subsequently, the AUD was mixed with multi-walled carbon nanotube (MWCNT) to yield a conductive coating solution, and the mixture was coated on the polycarbonate substrate. The pencil hardness, abrasion resistance and chemical resistance of the coating films from AUD were improved than those from WPUD, while the electrical conductivity of the coating films from AUD was decreased than that of WPUD. Also, the effect of acrylate types on the properties of coating films was investigated. The AUD obtained from HEMA showed the strongest pencil hardness, while the AUD obtained from MMA exhibited the strongest abrasion resistance, chemical resistance and electrical conductivity among several types of acrylate monomers.