• Title/Summary/Keyword: Natural ester

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Antioxidant Components from Aralia continentalis (땃두릅(Aralia continentails)의 항산화 성분)

  • Kang, Sam-Sik;Choi, Jae-Sue;Lee, Myung-Whan;Lee, Taik-Soo;Kim, Ju-Sun
    • Korean Journal of Pharmacognosy
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    • v.29 no.1
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    • pp.13-17
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    • 1998
  • The root of Aralia continentalis Kitagawa (Araliaceae) have been used as an analgesic and fever remedy, and for treatment of rheumatism in Chinese medicine, whereas the young leaves are used for ingredient of salad. Antioxidant activity of the young leaves of A. continentails was determined by measuring lipid peroxide produced when a mouse liver homogenate was exposed to the air at $37^{\circ}C$, using 2-thiobarbituric acid (TBA) and by evaluation the radical scavenging activity on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. Chromatographic separation of active fraction led to the isolation of six flavonoids, among which quercetin, hyperoside and kaempferol showed strong antioxidant activities, while 6"-O-acetyl astragalin, astragalin and trifolin were inactive. Adenosine, oleanolic acid 28-O-glucosyl ester and salsoloside C methyl ester isolated from the somewhat active BuOH fraction exhibited no antioxidant activities.

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Isolation of Triterpenoid Saponins from the Stems of Acer ginnala Maxim (신나무 줄기로부터 Saponin 성분의 분리)

  • Son, Yeun-Kyoung;Han, Yong-Nam
    • Korean Journal of Pharmacognosy
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    • v.33 no.4 s.131
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    • pp.301-304
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    • 2002
  • Two triterpenoid saponine were isolated from the stems of Acer ginnala Maxim. The structures of triterpenoid saponins were established as ilexoside O, $3-O-{\alpha}-L- rhamnopyranosyl(1{\rightarrow}2)-{\beta}-D-glucopyranosyl(1{\rightarrow}2)-{\beta}-D-xylopyranosyl-pubescenolic$ acid 28-{\beta}-D-glucopyranosyl$ ester(1) and ilexoside K, $3-O-{\beta}-D-glucopyranosyl(1{\rightarrow}2)-{\beta}-D-xylopyranosyl-pubes-cenolic$ acid $28-{\beta}-D-glucopyranosyl$ ester(2). Their chemical structures have been elucidated on the basis of spectral methods.

Winding Temperature Measurement in a 154 kV Transformer Filled with Natural Ester Fluid

  • Kweon, Dongjin;Koo, Kyosun
    • Journal of Electrical Engineering and Technology
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    • v.8 no.1
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    • pp.156-162
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    • 2013
  • This paper measures the hot spot temperatures in a single-phase, 154 kV, 15/20 MVA power transformer filled with natural ester fluid using optical fiber sensors and compares them with those calculated by conventional heat run tests. A total of 14 optical fiber sensors were installed on the high-voltage and low-voltage windings to measure the hot spot temperatures. In addition, three thermocouples were installed in the transformer to measure the temperature distribution during the heat run tests. In the low-voltage winding, the hot spot temperature was $108.4^{\circ}C$, calculated by the conventional heat run test. However, the hot spot temperature measured using the optical fiber sensor was $129.4^{\circ}C$ between turns 2 and 3 on the upper side of the low-voltage winding. Therefore, the hot spot temperature of the low-voltage winding measured using the optical fiber sensor was $21.0^{\circ}C$ higher than that calculated by the conventional heat run test.

Antioxident components from Aralia continentalis

  • Kim, Ju-Sun;Kang, Sam-Sik;Park, Jae-Sue
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 1998.11a
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    • pp.182-182
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    • 1998
  • The root of Aralia continentalis Kitagawa(Araliaceae) have been used as an analgesic and fever remedy, and for treatment of rheumatism in Chinese medicine, whereas the young leaves are used for salad. An antioxidant activity of the young leaves of A continentalis was determined by measuring lipid peroxide produced when a mouse liver homogenate was exposed to the air at 37$^{\circ}C$, using 2-thiobarbituric acid(TBA) and by evaluation the radical scavenging activity on 1,l-diphenyl-2 picrylhydrazyl (DPPH) radical. Bioassay guided fractionation of MeOH extract isolated six flavonoid compounds as active components from EtOAc fraction. Adenosine and two saponins were isolated from the weak active BuOH fraction. The antioxidant effect by DPPH radical scavenging activity showed that quercetin was the most active among these compounds. Hyperoside and kaempferol were also active, while 6"-O-acetyl astragalin, astragalin, trifolin, adenosine, oleanolic acid 28-O-glucosyl ester and salsoloside C methyl ester were almost inactive. All the compounds were identified by spectroscopic methods.

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Facile Synthesis of (2S,3R)-3-Amino-2-hydroxy-4-(4'-hydroxyphenyl)butanoic Acid. Application to the Synthesis of Inhibitors of Aminopeptidases

  • Moon, Byung-Jo;Huh, Kyung-Lan
    • Bulletin of the Korean Chemical Society
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    • v.12 no.1
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    • pp.71-74
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    • 1991
  • Facile methods are reported for the synthesis of optically pure derivatives of (2S,3R)-3-amino-2-hydroxy-4-(4'-hydroxyphenyl)b utanoic acid. To avoid troublesome synthesis of O-benzyl-N-Boc-D-tyrosine, without the protection of phenolic OH group of tyrosine N-Boc-D-tyrosine methyl ester was reduced with DiBAL to the aldehyde. The aldehyde was converted via the cyanohydrin to (2S,3R)-3-amino-2-hydroxy-4-(4'-hydroxyphenyl)butanoic acid (AHpHBA). The mixture of diastereomers was converted to the corresponding Boc-AHpHBA methyl ester derivatives and separated by chromatography over silica gel. Optically active (2S,3R)-AHpHBA was used to synthesize aminopeptidase inhibitors.

Chromatographic Determination of the Absolute Configuration in Sanjoinine A That Increases Nitric Oxide Production

  • Soohyun Um;Hyeongju Jeong;Joon Soo An;Se Jin Jo;Young Ran Kim;Dong-Chan Oh;Kyuho Moon
    • Biomolecules & Therapeutics
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    • v.31 no.5
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    • pp.566-572
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    • 2023
  • A chiral derivatization strategy with phenylglycine methyl ester (PGME) was employed to develop a straightforward method to determine the absolute configurations of N,N-dimethyl amino acids. The PGME derivatives were analyzed using liquid chromatography-mass spectrometry to identify the absolute configurations of various N,N-dimethyl amino acids based on their elution time and order. The established method was applied to assign the absolute configuration of the N,N-dimethyl phenylalanine in sanjoinine A (4), a cyclopeptide alkaloid isolated from Zizyphi Spinosi Semen widely used as herbal medicine for insomnia. Sanjoinine A displayed production of nitric oxide (NO) in LPS-activated RAW 264.7 cells.

Quantitative Analysis of ${\gamma}-oryzanol$ in Rice Bran (미강의 약리성분 감마-오리자놀의 정량)

  • Kwak, Tae-Soon;Park, Hee-Juhn
    • Korean Journal of Medicinal Crop Science
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    • v.5 no.2
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    • pp.113-118
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    • 1997
  • Phytochemical analysis on rice bran and its pitch was performed by the tool of TLC, UV- and IR-spetroscopy, so that it was found that they contained ${\gamma}-oryzanol$ and free sterol. GC-MS analysis of free sterol revealed that it was composed of ${\beta}-sitosterol$, campesterol and stigmasterol. Successive phytochemical analysis of ${\gamma}-oryzanol$ revealed that it was composed of ferulic acid ester of triterpene and sterol, respectively. Triterpene moieties of ${\gamma}-oryzanol$ were identified as follows: cycloartanol, cycloartenol, 24-methylenecycloartanol and unknown triterpene; And sterol moieties were found to be identical with free sterols. In addition, characteristic absorption band in UV spectrum (220-340 nm) was exclusively due to ${\gamma}-oryzanol$. Thus, it was suggested that rice brans of nearly all species of Oryza sativa can be quantitatively analyzed by UV absorption spectrometry, even when water soluble pigments was contained in the rice bran.

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Chemical Modification of Rupestonic Acid and Preliminarily In Vitro Antiviral Activity Against Influenza A3 and B Viruses

  • Yong, Jian-Ping;Aisa, Haji Akber
    • Bulletin of the Korean Chemical Society
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    • v.32 no.4
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    • pp.1293-1297
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    • 2011
  • To improve the biological activities of rupestonic acid, 21 new rupestonic acid fatty ester derivatives (2a-2h) and aromatic ester derivatives (2i-2u) were synthesized and preliminarily evaluated for their anti-influenza activity in vitro by the national center for drug screening of China, using the Oseltamivir and Ribavirin as reference drugs. The results showed that 2l ($IC_{50}=0.5{\mu}mol/L$) exhibited potent anti-influenza $A_3$ viral activity among the synthesized compounds and was 10-fold more potent than that of the reference drug Oseltamivir ($IC_{50}=5.1{\mu}mol/L$).

PAF Antagonistic Activity of 2-hydroxy-3-methoxybenzoic Acid Glucose Ester from Gentiana scabra

  • Huh, Hoon;Kim, Hye-Kyong;Lee, Hern-Ku
    • Archives of Pharmacal Research
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    • v.21 no.4
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    • pp.436-439
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    • 1998
  • In order to find out anti-platelet activating factor (PAF) from natural resources, Korean medicinal plants used for the treatments of peripheral circulation disorders were tested for their possible protective effects on PAF-induced anaphylactic shock. From the above screening, the methanol extract of Gentiana scabra showed a potent antagonistic activity against PAF. Water suspension of the extract was partitioned with $CH_2$$CI_2$ and EtOAc, successively. The EtOAc fraction which showed the highest activity was chromatographed on silica gel to yield 6 fractions. From the fraction which showed higher PAF-antagonistic activity than the other fractions, compound 1 was isolated by recrystallization. On the basis of spectral data, compound 1 was identified as 2-hydroxy-3-methoxybenzoic acid glucose ester. The compound prevented the mice from the PAF-induced death at a dose of 300 $\mu\textrm{g}$/mouse.

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