• Journal of Microbiology and Biotechnology
• /
• v.25 no.11
• /
• pp.1796-1800
• /
• 2015

Sporopollenin is a poorly characterized mixed aliphatic and aromatic polymer with ester and ether linkages. Recent studies have reported that α-pyrone polyketide compounds generated by Arabidopsis thaliana, polyketide synthase A (PKSA) and tetraketide α-pyrone reductase 1 (TKPR1), are previously unknown sporopollenin precursors. Here, the yeast Saccharomyces cerevisiae was introduced to test potential sporopollenin biosynthetic pathways in vivo. A PKSA/TKPR1 dual expressor was generated and various chain-length alkyl α-pyrones were identified by GC-MS. The growth rate of the strain containing PKSA/TKPR1 appeared normal. These results indicate that PKSA/TKPR1-expressing yeast would be a starting platform to investigate in vivo sporopollenin metabolism.

• Natural Product Sciences
• /
• v.4 no.2
• /
• pp.53-57
• /
• 1998

Leaves of Crataegus sinaica Boiss, contain the new C-glycosyl flavone $3"',4”’-di-O-acetyl-2“-O-{\alpha}-rhamnosylvitexin$, together with the hitherto unknown, dihydroflavonol 3-O-xyloside, (2R:3R)-dihydroquercetin-$3-O-{\beta}-xylopyranoside$. The known compounds (+)-catechin, (-)-epicatechin, vicenin-II, $2"-O-{\alpha}-rhamnosylvitexin$, and $4"'-O-acetyl-2"-O-{\alpha}-rhamnosylvitexin$ were also characterized. Structures were established by conventional methods of analysis and confirmed by $^1H-,\;^{13}C-NMR$, and ESI-MS.

• Korean Journal of Pharmacognosy
• /
• v.7 no.2
• /
• pp.95-97
• /
• 1976

Saponin was distributed in all tissues of Phytolacca americana and P. esculenta. Phytolaccoside E was a major saponin, but the callus tissues induced from stems of P. americana contained phytolaccoside B as a major component. Saponin contents in leaves and stems were almost similar to those in roots. Two unknown compounds, $C_{32}H_{50}O_{4}$ (triterpenoid) and $C_{18}H_{22}O_{5}{\cdot}H_2O$ (polyphenol) were isolated from seeds of both plant.

• Journal of Food Hygiene and Safety
• /
• v.11 no.2
• /
• pp.123-127
• /
• 1996

The isolation and chemical characterization of yellow food pigments from Monascus purpureus were studied according to the compositions of media. Monacus yellow pigments were isolated and purified by solvent fractionation, silicagel column chromatography, TLC and HPLC. The retention time of Monascus yellow pigments isolated by HPLC was respectively 5 min(I) and 9 min(II) as the yeast malt extract agar(YMA) media and was respectively 4.6 min(III), 5 min(I) 5.7 min(IV), 8.3 min(V), 9 min(II) and 10.7 min(Ⅵ) at the malt extract agar(MEA) media. The structure of monascin(I), ankaflavin(II), 6,11-dihydrorubropunctatin(III), 6,11-dihydromonascorubrin(V) and unknown compounds(IV,Ⅵ) was elucidated by EI-Mass, H and C NMR, UV-visible spectrometer. Therefore, it was suggested that 6,11-dihydrorubropunctatin(III) and 6,11-dihydromonascorubrin(V) are new intermediates of Monascus yellow pigments.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.46 no.3
• /
• pp.37-43
• /
• 2014

Kinetics of holocellulose hydrolysis in concentrated sulfuric acid was analyzed using $^1H$-NMR spectroscopy with different reaction time, temperature and acid concentration in secondary hydrolysis. In this work, reaction condition of secondary hydrolysis was similar to concentrated sulfuric acid process with electrodialysis or simulated moving bed chromatography process for sulfuric acid recycling. By $^1H$-NMR spectroscopy, acid hydrolyzates from higher secondary acid hydrolysis (25-35% acid concentration) was successfully analyzed without any difficulties in neutralization or adsorption of acid hydrolyzate to solid salt. Higher acid concentration, higher temperature and longer reaction time led to more cellulose for glucose conversion but accompanied with glucose to galactose isomerization, glucose to unknown compounds and degradation of glucose to organic acid via furans.

• Journal of Food Hygiene and Safety
• /
• v.10 no.4
• /
• pp.225.1-230
• /
• 1995

The ethanol extract from the root bark of Morus alba showed the strongest antimicrobial activity on the growth of almost all the tested microorganisms which were food-borne pathogens and food-related microorganisms. 1) In order to isolate and purify of antimicrobial substance extracted from the root bark of Morus alba, the antimicrobial substance from the ethanol extract which exhibited a strong antimicrobial activity was purified by solvent fractionation, silica gel column chromatography, TLC and HPLC. Among the fractions fractionated by 4 kind of solvents from the ethanol extract, the antimicrobial activity of ethyl acetate fraction had the strongest antimicrobial activity against B. subtilis. Unknown compound were isolated from the ethyl acetate fraction by silica gel column chromatography, TLC and HPLC and the compounds showed strong absorbance at 207, 217 and 285 nm, therefore, it was supposed to be a kinds of aromatic compound.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2007.10a
• /
• pp.215-222
• /
• 2007

Coating of Hot-dip galvannealed steel consists of various Fe-Zn intermetallic compounds. Since the coating is hard and there for is very brittle, the surface of steel sheet is easy to be ruptured during second manufacturing processing. This is called as powdering. In addition, forming equipment might be polluted with debris by powdering. Therefore, various research have been carried out to prohibit powdering fur improving the quality of GA steel. This paper carried out finite element analysis combined with damage model which simulate the failure of local layer of hot-dip galvannealed steel surface during v-bending test. Since the mechanical property of intermetallic compound was unknown exactly, we used the properties calculated from measurements. The specimen was divided into substrate, coating layer and interface layer. Local failure at coating layer or interface layer was simulated when elemental strain reached a prescribed strain.

• Korean Journal of Pharmacognosy
• /
• v.50 no.1
• /
• pp.32-36
• /
• 2019

Dendropanax morbifera Leveille, an endemic species in Korea, is best known as a tree that produces a resinous sap. Although D. morbifera is used in folk medicine for various diseases, its active ingredients are largely unknown. In this study, we investigated antioxidative activities of ethanolic extracts of three parts of this plant including leaves, debarked stems, and roots. The root extracts exhibited strong 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging activity compared with leaf or stem extracts. The root extracts showed hepatoprotective activity against t-butyl hydroperoxide-induced HepG2 cells, and reduced the ROS level in the cells. The root fractions lowered the mRNA level of COX-2 on lipopolysaccharide-stimulated Raw246.7 cells. These results suggest that ethanolic root extracts of D. morbifera are a source of antioxidant and hepatoprotective compounds, which indicate a potential for a botanical drug.

• Proceedings of the PSK Conference
• /
• 2003.10b
• /
• pp.200.2-200.2
• /
• 2003

Six compounds were isolated from the stems of Acanthopanax senticosus (Araliaceae). Their structures were elucidated as iso-fraxidin, H-sesamin, 5-hydroxymethylfurfural, eleutheroside B, eleutheroside E and an unknown compound by spectral analysis. Of them, 5-hydroxymethylfurfural was isolated for the first time from A. senticosus.

• Journal of Microbiology and Biotechnology
• /
• v.31 no.2
• /
• pp.171-180
• /
• 2021

Caffeine, a methylxanthine analog of purine bases, is a compound that is largely consumed in beverages and medications for psychoactive and diuretic effects and plays many beneficial roles in neuronal stimulation and enhancement of anti-tumor immune responses by blocking adenosine receptors in higher organisms. In single-cell eukaryotes, however, caffeine somehow impairs cellular fitness by compromising cell wall integrity, inhibiting target of rapamycin (TOR) signaling and growth, and overriding cell cycle arrest caused by DNA damage. Among its multiple inhibitory targets, caffeine specifically interacts with phosphatidylinositol 3-kinase (PI3K)-related kinases causing radiosensitization and cytotoxicity via specialized intermediate molecules. Caffeine potentiates the lethality of cells in conjunction with several other stressors such as oxidants, irradiation, and various toxic compounds through largely unknown mechanisms. In this review, recent findings on caffeine effects and cellular detoxification schemes are highlighted and discussed with an emphasis on the inhibitory interactions between caffeine and its multiple targets in eukaryotic microorganisms such as budding and fission yeasts.