• 식물조직배양학회지
• /
• 제24권4호
• /
• pp.233-238
• /
• 1997

Salicylic acid (SA) is involved in the establishment of systemic acquired resistance (SAR) in many plant including tobacco. Considering the important role of SA in disease resistance, biosynthetic and metabolic pathways of SA in tobacco have been studied extensively: The initial step for biosynthetic pathway of SA is conversion of phenylalanine to trans-cinnamic acid, followed by decarboxylation of trans-cinnamic acid to benzoic acid and ie subsequent ring hydroxylation at the C-2 position to form SA. In TMV inoculated tobacco, most of the newly synthesized SA is glucosylated or methylated. Methyl salicylate has been identified as a biologically active, volatile signal. In contrast, the two glucosylated forms accumulate in the vicinity of lesions and consist of SA glucoside, a major metabolite, and SA glucose ester, a relatively minor from. Two enzymes involved in SA biosynthesis and metabolism have been purified and characterized : benzoic acid 2-hydroxylase which catalyzes conversion of benzoic acid to SA; UDP-Glucose: SA 1-O-D glucosyltransferase which converts SA to SA glucose ester. Further studies of the biosynthetic and metabolic pathways of SA will help to elucidate the SAR signal transduction pathway and provide potential tools for the manipulation of disease resistance.

• Journal of Microbiology and Biotechnology
• /
• 제15권1호
• /
• pp.99-104
• /
• 2005

Microbacterium laevaniformans levansucrase synthesized various hetero-oligosaccharides by transferring fructosyl residue from sucrose to various saccharides as acceptors. The acceptor specificity test showed that reducing saccharides were more favorable acceptors than nonreducing saccharides. The transfructosylated product, fructosyl galactose, was produced in the presence of D-galactose as an acceptor. The chemical structure of the resulting fructosyl galactose was analyzed by yeast invertase and NMR, and identified as O-$\alpha$-D-galactosyl-(1${\to}$2)-$\beta$-D-fructofuranoside. These results indicate that the main transfructosylation activity of the enzyme is to make nonreducing transferred products via a transfer of fructosyl residue to acceptor molecules having reducing group. When nonreducing sugars, such as methyl $\alpha$-D-glucoside and methyl $\alpha$-D-galactoside, were used as an acceptor, the transfer product was also formed in spite of the reducing group blocked with methyl group. The fact that no transfer product was formed with sugar alcohols as acceptors was suggested to be due to marked conformational difference of acceptors.

• Journal of Microbiology
• /
• 제43권2호
• /
• pp.191-195
• /
• 2005

In this study, we attempted to characterize the Synechococcus sp. pee 7942 mutant resultant from a disruption in the gene encoding UDP-glucose: tetrahydrobiopterin a-glucosyltransferase (BGluT). 2D­PAGE followed by MALDI-TOF mass spectrometry revealed that phycocyanin rod linker protein 33K was one of the proteins expressed at lower level in the BGluT mutant. BGluT mutant cells were also determined to be more sensitive to high light stress. This is because photosynthetic O$_2$ exchange rates were significantly decreased, due to the reduced number of functional PSIs relative to the wild type cells. These results suggested that, in Synechococcus sp. pee 7942, BH4-glucoside might be involved in photosynthetic photoprotection.

• KSBB Journal
• /
• 제27권6호
• /
• pp.341-346
• /
• 2012

Indican (indoxyl-${\beta}$-D-glucoside) is a colorless natural compound and can be used as a precursor for the production of indigo. This production step only require an enzyme, ${\beta}$-glucosidase, that readily screened from microbial resource by using selective media supplemented with indican as a sole carbon source. Agrobacterium tumefaciens was well grown in this media and thus presumed to produce a related enzyme. The corresponding gene, encoding a protein with a calculated molecular mass of 51 kDa, was cloned and overexpressed as MBP fusion proteins. The purified enzyme was determined to be a dimer and showed the maximum activity for indican at pH 7.0 and $40^{\circ}C$. The kinetic parameters for indican, Km and Vmax, were determined to be 1.4 mM and 373.8 ${\mu}M/min/mg$, respectively. The conversion yield of indican into indigo using this enzyme was about 1.7-1.8 folds higher than that of previously isolated enzyme from Sinorhizobium meliloti. Additionally, this enzyme was able to hydrolyze various ${\beta}$-1,4 glycoside substrates.

• 생약학회지
• /
• 제31권3호
• /
• pp.351-356
• /
• 2000

The hepatoprotective effects of bergenin and its derivative, acetylbergenin, were evaluated against D-galactosamine-induced liver damage in rats. Bergenin is a C-glucoside of 4-O-methyl gallic acid that has been isolated from the cortex of Mallotus japonicus (Euphorbiaceae). Acetylbergenin was synthesized from acetylation of bergenin to increase lipophilic and physiological activities. Bergenin (50, 100 and 200 mg/kg) and acetylbergenin (25, 50 and 100 mg/kg) were administered orally once daily for successive 5 days after the injection of galactosamine (400 mg/kg, i.p.), respectively. The substantially elevated serum enzyme activities of alanine/aspartate aminotransferase, sorbitol dehydrogenase and ${\gamma}-glutamyltransferase$ due to galactosamine treatment were dose-dependently restored towards normalization by post-treatment with bergenin and acetylbergenin. Bergenin and acetylbergenin also significantly prevented the elevation of hepatic malondialdehyde formation and depletion of reduced glutathione content induced by galactosamine in a dose-dependent manner. In addition, the decreased activities of glutathione S-transferase and glutathione reductase were restored towards normalization. These results suggest that effects of bergenin and acetylbergenin may be related to complex mechanisms that involve prevention of lipid peroxidation and preservation of hepatic glutathione. The results of this study clearly indicate that bergenin and acetylbergenin have potent hepatotherapeutic action against galactosamine-induced hepatotoxicity in rats, and lipophilic acetylbergenin is more active in the antihepatotoxic effects against galactosamine than much less lipophilic bergenin.

• 생약학회지
• /
• 제16권3호
• /
• pp.141-150
• /
• 1985

Lipid and fatty acid compositions of free lipids and bound lipids from fresh ginseng, red ginseng and white ginseng were studied by means of silicic acid column chromatography, thin-layer chromatography and gas-liquid chromatography. Free lipid and bound lipid contents in those three samples were 1.21 to 1.45% and 0.32 to 0.45%. Neutral lipid fractions in free lipids from the samples were 76.6 to 79.7%, while glycolipid and phospholipid fractions were 11.6 to 14.7% and 8.5 to 8.7%, respectively. The major lipids were triglycerides, sterol esters and hydrocarbons, diglycerides and free sterols in neutral lipids, sterol glucoside, monogalactosyl diglyceride, esterified steryl glycoside, digalactosyl diglyceride in glycolipids and phosphatidyl ethanolamine, phosphatidyl glycerol, phosphatidyl choline and phosphatidyl inositol in phospholipids. Fourteen kinds of even numbered and four kinds of odd numbered fatty acids were identified in the four lipid fractions (TL, NL, GL and PL) by GLC, and the main fatty acids were linoleic acid, palmitic acid, oleic acid and linolenic acid.

• Natural Product Sciences
• /
• 제20권3호
• /
• pp.152-159
• /
• 2014

A phytochemical investigation of Spergularia marina (L.) Griseb. growing in Egypt, has been carried out, which resulted in the isolation of seven compounds from the different extracts of the plant namely; ${\beta}$-sitosterol glucoside, tricin (1) dihydroferulic acid (2), vanillic acid (3), 4-hydroxybenzoic acid (4), uracil (5) and 8-hydroxy cuminoic acid (6) Structure elucidation of the isolated compounds was carried out using different spectroscopic techniques. This is the first report for the isolation of these compounds from genus Spergularia. Furthermore, 8-Hydroxy cuminoic acid and uracil were isolated for the first time from family Caryophyllaceae. The chemical composition of the volatile components present in the petroleum ether extract of Spergularia marina (L.) Griseb. using combined gas chromatography-mass spectrometry (GC-MS) is reported here for the first time. Of the 97 components present, 59 were identified including three sulfur containing compounds which represented about 1.8% of the volatiles of the total petroleum ether extract. This prompted us to study and report its possible antimicrobial activity. In addition, the antibacterial and antifungal screening of different extracts of Spergularia marina (L.) Griseb. as well as some isolates have been performed using agar diffusion method.

• Natural Product Sciences
• /
• 제16권3호
• /
• pp.164-168
• /
• 2010

High-performance liquid chromatographic method with diode-array detector and electrospray ionization with multi-stage tandem mass spectroscopy (HPLC/DAD/ESI-$MS^n$) was used to identify the major constituents in a methanolic extract of Eclipta prostrata. The chromatographic separation was performed on a C18 column. Acetonitrile-water was used as a mobile phase. HPLC/DAD/ESI-$MS^n$ allowed the characterization of constituents of E. prostrata, mainly triterpenoids (eclalbasaponin I, II, III, IV, VI), flavonoids (luteolin 7-O-glucoside, demethylwedelolactone, wedelolactone, luteolin, demetylwedelolactone sulfate, luteolin sulfate, apigenin sulfate) and phenolic acids (5-O-caffeoylquinic acid, 3, 4-O-dicaffeoylquinic acid, 3, 5-O-dicaffeoylquinic acid, 4, 5-Odicaffeoylquinic acid).

• 생약학회지
• /
• 제26권2호
• /
• pp.130-138
• /
• 1995

Phytochemical study on the aerial parts of Solanum lyratum (Solanaceae) was carried out. On the basis of phytochemical and spectroscopic evidences, compound I was identified as mixtures of hexadecanoic acid methyl ester, 2,6,10,15-tetramethyl heptadecane, tricosane, tetracosane, pentacosane, docosanoic acid methyl ester, docosane, tricosanoic acid methyl ester, 8-hexyl pentadecane, tetracosanoic acid methyl ester, pentatriacontane, hexatriacontane, eicosane, hexacosane, hentriacontane and stigmasta-5,23-dien $3-{\beta}-ol$, and compound II, III, IV and V were identified as hexacosanoic acid methyl ester, ${\beta}-sitosterol-{\beta}-{_D}-glucoside$, $3-O-{\alpha}-{_L}-rhamnopyranosyl-(1->2)-{\beta}-{_D}-glucuronopyranosyl$ diosgenin and $3-O-{\alpha}-{_L}-rhamnopyranosyl-(1->6)-{\beta}-{_D}-glucopyranosyl$ quercetin (rutin), respectively. Rutin was identified as one of the active principles having antioxidative effect from S. lyratum.

• 생약학회지
• /
• 제25권1호
• /
• pp.11-19
• /
• 1994

Gleditsia japonica var. koraiensis NAKAI(Leguminosae) is commonly distributed in Korea and has been used as a folk medicine in the treatment of bronchitis, neoplasm and blennorrhgia in the Orient. The aqueous acetone extract of the leaves of G. japonica was subjected to a combination of Sephadex LH-20, Cosmosil $75C_{18}-OPN$, TSK-gel Toyopearl HW 40F, Avicel cellulose, and MCI-gel CHP 20P chromatographies with various solvent systems. Twelve compounds were isolated and confirmed to be vitexin(1), isovitexin(2), orientin(3), isoorientin(4), 4-caffeoyl quinic acid(5), 5-caffeoyl quinic acid(6), 3, 5-dicaffeoyl quinic acid(7), 4, 5-dicaffeoyl quinic acid(8), caffeic acid(9), quercetin(10), isoquercitrin(11) and luteolin-7-O-glucoside(12), on the basis of chemical and spectroscopic evidences.