Salvadenosine, a 5'-deoxy-5'-(methylthio) nucleoside from the Bahamian tunicate Didemnum sp.

Salvadenosine, (1) a rare 5'-deoxy-5'-(methylthio) nucleoside, was isolated from the deep-water Bahaman tunicate Didemnum sp. The structure was solved by integrated analysis of MS and 1D and 2D NMR data. We revise the structure of the known natural product, hamiguanosinol, which is a constitutional isomer of 1, to 5 by interpretation of the spectroscopic data and comparison with synthesized nucleosides.

Identification and analysis of the constituents in an aqueous extract of Tricholoma matsutake by HPLC coupled with diode array detection/electrospray ionization mass spectrometry.

The main constituents in an aqueous extract of Tricholoma matsutake (Tm) were identified by high-performance liquid chromatography coupled with diode array detection and electrospray ionization time-of-flight mass spectrometry (HPLC-DAD/TOF-MS) and ion trap mass spectrometry (HPLC-DAD/Trap-MSn). The main factors in the extraction process which affect the yields of nutrients were optimized by single-factor experiments and orthogonal experiment design. In total, 12 constituents were identified from the aqueous extract of Tm, including tyrosine, cytidine, uridine, eritadenine, phenylalanine, nicotinamide, inosine, guanosine, tryptophan, adenosine, 5'-deoxy-5'-methylthioadenosine and riboflavin. The optimized extraction conditions were: the ratio of water to sample was 10 : 1 (v/w), Tm was extracted by ultrasonic-assisted extraction for 10 min, followed by water bath heating at 60 °C for 1 h. Among these extraction factors, the heating temperature is significant based on analysis of variance (ANOVA). The yields of nutrients were affected dramatically at high temperature leading to the loss of nutrients, especially for nucleosides and some amino acids.

Purification and characterization of antioxidant components from the fruiting bodies of Pleurotus abalonus including 9-beta-d-ribofuranosidoadenine, 5'-deoxy-5'-(methylthio)adenosine, and a triterpenoid.

Although Pleurotus abalonus is a well-known edible mushroom in Asia, there is a dearth of information on its antioxidant activity. The present report is the first one focused on the purification and characterization of 9-beta-d-ribofuranosidoadenine (ADO), 5'-deoxy-5'-(methylthio) adenosine (MTA) and a triterpenoid complex from P. abalonus. Different antioxidant activities including inhibitory effects on hemolysis and lipid peroxidation in brain and kidney homogenates as well as significant synergistic effect on scavenging of hydroxyl radicals were demonstrated, which lays a foundation for the development of P. abalonus as a natural antioxidant applied in medicine.

[Isolation and structure elucidation of chemical constituents from Pinellia ternata].

OBJECTIVE: To isolate and identify the chemical constituents of ethanol extract of Pinellia ternata. METHODS: The constituents were isolated by silica-gel, Sephadex LH-20 chromatography and HPLC techniques. The structures were identified by spectroscopic analysis including 2D NMR techniques and chemical properties. RESULTS: Nine compounds were obtained and identified as uridine (1), 5'-S-methyl-5'-thioadenosine (2), adenine (3), chrysophanol (4), 5-hydroxymethylfurfural (5), nicotinamide (6), (2S)-1-O-(9Z, 12Z-octadecadienoyl)-3-O-beta-galactopyranosylglycerol (7), daucosterol (8), beta-sitosterol (9). CONCLUSION: Compounds 2, 6, 7 are isolated from this plant for the first time.

Conditioned media from lung cancer cell line A549 and PC9 inactivate pulmonary fibroblasts by regulating protein phosphorylation.

Pulmonary fibrosis is a devastating condition resulting from excess extracellular matrix deposition that leads to progressive lung destruction and scarring. In the pathogenesis of fibrotic diseases, activation of myofibroblasts by transforming growth factor-ß (TGF-ß) plays a crucial role. Since no effective therapy for pulmonary fibrosis is currently recognized, finding an effective antifibrotic agent is an important objective. One approach might be through identification of agents that inactivate myofibroblasts. In the current study we examined the potential of conditioned medium obtained from several types of cells to exhibit myofibroblast inactivating activity. Conditioned media from lung cancer cell lines A549 and PC9 were found to have this action, as shown by its ability to decrease α-smooth muscle actin expression in MRC-5 cells. Subsequently the inhibitory factor was purified from the medium and identified as 5'-deoxy-5'-methylthioadenosine (MTA), and its mechanism of action elucidated. Activation of protein kinase A and cAMP responsive element binding protein (CREB) were detected. MTA inhibited TGF-ß-induced mitogen-activated protein kinase activation. Furthermore, the gain-of-function mutant CREB caused inactivation of myofibroblasts. These results show that A549 and PC9 conditioned media have the ability to inactivate myofibroblasts, and that CREB-phosphorylation plays a central role in this process.

Quantification of 5'-deoxy-5'-methylthioadenosine in heat-treated natural rubber latex serum.

INTRODUCTION: 5'-Deoxy-5'-methylthioadenosine (MTA) is one of the biologically active components found in natural rubber latex (NRL) serum, a common waste product from rubber plantations. In this study the contents of MTA in heat-treated NRL serum were measured in order to assess the potential of the serum as an alternative source of MTA. OBJECTIVE: To devise an HPLC/UV-based quantitative analytical protocol for the determination of MTA, and to determine the effect of heat treatment on the content of MTA in NRL serum from various sources. METHODOLOGY: An HPLC/UV-based determination of MTA using an acidic eluant was devised and validated. In the heat treatment, the effect of refluxing times on MTA liberation was evaluated. RESULTS: The quantification protocol was validated with satisfying linearity, limits of detection and quantitation, precisions for peak areas and recovery percentages from intra- and inter-day operations. The amounts of MTA in the NRL sera from various sources increased with heat treatment to yield 5-12 µg MTA/mL of serum. CONCLUSION: The devised protocol was found to be satisfyingly applicable to the routine determination of MTA in NRL serum. The effect of heat treatment on the content of MTA also indicated another possible use for NRL serum, normally discarded in vast amounts by the rubber industry, as an alternative source of MTA.

[A new coumarin glycoside from Glehnia littoralis].

To study the chemical constituents from Glehnia littoralis, macroreticular resin column chromatography, repeated column chromatography on Sephadex LH-20 and reverse phase ODS were used to isolate the compounds whose structures were elucidated based on spectroscopic data (ESI-MS, 1D and 2D NMR). A new coumarin glycoside was isolated and identified as: bergaptol 5-O-beta-D-gentiobioside (1), along with eight known compounds: (7R, 8S)-dehydrodiconiferylalcohol-4, 9-di-O-beta-D-glucoside (2), cirtrusin A (3), (-)-seco-isolariciresinol 4-O-beta-D-glucopyranoside (4), baihuaqianhuside (5), xanthotoxol 8-O-beta-D-glucopyranoside (6), 5'-methylthioadenosine (7), adenosine (8), L-tryptophan (9). Compound 1 is a new coumarin glycoside, compounds 2 and 7 were isolated from this genus for the first time.

[HPLC of oligodeoxyribonucleoside phosphorothioates ]. / V'EAZKH oligodesokciribonukleozidtiofosfatov.

Conditions are described for the separation of synthetic oligodeoxyribonucleoside phosphorothioates by HPLC using a SCOUT WP PEI weak anion exchanger and for the separation of oligodeoxyribonucleotides with mixed phosphate and phosphorothioate internucleotide bonds on a Partisphere C18 support in ion-pair conditions. The influence of the nucleoside composition and the number of phosphorothioate bonds on the retention time was studied.

Analysis of oligo(deoxynucleoside phosphorothioate)s and their diastereomeric composition.

Short oligo(deoxynucleoside phosphorothioate)s were analyzed as a pool of individual diastereomeric species. The composition of such mixtures, determined by means of HPLC, indicates that consecutive couplings in commonly used phosphoramidite chemistry lead to increasing contents of the Rp isomer. Methods of analysis and mathematical basis for diastereomeric composition are discussed. Data presented include all 16 possible combinations of nucleosides in dinucleotide phosphorothioates, as well as examples of trimers and tetramers.

Synthesis of deuterated 7-(5'-deoxy-5'-methylthio-beta-D-ribofuranosyl)adenine-d3.

Synthesis of 7-(5'-deoxy-5'-methyl-thio-beta-D-ribofuranosyl)-adenine(7-MTA) has been developed from imidazole through 7-beta -D-ribofuranosyladenine. Deuterated 7-MTA-d3 was also synthesized by this synthetic procedure using deuterium labelled dimethyl disulfide-d6. The deuterium content of 7-MTA-d3 was 98.28%. The spectral and chemical properties of 7-MTA were defined.

5'-Methylthioadenosine nucleosidase. Purification and characterization of the enzyme from Lupinus luteus seeds.

5'-Methylthioadenosine nucleosidase (EC 3.2.2.9), the enzyme which catalyzes hydrolytic cleavage of 5'-methylthioadenosine with the formation of adenine and 5'-methylthioribose, has been purified to homogeneity from Lupinus luteus seeds. The nucleosidase has a native molecular weight of 62 000 and consists of two identical subunits, as judged by gel filtration and dodecylsulfate/polyacrylamide gel electrophoresis. The nucleosidase exhibits highest specificity towards the natural substrate with a Km of 4.1 X 10(-7) M for 5'-methylthioadenosine. It does not cleave adenine from S-adenosylhomocysteine. Among the synthetic analogs of 5'-methylthioadenosine tested, eleven compounds appear to be able to substitute as substrates. Furthermore, the enzyme can liberate hypoxanthinine from six inosyl (deaminated) derivatives obtained by enzymatic deamination of 5'-methylthioadenosine and its synthetic analogs. The Km for 5'-methylthioinosine is 55 microM, and the maximal velocity about 50-times lower than for 5'-methylthioadenosine. The reaction catalyzed by the nucleosidase can be inhibited by adenine (Ki = 11 microM), 3-deazaadenine (Ki = 19 microM), and 9-erythro(2-hydroxyl-3-nonyl)adenine (ki = 37 microM).

Affinity chromatography of thiol-containing purines and ribonucleic acid.

Evidence is presented for the specific interaction of 6-mercaptopurine with mercurated cellulose. Following from this, a new method is described for the affinity chromatography of thiol-containing molecules and of RNA containing incorporated 6-thioguanosine on columns of mercurated cellulose. This technique may find application in the study of RNA metabolism and gene expression.