The Nucleosides Contents and Their Variation in Natural Cordyceps sinensis and Cultured Cordyceps Mycelia

Aim: To compare the contents of nucleosides from natural Cordyceps sinensis and cultured Cordyceps mycelia, and to study the effect of humidity and heat on the content of nucleosides. Methods: The contents of nucleosides were determined by using high performance capillary electrophoresis (HPCE). Beckman P/ACE System 5010 apparatus equipped with a UV detector and a Beckman untreated fused-silica capillary (57 cm 75 mm, 50 cm effective length) was used. Before sample injection, the capillary was rinsed with 1 molL-1 sodium hydroxide solution and running buffer for 5 min, respectively. A voltage of 20 kV was applied for the separation. Pressure injection was 586 kPa for 6 seconds, and the wavelength of detector was 254 nm. The running time was 20 min at 20 oC. The effect of humidity and heat on the contents of nucleosides from natural Cordyceps sinensis and cultured Cordyceps mycelia was observed for 1, 3, 5 and 10 days at temperature 40 oC, and relative humidity 75%. Results: The content of nucleosides from natural Cordyceps sinensis was higher than that from cultured Cordyceps mycelia. But the contents of nucleosides from freshly collected natural Cordyceps sinensis were very low, even below the limit of quantitation. The contents of nucleosides from natural Cordyceps sinensis were significantly increased by humidity and heat, but this phenomenon was not observed in cultured Cordyceps mycelia. Conclusion: There are differences between the nucleosides from natural Cordyceps sinensis and cultured Cordyceps mycelia. The nucleosides in natural Cordyceps sinensis may be derived from the degradation of nucleic acids. This implies that adenosine being used for the quality control of natural Cordyceps sinensis may have to be reconsidered.

Simultaneous determination of ten nucleosides and bases in Ganoderma by micellar electrokinetic chromatography

Ganoderma(lingzhi)is a famous herbal medicine and edible supplement in oriental countries for a long history.In this study,a simple micellar electrokinetic chromatography(MEKC)method was established for the analysis of nucleosides and bases,the major bioactive components in Ganoderma for the first time.By optimizing the borate concentration,the sodium dodecyl sulfate(SDS)concentration and the pH value of running buffer,10 nucleosides and bases achieved an ideal separation.In real sample analysis,the developed method was successfully used to determine the 10 target analytes in 23 batches of Ganoderma samples from different regions.Results indicated that contents of 10 investigated analytes in each sample showed obvious variation.The principal components analysis(PCA)and hierarchical cluster analysis(HCA)analysis classified the samples into three groups,and the HCA tree visualized the relationships which was mainly contributed by geographical partition.The results indicated geographical origin to be an important factor that affect the accumulation of nucleosides and bases in Ganoderma.In summary,this study provides a simple and practical strategy for quality assessment and cultivation reference of Ganoderma.

Synthesis and X-Ray Structure of New Anticancer Nucleosides Based on 1-((2-Hydroxyethoxy)methyl)-5-(phenylthio)-1H-1,2,4-triazole-3-carboxamide

A pair of new anticancer nucleosides based on 1,2,4-triazole nucleosides and 1-((2-hydroxyethoxy) methyl)-5-(phenylthio)-1H-1,2,4-triazole-3-carboxamide have been synthesized, and have given the corresponding products in excellent yields. Its structures and conformations were confirmed by single crystal X-ray diffraction.

STEREOCHEMISTRY IN CYCLOPHOSPHORYLATION OF NUCLEOSIDES

In the presence of tetrazole,2'-substituted nucleosidesreacted ster■os■ifi■ally with n-BuOPIN■_2H_5■_2I_2 to nucleoside 3',5'-■lopnosphites with avial n-Buo group.The stereochemistry of oxidation of■y■lophosphite was investigated.

A new method for inversion of hydroxyl group of carbocyclic nucleosides

The hydroxyl group of carbocyclic nucleosides was inversed when the compounds were treated with Me3SiCl, KCN and a catalytic mount of NaI in DMF/CH3CN.

Interaction between N-phosphoryl-α-,β-and γ-amino acids and nucleosides

The reactions of four different N-（O,O＇-diisopropyl） phosphoamino acids （DIPP-aa）, such as N-phosphoryl-L-α-alanine （DIPP- L-α-Ala）, N-phosphoryl-D-α-alanine （DIPP-D-α-A1a）, N-phosphoryl-β-alanine （DIPP-β-A1a） and N-phosphoryl-γ-amino butyric acid （DIPP-γ-Aba）, and four nucleosides, adenosine （A）, guanosine （G）, cytidine （C） and uridine （U）, were studied by electrospray ionization tandem mass spectrometry （ESI-MS/MS） and HPLC/ESI-MS. DIPP-L-α-A1a and DIPP-D-α-A1a produced the same phosphorylated nucleosides, dinucleotides and phosphoroligopeptide. However, DIPP-β-A1a and DIPP-γ-Aba gave no relevant products.

Nucleosides 10: Synthesis of New Derivatives of Pyrimidine and Fused Pyrimidine Nucleosides of Expected Biological Activity

Pyrimidines, such as 6-amino-2-thio and 2-methylthiouracils and fused pyrimidines, such as thienopyrimidines reacted with 1-O-acetyl-2,3,5-tri-O- benzoyl-β-D-ribofuranose to get new derivatives of the corresponding nucleosides. The obtained protected nucleosides were deprotected by methanolic sodium methoxide to get the corresponding free uracil and thienopyrimidine nucleosides. The new nucleosides formed were tested for biological activity against some of microorganism (some fungi and bacteria species). Some of the tested products showed moderate activity and the results were reported.

STEREOSELCETIVE SYNTHESIS OF SOME NUCLEOSIDES

A new method for the synthesis of perbenzylated, peracetylated and perbenzoylated sugar nucleosides has been carefully studied. In this method trichloroacetoxy and trifluoroacetoxy groups were displaced efficiently in the reaction of nucleoside formation as leaving group. And this method was found to be widely applicable in the study of carbohydrate chemistry.

Simultaneous determination of five nucleosides and nucleobases in Panax notoginseng using high-performance liquid chromatography

Aim To quantitatively determine five nucleosides and nucleobases, including cytidine, uridine, guanosine, adenosine and uracil in different parts of Panax notoginseng. Methods Separation was performed on a Zorbax SB-Aq column using a gradient elution with mobile phase of 8 mmol^L-1 ammonium acetate aqueous solution （A） and methanol （B）. The assay was carried out at a flow rate of 1 mL·min^-1 at 25 ℃ with the diode-array detection at 260 nm. Results Cytidine, uridine, guanosine, adenosine and uracil had good linearity in the ranges of 1.79 - 57.40 μg·mL^-1 （r^2 = 1.0000）, 3.30 - 105.60 μg·mL^-1 （r^2 = 1.0000）, 3.09 - 98.80 μg·mL^ -1（r^2 = 0.9999）, 2.77 - 88.60 μg·mL^-1 （r^2 = 1.0000） and 0.38 - 12.30 μg·mL ^-1 （r^2 = 1.0000） with average recoveries of 93.9%, 96.5%, 92.7%, 93.2% and 98.8%, respectively. The content of cytidine, uridine, guanosine, adenosine and uracil in different parts of P. notogingeng were significantly different. Conclusion This is the first report on quantitative determination of nucleosides and nucleobases in P notoginseng.

Induction of Recombinant Uridine Phosphorylase and Its Application in Biosynthesis of Pyrimidine Nucleosides

Recombinant Escherichia coli pUDP,which overexpressed uridine phosphorylase（UPase）,was constructed.0.5 mmol·L 1lactose had a similar induction effect as the commonly used inducer IPTG during 2.5-5.5 h of cell growth.The lactose-induced UPase was stable at 50°C.Wet cells of pUDP was used as catalyst to biosynthesize 5-fluorouridine from 30 mmol·L 1uridine and 5-fluorouracil in phosphate buffer（pH 7.0）catalyzed at 50°C for 1.5 h and the yield of 5-fluorouridine was higher than 68%.Under the optimum reaction conditions for production of 5-fluorouridine,5-methyluridine and azauridine were synthesized from uridine by pUDP,the yield was 61.7%and 47.2%respectively.Deoxynucleosides were also synthesized by pUDP,but the yield was only about 20%.

An efficient and green preparation of 5-aminophosphonate substituted pyrimidine nucleosides under solvent-free conditions

An environmentally benign and highly efficient one-pot preparation of α-aminophosphonates under solvent-free conditions was developed. By employing this method, 5-aminophosphonate substituted pyrimidine nucleosides were synthesized in good to excellent yields starting from 5-forrnyl-2＇-deoxyuridine, aniline and dimethylphosphite.

Design and Synthesis of Lipids Bearing Nucleosides as Gene Vectors

Some novel lipids bearing nucleosides were designed and synthesized as gene vectors, and the structures of these compounds were characterized by UV, IR, 1HNMR, 13CNMR and elemental analysis.

Synthesis and antiviral activity of 4H-[1,2,5]oxadiazolo-[3,4-d]pyrimidine-5,7-dione 1-oxide nucleosides

A series of 4H-[1,2,5]oxadiazolo[3,4-d]pyrimidine-5,7-dione 1-oxide nucleosides was designed, synthesized and evaluated against vesicular stomatitis virus （VSV） in Wish cell. The antiviral activities of all compounds were stronger than those of acyclovir, while their toxicities were similar to those of acyclovir.

Apoptosis induced by nucleosides in the human hepatoma HepG2

AIM： To investigate the apoptotic effects of nucleosides on the human hepatoma HepG2. METHODS： The nucleosides included inosine （I）, cytidine （C）, uridine （U）, thymidine （T）, adenosine （A）, and guanosine （G）. Cells were incubated by the mediums with or without nudeosides at 37 ℃ in a 50 mL/L CO2 humidified atmosphere. RESULTS： It was found that the cell viabilities were significantly decreased, when cells were treated with 30 mmol/L I, 30 mmol/L C, 30 mmol/L U, 30 mmol/L T, 0.5 mmol/L A, and 0.5 mmol/L G after 12 h incubation （P〈0.05）. About the apoptotic phenomenon, the cell percentages of sub-G1 cells were significantly increased in the mediums containing nucleosides such as C, U, T, A, and G （P〈0.05）. Furthermore, the caspase-3 activity was increased, when the cells were incubated with T （P〈0.05）. The protein expressions of p53 and p21 showed no difference in each group. To investigate the mechanism of apoptosis induced by nucleosides, it was found that the contents of soluble Fas ligand contents were increased in HepG2 cells following I, U, T, and A treatment （P〈0.05）. But, TNF-α and cytochrome cwere undetectable. CONCLUSION： Thymidine may induce the apoptosis in HepG2, but the effective dosages and reactive time must be investigated in the future study. However, the apoptosis-inducing abilities of other nucleosides were still unclear in this study.

Graphene as adsorbent for highly efficient extraction of modified nucleosides in urine prior to liquid chromatography-tandem mass spectrometry analysis

RNA modifications have been involved in numerous biological processes, and aberrations of these modifications are tightly associated with various diseases including cancer. Herein, we developed graphenebased solid-phase extraction and robust ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS) combined with stable isotope-dilution for simultaneous enrichment and accurate determination of 17 modified nucleosides in human urine. We found graphene could effectively adsorb various modified nucleosides in human urine samples. With this method, we identified and quantified these modified nucleosides in urine samples collected from lung cancer patients and healthy controls.We revealed that the levels of 12 modified nucleosides were all diminished in urine from lung cancer patients, compared with healthy controls. It is worth noting that we demonstrated, for the first time, the presence of 5,2-O-dimethyluridine(m~5U_m) in human urine. Together, we established a robust analytical method for simultaneous determinations of 17 modified nucleosides in human urine, and our results revealed a close correlation between the concentrations of urinary modified nucleosides and the occurrence of lung cancer, implying the potential applications of these modified nucleosides as noninvasive biomarkers for the early detection of lung cancer. Moreover, this study will stimulate future investigations on the regulatory roles of RNA modifications in the initiation and progression of lung cancer.

Catalyst-Free Regio-and Diastereoselective Synthesis of Heterocyclic Nucleosides in the Eco-friendly Solvent 2-Methyltetrahydrofurant

An efficient and practical synthesis of heterocyclic nucleosides is developed by a catalyst-free highly regioselective and diastereose-lective[3+2]annulation of a-purine-substituted acrylates with nitrones.The reaction operates with excellent functional group toler-ance,very mild reaction conditions,and with the green,sustainable,and eco-friendly 2-methyltetrahydrofuran(2-MeTHF)as sol-vent.Compared with other reactions of electron-deficient olefin dipolarophiles with nitrones,different regioselective cycloaddition products were observed in this work.This 1,3-dipolar cycloaddition reaction gives a series of isoxazolidinyl nucleosides in good to excellent yields with promising applications in biochemistry and medicinal chemistry.

Simultaneous determination of 10 nucleosides and nucleobases from different cultivation years of Fritillaria unibracteata var. wabuensis by HPLC-DAD

Determination of nucleosides and nucleobases is important for the quality control of Fritillaria unibracteata Hsiao et K.C. Hsia var. wabuensis （FUW） due to their physiological and pharmacological actions. In the present study, we developed a sensitive and reliable HPLC-diode-array detection method to simultaneously determine ten nucleosides and nucleobases, including cytosine, uracil, cytidine, uridine, thymine, adenine, inosine, guanosine, thymidine and adenosine. Complete separation of all the analytes was achieved on a Zorbax 300 A 300 Extend C18 column with a gradient of methanol-ultrapure water at a flow rate of 1 mL/min in less than 30 min. The diode-array detector wavelength was set at 260 nm for the UV detection of nucleosides and nucleobases. The optimized method provided good linearity （R2〉0.9993 for all the analytes）, satisfactory precision （RSD〈3.715%）, good repeatability （RSD_〈3.748%） and good recovery （RSD from 97.688% to 102.923%）. In addition, the developed method was successfully applied to simultaneous determination of ten nucleosides and nucleobases from FUW, and their content changes of various cultivation time （1-7 years） were further analyzed for the first time. Our findings were useful for ensuring the cultivation time choice of artificial cultivation, quality control, pharmaceutical studies and clinical efficacy of FUW.

Risk of hepatitis B virus reactivation in oncological patients treated with tyrosine kinase inhibitors:A case report and literature analysis

Hepatitis B virus(HBV)reactivation(HBVr)represents a severe and potentially life-threatening condition,and preventive measures are available through blood test screening or prophylactic therapy administration.The assessment of HBVr traditionally considers factors such as HBV profile,including hepatitis B surface antigen(HBsAg)and antibody to hepatitis B core antigen,along with type of medication(chemotherapy;immunomodulants).Nevertheless,consideration of possible patient’s underlying tumor and the specific malignancy type(solid or hematologic)plays a crucial role and needs to be assessed for decision-making process.

A novel strain of Levilactobacillus brevis PDD-5 isolated from salty vegetables has beneficial effects on hyperuricemia through anti-inflammation and improvement of kidney damage

Hyperuricemia is a metabolic disorder caused by abnormal purine metabolism,resulting in abnormally high serum uric acid.In this study,a novel Levilactobacillus brevis PDD-5 isolated from salty vegetables was verified with the function of alleviating hyperuricemia.The relevant effects of L.brevis PDD-5 in lowering uric acid were analyzed by in vitro and in vivo experiments.The results showed that the L.brevis PDD-5 has(68.86±15.46)%of inosine uptake capacity and(95.75±3.30)%of guanosine uptake capacity in vitro.Oral administration of L.brevis PDD-5 to hyperuricemia rats reduced uric acid,creatinine,and urea nitrogen in serum,as well as decreased inosine and guanosine levels in the intestinal contents of rats.Analysis of relevant markers in the kidney by ELISA kits revealed that L.brevis PDD-5 alleviated oxidative stress and inflammation.Moreover,the gene expression of uric acid transporter 1(URAT1)and glucose transporter 9(GLUT9)was down-regulated,and the gene expression of organic anion transporter 1(OAT1)was up-regulated after treatment with L.brevis PDD-5.Western blot analysis showed that L.brevis PDD-5 alleviated hyperuricemia-induced kidney injury through the NLRP3 pathway.The se findings suggest that L.brevis PDD-5 can lower uric acid,repair kidney damage,and also has the potential to prevent uric acid nephropathy.

Molecular Recognition of Bases and Nucleosides by Mono-substituted Mononuclear Complexes of 1,4,7,10-Tetraaza-cyclododecane

The mononuclear macrocyclic polyamine metal complexes 5a-5e have been shown to form stable 1:1 complexes with bases and nucleosides. Their binding constants (K) were determined by UV-visible spectrometric titration. The results show that recognition ability of the complexes 5a-5e for uracil, U (Uri-dine), dT (Thymidine) is higher than that for the other bases or nucleosides (such as Cytidine, Guanosine, Adenosine). The metal ion also plays an important role for the recognition ability of complexes.