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.

Two Preparation Methods-dominated Cd^(Ⅱ)-Based Coordination Polymers with Mixed Adenine Nucleobase and 5-Nitroisophathalate Ligands: Synthesis, Structure and Fluorescence

Two new CdⅡ-based coordination polymers(CPs) with mixed adenine(Hade) nucleobase and 5-nitroisophathalate(nip) ligands, {[Cd(Hade)_(0.5)(H_2O)_2(nip)]·H_2O}n 1 and {[Cd(Hade)(H_2O)_(1.25)(CH_3OH)0.75(nip)]·0.75 CH_3OH·0.5H_2 O}_n 2, were successfully obtained by varying the preparation methods and structurally characterized. Crystal data for 1: monoclinic, C2/c space group with a = 10.5546(6), b = 17.3496(6), c = 16.1198(9) ?, β = 104.2800(10)o, V = 2860.6(2) ?3, Dc = 2.058 g/cm^3, Mr = 443.13, Z = 8, F(000) = 1752, μ = 1.585 mm^(–1), the final R = 0.0394 and wR = 0.1109 for 2285 observed reflections with I > 2σ(I). For 2: triclinic, P1 space group with a = 10.2032(7), b = 10.5098(8), c = 11.0223(8) ?, a = 65.7050(10)o, β = 74.5750(10)o, g = 61.5280(10)o, V = 943.38(12) ?~3, Dc = 1.888 g/cm3, Mr = 536.24, Z = 2, F(000) = 537, μ = 1.225 mm^(–1), the final R = 0.0225 and wR = 0.0702 for 3143 observed reflections with I > 2σ(I). 1 presents a crisscrossed layer with mutually orthogonal {Cd(nip)} chains aggregated by neutral m-N(7),N(9)-Hade connector. By contrast, 2 displays a linear chain with CdⅡ ions extended by bis-bidentate chelating-nip2–connectors, which are further assembled into a broad ribbon by N-H···N hydrogen-bonding interactions. Additionally, the two solid-state samples with comparable thermal stability exhibit favorable luminescent emissions at room temperature, suggesting their potential applications as fluorescence materials.

Interaction of Boron-Nitrogen Substitued Graphene Nanoribbon with Nucleobases: The Idea of Biosensor

In this paper we have designed a biosensor device built from B-N substituted graphene nanoribbon within density functional based tight-binding (DFTB) framework. We have investigated the interaction of the nucleobases adenine (A), Guanine (G), Cytosine (C) and Thymine (T) with device. Our calculation suggests that all the nucleobases have different interaction strength when they interact with device and shows that guanine has stronger interaction with device than other nucleobases. It reveals that the absorption energy shows the hierarchy: G > C > T > A. Our results also demonstrate the transport properties of the device and how the transport properties change due to the absorption of nucleobases on the device.

Constructing Artificial Nucleobase Compilation to Enable Precise Molecular Medicine

Nucleic acids are the hereditary information storage medium of life. Due to its high programmability and good biocompatibility, the applications of nucleic acids are not limited to their natural function. However, the efficiency of nucleic acids is often hampered by inherent limitations in numerous practical applications, including limited access to complex functional patterns due to only four building blocks, facile degradation by nucleases, rapid renal clearance, poor pharmacokinetic properties, and so on. To end this, the researchers developed unnatural base pairs (UBPs) and numerous artificial analogues of nucleosides and oligonucleotides in recent decades. The developed UBPs and nucleoside base analogues together constitute artificial nucleobase compilation, which promotes the development of biomedical sciences. Here, we describe the development of artificial nucleobase compilation and summarized its applications in precise molecular medicine, including PCR-based diagnostics, aptamer-based diagnostics, nucleobase analogue drugs construction, ASO modification, aptamer-based therapeutics and biomaterials construction. This review provides an overview of current opportunities and challenges of artificial nucleobase-related precise molecular medicine.

A Novel Nucleobase Modification Strategy for Controlling RNA-Guided Nucleic Acid Cleavage

Clustered regularly interspaced short palindromic repeat(CRISPR)technologies have opened new scientific avenues widely used in biomedical research.But simple and efficient strategies to reversibly control CRISPR are lacking.In contrast to previous methods of attaching molecules to the ribose of guide RNAs(gRNAs),we focused on molecules that can directly react with nucleobases.Here,we developed a new strategy to switch off the CRISPR system by efficiently installing 4-(bromomethyl)phenylboronic acid onto nucleobases in gRNAs.CRISPR can then be activated by hydrogen peroxide(H_(2)O_(2)).Collectively,this work demonstrates boronic acid reversibly modulating CRISPR systems through a H_(2)O_(2)-responsive manner.

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.

Utilization of H-bond interaction of nucleobase Uralic with antitumor methotrexate to design drug carrier with ultrahigh loading efficiency and pH-responsive drug release

A novel Uralic(U)-rich linear-hyperbranched mono-methoxy poly(ethylene glycol)-hyperbranched polyglycerol-graft-Uralic(mPEG-HPG-g-U)nanoparticle(NP)was prepared as drug carrier for antitumor methotrexate(MTX).Due to the H-bond interaction of U with MTX and hydrophobic interaction,this NP exhibited high drug loading efficiency of up to 40%,which was significantly higher than that of traditional NPs based on U-absent copolymers(<15%).In addition,MTX-loaded mPEG-HPG-g-U NPs also demonstrated an acidity-accelerated drug release behavior.

Optically Active Nucleobase-Functionalized Polynorbornenes Mimicking Double-Helix DNA

The development of synthetic polymers that mimic the double-stranded helical structure of DNA is a fascinating topic in polymer science.In this study,we designed and synthesized two chiral norbornene monomers containing adenine and thymine,which were mixed to form a hydrogen-bonding complementary complex,by which a ring-opening metathesis polymerization(ROMP)was performed.High-resolution transmission electron microscopy(HRTEM)undoubtedly showed the self-assembly of the optically active complementary nucleobasefunctionalized polynorbornenes into a double helix.Computer simulations and a two-dimensional nuclear Overhauser effect spectroscopy(2DNOESY)experiment showed that the doublestranded helical polynorbornene was derived from a copolymer of alternating adenine and thymine units.

Preparation of Platinum(II) Complexes with 1-β-D-Ribofuranosyl-1,2,4-triazole-3-carboxamide and its Deoxy-analogue

The platinum (II) complexes of the [Pt (N4,N7-Ribavirin) (DMSO) Cl], [Pt (N4,N7-De-oxyribavirin) (DMSO) Cl] were obtained by the reactions of cis-[Pt (DMSO)2 Cl2] and K[Pt (DMSO) Cl3] with 1-??-D-ribofuranosyl-1,2,4-triazole-3-carboxamide (Ribavirin) and its deoxy-analogue (deoxyribavirin). The preparation of 1-(2'-deoxy-?-D-ribofuranosyl) -1,2,4-triazole-3-carboxamide was also performed through a four-step procedure, protection of 3', 5'-dihydroxyl group of Ribavirin with 1,3-dichloro-1,1,3,3-tetraisopropyldisiloxane (TPDS-Cl), phenoxythio-carbonylation of the 2'-hydroxyl group of 3', 5'-O-TPDS-Ribavirin with phenoxythiocarbonyl-chloride (PTC-Cl), reduction of 2′-O-phenoxythiocarbonyl ester of 3', 5'-O-TPDS-Ribavirin with tri-n-butyltin hydride and AIBN, deprotection of 3', 5'-O-TPDS-Ribavirin with tetrabutylammon-ium fluoride in THF.

Two dimensional nanocarbons from biomass and biological molecules:Synthetic strategies and energy related applications

Two-dimensional(2D)carbon materials with ultrathin thickness,large lateral size,large surface area,accessible active sites and unique physical-chemical properties have been proven to be attractive electrode materials or catalysts for high-efficient energy storage and conversion materials.However,the conventional synthesis method for 2D carbon materials heavily depends on fossil-based feedstocks and goes through harsh conditions(e.g.,chemical vapor deposition),which are unsustainable and costly.Besides,the top-down method needs to use massive strong acids/oxidants,which is environmentallyunfriendly.Therefore,it is necessary to commit to seek green,sustainable and cost-effective approach for the synthesis of 2D carbon materials.As of now,biomass or biological molecules as carbon-rich resources have been viewed as a promising candidate for the 2D carbon material preparation owing to its abundance,renewability,nontoxicity and low-cost.Especially for nucleobases,as an emerging molecule have been shown great advantages for the construction of 2D materials guided by its multiple hydrogen-bonding interaction.Recently,our group have proposed a rather innovative strategy to produce 2D carbon materials by carbonization of nucleobases which has relatively high electrode potentials.These nucleobases can form planar network structure through hydrogen bonding interaction.Such hydrogenbonding can be stable at relatively high temperature,which confines C-C or C-N polymerization in a 2D plane.As a result,direct carbonization of nucleobases enables the formation of 2D carbon with highly sp2-conjugated and feature of heteroatom doping.This review systematically summarizes the recent development of the strategies to synthesize 2D sustainable carbon materials from biomass and biological molecules.The corresponding electrochemical applications such as lithium ion batteries,supercapacitors and fuel cell are selectively presented.At the end,the summary and future perspectives in this important field are provided to inspire further exploration.

Hierarchical Self-assembly of G-Quadruplexes Based Hydrogel Consisting of Guanine and Peptide Epitope

Guanosine-based hydrogels have attracted considerable attention because of their simplicity and easy preparation.However,the sugar moiety limits its further applications because of the necessity of sugar in the hydrogel formation.This work reports a G-quadruplexes-based hydrogel consisting of guanine and peptide epitope to form a supramolecular hydrogel in the presence of metal cations.Using the metal ion-responsive peptide epitope from the ion channel to replace sugar motif at N9 position of guanosine results in a novel nucleopeptide.The results show that the gelation time,the diameter of nanofibers,the anisotropic property,and the mechanical property of the hydrogel can be simply controlled using metal cations.The magnesium and calcium ions direct the alignment of nanofibers to form anisotropic nano-bundles.The mechanistic studies indicate the formation of G-quadruplexes in the hydrogel.Compared to the storage modulus of nucleopeptide without the metal cation,adding zinc ions results in an over three-order increase in mechanical properties.Cytotoxicity experiment indicates the good biocompatibility of our hydrogel.Moreover,we demonstrate that the guanine-capped peptide could release STING agonist in a controlled manner.This work illustrates a simple way to modulate the property of the nucleopeptide hydrogel to develop soft materials.

Analysis of the bioactive components from different growth stages of Fritillaria taipaiensis P. Y. Li

High-performance liquid chromatography(HPLC)coupled with an evaporative light scattering detector(ELSD)or a diode array detector(DAD)were utilized for the quantitative analysis of 4 alkaloids(peimisine,sipeimine,peimine and peiminine)and 9 nucleosides and nucleobases(uracil,uridine,adenosine,adenine,inosine,thymine,cytidine,guanosine and thymidine)from Fritillaria taipaiensis P.Y.Li that had been cultivated in the same field for 2–6 years.The content of peimisine,sipeimine,peimine,peiminine,uracil,thymine,adenine and inosine in plants cultivated for 2–4 years was significantly higher than that of plants cultivated for 5–6 years,while the content of cytidine,uridine,guanosine,thymidine and adenosine did not change over this period.This is the first evaluation of variation in the bioactive compounds in F.taipaiensis over its life cycle.