The first hemiterpene-quassinoid adducts,bruquass A and B(1 and 2),were rapidly isolated and identified from Brucea javanica using an integrated analytical strategy.They possessed unusual carbon skeletons formed by th...The first hemiterpene-quassinoid adducts,bruquass A and B(1 and 2),were rapidly isolated and identified from Brucea javanica using an integrated analytical strategy.They possessed unusual carbon skeletons formed by the coupling of quassinoids with hemiterpene units via vinylogous aldol reactions.Their structural configurations were determined through comprehensive spectroscopic analysis and electronic circular dichroism(ECD) calculations.Plausible biosynthetic pathways for 1 and 2 were proposed,and guided by these biogenetic insights,the biomimetic synthesis of compound 1 was successfully achieved.Furthermore,compounds 1 and 2 exhibited significant antifeedant activity against Plutella xylostella.The bioactivity assessment results open up the prospects of 1 and 2 as a promising new class of botanical insecticide.展开更多
Seven novel acylphloroglucinol-sesquiterpenoid adducts,designated as dryatraols J-P(1-7),were isolated from the rhizomes of Dryopteris atrata(Wall.ex Kunze)Ching.The structures,including absolute configurations,were e...Seven novel acylphloroglucinol-sesquiterpenoid adducts,designated as dryatraols J-P(1-7),were isolated from the rhizomes of Dryopteris atrata(Wall.ex Kunze)Ching.The structures,including absolute configurations,were elucidated using comprehensive spectroscopic data,calculated 13C Nuclear Magnetic Resonance-Diastereotopic Probability Assignment Plus(13C NMR-DP4+)probability analysis,and ECD calculations.These structures represent a rare subclass of carbon skeleton of acylphloroglucinol-sesquiterpenoid adducts with a furan ring connecting the acylphloroglucinol and sesquiterpenoid moieties.Notably,compounds 1-6 are the first reported examples of acylphloroglucinol-sesquiterpenoid adducts with dimeric acylphloroglucinol incorporated into the aristolane-or rulepidanol-type sesquiterpene,while compound 7 features a hydroxylated monomeric acylphloroglucinol motif.A preliminary evaluation of their antiviral activities revealed that compounds 1-6 exhibited more potent activities against respiratory syncytial virus(RSV)with IC50 values ranging from 0.75 to 3.12μmol·L^(-1) compared to the positive control(ribavirin).展开更多
Objective： Aflatoxin B1 （AFB1）, which can cause the formation of AFB1-DNA adducts, is a known human carcinogen. AFB1-exposure individuals with inherited susceptible carcinogen-metabolizing or repairing genotypes ma...Objective： Aflatoxin B1 （AFB1）, which can cause the formation of AFB1-DNA adducts, is a known human carcinogen. AFB1-exposure individuals with inherited susceptible carcinogen-metabolizing or repairing genotypes may experience an increased risk of genotoxicity. This study was designed to investigate whether the polymorphisms of two genes, the metabolic gene Glutathione S-transferase M1 （GSTM1） and DNA repair gene x-ray repair cross-complementing group 3 （XRCC3）, can affect the levels of AFB1-DNA adducts in Guangxi Population （n= 966） from an AFB1-exposure area. Methods： AFB1-DNA adducts were measured by ELISA, and GSTM1 and XRCC3 codon 241 genotypes were identified by PCR-RFLP. Results： The GSTM1-null genotype [adjusted odds ratio （OR） = 2.09; 95% confidence interval （CI） = 1.61-2.71] and XRCC3 genotypes with 241 Met alleles [i.e., XRCC3-TM and -MM, adjusted ORs （95% CI） were 1.43 （1.08-1.89） and 2.42 （1.13-5.22）, respectively] were significantly associated with higher levels of AFB1-DNA adducts. Compared with those individuals who did not express any putative risk genotypes as reference （OR = 1）, individuals featuring all of the putative risk genotypes did experience a significantly higher DNA-adduct levels （adjusted ORs were 2.87 for GSTM1-null and XRCC3-TM; 5.83 for GSTM1-null and XRCC3-MM）. Additionally, there was a positive joint effect between XRCC3 genotypes and long-term AFB1 exposure in the formation of AFB1-DNA adducts. Conclusion： These results suggest that individuals with susceptible genotypes GSTM1-null, XRCC3-TM, or XRCC3-MM may experience an increased risk of DNA damage elicited by AFB1 exposure.展开更多
Mulberry Diels-Alder-type adducts(MDAAs)are unique phenolic natural products biosynthetically derived from the intermolecular[4+2]-cycloaddition of dienophiles(mainly chalcones)and dehydroprenylphenol dienes,which are...Mulberry Diels-Alder-type adducts(MDAAs)are unique phenolic natural products biosynthetically derived from the intermolecular[4+2]-cycloaddition of dienophiles(mainly chalcones)and dehydroprenylphenol dienes,which are exclusively distributed in moraceous plants.A total of 166 MDAAs with diverse skeletons have been isolated and identified since 1980.Structurally,the classic MDAAs characterized by the chalcone-skeleton dienophiles can be divided into eight groups(Types A−H),while others with non-chalcone dienophiles or some variations of classic MDAAs are non-classic MDAAs(Type I).These compounds have attracted significant attention of natural products and synthetic chemists due to their complex architectures,remarkable biological activities,and synthetic challenges.The present review provides a comprehensive summary of the structural properties,bioactivities,and syntheses of MDAAs.Cited references were collected between 1980 and 2021 from the SciFinder,Web of Science,and China National Knowledge Internet(CNKI).展开更多
Water-soluble b-alanine C60 adducts were synthesized, and the scavenging ability to superoxygen anion radical O2- and hydroxyl radical.OH were studied by autoxidation of pyrogallol and chemiluminescence, respectively....Water-soluble b-alanine C60 adducts were synthesized, and the scavenging ability to superoxygen anion radical O2- and hydroxyl radical.OH were studied by autoxidation of pyrogallol and chemiluminescence, respectively. It was found thatβ-alanine C60 adducts showed an excellent efficiency in eliminating superoxygen anion radical and hydroxyl radical. The 50% inhibition concentration (IC50) for superoxygen anion radical and hydroxyl radical were 0.15 mg/mL and 0.048 mg/mL, respectively. The difference should be mainly attributed to the different scavenging mechanisms.展开更多
Myrcauones A-D(1-4),four new phloroglucinol-terpene adducts were isolated from the leaves of Myrciaria cauliflora.Their structures with absolute configurations were elucidated by combination of spectroscopic analysis,...Myrcauones A-D(1-4),four new phloroglucinol-terpene adducts were isolated from the leaves of Myrciaria cauliflora.Their structures with absolute configurations were elucidated by combination of spectroscopic analysis,single crystal X-ray diffraction,and electronic circular dichroism(ECD)calculations.Compound 1 was a rearranged isobutylphloroglucinol-pinene adduct featuring an unusual 2,3,4,4a,10,11-hexahydro-1H-3,11a-methanodibenzo[b,f]oxepin backbone.Compound 4 showed moderate antibacterial activity against Gram-positive bacteria including multiresistant strains.展开更多
Two novel acid-base adducts,[H2L1^2＋]（Hpbda）2（1,L1 = 1,4-di（lH-imidazol-4-yl）benzene,H2pbda = 1,4-benzenedicarboxylic acid） and[H2L2^2＋]（NO3）2（2,L2 = l,4-di（l-carboxymethyl-imidazol-4-yl）benzene）,have be...Two novel acid-base adducts,[H2L1^2＋]（Hpbda）2（1,L1 = 1,4-di（lH-imidazol-4-yl）benzene,H2pbda = 1,4-benzenedicarboxylic acid） and[H2L2^2＋]（NO3）2（2,L2 = l,4-di（l-carboxymethyl-imidazol-4-yl）benzene）,have been prepared and characterized by single-crystal X-ray diffraction,IR spectroscopy and elemental analysis.Compound 1 crystallizes in monoclinic,space group P21/n with a = 5.3525（11）,b = 9.1471（19）,c = 19.314（4） ？,β = 92.342（3）°,V= 944.8（3） A°3,Z = 2,C16H16N6O（10）,Mr = 452.35,Dc = 1.590 g/cm^3,μ = 0.135 mm^-1,S = 1.058,F（000） = 468,the final R = 0.0661 and wR = 0.1887 for 2298 observed reflections（I〉 2σ（I））.Compound 2 crystallizes in monoclinic,space group P21/c with a = 9.6923（10）,b = 17.2950（17）,c = 7.1880（7） ？,β =94.801（2）°,V= 1200.7（2）A°3,Z = 2,C（28）H（22）N4O8,Mr = 542.50,Dc = 1.501 g/cm^3,μ = 0.112 mm^-1,S= 1.060,F（000） = 564,the final R = 0.0394 and wR = 0.1017 for 2768 observed reflections（I 〉2σ（I））.In the title compounds,both of L1 and L2 ligands act as weak base to accept protons to exhibit diprotonated H2L1^2＋ and H2L2^2＋ form,which can effectively employ as hydrogen bonding donors to combine anion moieties to form binary adducts respectively.In the crystal packing diagram of two polymers,there exist extensive noncovalent interactions including charge-transfer interactions,C（N）-H…π and N-H…O,C-H…O,O-H…O hydrogen bonding interactions between co-crystal moieties which consolidate the structures of supramolecular polymers,thus generating three-dimensional（3D） frameworks.展开更多
Low levels (ng/g) of musk ketone (MK),used as a fragrance additive in the formulation of personal care products,are frequently detected in the water and other environment.Thus,aquatic organisms can be continuously exp...Low levels (ng/g) of musk ketone (MK),used as a fragrance additive in the formulation of personal care products,are frequently detected in the water and other environment.Thus,aquatic organisms can be continuously exposed to MK.In this study,kinetics and dose-response assessments of 2-amino-MK (AMK) metabolite,bound to cysteine-hemoglobin (Hb) in rainbow trout,formed by enzymatic nitro-reduction of MK have been demonstrated.Trout were exposed to a single exposure of 0.010,0.030,0.10,and 0.30 mg MK/g fish.Tw...展开更多
Theoretical investigation on the structures of the octacoordinated [Nd(CO3)4]5-and the nonacoordinated [Nd(CO3)4.OH2]5-complexes, using the SPARKLE parameters of the lanthanides within MOPAC, revealed that they posses...Theoretical investigation on the structures of the octacoordinated [Nd(CO3)4]5-and the nonacoordinated [Nd(CO3)4.OH2]5-complexes, using the SPARKLE parameters of the lanthanides within MOPAC, revealed that they possessed dodecahedral and square antiprismatic structures respectively with an average Nd-O distance of 0.249 nm. These structures and the Nd-O distances agreed well with those experimentally found in the crystal structures. Replacing the water molecule with a fluoride ion or a mondentatecarbonato ligand resulted in a nonacoordinated distorted square antiprismatic structures where the trans-carbonato groups were twisted. The corresponding decacoordinated structures with two fluoride ions or a bidentatecarbonato group, [Nd(CO3)4·F2]7-and [Nd(CO3)5]7-, were also investigated. In both cases considerable twisting of the transcarbonato groups was observed.展开更多
Aristolochic acid （AA） is a known nephrotoxin and potential carcinogen, which can form covalent DNA adducts after metabolic activation in vivo and in vitro. A simple method for preparation and characterization of ar...Aristolochic acid （AA） is a known nephrotoxin and potential carcinogen, which can form covalent DNA adducts after metabolic activation in vivo and in vitro. A simple method for preparation and characterization of aristolochic acid-DNA adducts was developed. Four AA-adducts were synthesized by a direct reaction of AAI/AAII with 2′-deoxynucleosides. The reaction mixture was first cleaned-up and pre-concentrated using solid phase extraction （SPE）, and further purified by a reversed-phase high performance liquid chromatography （HPLC）. By the application of developed SPE procedure, matrices and byproducts in reaction mixture could be greatly reduced and adducts of high purity （more than 94% as indicated by HPLC） were obtained. The purified AA-DNA adducts were identified and characterized with liquid-electrospray ionization-quadrupole-time of flight-mass spectrometry （LC-ESI-Q-TOF-MS/MS） and LC-Diode array detector-fluorescence （LC-DAD-FL） analysis. This work provides a robust tool for possible large-scale preparation of AA-DNA adduct standards, which can promote the further studies on carcinogenic and mutagenic mechanism of aristolochic acids.展开更多
A simple and convenient procedure for stercoselective synthesis of （Z）-allyl selenides has been developed by a one-pot reaction of diselenides with Baylis-Hillman adducts in the presence of samarium metal-trimethyls...A simple and convenient procedure for stercoselective synthesis of （Z）-allyl selenides has been developed by a one-pot reaction of diselenides with Baylis-Hillman adducts in the presence of samarium metal-trimethylsilyl chloride under mild conditions. Presumably, the diselenides are cleaved by Sm/TMSCI system to form selemde anions, which then undergo SN2＇ substitution of Baylis-Hillman adducts to produce the （Z）-allyl selenides.展开更多
Deconjugation of cyclopent-2-enone aldols were attempted under various conditions, and the desired deconjugated product was achieved via dianion approach. Various results obtained in this study are explained by struct...Deconjugation of cyclopent-2-enone aldols were attempted under various conditions, and the desired deconjugated product was achieved via dianion approach. Various results obtained in this study are explained by structure and transition state analysis.展开更多
The B3LYP/6-31G^＊ level of theory was used for the optimization of nonclassical platinum drugs with planar aromatic heterocycle ligands in addition to their monoaqua species, diaqua species and monofunctional adducts...The B3LYP/6-31G^＊ level of theory was used for the optimization of nonclassical platinum drugs with planar aromatic heterocycle ligands in addition to their monoaqua species, diaqua species and monofunctional adducts. Single point calculations were performed on optimized geometries using the MP2/6-31G^＊＊ method, and the Lanl2dz pseudo potential for the Pt atom remained constant in all calculations. It can be easily seen that the trans effect can influence both geometrical structures and bond dissociating energies （BDEs）. On the basis of our calculation, we get that the long-lived monofunctional adducts with chloride ligand may be in existence, because they possessed higher stability energies, easily dissociated chloride compared with the monoaqua species dissociating chloride and that replacement of the first chloride by bases became exothermic in solution. Our calculated results also demonstrate that the strongest H-bonds appear in the complexes of q-wG and t-wG using different methods. In comparison with adenine complexes, the corresponding guanine complexes possess larger interaction energies as well as higher stability energies either corrected by basis set superposition error （bsse） of Boys-Bernardi counterpoise method or uncorrected both in gas phase and in solution with one exception that the stability energy of q-CIA complex in solution is larger than that of q,CIG complex. Finally, the nature of bond was analyzed in terms of partial charges distribution based on NBO population.展开更多
A laser flash photolysis study of the reactivity of Cl˙with glyoxal, glyoxal mono- and dibisulfite adducts, 1-hydroxy-2, 2-diol-ethanesulfonate and 1, 2-dihydroxy-1, 2-ethanedi sulfonate in the aqueous phase was ca...A laser flash photolysis study of the reactivity of Cl˙with glyoxal, glyoxal mono- and dibisulfite adducts, 1-hydroxy-2, 2-diol-ethanesulfonate and 1, 2-dihydroxy-1, 2-ethanedi sulfonate in the aqueous phase was carried out. The obtained rate constants can be used for atmospheric modeling.展开更多
Objective. DNA modification fixed as mutations in the cells may be an essential factor in the initiation step of chemical carcinogenesis. In order to explore the mechanism of gene mutation...Objective. DNA modification fixed as mutations in the cells may be an essential factor in the initiation step of chemical carcinogenesis. In order to explore the mechanism of gene mutation and cell transformation induced by glycidyl methacrylate (GMA), the current test studied the characteristics of GMA DNA adducts formation in vitro. Methods. In vitro test, dAMP, dCMP, dGMP, dTMP and calf thymus DNA were allowed to react with GMA (Glycidyl Methacrylate). After the reaction, the mixtures were detected by UV and subjected to reversed phase HPLC on ultrasphere ODS reversed phase column, the reaction products were eluted with a linear gradients of methanol (solvent A) and 10mmol/L ammonium formate, pH5 0 (solvent B). The synthesized adducts were then characterized by UV spectroscopy in acid (pH1 0), neutral (pH7 2), alkaline (pH11 0) and by mass spectroscopy. Results. The results showed that GMA could bind with dAMP, dCMP, dGMP and calf thymus DNA by covalent bond, and the binding sites were specific (N 6 of adenine, N 3 of cytosine). Meanwhile, a main GMA DNA adduct in the reaction of GMA with calf thymus DNA was confirmed as N 3 methacrylate 2 hydroxypropy1 dCMP. Conclusions. GMA can react with DNA and /or deoxynucleotide monophosphate and generate some adducts such as N 6 methacrylate 2 hydroxypropyl dAMP and N 3 methacrylate 2 hydroxypropyl dCMP, ets. Formation of GMA DNA adducts is an important molecular event in gene mutation and cell transformation induced by GMA.展开更多
Substantial data have been generated during the past 5 years in both experimental systems and human populations which shed light on the potential role of carcinogen-macromolecular adducts in human cancer risk assessme...Substantial data have been generated during the past 5 years in both experimental systems and human populations which shed light on the potential role of carcinogen-macromolecular adducts in human cancer risk assessment. The use of DNA and protein adducts is based on the fundamental concept in chemical carcinogenesis that most genotoxins are metabolized to electrophilic 'ultimate' carcinogens that are capable of forming covalent adducts with cellular macromolecules. This report examines the relative usefulness and limitations of using DNA and protein adducts and related techniques for assessing human exposure to genotoxic carcinogens. Data discussed in this report clearly demonstrate that these biomarkers not only allow early detection of potential cancer hazard in humans, but they can also significantly increase the power of conventional cancer epidemiological studies in determining true causal relationships. In addition, such biomarkers can improve extrapolation of cancer risks from laboratory animals to humans or from one human population to another.展开更多
Aliphatic α-oxo ketene cyclic dithioacetals 1 were reacted with allyl magne- sium bromide to afford the 1,2-addition products 2.Catalyzed by boron trifluoride etherate,the adducts 2 were etherified by methanol to aff...Aliphatic α-oxo ketene cyclic dithioacetals 1 were reacted with allyl magne- sium bromide to afford the 1,2-addition products 2.Catalyzed by boron trifluoride etherate,the adducts 2 were etherified by methanol to afford the corresponding methyl ethers 3.This process provides a new method for the protection of the acid sensitive hydroxyl group in 2 under mild condition.展开更多
The title of this little assay coins three new words: Pre-Chelates, Post-Adducts and Implexes. These, very daring new excursions into the scientific English language, come from the developments of Quelamycin and Sodiu...The title of this little assay coins three new words: Pre-Chelates, Post-Adducts and Implexes. These, very daring new excursions into the scientific English language, come from the developments of Quelamycin and Sodium L-Thioproline, through our different group studies arriving to cancer reversal by a dual strategy. It is enough to read all our published materials, cites and related papers, dealing more or less with the chemistry and possible mechanism of action of these compounds, to gather somewhat what signified our monomeric-triferric-doxorubicine, as possibly one of the first Pre-Chelates and our Sodium L-Thioproline, probably as one of the first Post-Adducts. Both molecules come to the human patients with cancer blood from the exterior. After this indication, it will be proposed a seed concept of a new type of molecules, the “Implexes” in which the metals will be embraced instead of being linked.展开更多
Complexes of the general formula [MBr2(TMTU)n] (where M is Mn, Fe, Co, Ni, Cu, Zn or Cd;TMTU is Tetramethylthiourea;n is 0.75, 2 or 3) were obtained by the reaction of salts and ligand in solution. The bromides were s...Complexes of the general formula [MBr2(TMTU)n] (where M is Mn, Fe, Co, Ni, Cu, Zn or Cd;TMTU is Tetramethylthiourea;n is 0.75, 2 or 3) were obtained by the reaction of salts and ligand in solution. The bromides were selected among several other salts because they had thermochemical data in the literature. Properties as capillary melting points;C, H, N, Br and metal contents;TG/DTG and DSC curves;and IR and electronic spectra were determined. The values of several thermodynamic parameters for the complexes were found by solution calorimetry. From them, the standard enthalpies of the metal-sulphur coordinated bonds were calculated. The standard enthalpies of the formation of the gaseous phase adducts also were estimated.展开更多
The word “clusters” in scientific terminology as aggregated molecules or atoms appeared in chemistry relatively recently. The terms clusters have been used intensively since the discovery of fullerenes. The term clu...The word “clusters” in scientific terminology as aggregated molecules or atoms appeared in chemistry relatively recently. The terms clusters have been used intensively since the discovery of fullerenes. The term cluster is not a new one for other branches of science such as astrophysics-star cluster, globular cluster, galaxy cluster, in biology and medicine-cancer cluster, genetic cluster, or in computing-data cluster. Adducts in chemistry were known significantly earlier. Both clusters and adducts are assemblies of atoms or molecules that are held together by weak van der Waals or London dispersion forces. Clusters are homogeneous and usually consist of one sort of atom or molecule. Clusters can also be a host for other types of atoms or molecules. Adducts usually consist of two different types of molecules, one of which is the host molecule. Both clusters and adducts are well defined by IUPAC. The present short review describes some important phenomena of these intriguing associations, which have interest for chemical extraction, separation, analysis, and for nature in general.展开更多
基金funded by the National Natural Science Foundation Regional Innovation and Development Joint Fund(No.U22A20381)National Key R&D Program of China (No.2024YFC3506600)+3 种基金Natural Science Foundation of Liaoning Province of China (No.2024-MS-086)Shenyang City Middle and Young Science and Technology Talents Cultivation Special U40 Outstanding Youth Project (No.RC230803)Science and Technology Planning Project of Liaoning Province (No.2021JH1/10400049)Song Shaojiang Expert Workstation of Yunnan Province (No.202305AF150030)。
文摘The first hemiterpene-quassinoid adducts,bruquass A and B(1 and 2),were rapidly isolated and identified from Brucea javanica using an integrated analytical strategy.They possessed unusual carbon skeletons formed by the coupling of quassinoids with hemiterpene units via vinylogous aldol reactions.Their structural configurations were determined through comprehensive spectroscopic analysis and electronic circular dichroism(ECD) calculations.Plausible biosynthetic pathways for 1 and 2 were proposed,and guided by these biogenetic insights,the biomimetic synthesis of compound 1 was successfully achieved.Furthermore,compounds 1 and 2 exhibited significant antifeedant activity against Plutella xylostella.The bioactivity assessment results open up the prospects of 1 and 2 as a promising new class of botanical insecticide.
基金supported by the National Natural Science Foundation of China(Nos.82173695,82003609 and 82003743)the Guangdong Basic and Applied Basic Research Foundation(Nos.2023A1515011896 and 2020A1515110453)+1 种基金the Science and Technology Planning Project of Guangzhou City(No.2023A03J0566)the High-performance Public Computing Service Platform of Jinan University.
文摘Seven novel acylphloroglucinol-sesquiterpenoid adducts,designated as dryatraols J-P(1-7),were isolated from the rhizomes of Dryopteris atrata(Wall.ex Kunze)Ching.The structures,including absolute configurations,were elucidated using comprehensive spectroscopic data,calculated 13C Nuclear Magnetic Resonance-Diastereotopic Probability Assignment Plus(13C NMR-DP4+)probability analysis,and ECD calculations.These structures represent a rare subclass of carbon skeleton of acylphloroglucinol-sesquiterpenoid adducts with a furan ring connecting the acylphloroglucinol and sesquiterpenoid moieties.Notably,compounds 1-6 are the first reported examples of acylphloroglucinol-sesquiterpenoid adducts with dimeric acylphloroglucinol incorporated into the aristolane-or rulepidanol-type sesquiterpene,while compound 7 features a hydroxylated monomeric acylphloroglucinol motif.A preliminary evaluation of their antiviral activities revealed that compounds 1-6 exhibited more potent activities against respiratory syncytial virus(RSV)with IC50 values ranging from 0.75 to 3.12μmol·L^(-1) compared to the positive control(ribavirin).
基金supported by the National Natural Science Foundation of China (No.39860032)the Youth Science Foundation of Guangxi (No.0833097)
文摘Objective： Aflatoxin B1 （AFB1）, which can cause the formation of AFB1-DNA adducts, is a known human carcinogen. AFB1-exposure individuals with inherited susceptible carcinogen-metabolizing or repairing genotypes may experience an increased risk of genotoxicity. This study was designed to investigate whether the polymorphisms of two genes, the metabolic gene Glutathione S-transferase M1 （GSTM1） and DNA repair gene x-ray repair cross-complementing group 3 （XRCC3）, can affect the levels of AFB1-DNA adducts in Guangxi Population （n= 966） from an AFB1-exposure area. Methods： AFB1-DNA adducts were measured by ELISA, and GSTM1 and XRCC3 codon 241 genotypes were identified by PCR-RFLP. Results： The GSTM1-null genotype [adjusted odds ratio （OR） = 2.09; 95% confidence interval （CI） = 1.61-2.71] and XRCC3 genotypes with 241 Met alleles [i.e., XRCC3-TM and -MM, adjusted ORs （95% CI） were 1.43 （1.08-1.89） and 2.42 （1.13-5.22）, respectively] were significantly associated with higher levels of AFB1-DNA adducts. Compared with those individuals who did not express any putative risk genotypes as reference （OR = 1）, individuals featuring all of the putative risk genotypes did experience a significantly higher DNA-adduct levels （adjusted ORs were 2.87 for GSTM1-null and XRCC3-TM; 5.83 for GSTM1-null and XRCC3-MM）. Additionally, there was a positive joint effect between XRCC3 genotypes and long-term AFB1 exposure in the formation of AFB1-DNA adducts. Conclusion： These results suggest that individuals with susceptible genotypes GSTM1-null, XRCC3-TM, or XRCC3-MM may experience an increased risk of DNA damage elicited by AFB1 exposure.
基金supported by the National Natural Science Foundation of China (Nos.81973203 and 81973195)the Guangdong Basic and Applied Basic Research Foundation,China (No.2020A1515010841)+2 种基金the Open Program of Shenzhen Bay Laboratory (No.SZBL2021080601007)the Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) (No.SML2021SP301)the Key-Area Research and Development Program of Guangdong Province,China (No.2020B1111110003).
文摘Mulberry Diels-Alder-type adducts(MDAAs)are unique phenolic natural products biosynthetically derived from the intermolecular[4+2]-cycloaddition of dienophiles(mainly chalcones)and dehydroprenylphenol dienes,which are exclusively distributed in moraceous plants.A total of 166 MDAAs with diverse skeletons have been isolated and identified since 1980.Structurally,the classic MDAAs characterized by the chalcone-skeleton dienophiles can be divided into eight groups(Types A−H),while others with non-chalcone dienophiles or some variations of classic MDAAs are non-classic MDAAs(Type I).These compounds have attracted significant attention of natural products and synthetic chemists due to their complex architectures,remarkable biological activities,and synthetic challenges.The present review provides a comprehensive summary of the structural properties,bioactivities,and syntheses of MDAAs.Cited references were collected between 1980 and 2021 from the SciFinder,Web of Science,and China National Knowledge Internet(CNKI).
文摘Water-soluble b-alanine C60 adducts were synthesized, and the scavenging ability to superoxygen anion radical O2- and hydroxyl radical.OH were studied by autoxidation of pyrogallol and chemiluminescence, respectively. It was found thatβ-alanine C60 adducts showed an excellent efficiency in eliminating superoxygen anion radical and hydroxyl radical. The 50% inhibition concentration (IC50) for superoxygen anion radical and hydroxyl radical were 0.15 mg/mL and 0.048 mg/mL, respectively. The difference should be mainly attributed to the different scavenging mechanisms.
基金supported by the National Key R&D Program of China(No.2017YFC1703800)the Program for the National Natural Science Foundation of China(Nos.81822042,81630095)+2 种基金the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2017BT01Y036)Key-Area Research and Development Program of Guangdong Province(2020B1111110004)the High-performance Computing Platform of Jinan University.
文摘Myrcauones A-D(1-4),four new phloroglucinol-terpene adducts were isolated from the leaves of Myrciaria cauliflora.Their structures with absolute configurations were elucidated by combination of spectroscopic analysis,single crystal X-ray diffraction,and electronic circular dichroism(ECD)calculations.Compound 1 was a rearranged isobutylphloroglucinol-pinene adduct featuring an unusual 2,3,4,4a,10,11-hexahydro-1H-3,11a-methanodibenzo[b,f]oxepin backbone.Compound 4 showed moderate antibacterial activity against Gram-positive bacteria including multiresistant strains.
基金supported by the National Natural Science Foundation of China(No.21171040 and 21302019)the disguished organic project(2013JCJS01)
文摘Two novel acid-base adducts,[H2L1^2＋]（Hpbda）2（1,L1 = 1,4-di（lH-imidazol-4-yl）benzene,H2pbda = 1,4-benzenedicarboxylic acid） and[H2L2^2＋]（NO3）2（2,L2 = l,4-di（l-carboxymethyl-imidazol-4-yl）benzene）,have been prepared and characterized by single-crystal X-ray diffraction,IR spectroscopy and elemental analysis.Compound 1 crystallizes in monoclinic,space group P21/n with a = 5.3525（11）,b = 9.1471（19）,c = 19.314（4） ？,β = 92.342（3）°,V= 944.8（3） A°3,Z = 2,C16H16N6O（10）,Mr = 452.35,Dc = 1.590 g/cm^3,μ = 0.135 mm^-1,S = 1.058,F（000） = 468,the final R = 0.0661 and wR = 0.1887 for 2298 observed reflections（I〉 2σ（I））.Compound 2 crystallizes in monoclinic,space group P21/c with a = 9.6923（10）,b = 17.2950（17）,c = 7.1880（7） ？,β =94.801（2）°,V= 1200.7（2）A°3,Z = 2,C（28）H（22）N4O8,Mr = 542.50,Dc = 1.501 g/cm^3,μ = 0.112 mm^-1,S= 1.060,F（000） = 564,the final R = 0.0394 and wR = 0.1017 for 2768 observed reflections（I 〉2σ（I））.In the title compounds,both of L1 and L2 ligands act as weak base to accept protons to exhibit diprotonated H2L1^2＋ and H2L2^2＋ form,which can effectively employ as hydrogen bonding donors to combine anion moieties to form binary adducts respectively.In the crystal packing diagram of two polymers,there exist extensive noncovalent interactions including charge-transfer interactions,C（N）-H…π and N-H…O,C-H…O,O-H…O hydrogen bonding interactions between co-crystal moieties which consolidate the structures of supramolecular polymers,thus generating three-dimensional（3D） frameworks.
文摘Low levels (ng/g) of musk ketone (MK),used as a fragrance additive in the formulation of personal care products,are frequently detected in the water and other environment.Thus,aquatic organisms can be continuously exposed to MK.In this study,kinetics and dose-response assessments of 2-amino-MK (AMK) metabolite,bound to cysteine-hemoglobin (Hb) in rainbow trout,formed by enzymatic nitro-reduction of MK have been demonstrated.Trout were exposed to a single exposure of 0.010,0.030,0.10,and 0.30 mg MK/g fish.Tw...
文摘Theoretical investigation on the structures of the octacoordinated [Nd(CO3)4]5-and the nonacoordinated [Nd(CO3)4.OH2]5-complexes, using the SPARKLE parameters of the lanthanides within MOPAC, revealed that they possessed dodecahedral and square antiprismatic structures respectively with an average Nd-O distance of 0.249 nm. These structures and the Nd-O distances agreed well with those experimentally found in the crystal structures. Replacing the water molecule with a fluoride ion or a mondentatecarbonato ligand resulted in a nonacoordinated distorted square antiprismatic structures where the trans-carbonato groups were twisted. The corresponding decacoordinated structures with two fluoride ions or a bidentatecarbonato group, [Nd(CO3)4·F2]7-and [Nd(CO3)5]7-, were also investigated. In both cases considerable twisting of the transcarbonato groups was observed.
基金supported by the National Basic Research Program (973) of China (No. 2007CB407305,2008CB417201)the National High Technology Research and Development Program (863) of China (No.2007AA06A407)the National Natural Science Foundation of China (No. 20737003, 20621703, 20805057)
文摘Aristolochic acid （AA） is a known nephrotoxin and potential carcinogen, which can form covalent DNA adducts after metabolic activation in vivo and in vitro. A simple method for preparation and characterization of aristolochic acid-DNA adducts was developed. Four AA-adducts were synthesized by a direct reaction of AAI/AAII with 2′-deoxynucleosides. The reaction mixture was first cleaned-up and pre-concentrated using solid phase extraction （SPE）, and further purified by a reversed-phase high performance liquid chromatography （HPLC）. By the application of developed SPE procedure, matrices and byproducts in reaction mixture could be greatly reduced and adducts of high purity （more than 94% as indicated by HPLC） were obtained. The purified AA-DNA adducts were identified and characterized with liquid-electrospray ionization-quadrupole-time of flight-mass spectrometry （LC-ESI-Q-TOF-MS/MS） and LC-Diode array detector-fluorescence （LC-DAD-FL） analysis. This work provides a robust tool for possible large-scale preparation of AA-DNA adduct standards, which can promote the further studies on carcinogenic and mutagenic mechanism of aristolochic acids.
基金Project (No. 2004C21032) supported by the Key Technologies R &D Program of Zhejiang Province, China
文摘A simple and convenient procedure for stercoselective synthesis of （Z）-allyl selenides has been developed by a one-pot reaction of diselenides with Baylis-Hillman adducts in the presence of samarium metal-trimethylsilyl chloride under mild conditions. Presumably, the diselenides are cleaved by Sm/TMSCI system to form selemde anions, which then undergo SN2＇ substitution of Baylis-Hillman adducts to produce the （Z）-allyl selenides.
文摘Deconjugation of cyclopent-2-enone aldols were attempted under various conditions, and the desired deconjugated product was achieved via dianion approach. Various results obtained in this study are explained by structure and transition state analysis.
基金This work was supported by the Science Foundation of Jinan University (639)
文摘The B3LYP/6-31G^＊ level of theory was used for the optimization of nonclassical platinum drugs with planar aromatic heterocycle ligands in addition to their monoaqua species, diaqua species and monofunctional adducts. Single point calculations were performed on optimized geometries using the MP2/6-31G^＊＊ method, and the Lanl2dz pseudo potential for the Pt atom remained constant in all calculations. It can be easily seen that the trans effect can influence both geometrical structures and bond dissociating energies （BDEs）. On the basis of our calculation, we get that the long-lived monofunctional adducts with chloride ligand may be in existence, because they possessed higher stability energies, easily dissociated chloride compared with the monoaqua species dissociating chloride and that replacement of the first chloride by bases became exothermic in solution. Our calculated results also demonstrate that the strongest H-bonds appear in the complexes of q-wG and t-wG using different methods. In comparison with adenine complexes, the corresponding guanine complexes possess larger interaction energies as well as higher stability energies either corrected by basis set superposition error （bsse） of Boys-Bernardi counterpoise method or uncorrected both in gas phase and in solution with one exception that the stability energy of q-CIA complex in solution is larger than that of q,CIG complex. Finally, the nature of bond was analyzed in terms of partial charges distribution based on NBO population.
文摘A laser flash photolysis study of the reactivity of Cl˙with glyoxal, glyoxal mono- and dibisulfite adducts, 1-hydroxy-2, 2-diol-ethanesulfonate and 1, 2-dihydroxy-1, 2-ethanedi sulfonate in the aqueous phase was carried out. The obtained rate constants can be used for atmospheric modeling.
文摘Objective. DNA modification fixed as mutations in the cells may be an essential factor in the initiation step of chemical carcinogenesis. In order to explore the mechanism of gene mutation and cell transformation induced by glycidyl methacrylate (GMA), the current test studied the characteristics of GMA DNA adducts formation in vitro. Methods. In vitro test, dAMP, dCMP, dGMP, dTMP and calf thymus DNA were allowed to react with GMA (Glycidyl Methacrylate). After the reaction, the mixtures were detected by UV and subjected to reversed phase HPLC on ultrasphere ODS reversed phase column, the reaction products were eluted with a linear gradients of methanol (solvent A) and 10mmol/L ammonium formate, pH5 0 (solvent B). The synthesized adducts were then characterized by UV spectroscopy in acid (pH1 0), neutral (pH7 2), alkaline (pH11 0) and by mass spectroscopy. Results. The results showed that GMA could bind with dAMP, dCMP, dGMP and calf thymus DNA by covalent bond, and the binding sites were specific (N 6 of adenine, N 3 of cytosine). Meanwhile, a main GMA DNA adduct in the reaction of GMA with calf thymus DNA was confirmed as N 3 methacrylate 2 hydroxypropy1 dCMP. Conclusions. GMA can react with DNA and /or deoxynucleotide monophosphate and generate some adducts such as N 6 methacrylate 2 hydroxypropyl dAMP and N 3 methacrylate 2 hydroxypropyl dCMP, ets. Formation of GMA DNA adducts is an important molecular event in gene mutation and cell transformation induced by GMA.
文摘Substantial data have been generated during the past 5 years in both experimental systems and human populations which shed light on the potential role of carcinogen-macromolecular adducts in human cancer risk assessment. The use of DNA and protein adducts is based on the fundamental concept in chemical carcinogenesis that most genotoxins are metabolized to electrophilic 'ultimate' carcinogens that are capable of forming covalent adducts with cellular macromolecules. This report examines the relative usefulness and limitations of using DNA and protein adducts and related techniques for assessing human exposure to genotoxic carcinogens. Data discussed in this report clearly demonstrate that these biomarkers not only allow early detection of potential cancer hazard in humans, but they can also significantly increase the power of conventional cancer epidemiological studies in determining true causal relationships. In addition, such biomarkers can improve extrapolation of cancer risks from laboratory animals to humans or from one human population to another.
文摘Aliphatic α-oxo ketene cyclic dithioacetals 1 were reacted with allyl magne- sium bromide to afford the 1,2-addition products 2.Catalyzed by boron trifluoride etherate,the adducts 2 were etherified by methanol to afford the corresponding methyl ethers 3.This process provides a new method for the protection of the acid sensitive hydroxyl group in 2 under mild condition.
文摘The title of this little assay coins three new words: Pre-Chelates, Post-Adducts and Implexes. These, very daring new excursions into the scientific English language, come from the developments of Quelamycin and Sodium L-Thioproline, through our different group studies arriving to cancer reversal by a dual strategy. It is enough to read all our published materials, cites and related papers, dealing more or less with the chemistry and possible mechanism of action of these compounds, to gather somewhat what signified our monomeric-triferric-doxorubicine, as possibly one of the first Pre-Chelates and our Sodium L-Thioproline, probably as one of the first Post-Adducts. Both molecules come to the human patients with cancer blood from the exterior. After this indication, it will be proposed a seed concept of a new type of molecules, the “Implexes” in which the metals will be embraced instead of being linked.
文摘Complexes of the general formula [MBr2(TMTU)n] (where M is Mn, Fe, Co, Ni, Cu, Zn or Cd;TMTU is Tetramethylthiourea;n is 0.75, 2 or 3) were obtained by the reaction of salts and ligand in solution. The bromides were selected among several other salts because they had thermochemical data in the literature. Properties as capillary melting points;C, H, N, Br and metal contents;TG/DTG and DSC curves;and IR and electronic spectra were determined. The values of several thermodynamic parameters for the complexes were found by solution calorimetry. From them, the standard enthalpies of the metal-sulphur coordinated bonds were calculated. The standard enthalpies of the formation of the gaseous phase adducts also were estimated.
文摘The word “clusters” in scientific terminology as aggregated molecules or atoms appeared in chemistry relatively recently. The terms clusters have been used intensively since the discovery of fullerenes. The term cluster is not a new one for other branches of science such as astrophysics-star cluster, globular cluster, galaxy cluster, in biology and medicine-cancer cluster, genetic cluster, or in computing-data cluster. Adducts in chemistry were known significantly earlier. Both clusters and adducts are assemblies of atoms or molecules that are held together by weak van der Waals or London dispersion forces. Clusters are homogeneous and usually consist of one sort of atom or molecule. Clusters can also be a host for other types of atoms or molecules. Adducts usually consist of two different types of molecules, one of which is the host molecule. Both clusters and adducts are well defined by IUPAC. The present short review describes some important phenomena of these intriguing associations, which have interest for chemical extraction, separation, analysis, and for nature in general.
