RESUMO
Aristolochic acids are one of the major compounds in aristolochia plants, which are nephrotoxic and carcinogenic. A method was established for the detection and identification of aristolochic acids and their DNA adducts in four different herbs using ultra-high performance liquid chromatography-ion mobility quadrupole time-of flight mass spectrometry. Solid phase extraction conditions were optimized to improve the sensitivity of the experiment by using 40 mg of C18 as adsorbent and 100 µL ethanol as elution solvent. At a collision energy of 10-40 eV, these compounds and cleavage patterns were precisely identified and analyzed by secondary fragmentation and collision cross section values. The obtained mass spectrometry data were then analyzed by targeted metabolomics, including principal component analysis, partial least squares-discriminant analysis and hierarchical clustering analysis, and importing the samples in the established model, the confidence values can reach 0.61 and 0.76. All in all, this method can provide a useful tool for the detection of aristolochic acids and deoxyribonucleic acid adducts. In conclusion, this method was successfully used for the detection and identification of aristolochic acids and their DNA adducts.
Assuntos
Aristolochia , Ácidos Aristolóquicos , Adutos de DNA , Metabolômica , Ácidos Aristolóquicos/química , Ácidos Aristolóquicos/análise , Adutos de DNA/análise , Adutos de DNA/química , Cromatografia Líquida de Alta Pressão/métodos , Aristolochia/química , Metabolômica/métodos , Espectrometria de Massas/métodos , Extração em Fase Sólida , Análise de Componente Principal , Espectrometria de Mobilidade Iônica/métodosRESUMO
Aristolochic acids (AAs), which are a group of nitrophenanthrene carboxylic acids formed by Aristolochia plant, have become an increasing serious threat to humans due to their nephrotoxicity and carcinogenicity. Fast and accurate approaches capable of simultaneous sensing of aristolochic acids (I-IV) are vital to avoid intake of such compounds. In this research, the novel ratiometric fluorescence zinc metal-organic framework and its nanowire have been prepared. The two different coordination modes (tetrahedral configuration and twisted triangular bipyramidal configuration) within zinc metal-organic framework lead to the significant double emissions. The ratiometric fluorescence approach based on nanowire provides a broader concentration range (3.00 × 10-7~1.00 × 10-4 M) and lower limit of detection (3.70 × 10-8 M) than that based on zinc metal-organic framework (1.00 × 10-6~1.00 × 10-4 M, 5.91 × 10-7 M). The RSDs of the results are in the range 1.4-3.5% (nanowire). The density functional theory calculations and UV-Vis absorption verify that the sensing mechanism is due to charge transfer and energy transfer. Excellent spiked recoveries for AAs(I-IV) in soil and water support that nanowire is competent to simultaneously detect these targets in real samples, and the proposed approach has potential as a fluorescence sensing platform for the simultaneous detection of AAs (I-IV) in complex systems.
Assuntos
Ácidos Aristolóquicos , Limite de Detecção , Estruturas Metalorgânicas , Nanofios , Ácidos Aristolóquicos/análise , Ácidos Aristolóquicos/química , Estruturas Metalorgânicas/química , Nanofios/química , Zinco/química , Espectrometria de Fluorescência/métodos , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química , Medições Luminescentes/métodos , Corantes Fluorescentes/químicaRESUMO
Aristolochic acids (AAs) naturally occurring in the herbal genus Aristolochia are associated with a high risk of kidney failure, multiple tumors and cancers. However, approaches with high selectivity and rapidity for measuring AAs in biological samples are still inadequate. Inspired by the mechanism of AAs-induced nephrotoxicity, we designed a hybrid magnetic polymer-porous agarose (denoted as MNs@SiO2M@DNV-A), mimicking the effect of basic and aromatic residues of organic anion transporter 1 (OAT1) for efficient enriching aristolochic acid I (AA I) and aristolochic acid II (AA II) in the plasma. The monomers of vinylbenzyl trimethylammonium chloride (VBTAC), N-vinyl-2-pyrrolidinone (NVP) and divinylbenzene (DVB) were employed to construct the polymer layer, which provided a selective adsorption for AAs by multiple interactions. The porous agarose shell contributed to remove interfering proteins in the plasma samples. A magnetic solid-phase extraction (MSPE) based on the proposed composite enhanced the selectivity toward AA I and AA II in the plasma samples. In combination of HPLC analysis, the proposed method was proved to be applicable to fast and specific quantification of AAs in blood samples, which was characterized by a good linearity, high sensitivity, acceptable recovery, excellent repeatability and satisfactory reusability.
Assuntos
Ácidos Aristolóquicos , Compostos de Amônio Quaternário , Sefarose , Extração em Fase Sólida , Ácidos Aristolóquicos/química , Ácidos Aristolóquicos/isolamento & purificação , Ácidos Aristolóquicos/sangue , Sefarose/química , Extração em Fase Sólida/métodos , Compostos de Amônio Quaternário/química , Cromatografia Líquida de Alta Pressão/métodos , Porosidade , Limite de Detecção , Animais , Humanos , Polímeros/química , Adsorção , Reprodutibilidade dos TestesRESUMO
Bitter taste receptors, particularly TAS2R14, play central roles in discerning a wide array of bitter substances, ranging from dietary components to pharmaceutical agents1,2. TAS2R14 is also widely expressed in extragustatory tissues, suggesting its extra roles in diverse physiological processes and potential therapeutic applications3. Here we present cryogenic electron microscopy structures of TAS2R14 in complex with aristolochic acid, flufenamic acid and compound 28.1, coupling with different G-protein subtypes. Uniquely, a cholesterol molecule is observed occupying what is typically an orthosteric site in class A G-protein-coupled receptors. The three potent agonists bind, individually, to the intracellular pockets, suggesting a distinct activation mechanism for this receptor. Comprehensive structural analysis, combined with mutagenesis and molecular dynamic simulation studies, elucidate the broad-spectrum ligand recognition and activation of the receptor by means of intricate multiple ligand-binding sites. Our study also uncovers the specific coupling modes of TAS2R14 with gustducin and Gi1 proteins. These findings should be instrumental in advancing knowledge of bitter taste perception and its broader implications in sensory biology and drug discovery.
Assuntos
Ácidos Aristolóquicos , Colesterol , Ácido Flufenâmico , Receptores Acoplados a Proteínas G , Paladar , Humanos , Ácidos Aristolóquicos/metabolismo , Ácidos Aristolóquicos/química , Ácidos Aristolóquicos/farmacologia , Sítios de Ligação/efeitos dos fármacos , Colesterol/química , Colesterol/metabolismo , Colesterol/farmacologia , Microscopia Crioeletrônica , Ácido Flufenâmico/química , Ácido Flufenâmico/metabolismo , Ácido Flufenâmico/farmacologia , Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP/química , Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP/metabolismo , Ligantes , Modelos Moleculares , Simulação de Dinâmica Molecular , Mutação , Receptores Acoplados a Proteínas G/agonistas , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Receptores Acoplados a Proteínas G/ultraestrutura , Paladar/efeitos dos fármacos , Paladar/fisiologia , Transducina/química , Transducina/metabolismoRESUMO
Aristolochic acids I and II (AA-I/II) are carcinogenic principles of Aristolochia plants, which have been employed in traditional medicinal practices and discovered as food contaminants. While the deleterious effects of AAs are broadly acknowledged, there is a dearth of information to define the mechanisms underlying their carcinogenicity. Following bioactivation in the liver, N-hydroxyaristolactam and N-sulfonyloxyaristolactam metabolites are transported via circulation and elicit carcinogenic effects by reacting with cellular DNA. In this study, we apply DNA adduct analysis, X-ray crystallography, isothermal titration calorimetry, and fluorescence quenching to investigate the role of human serum albumin (HSA) in modulating AA carcinogenicity. We find that HSA extends the half-life and reactivity of N-sulfonyloxyaristolactam-I with DNA, thereby protecting activated AAs from heterolysis. Applying novel pooled plasma HSA crystallization methods, we report high-resolution structures of myristic acid-enriched HSA (HSAMYR) and its AA complexes (HSAMYR/AA-I and HSAMYR/AA-II) at 1.9 Å resolution. While AA-I is located within HSA subdomain IB, AA-II occupies subdomains IIA and IB. ITC binding profiles reveal two distinct AA sites in both complexes with association constants of 1.5 and 0.5 · 106 M-1 for HSA/AA-I versus 8.4 and 9.0 · 105 M-1 for HSA/AA-II. Fluorescence quenching of the HSA Trp214 suggests variable impacts of fatty acids on ligand binding affinities. Collectively, our structural and thermodynamic characterizations yield significant insights into AA binding, transport, toxicity, and potential allostery, critical determinants for elucidating the mechanistic roles of HSA in modulating AA carcinogenicity.
Assuntos
Ácidos Aristolóquicos , Albumina Sérica Humana , Ácidos Aristolóquicos/metabolismo , Ácidos Aristolóquicos/química , Humanos , Cristalografia por Raios X , Albumina Sérica Humana/metabolismo , Albumina Sérica Humana/química , Adutos de DNA/metabolismo , Adutos de DNA/química , Ligação Proteica , Ácido Mirístico/metabolismo , Ácido Mirístico/químicaRESUMO
Air pollution, tobacco smoke, and red meat are associated with renal cell cancer (RCC) risk in the United States and Western Europe; however, the chemicals that form DNA adducts and initiate RCC are mainly unknown. Aristolochia herbaceous plants are used for medicinal purposes in Asia and worldwide. They are a significant risk factor for upper tract urothelial carcinoma (UTUC) and RCC to a lesser extent. The aristolochic acid (AA) 8-methoxy-6-nitrophenanthro-[3,4-d]-1,3-dioxolo-5-carboxylic acid (AA-I), a component of Aristolochia herbs, contributes to UTUC in Asian cohorts and in Croatia, where AA-I exposure occurs from ingesting contaminated wheat flour. The DNA adduct of AA-I, 7-(2'-deoxyadenosin-N6-yl)-aristolactam I, is often detected in patients with UTUC, and its characteristic A:T-to-T:A mutational signature occurs in oncogenes and tumor suppressor genes in AA-associated UTUC. Identifying DNA adducts in the renal parenchyma and pelvis caused by other chemicals is crucial to gaining insights into unknown RCC and UTUC etiologies. We employed untargeted screening with wide-selected ion monitoring tandem mass spectrometry (wide-SIM/MS2) with nanoflow liquid chromatography/Orbitrap mass spectrometry to detect DNA adducts formed in rat kidneys and liver from a mixture of 13 environmental, tobacco, and dietary carcinogens that may contribute to RCC. Twenty DNA adducts were detected. DNA adducts of 3-nitrobenzanthrone (3-NBA), an atmospheric pollutant, and AA-I were the most abundant. The nitrophenanthrene moieties of 3-NBA and AA-I undergo reduction to their N-hydroxy intermediates to form 2'-deoxyguanosine (dG) and 2'-deoxyadenosine (dA) adducts. We also discovered a 2'-deoxycytidine AA-I adduct and dA and dG adducts of 10-methoxy-6-nitro-phenanthro-[3,4-d]-1,3-dioxolo-5-carboxylic acid (AA-III), an AA-I isomer and minor component of the herbal extract assayed, signifying AA-III is a potent kidney DNA-damaging agent. The roles of AA-III, other nitrophenanthrenes, and nitroarenes in renal DNA damage and human RCC warrant further study. Wide-SIM/MS2 is a powerful scanning technology in DNA adduct discovery and cancer etiology characterization.
Assuntos
Ácidos Aristolóquicos , Carcinoma de Células Renais , Carcinoma de Células de Transição , Neoplasias Renais , Neoplasias da Bexiga Urinária , Ratos , Animais , Humanos , Adutos de DNA , Carcinoma de Células Renais/patologia , Carcinoma de Células de Transição/patologia , Farinha/análise , Neoplasias da Bexiga Urinária/patologia , Triticum , Ácidos Aristolóquicos/química , DNA , Rim/patologia , Neoplasias Renais/induzido quimicamente , Neoplasias Renais/patologia , Fígado/química , Ácidos Carboxílicos , Carcinógenos/químicaRESUMO
Aristolochic acid, a substance in herbs, is highly nephrotoxic, so it is crucial to develop an assay that can rapidly and accurately analyze its content. In this study, bowl-shaped hollow carbon spheres (BHCs) were synthesized using a complex template method, and a MoS2 layer was grown in situ on their surface using a hydrothermal method. The synthesized MoS2-BHCs were used to fabricate an electrochemical sensor for the ultrasensitive and highly selective detection of aristolochic acids (AAs). The optimal conditions for AA detection were determined by tailoring the amount of MoS2 used to modify the BHCs and the pH of the electrolyte. Under optimal conditions, the MoS2-BHC-based sensor presented excellent AA detection performance. The linear concentration ranges of the MoS2-BHC-based sensor for the detection of AA were 0.05-10 µmol L-1 and 10-80 µmol L-1, and the limit of detection of the sensor was 14.3 nmol L-1. Moreover, the MoS2-BHC-based sensor detected AA in Aristolochia and Asarum sieboldii samples. The results were consistent with high-performance liquid chromatography data, demonstrating the satisfactory recovery and accuracy of the sensor. Therefore, we believe that MoS2-BHC-based sensors can be used as effective platforms for detecting AA in traditional Chinese herbs.
Assuntos
Antineoplásicos , Ácidos Aristolóquicos , Molibdênio/química , Ácidos Aristolóquicos/análise , Ácidos Aristolóquicos/química , Carbono , Cromatografia Líquida de Alta Pressão/métodosRESUMO
Aristolochic acids (AAs) are naturally occurring genotoxic carcinogens linked to Balkan endemic nephropathy and aristolochic acid nephropathy. Aristolochic acid I and II (AA-I and AA-II) are the most abundant AAs, and AA-I has been reported to be more genotoxic and nephrotoxic than AA-II. This study aimed to explore metabolic differences underlying the differential toxicity. We developed a novel microdialysis sampling coupled with solid-phase extraction liquid chromatography-tandem mass spectrometry (MD-SPE-LC-MS/MS) to simultaneously study the toxicokinetics (TK) of AA-I and AA-II and their corresponding aristolactams (AL-I and AL-II) in the blood of Sprague Dawley rats co-treated with AA-1 and AA-II. Near real-time monitoring of these analytes in the blood of treated rats revealed that AA-I was absorbed, distributed, and eliminated more rapidly than AA-II. Moreover, the metabolism efficiency of AA-I to AL-I was higher compared to AA-II to AL-II. Only 0.58% of AA-I and 0.084% of AA-II was reduced to AL-I and AL-II, respectively. The findings are consistent with previous studies and support the contention that differences in the in vivo metabolism of AA-I and AA-II may be critical factors for their differential toxicities.
Assuntos
Ácidos Aristolóquicos , Nefropatia dos Bálcãs , Nefropatias , Ratos , Animais , Cromatografia Líquida/métodos , Ácidos Aristolóquicos/toxicidade , Ácidos Aristolóquicos/química , Espectrometria de Massas em Tandem/métodos , Ratos Sprague-Dawley , Microdiálise , ToxicocinéticaRESUMO
Aristolochic acids are known for nephrotoxicity, and implicated in multiple cancer types such as hepatocellular carcinomas demonstrated by recent studies. Natural products that are analogues to aristolochic acids have been constantly isolated from organisms; a larger chemical space of these compounds and a wider coverage of biological sources should be determined in consideration of the potential hazard of aristolochic acid analogues and the wide distribution of their biological sources in the nature. Therefore, we carried out an in silico research of naturally occurring aristolochic acid analogues and their biological sources, as a supplement to existing studies. The result shows a chemical space of 238 naturally occurring aristolochic acid analogues that are present in 175 species of biological sources including 44 traditional medicines. With the computational estimation for toxicity and the implication in hazard assessment of a biological source with the presence of aristolochic acid analogues, we propose that additional awareness should be raised to the public for avoidance of toxic species, especially those that are used as herbal medicines and easily accessible.
Assuntos
Ácidos Aristolóquicos/química , Biologia Computacional/métodos , Ácidos Aristolóquicos/classificação , Ácidos Aristolóquicos/toxicidade , Avaliação Pré-Clínica de Medicamentos , Filogenia , Eletricidade Estática , Testes de Toxicidade AgudaRESUMO
Previous reports demonstrated that aristolochic acids (AAs) exposure-induced nephrotoxicity, mutations, and tumorigenesis are mainly due to aristolochic acid I (AAI). Notably, the chemical structure of aristolochic acid IVa (AAIVa), which exists at higher levels in many Aristolochiaceae herbs, is extremely similar to AAI. In lack of toxicological data, it is unknown whether AAIVa exposure leads to aristolochic acid nephropathy (AAN), mutations, and tumorigenesis as of AAI. To answer these questions, mice were administered AAIVa by single or repeated long-term gavage, while AAI was used as a positive control. We found that single gavage of 40 mg/kg of AAIVa exhibited no obvious toxicity. Also, there were no tumors or death in mice administrated with 1 and 10 mg/kg of AAIVa for 6 months followed by a 12-month recovery time. There were no noteworthy alterations in gene mutation frequency in the kidney, liver, and stomach between the AAIVa and control mice. Fascinatingly, AA-associated mutational signatures, adenine-to-thymine (A>T) transversions, were absent in AAIVa-treated mice. Nonetheless, 10 mg/kg of AAIVa triggered lymphocytic infiltration and slight fibrous hyperplasia in the kidney at the 6th month; however, these were alleviated at the 12th and 18th months. On the contrary, AAI (positive control) caused severe diffuse fibrosis, tubular atrophy, necrosis, tumors in the forestomach and kidney, and death after the 6th month. It seems that long-term AAIVa exposure induced mild renal lesions could be due to the activation of the canonical or noncanonical transforming growth factor-ß (TGFß) pathway. Overall, these findings suggest that the mutagenicity and carcinogenic risk of AAIVa are very low.
Assuntos
Ácidos Aristolóquicos/toxicidade , Nefropatias/induzido quimicamente , Animais , Ácidos Aristolóquicos/administração & dosagem , Ácidos Aristolóquicos/química , Carcinógenos/administração & dosagem , Carcinógenos/química , Carcinógenos/toxicidade , Relação Dose-Resposta a Droga , Feminino , Nefropatias/fisiopatologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Mutagênicos/administração & dosagem , Mutagênicos/química , Mutagênicos/toxicidade , Fatores de TempoRESUMO
Aristolochic acids (AAs) are a family of natural compounds with AA I and AA II being known carcinogens, whose bioactivation causes DNA adducts formation. However, other congeners have rarely been investigated. This study aimed to investigate genotoxicity of AA IVa, which differs from AA I by a hydroxyl group, abundant in Aristolochiaceae plants. AA IVa reacted with 2'-deoxyadenosine (dA) and 2'-deoxyguanosine (dG) to form three dA and five dG adducts as identified by high-resolution mass spectrometry, among which two dA and three dG adducts were detected in reactions of AA IVa with calf thymus DNA (CT DNA). However, no DNA adducts were detected in the kidney, liver, and forestomach of orally dosed mice at 40 mg/kg/day for 2 days, and bone marrow micronucleus assay also yielded negative results. Pharmacokinetic analyses of metabolites in plasma indicated that AA IVa was mainly O-demethylated to produce a metabolite with two hydroxyl groups, probably facilitating its excretion. Meanwhile, no reduced metabolites were detected. The competitive reaction of AA I and AA IVa with CT DNA, with adducts levels varying with pH of reaction revealed that AA IVa was significantly less reactive than AA I, probably by hydroxyl deprotonation of AA IVa, which was explained by theoretical calculations for reaction barriers, energy levels of the molecular orbits, and charges at the reaction sites. In brief, although it could form DNA adducts in vitro, AA IVa was non-genotoxic in vivo, which was attributed to its low reactivity and biotransformation into an easily excreted metabolite rather than bioactivation.
Assuntos
Ácidos Aristolóquicos/toxicidade , Adutos de DNA/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , DNA/efeitos dos fármacos , Animais , Ácidos Aristolóquicos/administração & dosagem , Ácidos Aristolóquicos/química , Carcinógenos/administração & dosagem , Carcinógenos/química , Carcinógenos/toxicidade , Concentração de Íons de Hidrogênio , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Testes para Micronúcleos , Testes de MutagenicidadeRESUMO
Aristolochic acid (AA) has been reported to cause a series of health problems, including aristolochic acid nephropathy and liver cancer. However, AA-containing herbs are highly safe in combination with berberine (Ber)-containing herbs in traditional medicine, suggesting the possible neutralizing effect of Ber on the toxicity of AA. In the present study, in vivo systematic toxicological experiments performed in zebrafish and mice showed that the supramolecule self-assembly formed by Ber and AA significantly reduced the toxicity of AA and attenuated AA-induced acute kidney injury. Ber and AA can self-assemble into linear heterogenous supramolecules (A-B) via electrostatic attraction and π-π stacking, with the hydrophobic groups outside and the hydrophilic groups inside during the drug combination practice. This self-assembly strategy may block the toxic site of AA and hinder its metabolism. Meanwhile, A-B linear supramolecules did not disrupt the homeostasis of gut microflora as AA did. RNA-sequence analysis, immunostaining, and western blot of the mice kidney also showed that A-B supramolecules almost abolished the acute nephrotoxicity of AA in the activation of the immune system and tumorigenesis-related pathways.
Assuntos
Ácidos Aristolóquicos/toxicidade , Berberina/uso terapêutico , Medicamentos de Ervas Chinesas/toxicidade , Nefropatias/prevenção & controle , Substâncias Macromoleculares/uso terapêutico , Animais , Ácidos Aristolóquicos/química , Berberina/química , Interações Medicamentosas , Medicamentos de Ervas Chinesas/química , Disbiose/prevenção & controle , Microbioma Gastrointestinal/efeitos dos fármacos , Expressão Gênica/efeitos dos fármacos , Rim/efeitos dos fármacos , Rim/metabolismo , Rim/patologia , Nefropatias/induzido quimicamente , Nefropatias/patologia , Células Matadoras Naturais/efeitos dos fármacos , Substâncias Macromoleculares/química , Substâncias Macromoleculares/toxicidade , Masculino , Camundongos Endogâmicos C57BL , Neutrófilos/efeitos dos fármacos , Fator de Transcrição RelA/metabolismo , Peixe-Zebra , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
Aristolochic acid analogues (AAAs), naturally existing in herbal Aristolochia and Asarum genera, were once widely used in traditional pharmacopeias because of their anti-inflammatory properties, but lately they were identified as potential nephrotoxins and mutagens. A method for rapid characterization of AAAs in serum was developed using ion mobility spectrometry coupled with mass spectrometry (IMS-MS). Five AAAs, containing four aristolochic acids and one aristolactam, were separated and identified within milliseconds. AAAs were separated in gas phase based on the difference of their ion mobility (K0), and then identified based on their K0 values, m/z, and product ions from MS/MS. Quantitative analysis of AAAs was performed using an internal standard with a satisfactory sensitivity. Limits of detection (signal-to-noise = 3) and quantification (signal-to-noise = 10) were 1-5 ng/mL and 3-8 ng/mL, respectively. The method was validated and successfully applied to the pharmacokinetics study of AAAs in rats, offering a promising way for fast screening and evaluation of AAAs in biological samples.
Assuntos
Ácidos Aristolóquicos/sangue , Animais , Aristolochia/química , Ácidos Aristolóquicos/química , Asarum/química , Medicamentos de Ervas Chinesas/química , Medicamentos de Ervas Chinesas/farmacocinética , Espectrometria de Mobilidade Iônica/economia , Espectrometria de Mobilidade Iônica/métodos , Limite de Detecção , Masculino , Mutagênicos/química , Mutagênicos/farmacocinética , Ratos Sprague-DawleyRESUMO
Aristolochic acid â is a nephrotoxic compound and exist in some traditional Chinese medicines at trace level. Up to now, specific enrichment of aristolochic acid â remains important procedure and key problem in its analysis. In this study, melamine was proposed as the recognition unit and grafted on the surface of metal-organic framework to fabricate a specific material for aristolochic acid â . This material was prepared by using a two-step strategy and the preparation process was optimized. The physical and chemical properties were investigated using scanning electron microscopy, Fourier-transfer infrared spectroscopy, X-ray diffraction and nitrogen adsorption-desorption techniques. Adsorption properties were evaluated by binding experiments. The melamine modified material exhibited a uniform morphology, high specific surface area (460.20 m2 g-1), high adsorption capacity (25.57 mg g-1), fast mass transfer rate and excellent selectivity. Further, a specific and sensitive method was established by using this material as adsorbent of mini-solid phase extraction. The limit of detection was as low as 0.02 µg mL-1. Therefore, melamine modified metal-organic framework is an ideal adsorbent for the recognition and enrichment of aristolochic acid â .
Assuntos
Ácidos Aristolóquicos , Estruturas Metalorgânicas/química , Extração em Fase Sólida/métodos , Triazinas/química , Ácidos Aristolóquicos/análise , Ácidos Aristolóquicos/química , Ácidos Aristolóquicos/isolamento & purificação , Medicamentos de Ervas Chinesas/química , Limite de Detecção , Medicina Tradicional ChinesaRESUMO
A novel aristololactam alkaloid, dasymalactam A (1), together with nine known analogues (2-10), were isolated from the roots of Dasymaschalon rostratum. Their structures were elucidated by IR, NMR and MS spectrums and comparisons with data reported in the literature. All compounds demonstrated weak cytotoxicity against Hela, MCF-7, A-549, MGC-803, and COLO-205 human cancer cell lines.
Assuntos
Alcaloides/isolamento & purificação , Annonaceae/química , Ácidos Aristolóquicos/isolamento & purificação , Raízes de Plantas/química , Alcaloides/química , Alcaloides/farmacologia , Ácidos Aristolóquicos/química , Ácidos Aristolóquicos/farmacologia , Linhagem Celular Tumoral , Doxorrubicina/farmacologia , Humanos , Concentração Inibidora 50RESUMO
A molecularly imprinted ratiometric fluorescent probe (MIRF probe) was synthesized for the determination of aristolochic acid I (AAI) based on the Schiff-base fluorescent compound N,N'-bis(o-carboxybenzylidene)-p-4,4'-diaminobiphenyl (BDDB). The BDDB was immobilized in the silica nanoparticle (BDDB@SiO2) as an internal standard material. The blue-emitting BDDB@SiO2 and the yellow-emitting carbon quantum dots (y-CDs) were wrapped in the molecularly imprinted polymer (MIP) to provide a reliable reference signal at 440 nm and a fluorescent response signal at 530 nm at the excitation wavelength of 365 nm, respectively. In the preparation of the MIP of the MIRF probe, 4-vinylbenzoic acid as the functional monomer and AAI as the template molecule were used. An imprinting factor of 2.25 was obtained. Under the optimum conditions, the fluorescent response signal at 530 nm was quenched gradually by AAI in the range 1.0 to 120.0 µmol/L, while the reference signal at 440 nm remained unchanged. The limit of detection was 0.45 µmol/L, and the fluorescent color of the MIRF probe changed gradually from yellow to green to blue, which illustrated that the developed probe had a specific AAI recognition ability, a good anti-interference ability, and a sensitively visual determination ability. The probe was successfully applied to the AAI determination in traditional Chinese medicine (TCM) Asarum. The results showed that it had satisfactory recoveries (95.5-107.3%) and low relative standard deviations (2.0%). Furthermore, this method has a potential for the onsite naked eye determination of AAI in TCM samples.Graphical abstract.
Assuntos
Ácidos Aristolóquicos/química , Corantes Fluorescentes/química , Impressão Molecular/métodos , Reprodutibilidade dos Testes , Espectrometria de FluorescênciaRESUMO
Exposure to aristolochic acid I and II (AAI and AAII) has been implicated in aristolochic acid nephropathy and urothelial carcinoma. The toxicological effects of AAs are attributed to their ability to form aristolacatam (AL)-purine DNA adducts. Among these lesions, the AL-adenine (ALI-N6-A and ALII-N6-A) adducts cause the "signature" A â T transversion mutations associated with AA genotoxicity. To provide the currently missing structural basis for the induction of these signature mutations, the present work uses classical all-atom molecular dynamics simulations to examine different (i.e., preinsertion, insertion, and postextension) stages of replication past the most abundant AA adduct (ALI-N6-A) by a representative lesion-bypass DNA polymerase (Dpo4). Our analysis reveals that, before dNTP incorporation (i.e., preinsertion step), ALI-N6-A adopts a nearly planar conformation at the N6-linkage and the ALI moiety intercalates within the DNA helix. Since this conformation occupies the dNTP binding site, the same planar lesion conformation results in a significant distortion of the polymerase active site at the insertion step and therefore replication will likely not be successful. However, if ALI-N6-A undergoes a small conformational change to introduce non-planarity at the N6-linkage during the insertion step, minimal distortion occurs in the Dpo4 active site upon incorporation of dATP. This insertion and subsequent extension would initially lead to A:A mismatches and then result in A â T transversion mutations during the second round of replication. In contrast, if a large conformation flip of the ALI moiety occurs at the insertion step to reorient the bulky moiety from an intercalated position into the major groove, dTTP (non-mutagenic) incorporation will be favored. Molecular dynamics (MD) simulations on postextension complexes reveal that damaged DNA will likely further rearrange during later replication steps to acquire a base-displaced intercalated conformation that is similar to that previously reported for (unbound) ALI-N6-A adducted DNA, with the exception of slight non-planarity at the lesion site. Overall, our results provide a structural explanation for both the successful non-mutagenic lesion bypass and the preferential misincorporation of dATP opposite ALI-N6-A and thereby rationalize the previously reported induction of A â T signature transversion mutations associated with AAs. This work should thereby inspire future biochemical experiments and modeling studies on the replication of this important class of DNA lesions by related human translesion synthesis polymerases.
Assuntos
Ácidos Aristolóquicos/química , Adutos de DNA/química , DNA Polimerase Dirigida por DNA/química , Simulação de Dinâmica Molecular , Ácidos Aristolóquicos/genética , Ácidos Aristolóquicos/metabolismo , Adutos de DNA/genética , Adutos de DNA/metabolismo , Replicação do DNA/genética , DNA Polimerase Dirigida por DNA/metabolismo , Teoria da Densidade Funcional , Humanos , Estrutura Molecular , MutaçãoRESUMO
Aristolochic acids (AAs), the major components in Aristolochia manshuriensis Kom stems (AMK), may cause Chinese herb nephropathy during clinical application. Therefore, it is necessary to distinguish AMK from other herbs and Chinese medicines using AAs with high purity as standards. So, an efficient method for separation and purification of AAs is required because of their similar structures. In this study, six AAs with purities of >98% were obtained by pH-zone-refining counter-current chromatography (PZRCCC) in a single run. The optimum two-phase solvent system was petroleum ether-ethyl acetate-methanol-water (3:7:3:7, v/v). Triethylamine (10â¯mM) was added to the aqueous mobile phase and trifluoroacetic acid (10â¯mM) to the organic stationary phase. As a result, 9.7â¯mg aristolochic acid IIIa, 12.0â¯mg aristolochic acid IVa, 32.2â¯mg aristolochic acid II, 103.7â¯mg aristolochic acid I, 24.6â¯mg aristolic acid II, and 26.1â¯mg aristolic acid I were obtained from 800â¯mg AAs crude extract. The elution order of AAs during PZRCCC separation corresponded with the pKa values and hydrophobicities of the target compounds. PZRCCC is an efficient method for isolation of AAs with similar structures.
Assuntos
Aristolochia/química , Ácidos Aristolóquicos/isolamento & purificação , Distribuição Contracorrente/métodos , Ácidos Aristolóquicos/química , Concentração de Íons de Hidrogênio , Extratos Vegetais/química , Caules de Planta/química , Solventes/químicaRESUMO
"Chiniy-tref" (CT) is a traditional preparation used in folk medicine in Martinique Island (French West Indies) that is nowadays mainly taken orally to prevent or act against any "manifestation of evil". CT is easily prepared at home by macerating larvae of the endemic swallowtail Battus polydamas (ssp.) cebriones (Dalman, 1823), sometimes accompanied by a leaf of its host-plant Aristolochia trilobata L., in commercial rum. We have previously reported the detection of nephrotoxic and carcinogenic aristolochic acids (AAs) I and II in CT, leading the Regional Health Agency (ARS) of Martinique to issue an alert regarding the potential risks associated with its consumption in 2015. In order to complete the toxicity risk assessment for oral consumption of CT, a full qualitative analysis of AAs and their analogues (AAAs) was performed, as well as a quantitative determination of the major AAs, namely AAs I and II. The phytochemical profiling of AAAs present in CT, that also corresponds to that of B. polydamas cebriones larvae feeding on A. trilobata, has been established for the first time by ultra-high performance liquid chromatography/electrospray ionization quadrupole time of-flight tandem mass spectrometry. AAs I and II were quantified in a small panel of tinctures by using a validated UHPLC/UV method, allowing us to estimate the probable daily intakes of these toxins by CT consumers. The results proved the existence of a real risk of renal toxicity and carcinogenicity associated with the chronic oral consumption of CT in Martinique, and more generally of similar "snake bottles" throughout the Caribbean.
Assuntos
Aristolochia/química , Ácidos Aristolóquicos/análise , Borboletas/química , Medicina Tradicional , Animais , Ácidos Aristolóquicos/química , Larva/química , Martinica , Toxinas Biológicas/análise , Toxinas Biológicas/químicaRESUMO
An understanding of the fate of organic compounds originating from plants in soil is crucial for determining their persistence and concentrations in the environment. Aristolochic acids are believed to be the causal agents that induce Balkan endemic nephropathy by food contamination through soil adsorption of humic acids, major components of soil. Aristolochic acids are active chemicals in Aristolochia plant species found in endemic villages. In this article, molecular structure interactions between 18 structures of aristolochic acids with an inserted humic acid structure were studied. These structures were optimized in vacuo and by periodic box simulation with water solvate using the computational molecular mechanics MM+ method with HyperChem software. The QSPR models were used for correlation of the relationship between the hydrophobicity values of 18 AA structures coupled with a HA structure by MM+ and QSAR+ properties. Computational hydrophobicity values were considered dependent variables and were related to the structural features obtained by molecular and quantum mechanics calculations by multiple linear regression approaches. The obtained model was validated, and the results indicated differing hydrophobicity between the MM+ and QSAR+ properties.