Liquid Chromatography-High-Resolution Mass Spectrometry (LC-HRMS) Analysis Following Voluntary Carvedilol Poisoning in a Subject with Cirrhosis: A Case Report.

Accidental or intentional carvedilol poisoning is rarely reported. Here, we describe a case of attempted suicide with a large quantity of immediate-release carvedilol (75 mg) and alcohol. In order to determine the kinetics, liquid chromatography-high-resolution mass spectrometry analyses were performed. The results for the plasma concentration of carvedilol were 906 µg/L 3 h after ingestion, 288 µg/L 12 h after ingestion and 103 µg/L 24 h after ingestion. A one-compartment model with linear and first order best described the elimination of the carvedilol, and the estimated half-life was 5.8 h. The result 3 h after ingestion represented the highest concentration ever observed for this drug. However, the patient was cirrhotic, and liver function was impaired with decreased Factor V (45%) and prothrombin ratio (61%). These conditions may explain the high concentrations of carvedilol. The patient was treated with glucagon and discharged from the hospital the following day.

Co-rotating twin screw process for continuous manufacturing of solid crystal suspension: A promising strategy to enhance the solubility, permeation and oral bioavailability of Carvedilol.

Background: In the current work, co-rotating twin-screw processor (TSP) was utilized to formulate solid crystal suspension (SCS) of carvedilol (CAR) for enhancing its solubility, dissolution rate, permeation and bioavailability using mannitol as a hydrophilic carrier. Methods: In-silico molecular dynamics (MD) studies were done to simulate the interaction of CAR with mannitol at different kneading zone temperatures (KZT). Based on these studies, the optimal CAR: mannitol ratios and the kneading zone temperatures for CAR solubility enhancement were assessed. The CAR-SCS was optimized utilizing Design-of-Experiments (DoE) methodology using the Box-Behnken design. Saturation solubility studies and in vitro dissolution studies were performed for all the formulations. Physicochemical characterization was performed using differential scanning calorimetry , Fourier transform infrared spectroscopy, X-ray diffraction studies, and Raman spectroscopy analysis. Ex vivo permeation studies and in vivo pharmacokinetic studies for the CAR-SCS were performed. Stability studies were performed for the DoE-optimized CAR-SCS at accelerated stability conditions at 40 ºC/ 75% RH for three months. Results: Experimentally, the formulation with CAR: mannitol ratio of 20:80, prepared using a KZT of 120 ºC at 100 rpm screw speed showed the highest solubility enhancement accounting for 50-fold compared to the plain CAR. Physicochemical characterization confirmed the crystalline state of DoE-optimized CAR-SCS. In-vitro dissolution studies indicated a 6.03-fold and 3.40-fold enhancement in the dissolution rate of optimized CAR-SCS in pH 1.2 HCl solution and phosphate buffer pH 6.8, respectively, as compared to the pure CAR. The enhanced efficacy of the optimized CAR-SCS was indicated in the ex vivo and in vivo pharmacokinetic studies wherein the apparent permeability was enhanced 1.84-fold and bioavailability enhanced 1.50-folds compared to the plain CAR. The stability studies showed good stability concerning the drug content. Conclusions: TSP technology could be utilized to enhance the solubility, bioavailability and permeation of poor soluble CAR by preparing the SCS.

UHPLC Enantiomer Resolution for the ɑ/ß-Adrenoceptor Antagonist R/S-Carvedilol and Its Major Active Metabolites on Chiralpak IB N-5.

Carvedilol (CAR), a racemic lipophilic aryloxy propanolamine, acts as a selective α1-adrenoreceptor antagonist and a nonselective ß-adrenoreceptor antagonist. CAR metabolism mainly produces three active metabolites: desmethyl carvedilol (DMC), 4'-hydroxy carvedilol (4'OHC) and 5'-hydroxy carvedilol (5'OHC). The oxidative S-(-)-metabolites contribute to the ß-antagonistic effect, yet not to the α-antagonistic effect to be observed after drug dosage. Therefore, the three ß-adrenoceptor blocking metabolites, which are structurally closely related to the parent CAR, are included into the development of a bioanalytical quantitative method for all major active species relevant with respect to adrenoceptor-blockade. Because of the given pharmacological profile, resolution of the enantiomers of carvedilol, of 4'- and 5'-hydroxy carvedilol as well as of DMC, is mandatory. The current study aims to determine the response surface for the enantiomer separation of the parent CAR as well as the major metabolites on a suitable chiral stationary phase. Design of experiment approach (DoE) was utilized in an initial screening phase followed by central-composite design for delimitation of the response surface for resolution of the four enantiomeric pairs in least run time. The impact of chromatographic variables (composition and percentage of organic modifier(s), buffer type, buffer pH, flow rate) on critical peaks resolution and adjusted retention time was evaluated, in order to select the most significant critical quality attributes. On this basis, a robust UHPLC-UV method was developed and optimized for the simultaneous, enantioselective determination of CAR along with its major active metabolites (4'OHC, 5'OHC, and DMC) on Chiralpak IBN-5. The optimized UHPLC-UV method (which includes metoprolol as the internal standard) was validated according to the ICH M10 guidelines for bioanalytical methods and proven to be linear, precise, accurate, and robust. The validated assay was applied to plasma samples from cardiovascular patients treated with rac-CAR (blood randomly drawn at different times after oral CAR intake). In order to provide more insight into the mechanism of the enantiomer separation of CAR and its metabolites on the CSP, docking experiments were performed. Molecular simulation studies suggest the chiral recognition to be mainly due to different binding poses of enantiomers of the same compound.

N-Palmitoyl Serinol Stimulates Ceramide Production through a CB1-Dependent Mechanism in In Vitro Model of Skin Inflammation.

Ceramides, a class of sphingolipids containing a backbone of sphingoid base, are the most important and effective structural component for the formation of the epidermal permeability barrier. While ceramides comprise approximately 50% of the epidermal lipid content by mass, the content is substantially decreased in certain inflammatory skin diseases, such as atopic dermatitis (AD), causing improper barrier function. It is widely accepted that the endocannabinoid system (ECS) can modulate a number of biological responses in the central nerve system, prior studies revealed that activation of endocannabinoid receptor CB1, a key component of ECS, triggers the generation of ceramides that mediate neuronal cell fate. However, as the impact of ECS on the production of epidermal ceramide has not been studied, we here investigated whether the ECS stimulates the generation of epidermal ceramides in an IL-4-treated in vitro model of skin inflammation using N-palmitoyl serinol (PS), an analog of the endocannabinoid N-palmitoyl ethanolamine. Accordingly, an IL-4-mediated decrease in cellular ceramide levels was significantly stimulated in human epidermal keratinocytes (KC) following PS treatment through both de novo ceramide synthesis- and sphingomyelin hydrolysis-pathways. Importantly, PS selectively increases ceramides with long-chain fatty acids (FAs) (C22-C24), which mainly account for the formation of the epidermal barrier, through activation of ceramide synthase (CerS) 2 and Cer3 in IL-4-mediated inflamed KC. Furthermore, blockade of cannabinoid receptor CB1 activation by AM-251 failed to stimulate the production of total ceramide as well as long-chain ceramides in response to PS. These studies demonstrate that an analog of endocannabinoid, PS, stimulates the generation of specific ceramide species as well as the total amount of ceramides via the endocannabinoid receptor CB1-dependent mechanism, thereby resulting in the enhancement of epidermal permeability barrier function.

Topical N-palmitoyl serinol, a commensal bacterial metabolite, prevents the development of epidermal permeability barrier dysfunction in a murine model of atopic dermatitis-like skin.

Recent studies have demonstrated that commensal bacterial metabolites benefit human health. Because of the crucial role of the epidermal permeability barrier in cutaneous and extracutaneous function, we assessed whether the topical applications of N-palmitoyl serinol (NPS) would improve the epidermal permeability barrier in murine skin. Our results show that the topical application of 0.5% NPS in ethanol twice daily for 1 week lowered basal transepidermal water loss rates and accelerated barrier recovery in normal mice. Moreover, topical NPS prevented the emergence of epidermal permeability barrier dysfunction in a murine model of allergic contact dermatitis. These results suggest that topical NPS could be used to prevent or treat skin disorders characterized by inflammation and an abnormal epidermal permeability barrier.

Des études récentes ont démontré que les métabolites des bactéries commensales sont bénéfiques pour la santé humaine. En raison du rôle crucial de la barrière de perméabilité épidermique dans la fonction cutanée et extra-cutanée, nous avons évalué si les applications topiques de N-palmitoyl sérinol (NPS) amélioreraient la barrière de perméabilité épidermique dans la peau murine. Nos résultats montrent que l'application topique de 0,5 % de NPS dans de l'éthanol deux fois par jour pendant 1 semaine a réduit les taux de base de perte d'eau trans-épidermique et accéléré la récupération de la barrière chez les souris normales. De plus, le NPS topique a empêché l'émergence d'un dysfonctionnement de la barrière de perméabilité épidermique dans un modèle murin de dermatite de contact allergique. Ces résultats suggèrent que le NPS topique pourrait être utilisé pour prévenir ou traiter les troubles cutanés caractérisés par une inflammation et une barrière de perméabilité épidermique anormale.(Traduit par Docteur Serge Messier).

Design, synthesis and in vitro biological evaluation of a novel class of anti-adenovirus agents based on 3-amino-1,2-propanediol.

Nowadays there is not an effective drug for the treatment of infections caused by human adenovirus (HAdV) which supposes a clinical challenge, especially for paediatric and immunosuppressed patients. Here, we describe the design, synthesis and biological evaluation as anti-adenovirus agents of a new library (57 compounds) of diester, monoester and triazole derivatives based on 3-amino-1,2-propanediol skeleton. Seven compounds (17, 20, 26, 34, 44, 60 and 66) were selected based on their high anti-HAdV activity at low micromolar concentration (IC50 from 2.47 to 5.75 µM) and low cytotoxicity (CC50 from 28.70 to >200 µM). In addition, our mechanistic assays revealed that compounds 20 and 44 might be targeting specifically the HAdV DNA replication process, and compound 66 would be targeting HAdV E1A mRNA transcription. For compounds 17, 20, 34 and 60, the mechanism of action seems to be associated with later steps after HAdV DNA replication.

A preliminary metabolites identification of a novel compound with ß-adrenolytic activity.

BACKGROUND: The identification of main metabolites and assessment of renal excretion of a novel compound with ß-adrenolytic activity (2RS)-1-(1H-indol-4-yloxy)-3-((2-(2-methoxyphenoxy)ethyl)amino)propan-2-ol, briefly called (RS)-9 or 2F109, were studied in vivo in rat serum, urine, faeces, liver, intestine, lungs and kidneys, and in vitro in rat liver microsomes. METHODS: Structures of the metabolites have been developed by comparing the high-resolution product ion mass spectra of metabolites and the parent compound based on the differences in mass values of main fragments. Quantitative analysis of (RS)-9 was done using a system of liquid chromatography coupled with a triple quadrupole mass spectrometer API 2000. Identification studies of predicted metabolites were made by a high-resolution mass spectrometer LTQ XL Orbitrap Discovery and using a Roxy™ system, for online electrochemical mimicry of oxidative metabolism by cytochrome P450s connected to QTRAP 5500. RESULTS: For (RS)-9 (m/z 357.2084) phase I metabolites derived from oxidation process: hydroxyl derivatives (m/z 373.2470) and dihydroxyl derivatives (m/z 389.4318), and phase II metabolites: N-methylated compound (m/z 371.1612), O-glucuronide (m/z 533.5118), and sulfate (m/z 437.2350) were identified. CONCLUSION: (RS)-9 was extensively metabolised to several phase I and II metabolites, and renal excretion was a minor route in its elimination.

Structure, thermotropic phase behavior and membrane interaction of N-acyl-ß-alaninols. Homologs of stress-combating N-acylethanolamines.

ß-Alaninol and its derivatives were reported to exhibit interesting biological and pharmacological activities and showed potential application in formulating drug delivery vehicles. In the present study, we report the synthesis and characterization of N-acyl-ß-alaninols (NABAOHs) bearing saturated acyl chains (n = 8-20) with respect to thermotropic phase behavior, supramolecular organization and interaction with diacylphosphatidylcholine, a major membrane lipid. Results obtained from DSC and powder XRD studies revealed that the transition temperatures (Tt), transition enthalpies (ΔHt), transition entropies (ΔSt) and d-spacings of NABAOHs show odd-even alteration. A linear dependence was observed in the values of ΔHt and ΔSt on the acyl chain length, independently for even and odd acyl chains in both dry and hydrated states; further, the even chainlength molecules exhibited higher values than the odd chainlength series. The crystals structures of N-lauroyl-ß-alaninol and N-palmitoyl-ß-alaninol, solved in monoclinic system in the P21/c space group, show that the NABAOHs adopt a tilted bilayer structure. A number of NH⋯O, O-H⋯O, and C-H⋯O hydrogen bonds between the hydroxyl and amide moieties of the head groups of NABAOH molecules belonging to adjacent and opposite layers stabilize the overall supramolecular organization of the self-assembled bilayer system. DSC studies on the interaction of N-myristoyl-ß-alaninol (NMBAOH) with dimyristoylphosphatidylcholine (DMPC) indicate that these two lipids mix well up to 45 mol% NMBAOH, whereas phase separation was observed at higher contents of NMBAOH. Transmission electron microscopic studies reveal that mixtures containing 20-50 mol% NMBAOH form stable ULVs of 90-150 nm diameter, suitable for use in drug delivery applications.

Synthesis of erythro- B13 enantiomers and stereospecific action of full set of B13-isomers in MCF7 breast carcinoma cells: Cellular metabolism and effects on sphingolipids.

B13 is an acid ceramidase (ACDase) inhibitor. The two chiral centers of this aromatic amido alcohol lead to four stereoisomers, yet we have little knowledge about its erythro- enantiomers, (1R, 2S) and (1S, 2R). In this paper, for the first time, the synthesis of two erythro- enantiomers is described, and the compounds are evaluated along with two threo- enantiomers, (1R, 2R) and (1S, 2S). The key metabolites and sphingolipid (SL) profile of the full set of B13 stereoisomers in MCF7 breast carcinoma cells are presented. The results demonstrated that the erythro- enantiomers were more effective than the threo- enantiomers on growth inhibition in MCF7 cells, although there were no statistically significant differences within the threo- and erythro- series. Measurement of intracellular levels of the compounds indicated that the erythro- seemed a little more cell permeable than the threo- enantiomers; also, the (1R, 2S) isomer with the same stereo structure as natural ceramide (Cer) could be hydrolyzed and phosphorylated in MCF7 cells. Furthermore, we also observed the formation of C16 homologs from the full set of B13 isomers within the cells, indicating the occurrence of de-acylation and re-acylation of the amino group of the aromatic alcohol. Moreover, the decrease in the Cer/Sph ratio suggests that the growth inhibition from (1R, 2S) isomer is not because of the inhibition of ceramidases. Taken together, (1R, 2S) could be developed as a substitute of natural Cer.

OH radical reactions with the hydrophilic component of sphingolipids.

In this work, using the example of model compounds, we studied the reactions resulting from the interaction of OH radicals with the hydrophilic part of sphingolipids. We compared the stopped-flow EPR spectroscopy and pulse radiolysis with optical detection methods to characterize radical intermediates formed in the reaction of OH radicals with glycerol, serinol and N-boc-serinol. Quantum chemical calculations were also performed to help interpret the observed experimental data. It was shown that H-abstraction from the terminal carbon atom is the main process that is realized for all the studied compounds. The presence of the unsubstituted amino group (-NH2) is seen to completely change the reaction properties of serinol in comparison with those observed in glycerol and N-boc serinol.

Quantification of 10 bioactive components of Yazhangsan in rat plasma by LC-MS/MS and its application.

Yazhangsan (YZS) is a common prescription for the treatment of cough and asthma caused by wind-cold. The purpose of this study was to investigate the pharmacokinetic profiles of 10 bioactive components in YZS. A simple, sensitive and reliable high-performance liquid chromatography coupled with a triple-quadruple mass spectrometry method (LC-MS/MS) was developed and fully validated in this study for the measurement of these 10 bioactive compounds in rat plasma. One-step protein precipitation method using methanol was applied to the treatment of rat plasma samples. Chromatographic separation was conducted on a C18 column by gradient elution, and water (containing 0.1% formic acid) and acetonitrile were chosen as the mobile phase. The analytes were quantified by using a mass spectrometer in multiple reaction monitoring scanning mode, and electrospray ionization was performed in positive and negative ion modes. The established method met the requirements for the quantification of these 10 bioactive compounds in biological samples, and it was successfully applied to the pharmacokinetic study of 10 components in rats after the intragastrical administration of YZS. This study will lay a foundation for the investigation of the mechanism of action of YZS and provide useful data for the rational use of YZS in clinical.

(Hetero)Aryloxyaminopropanols with N-Phenylpiperazine Structural Fragment - Review of Cardiovascular Activity.

Aryloxyphenylpiperazinylpropanols are a group of compounds exhibiting a wide range of biological activities, affecting the central nervous system and many cardiovascular mechanisms among them. As cardiovascular agents, aryloxyphenylpiperazinylpropanols work as antihypertensives, antiarrhythmics, cardiotonics or antiaggregants. The mechanism of action is almost always an α1-adrenolytic or combined α1- and ß-adrenolytic effect, but sometimes other mechanisms (e.g., Ca2+ antagonism or phosphodiesterase inhibition) can positively participate. In some cases, compounds with a small modification of the connecting chain also exhibit the desired cardiovascular effects. Several studies dealt with chirality of aryloxyphenylpiperazinylpropanols and determined the differences between the particular activities of racemic and enantiomeric compounds.

Novel propanolamine derivatives attached to 2-metoxifenol moiety: Synthesis, characterization, biological properties, and molecular docking studies.

The synthesis of seven new ß-amino alcohols was designed and performed by starting from eugenol, a natural phenolic compound known to be biologically active. The synthesized compounds were obtained in yields ranging from 54 to 81%. Molecule structures were determined with FT-IR, 1H NMR and 13C NMR spectroscopies. In addition, the inhibitory effects of these substances on acetylcholinesterase (AChE), α-glycosidase (α-Gly), human carbonic anhydrase I (hCA I), and human carbonic anhydrase II (hCA II) enzymes have been investigated. It has been seen that all compounds have a better ability to inhibit compared to existing tried inhibitors. Among these, the best inhibitor against AChE enzyme is 2b (Ki 62.08 ± 11.67 µM and IC50 90.33), and against α-Gly, 2c showed the highest effect (Ki 0.33 ± 0.08 µM and IC50 0.28). The best inhibitor against hCA I, and hCA II enzymes is compound 2f. For hCA I and hCA II, Ki value was measured as 9.68 ± 1.32 and 11.46 ± 2.64 µM and IC50 values as 7.37 and 8.26 µM respectively. The interactions of the studied new propanolamine derivatives with the enzymes were done by molecular docking calculations and their biological activities were compared to the experimental tests. Studied enzymes in molecular docking calculations are acetylcholinesterase (AChE) is PDB ID: 4M0E, α-glycosidase (α-Gly) is PDB ID: 1R47, human carbonic anhydrase isoenzyme I (hCA I) PDB ID: 3LXE is human carbonic anhydrase isoenzyme II (hCA II) is PDB ID: 5 AML.

Core-crosslinked nanomicelles based on crosslinkable prodrug and surfactants for reduction responsive delivery of camptothecin and improved anticancer efficacy.

As an important DNA topoisomerase I inhibitor in oncotherapy, camptothecin (CPT) with traditional formulation only shows a limited clinical application mainly because of its poor solubility. In this study, a novel redox responsive nanoscaled delivery system was developed to overcome the inherent defect of CPT. Firstly, a CPT prodrug (CPT-LA) and two crosslinkable surfactants (SO-LA and MPEG-LA) was synthesized, all of which contained the same lipoic acid (LA) structure. In the preparation, highly core-crosslinked structure was formed by adding a thiol crosslinker, which can induce LA ring opening polymerization and disulfide crosslinking. The resulting CPT-LA core-crosslinked nanomicelles (CPT-LA CNM) were formulated with a highly crosslinked core and a PEG hydrophilic shell. Dynamic light scattering (DLS) characterization indicated that CPT-LA CNM possessed a narrow size distribution (184.6 ± 3.6 nm) and negatively charged zeta potential (-3.5 ± 1.2 mV). The storage and physiological stabilities showed that the size distribution of CPT-LA CNM was relatively stable in both conditions which were neutral PBS at 4 °C (1 week period) and PBS containing 10% serum at 37 °C (24 h period). Moreover, the effective CPT release behavior of CPT-LA CNM was confirmed in the reducing circumstances containing dithiothreitol (DTT). Under confocal laser scanning microscopy (CLSM), CPT-LA CNM demonstrated a rapid cellular uptake behavior against cancer cells when compared to CPT suspension. Finally, the enhanced anticancer efficacy of CPT-LA CNM was also detected by in vitro cytotoxicity and cell apoptosis assay. In summary, the core-crosslinked CPT-LA CNM could be a promising CPT delivery system because of high stability, effectively controlled release as well as improved anticancer activity.

Arylaminopropanone Derivatives as Potential Cholinesterase Inhibitors: Synthesis, Docking Study and Biological Evaluation.

Neurodegenerative diseases in which the decrease of the acetylcholine is observed are growing worldwide. In the present study, a series of new arylaminopropanone derivatives with N-phenylcarbamate moiety (1-16) were prepared as potential acetylcholinesterase and butyrylcholinesterase inhibitors. In vitro enzyme assays were performed; the results are expressed as a percentage of inhibition and the IC50 values. The inhibitory activities were compared with reference drugs galantamine and rivastigmine showing piperidine derivatives (1-3) as the most potent. A possible mechanism of action for these compounds was determined from a molecular modelling study by using combined techniques of docking, molecular dynamics simulations and quantum mechanics calculations.

Chiral Fluorescent Silicon Nanoparticles for Aminopropanol Enantiomer: Fluorescence Discrimination and Mechanism Identification.

As an important chiral molecule for the preparation of levofloxacin, the optical purity of L-aminopropanol has a crucial effect on the pharmacology and pharmacodynamics of levofloxacin. Therefore, it is of great significance to discriminate D-aminopropanol and L-aminopropanol. In this paper, an effective aminopropanol enantiomer recognition method was established on the basis of the chiral fluorescent silicon nanoparticles (SiNPs) probe. The chiral fluorescent SiNPs were fabricated via a one-step aqueous solution synthesis strategy, which avoided multiple steps, pressurizing operation, and time-consuming postmodified procedures. Significantly, D-aminopropanol could significantly enhance the fluorescence of the chiral SiNPs, while L-aminopropanol could not affect the fluorescence of the chiral SiNPs. This could have occurred because of the stronger interaction between the chiral SiNPs and D-aminopropanol than that of L-aminopropanol. Thus, the rapid and selective recognition of the aminopropanol enantiomer was ideally realized. The mechanism of the chiral SiNPs recognizing aminopropanol was simulated by density functional theory quantum mechanical calculations. Interestingly, this was also proved by the separation of aminopropanol enantiomer using this chiral SiNPs-modified silica column in normal phase liquid chromatography. To the best of our knowledge, this is the first time that the chiral fluorescent SiNPs were synthesized and used to detect the aminopropanol enantiomer successfully. This work will inspire additional syntheses of chiral silicon nanomaterials and other nanomaterials with excellent properties and will enable application of chiral nanomaterials to other fields.

Incorporation of Pseudo-complementary Bases 2,6-Diaminopurine and 2-Thiouracil into Serinol Nucleic Acid (SNA) to Promote SNA/RNA Hybridization.

Serinol nucleic acid (SNA) is a promising candidate for nucleic acid-based molecular probes and drugs due to its high affinity for RNA. Our previous work revealed that incorporation of 2,6-diaminpurine (D), which can form three hydrogen bonds with uracil, into SNA increases the melting temperature of SNA-RNA duplexes. However, D incorporation into short self-complementary regions of SNA promoted self-dimerization and hindered hybridization with RNA. Here we synthesized a SNA monomer of 2-thiouracil (sU), which was expected to inhibit base pairing with D by steric hindrance between sulfur and the amino group. To prepare the SNA containing D and sU in high yield, we customized the protecting groups on D and sU monomers that can be readily deprotected under acidic conditions. Incorporation of D and sU into SNA facilitated stable duplex formation with target RNA by suppressing the self-hybridization of SNA and increasing the stability of the heteroduplex of SNA and its complementary RNA. Our results have important implications for the development of SNA-based probes and nucleic acid drugs.

A Quencher-Free Linear Probe from Serinol Nucleic Acid with a Fluorescent Uracil Analogue.

With the goal of developing a quencher-free probe composed of an artificial nucleic acid, the fluorescent nucleobase analogue 5-(perylenylethynyl)uracil (Pe U), which was incorporated into totally artificial serinol nucleic acid (SNA) as a substitute for thymine, has been synthesized. In the context of a 12-mer duplex with RNA, these fluorophores reduce duplex stability slightly compared with that of an SNA without Pe U modification; thus suggesting that structural distortion is not induced by the modification. If two Pe Us were incorporated at separate positions in an SNA, the fluorescent emission at λ≈490 nm was clearly enhanced upon hybridization with complementary RNA. A quencher-free SNA linear probe containing three Pe Us, each separated by six nucleobases, has been designed. Detection of target RNA with high sensitivity and discrimination of a single-base mismatch has also been demonstrated.

Design, Synthesis, Antibacterial Evaluation, and Induced Apoptotic Behaviors of Epimeric and Chiral 18ß-Glycyrrhetinic Acid Ester Derivatives with an Isopropanolamine Bridge against Phytopathogens.

Because only a handful of agrochemicals can manage bacterial infections, the discovery and development of innovative, inexpensive, and high-efficiency antibacterial agents targeting these infections are challenging. Herein, a series of novel epimeric and chiral 18ß-glycyrrhetinic acid (GA) ester derivatives with various tertiary amine pendants were designed, synthesized, and screened for pharmacological activity. Results showed that some of the title compounds were conferred with significantly enhanced antibacterial activity toward phytopathogens Xanthomonas oryzae pv oryzae (A2, B1-B3, and C1, EC50 values within 3.81-4.82 µg/mL) and Xanthomonas axonopodis pv citri (B1, EC50 = 3.18 µg/mL; B2, EC50 = 2.76 µg/mL). These activities are superior to those of GA (EC50 > 400 µg/mL), thiodiazole copper, and bismerthiazol. Pharmacophore studies revealed that the synergistic combination of GA skeleton and tertiary amine scaffolds contributed to the biological actions. In vivo experiments displayed their promising applications in controlling bacterial infections. Antibacterial mechanism studies revealed that the title compounds could trigger apoptosis in the tested pathogens, evident by bacteria morphological changes observed in scanning electron microscopy images. This outcome should motivate the development of various apoptosis inducers against plant bacterial diseases by a novel mode of action compared to that of existing agricultural chemicals.

Light-Responsive Serinol-Based Polyurethane Nanocarrier for Controlled Drug Release.

In the present work, a new and facile strategy for the synthesis of light-responsive polyurethanes (LrPUs) based on serinol with o-nitrobenzyl pendent groups is developed. Stable monodisperse nanoparticles from these LrPUs can be formulated reproducibly in a simple manner, which is shown by dynamic light scattering (DLS) measurements. Upon irradiation with UV light, both polymers and nanoparticles undergo rapid degradation, which is investigated by DLS, scanning electron microscopy, size exclusion chromatography, and UV-vis spectroscopy. The nanoparticles are also employed for the encapsulation of the model drug Nile Red, and by exposure to UV light, a burst release of the payload is detected via fluorescence spectroscopy. This strategy can be easily applied to the straightforward synthesis of various new serinol-based monomers with different stimuli-responsive properties and therefore expand the family of biodegradable polymers.