Design and evaluation of semicarbazide-embeddedd stationary phases for liquid chromatography

Semicarbazide, as a derivative of urea, constitutes a great variety of functional molecules for different needs. Herein, novel stationary phases with an incorporated semicarbazide group were proposed. Using aliphatic (docosanoyl, C22) and aromatic (benzoyl, Bz) hydrazides, the semicarbazide-embedded ligands were synthesized before chemical modification of the silica gel, allowing for an accurate interpretation of the chromatographic properties of the corresponding packings. The new stationary phases were water-wettable, due to the presence of highly polar groups. In particular, Bz-semicarbazide (Bz-SCD) stationary phase was sufficiently hydrophilic to run in hydrophilic interaction (HILIC) mode, whilst the C22 (C22-SCD) equivalent, in spite of its reversed-phase nature, was markedly less hydrophobic than the referenced polar-embedded ones. The versatility of C22-SCD was demonstrated with a large selection of analytes, including geometric isomers and standard mixtures of polycyclic aromatic hydrocarbons, sulfonamides, sulfonylurea, substituted ureas, pyridines and carbamates, fat-soluble colorants, antifungal metabolites, angiotensin II receptor blockers and calcium channel blockers.

Tractable Quinolone Hydrazides Exhibiting Sub-Micromolar and Broad Spectrum Antitrypanosomal Activities

Nagana and Human African Trypanosomiasis (HAT), caused by (sub)species of Trypanosoma, are diseases that impede human and animal health, and economic growth in Africa. The few drugs available have drawbacks including suboptimal efficacy, adverse effects, drug resistance, and difficult routes of administration. New drugs are needed. A series of 20 novel quinolone compounds with affordable synthetic routes was made and evaluated in vitro against Trypanosoma brucei and HEK293 cells. Of the 20 compounds, 12 had sub-micromolar potencies against the parasite (EC50 values=0.051-0.57 μM), and most were non-toxic to HEK293 cells (CC50 values>5 μM). Two of the most potent compounds presented sub-micromolar activities against other trypanosome (sub)species (T. cruzi and T. b. rhodesiense). Although aqueous solubility is poor, both compounds possess good logD values (2-3), and either robust or poor microsomal stability profiles. These varying attributes will be addressed in future reports.

Toughening Hydrogels by forming Robust Hydrazide-transition Metal Coordination Complexes

Energy dissipation based on dynamic fracture of metal ligands is one of effective means to toughen hydrogel materials for specific applications in biomedical and engineering fields. Exploration of new kinds of metal-ligand coordinates with robust bonding strength is crucial for the facile synthesis of tough gels. Reported here is a hydrogel toughening strategy based on the formation of robust coordination complexes between the hydrazide ligands and zinc ions. The resultant hydrogels exhibit high strength and toughness at room temperature. Their mechanical properties show temperature dependence due to the dynamic nature of coordination bonds. In addition, the amine group of hydrazides in the gel matrix provides reactive site for Schiff's base reaction, enabling surface modification without influence on overall mechanical performances of the gel. The hydrazide ligands are easy-synthesis and can form robust coordination with several transition metals. Such metal-ligand coordinates should be suitable to other systems to develop tough soft materials with versatile applications.

Design, synthesis, and biological activity studies on benzimidazole derivatives targeting myeloperoxidase

Myeloperoxidase (MPO) plays a key role in human antimicrobial system by oxidizing vital molecules of microorganisms in phagolysosomes through produced hypochlorous acid (HOCl). However, MPO can be released outside the phagocyte and produces reactive intermediates leading to tissue damage. MPO, as a local mediator of tissue damage, has been associated with inflammatory diseases such as renal injury, multiple sclerosis, cardiovascular and neurodegenerative diseases. Therefore, the enzyme currently draws attention as a potential therapeutic target. In this study, isomeric 1,3-dihydro-2H-benzo[d]imidazole-2-thione derivatives having amide, hydrazide and hydroxamic acid groups either on nitrogen or on sulphur atom were designed and their inhibitory activity was determined on chlorination and peroxidation cycles of MPO. Among the compounds, 2-(2-thioxo-2,3-dihydro-1H-benzo[d]imidazole-1-yl)acetohydrazide(C19) was found as the most active inhibitor on both cycles.

Hydrazides as Potential HDAC Inhibitors: Structure-activity Relationships and Biological Implications

Epigenetic modulations by HDACs are associated with multiple disease conditions. In this context, HDACs play vital roles in the progression of diseases including several cancers, neurodegenerative diseases, inflammatory diseases, and metabolic disorders. Though several HDAC inhibitors have been established as drug candidates, their usage has been restricted because of broad-spectrum inhibition, highly toxic character, and off-target adverse effects. Therefore, specific HDAC selectivity is essential to get rid of such adverse effects. Hydrazide-based compounds have already been proven to exert higher inhibitory efficacy and specific HDAC selectivity. In this article, the detailed structure-activity relationship (SAR) of the existing hydrazide-based HDAC inhibitors has been elucidated to gather crucial information that can be utilized further for the development of promising drug candidates for combating diverse diseases in the future.

Synthesis, crystal structure, and a molecular modeling approach to identify effective antiviral hydrazide derivative against the main protease of SARS-CoV-2

In the fall of 2019, a new type of coronavirus took place in Wuhan city, China, and rapidly spread across the world and urges the scientific community to develop antiviral therapeutic agents. In our effort we have synthesized a new hydrazide derivative, (E)-N'-(1-(4-bromophenyl)ethylidene)-2-(6-methoxynaphthalen-2-yl)propanehydrazide for this purpose because of its potential inhibitory proprieties. The asymmetric unit of the title molecule consists of two independent molecules differing noticeably in conformation. In the crystal, the independent molecules are linked by N-H···O and C-H···O hydrogen bonds and C-H···π(ring) interactions into helical chains extending along the b-axis direction. The chains are further joined by additional C-H···π(ring) interactions into the full 3-D structure. To obtain a structure-activity relationship, the DFT-NBO analysis is performed to study the intrinsic electronic properties of the title compound. Molecular modeling studies were also conducted to examine the binding affinity of the compound for the SARS-CoV-2 main protease enzyme and to determine intermolecular binding interactions. The compound revealed a stable binding mode at the enzyme active pocket with a binding energy value of -8.1 kcal/mol. Further, stable dynamics were revealed for the enzyme-compound complex and reported highly favorable binding energies. The net MMGBSA binding energy of the complex is -37.41 kcal/mol while the net MMPBSA binding energy is -40.5 kcal/mol. Overall, the compound disclosed the strongest bond of ing the main protease enzyme and might be a good lead for further structural optimization.

Hydrazide Derivatives for Defect Passivation in Pure CsPbI3 Perovskite Solar Cells

All-inorganic CsPbI₃ perovskite presents preeminent chemical stability and a desirable band gap as the front absorber for perovskite/silicon tandem solar cells. Unfortunately, CsPbI₃ perovskite solar cells (PSCs) still show low efficiency due to high density of defects in solution-prepared CsPbI₃ films. Herein, three kinds of hydrazide derivatives (benzoyl hydrazine (BH), formohydrazide (FH) and benzamide (BA)) are designed to reduce the defect density and stabilize the phase of CsPbI₃ . Calculation and characterization results corroborate that the carboxyl and hydrazine groups in BH form strong chemical bonds with Pb²⁺ ions, resulting in synergetic double coordination. In addition, the hydrazine group in the BH also forms a hydrogen bond with iodine to assist the coordination. Consequently, a high efficiency of 20.47 % is achieved, which is the highest PCE among all pure CsPbI₃ -based PSCs reported to date. In addition, an unencapsulated device showed excellent stability in ambient air.

Insight into the Crystal Structures and Potential of Two Newly Synthesized Naproxen-Based Hydrazide Derivatives as Potent COX-2 Inhibitors

Although nonsteroidal anti-inflammatory drugs (NSAIDs) are medicines that are widely used to relieve pain, reduce inflammation, and bring down high temperature, literature confirmed that they still have harmful side effects. Most of their side effects are in the digestive system due to the carboxylic group. As naproxen is one of the NSAIDs, in this work, we try to mask the carboxylic group in naproxen with a relatively safe functional group. So, herein, we report the synthesis of new naproxen-based hydrazones derivatives, namely, (E)-N'-1-(4-chlorophenyl)ethylidene)-2-(6-methoxynaphthalen-2-yl)propane hydrazide (4a) and (E)-N'-(4-hydroxybenzylidene)-2-(6-methoxynaphthalen-2-yl)propane hydrazide ethanol solvate (4b). The compounds were confirmed by X-ray diffraction studies. Hirshfeld surface analyses and energy frameworks of 4a and 4b have been carried out and blind molecular docking studies of them to the COX-2 enzyme were undertaken to obtain binding affinities for judging whether the compounds could act as anti-inflammatory agents. The compounds interact with the key residues: Arg120, Val349, Leu352, Tyr355, Val523, Ala527, Ser530, and Leu531 of the active enzyme pocket. Molecular dynamics studies predicted that the complexes of 4a and 4b with COX-2 are structurally stable and no major conformational changes were observed. Confirmation of the docking and simulation data was achieved by a binding free energies analysis that indicated the dominance of van der Waals energy. The compounds are drug-like molecules as they obey all prominent drug-like rules and have acceptable pharmacokinetic profiles. To investigate the relationship between their intrinsic electronic properties and their possible similarities to actual drugs, the gas-phase DFT optimizations and NBO analyses were also performed in this study.

Synthesis, Characterization, Antiproliferative Activity of Galloyl Derivatives and Investigation of Cytotoxic Properties in HepG2/C3A cells

BACKGROUND

Appropriate substituents in the galloyl group could lead to significant biological properties.

OBJECTIVE

Novel galloyl-substituted compounds bearing 2-substituted-1,3,4-oxadiazol-5-yl, 5-substituted-1,2,4-triazol-3-yl, and carboxamide groups were synthesized and evaluated for their antiproliferative activity. Additionally, galloyl hydrazide (2) was evaluated by performing cytotoxicity, membrane integrity, cell cycle, and apoptosis assays in HepG2/C3A cells.

METHOD

General procedure was used for the synthesis of galloyl-substituted (3-9, 11) and characterized by their spectroscopic data (1H and 13C NMR). The antiproliferative activity of all novel galloyl derivatives was evaluated against nine human tumors and one nontumoral cell line. Three response parameters (GI50, TGI, and LC50) were calculated. The cytotoxicity test was performed for the resazurin assay. The membrane integrity, cell cycle, and apoptosis assays were performed by flow cytometry.

RESULTS

The substitution of the methoxy group of the galloyl ring system for a carboxamide group (3, 4, 5, and 6) produced compounds with moderate antitumoral activity, particularly 6, against six human cancer cell lines, K-562, PC-3, NCI-ADR/RES, OVCAR, 786-0 and NCI-H460, with GI50 values ≤ 9.45 µg/mL. Triazole derivatives 7 and 8 exhibited higher antitumoral activity toward OVCAR, MCF-7 and leukemia K-562 cell lines, exhibiting GI50 values less than 10 µg/mL. Compound 11 displayed significant activity against PC-3 (GI50 = 4.31 µg/mL), OVCAR (GI50 = 8.84 µg/mL) and K-562 (GI50 = 8.80 µg/mL) cell lines. Galloyl hydrazide (2) had cytotoxic activity in HepG2/C3A cells (IC50 = 153.7 µg/mL). In membrane permeability, cell count, cell cycle, and apoptosis assays, as determined using the IC50 of compound (2) in HepG2/C3A cells, increased membrane permeability, decreased cell count, altered cell cycle, and initial apoptosis was observed compared to the control group.

CONCLUSION

Thus, our results showed for the first time the synthesis, antiproliferative activity, and cytotoxicity of galloyl-substituted compounds. Galloyl-substitution does not have a very strong synergistic effect in the inhibition of cancer cell proliferation compared with galloyl hydrazide (2). Compound 2 demonstrated promising activity in HepG2/C3A hepatocarcinoma cells.

Hydrazide-assisted directional antibody conjugation of gold nanoparticles to enhance immunochromatographic assay

The analytical performance of immunochromatographic assay (ICA) is usually determined by the biological activity of antibody and gold nanoparticle conjugates (AuNP probes). However, conventional probes are constructed using the nondirectional coupling method that can cause the improper orientation of antibodies with the poor accessibility of antigen-binding sites. To address these issues, we report a site-specific directional coupling strategy to enhance the bioactivity of AuNP probes through the specific covalent binding of the aldehyde group in the Fc domain of antibodies with the hydrazide group modified on the surface of AuNPs. Through this design, the antibodies can be erected on the AuNP surface to fully expose the Fab domain and achieve the maximized functional availability. Leveraging these AuNP probes as ICA labels, we demonstrate an improved detection of the hepatitis B surface antigen with less used amount of labeled antibody (0.2 mg/pmol AuNPs), shorter reaction time (10 min), better antibody bioactivity, and higher detection sensitivity (2 ng/mL) compared with the carbodiimide method. Overall, this work provides great promise for the design and the construction of high-performance probes to enhance the detection performance of ICA sensors.

Discovery of hydrazide-containing oseltamivir analogues as potent inhibitors of influenza A neuraminidase

Neuraminidase (NA) inhibitors play a prime role in treating influenza. However, a variety of viruses containing mutant NAs have developed severe drug resistance towards NA inhibitors, so it is of crucial significance to solve this problem. Encouraged by urea-containing compound 12 disclosed by our lab, we designed a series of oseltamivir derivatives bearing hydrazide fragment for targeting the 150 cavity. Among the synthesized compounds, compound 17a showed 8.77-fold, 4.12-fold, 203-fold and 6.23-fold more potent activity than oseltamivir carboxylate against NAs from H5N1, H1N1, H5N1-H274Y, H1N1-H274Y, respectively. Meanwhile, the best compound 17a exhibited satisfactory metabolic stability in vitro. This study offers an important reference for the structural optimization of oseltamivir aiming at potent inhibition against H274Y mutant of NAs.

Synthesis and conformation of backbone N-aminated peptides

The chemical modification of peptides is a promising approach for the design of protein-protein interaction inhibitors and peptide-based drug candidates. Among several peptidomimetic strategies, substitution of the amide backbone maintains side-chain functionality that may be important for engagement of biological targets. Backbone amide substitution has been largely limited to N-alkylation, which can promote cis amide geometry and disrupt important H-bonding interactions. In contrast, N-amination of peptides induces distinct backbone geometries and maintains H-bond donor capacity. In this chapter we discuss the conformational characteristics of designed N-amino peptides and present a detailed protocol for their synthesis on solid support. The described methods allow for backbone N-amino scanning of biologically active parent sequences.

Structural basis of the conformational changes in Microbacterium hydrocarbonoxydans IclR transcription factor homolog due to ligand binding

Microbacterium hydrocarbonoxydans has been isolated using an unnatural acylhydrazide compound as the sole carbon source. The compound is hydrolyzed by bacterial hydrazidase, and the gene expression of the enzyme is considered to be controlled by a transcription factor of the Isocitrate lyase Regulator (IclR) family, belonging to the one-component signaling systems. Recently, we reported the crystal structure of an unliganded IclR homolog from M. hydrocarbonoxydans, named putative 4-hydroxybenzoate response regulator (pHbrR), which has a unique homotetramer conformation. In this study, we report the crystal structure of pHbrR complexed with 4-hydroxybenzoic acid, the catalytic product of hydrazidase, at 2.0 Å resolution. pHbrR forms a homodimer with multimeric rearrangement in the unliganded state. Gel filtration column chromatography results suggested dimer-tetramer rearrangement. We observed conformational change in the loop region covering the ligand-binding site, and domain rearrangements in the monomer. This study reports the first liganded IclR family protein structure that demonstrates large structural rearrangements between liganded and unliganded proteins, which may represent a general model for IclRs.

In Vitro Synthesis, Structure elucidation and its antioxidant properties of Platinum(IV)-hydrazide complexes: Molecular modeling of free-hydrazides suggested as potent lipoxygenase inhibitor

BACKGROUND

Combination of biologically active ligand and metal in one molecule may increase the activity and reduce the toxicity.

OBJECTIVES

In this study synthesis and characterization of platinum(IV) complexes with bioactive hydrazide ligands is discussed.

METHOD

Elemental analysis, conductivity measurements and spectroscopic studies were used to elucidate the structure of complexes.

RESULTS

Our study suggests that hydrazide ligands coordinate with Pt(IV) in bidenate fashion. The platinum(IV) complexes have octahedral geometry with metal to ligand ratio of 1:2. Hydrazide ligands coordinated with central metal platinum(IV) by oxygen of carbonyl group and nitrogen of primary amine. Synthesized complexes exhibited variable DPPH radical scavenging and lipoxygenase inhibition activity. Furthermore, it is also found that Pt(IV)-hydrazide complexes are more potent superoxide and nitric oxide radical scavengers than their uncoordinated hydrazide ligands while in case of lipoxygenase enzyme inhibition, some of the free hydrazide ligands are more active than their respective Pt(IV) complexes. In silico docking technique explores molecular interactions of synthesized ligands in the active site of lipoxygenase enzyme. Predicted docking energies are in good agreement with experimental data suggesting that in silico studies might be useful for discovery of therapeutic candidates.

CONCLUSION

Structure function relationship demonstrates that the radical scavenging and enzyme inhibition activities of the Pt(IV) compounds are effected by nature of ligand, position of substituent, electronic and steric effects. However, electronic factor seem to play more important role than other factors.

Experimental and theoretical studies of Palladium-hydrazide complexes' interaction with DNA and BSA, in vitro cytotoxicity activity and plasmid cleavage ability

New palladium complexes with general formula trans-[Pd(L)₂(OAc)₂] (1,2), (L = Benzhydrazide and 2-Furoic hydrazide) have been synthesized and characterized with various methods including elemental analysis, FT-IR, ¹HNMR and mass spectroscopy. Afterward their interactions with bovine serum albumin and calf thymus deoxyribonucleic acid have been investigated by UV-vis absorption, fluorescence emission and circular dichroism spectroscopy. Also, site-selective replacement experiments with site probes have been carried out. Analysis of fluorescence spectrum indicated static quenching mechanism. Spectroscopic measurements for DNA binding showed the groove binding to DNA for both complexes. Furthermore, cytotoxicity studies of complexes and cis-platin have been done against colon carcinoma (CT26) and breast cancer (4T1) cell lines. Evaluation of complexes (1) and (2) on induction of apoptosis in CT26 cells has been done. Finally, plasmid cleavage ability of (1) and (2) was investigated by gel electrophoresis that indicate the more activity of (1) than (2).

A robust glycan labeling strategy using a new cationic hydrazide tag for MALDI-MS-based rapid and sensitive glycomics analysis

Chemical derivatization of glycans is a common strategy to increase the analytical performance of MALDI-MS-based glycan profiling techniques. Hydrazide, one of the most popular tags, offers important advantages including allowing purification-free procedures. Several hydrazides have thus been used for glycomics combined with an on-target strategy to further simplify the analytical procedures. Usually, gentle heating and mildly acidic conditions with somewhat long reaction times are needed for these hydrazide derivatizations to reach a high reaction efficiency, which makes the current hydrazide tags not yet perfectly conducive to high-throughput analysis. To further optimize these hydrazide tags for high-throughput analysis, based on the structure of a reported hydrazide and the theoretical calculations, a new cationic hydrazide tag, 4-(hydrazinecarbonyl)-N,N,N-trimethylbenzenaminium (HTMBA), was designed, synthesized and tested in this work. HTMBA could completely derivatize glycans at room temperature in several seconds under very mildly acidic conditions (<3% acetic acid). A 19-fold enhancement in the signal intensity was obtained without interference from alkali adduct ions in the MALDI-MS detection of HTMBA-labeled maltoheptaose. To broaden the applicability of HTMBA, an HTMBA on-target derivatization (HOD) strategy was developed and fully validated with maltoheptaose and RNase B, and the method showed a good repeatability and stability. Finally, the HOD strategy was successfully applied to serum samples, 44 glycans in human serum were detected, and the O-acetylation information of sialic acid in horse serum was preserved. These results showed that the HOD strategy was suitable for the MS-based rapid analysis of all glycoforms in complex biological samples.

Clean Grinding Technique: A Facile Synthesis and In Silico Antiviral Activity of Hydrazones, Pyrazoles, and Pyrazines Bearing Thiazole Moiety against SARS-CoV-2 Main Protease (Mpro)

A novel series of some hydrazones bearing thiazole moiety were generated via solvent-drop grinding of thiazole carbohydrazide 2 with various carbonyl compounds. Also, dehydrative-cyclocondensation of 2 with active methylene compounds or anhydrides gave the respective pyarzole or pyrazine derivatives. The structures of the newly synthesized compounds were established based on spectroscopic evidences and their alternative syntheses. Additionally, the anti-viral activity of all the products was tested against SARS-CoV-2 main protease (M^pro) using molecular docking combined with molecular dynamics simulation (MDS). The average binding affinities of the compounds 3a, 3b, and 3c (−8.1 ± 0.33 kcal/mol, −8.0 ± 0.35 kcal/mol, and −8.2 ± 0.21 kcal/mol, respectively) are better than that of the positive control Nelfinavir (−6.9 ± 0.51 kcal/mol). This shows the possibility of these three compounds to effectively bind to SARS-CoV-2 Mpro and hence, contradict the virus lifecycle.

Tubulin inhibitors: Discovery of a new scaffold targeting extra-binding residues within the colchicine site through anchoring substituents properly adapted to their pocket by a semi-flexible linker

Bis-hydrazides 13a-h were designed and synthesized as potential tubulin inhibitors selectively targeting the colchicine site between α- and β-tubulin subunits. The newly designed ring-B substituents were assisted at their ends by 'anchor groups' which are expected to exert binding interaction(s) with new additional amino acid residues in the colchicine site (beyond those amino acids previously reported to interact with reference inhibitors as CA-4 and colchicine). Conformational flexibility of bis-hydrazide linker assisted these 'extra-binding' properties through reliving ligands' strains in the final ligand-receptor complexes. Compound 13f displayed the most promising computational and biological study results in the series: MM/GBSA binding energy of -62.362 kcal/mol (extra-binding to Arg α:221, Thr β:353 & Lys β:254); 34% NCI-H522 cells' death (at 10 µM), IC₅₀ = 0.073 µM (MTT assay); significant cell cycle arrest at G2/M phase; 11.6% preG1 apoptosis induction and 83.1% in vitro tubulin inhibition (at concentration = IC₅₀). Future researchers in bis-hydrazide tubulin inhibitors are advised to consider the 2-chloro-N-(4-substituted-phenyl)acetamide derivatives as compound 13f due to extra-binding properties of their ring B.

Design and synthesis of novel 2-(6-thioxo-1,3,5-thiadiazinan-3-yl)-N'-phenylacethydrazide derivatives as potential fungicides

A series of novel 2-(6-thioxo-1,3,5-thiadiazinan-3-yl)-N'-phenylacethydrazide derivatives were designed, synthesized and evaluated for their antifungal activities against Fusarium graminearum (Fg), Rhizoctonia solani (Rs), Botrytis cinerea (Bc) and Colletotrichum capsici (Cc). The bioassay results in vitro showed that most of the title compounds exhibited impressive antifungal activities against the above plant fungi. Particularly, the compounds 5c, 5f, 5g, 5i, 5m and 5p displayed desirable anti-Rs activities, with the corresponding EC₅₀ values of 0.37, 0.32, 0.49, 0.50, 0.46 and 0.45 µg/mL, respectively, which are superior to the positive control carbendazim (0.55 µg/mL). Further in vivo bioassay results showed that the anti-Rs activity of title compound 5f at 200 µg/mL reached 95.84% on detached rice leaves and 93.96% on rice plants. Featuring convenient synthesis, novel structures and desirable antifungal activity, these 2-(6-thioxo-1,3,5-thiadiazinan-3-yl)-N'-phenylacethydrazide derivatives could be further studied as the potential candidates of novel agricultural fungicides.

Sensitive and robust MALDI-TOF-MS glycomics analysis enabled by Girard's reagent T on-target derivatization (GTOD) of reducing glycans

Sensitive glycomics analysis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) is of great importance but significantly hampered by their low ionization efficiency and labile sialic acid moieties. Chemical derivatization offers a viable way to improve both the ionization efficiency and analytical sensitivity of the glycans in MS analysis by altering their hydrophobicity or charge property. Here we employed Girard's reagent T (GT) for on-target derivatization (GTOD) of reducing glycan under mild acid condition to form stable hydrazones at room temperature, allowing rapid and sensitive identification of neutral and sialylated glycans in positive-ion mode as only permanently positive charged molecular ions without multiple ion adducts by MALDI-TOF-MS. The MS signal intensities of lactose, sialylated N-glycans derived from bovine fetuin and neutral N-glycans derived from RNaseB and ovalbumin were boosted by 7.44, 9.13, 12.96 and 13.47 folds on average (n = 3), respectively. More importantly, after GTOD strategy, unwanted desialylation of sialylated glycans during MS was suppressed. The detection limit of the assay is desirable since the nanogram of N-glycans derived from 0.16 μg ovalbumin could be detected. The assay demonstrated good stability (RSD≤2.95%, within 10 days), reliable reproducibility (RSD = 2.96%, n = 7) and a desirable linear dynamic range from 78 nmol/mL to 10 μmol/mL. The strategy has been successfully applied to MS analysis of reducing glycans from human milks, neutral and sialylated O-, N-glycans from glycoproteins, and reducing glycans derived from glycosphingolipids, presenting neater [M]⁺ signals which allow detection of more low-abundance glycans and assignation of Neu5Ac vs. Neu5Gc or fucose vs. hexose in glycans due to the absence of the ambiguous interpretation from multiple peaks (ion adducts [M+Na]⁺ and [M+K]⁺). Moreover, the GTOD assay prevents desialylation during MALDI-TOF-MS profiling and enables distinct linkage-specific characterization of terminal sialic acids of N-glycans derived from human serum protein when combines with an esterification.

Design, synthesis and antifungal activity evaluation of coumarin-3-carboxamide derivatives

A series of coumarin-3-carboxamides/hydrazides have been designed and synthesized, all the target compounds were evaluated in vitro for their antifungal activity against Botrytis cinerea, Alternaria solani, Gibberella zeae, Rhizoctorzia solani, Cucumber anthrax and Alternaria leaf spot, some of the designed compounds 4a-4g exhibited potential activity in the primary assays, this highlighted by the compounds 4a, 4d, 4e and 4f, EC₅₀ values of which against Rhizoctorzia solani were as low as 1.80 μg/mL, 2.50 μg/mL, 2.25 μg/mL and 2.10 μg/mL, respectively, exhibiting more effective control with that of the positive control than Boscalid. Furthermore, compounds 4a and 4e represented equivalent antifungal activity with Boscalid against Botrytis cinerea.

Advances and Challenges of HDAC Inhibitors in Cancer Therapeutics

Since the identification and cloning of human histone deacetylases (HDACs) and the rapid approval of vorinostat (Zolinza®) for the treatment of cutaneous T-cell lymphoma, the field of HDAC biology has met many initial successes. However, many challenges remain due to the complexity involved in the lysine posttranslational modifications, epigenetic transcription regulation, and nonepigenetic cellular signaling cascades. In this chapter, we will: review the discovery of the first HDAC inhibitor and present discussion regarding the future of next-generation HDAC inhibitors, give an overview of different classes of HDACs and their differences in lysine deacylation activity, discuss different classes of HDAC inhibitors and their HDAC isozyme preferences, and review HDAC inhibitors' preclinical studies, their clinical trials, their pharmacokinetic challenges, and future direction. We will also discuss the likely reason for the failure of multiple HDAC inhibitor clinical trials in malignancies other than lymphoma and multiple myeloma. In addition, the potential molecular mechanism(s) that may play a key role in the efficacy and therapeutic response rate in the clinic and the likely patient population for HDAC therapy will be discussed.

New hydrazides derivatives of isoniazid against Mycobacterium tuberculosis: Higher potency and lower hepatocytotoxicity

Tuberculosis (TB) is one of the leading causes of death worldwide. The emergence of multi-drug resistant strains of Mycobacterium tuberculosis (Mtb) and TB-HIV co-infection are major public health challenges. The anti-TB drugs of first choice were developed more than 4 decades ago and present several adverse effects, making the treatment of TB even more complicated and the development of new chemotherapeutics for this disease imperative. In this work, we synthesized two series of new acylhydrazides and evaluated their activity against different strains of Mtb. Derivatives of isoniazid (INH) showed important anti-Mtb activity, some being more potent than all anti-TB drugs of first choice. Moreover, three compounds proved to be more potent than INH against resistant Mtb. The Ames test showed favorable results for two of these substances compared to INH, one of which presented expressly lower toxicity to HepG2 cells than that of INH. This result shows that this compound has the potential to overcome one of the main adverse effects of this drug.

A statistical view of protein chemical synthesis using NCL and extended methodologies

Native chemical ligation and extended methodologies are the most popular chemoselective reactions for protein chemical synthesis. Their combination with desulfurization techniques can give access to small or challenging proteins that are exploited in a large variety of research areas. In this report, we have conducted a statistical review of their use for protein chemical synthesis in order to provide a flavor of the recent trends and identify the most popular chemical tools used by protein chemists. To this end, a protein chemical synthesis (PCS) database (http://pcs-db.fr) was created by collecting a set of relevant data from more than 450 publications covering the period 1994-2017. A preliminary account of what this database tells us is presented in this report.

In vitro and in vivo assessments of two novel hydrazide compounds against breast cancer as well as mammary tumor cells

PURPOSE

The hydrazide backbone is a well-known structural core system found in a broad range of biologically activated compounds. Among which, the compounds with anticancer activity have been cited in a number of studies. With this object in mind, we focused on the in vitro and in vivo anticancer potential of two novel hydrazide derivatives bearing furan or thiophen substituents (compounds 1 and 2).

METHODS

The cytotoxic property was evaluated using MTT assay against MCF-7 human breast adenocarcinoma cell line, while the in vivo antitumor activity was investigated in BALB/c mice bearing 4T1 mammary carcinoma cells. Flow cytometry was used for cell cycle analysis, and detection of apoptosis was examined by Annexin-V-FLUOS/PI assay. Protein expression of Bax, Bcl-2 and procaspase-3 was estimated by Western blotting.

RESULTS

Compounds 1 and 2 were found to be cytotoxic towards breast cancer cells presenting IC₅₀ values of 0.7 and 0.18 µM, respectively, and selectivity over normal fibroblast cells. Our findings further indicated that 2 × IC₅₀ concentrations of both compounds induce early stage apoptosis and increase percentage of sub-G1 population in MCF-7 cells at 48 h. An elevation in Bax/Bcl-2 ratio and caspase-3 cleavage suggested that apoptosis induced by the two compounds is through a caspase- and mitochondrial-dependent pathway. In the in vivo study, compounds 1 and 2 at doses of 10 and 1 mg/Kg/day, respectively, significantly hindered the growth of tumor after 3 weeks of i.p. administration, when compared to vehicle-treated mice.

CONCLUSION

Collectively, the great potential exhibited by compound 2 could make it a promising chemotherapeutic candidate for human cancers, especially for breast cancer.

New hydrazine and hydrazide quinoxaline 1,4-di-N-oxide derivatives: In silico ADMET, antiplasmodial and antileishmanial activity

We report the design (in silico ADMET criteria), synthesis, cytotoxicity studies (HepG-2 cells), and biological evaluation of 15 hydrazine/hydrazide quinoxaline 1,4-di-N-oxide derivatives against the 3D7 chloroquine sensitive strain and FCR-3 multidrug resistant strain of Plasmodium falciparum and Leishmania infantum (axenic amastigotes). Fourteen of derivatives are novel quinoxaline 1,4-di-N-oxide derivatives. Compounds 18 (3D7 IC₅₀=1.40μM, FCR-3 IC₅₀=2.56μM) and 19 (3D7 IC₅₀=0.24μM, FCR-3 IC₅₀=2.8μM) were identified as the most active against P. falciparum, and they were the least cytotoxic (CC₅₀-values>241μM) and most selective (SI>86). None of the compounds tested against L. infantum were considered to be active. Additionally, the functional role of the hydrazine and hydrazide structures were studied in the quinoxaline 1,4-di-N-oxide system.

Synthesis, biological evaluation and 3D-QSAR study of hydrazide, semicarbazide and thiosemicarbazide derivatives of 4-(adamantan-1-yl)quinoline as anti-tuberculosis agents

We report synthesis, anti-tuberculosis activity and 3D-QSAR study of forty nine hydrazide, semicarbazide and thiosemicarbazide derivatives of 4-(adamantan-1-yl)quinoline. The most potent compounds upon evaluation for anti-tuberculosis activity exhibited MIC99 of 3.125 μg/mL against Mycobacterium tuberculosis H37Rv strain. We applied the in silico technique of 3D-QSAR to study structure activity relationship of the synthesized compounds. The developed CoMFA model exhibited excellent r(2)ncv of 0.971, and r(2)cv of 0.543. The predicted r(2)pred of 0.883 showed that the predicted values were in good agreement with the experimental values. Further, the contour map analysis, suggested that the sterically bulky and electronegative substitutions at the para position of the phenyl ring are favorable for anti-tuberculosis activity.

Stationary phases for the enrichment of glycoproteins and glycopeptides

The analysis of protein glycosylation is important for biomedical and biopharmaceutical research. Recent advances in LC-MS analysis have enabled the identification of glycosylation sites, the characterisation of glycan structures and the identification and quantification of glycoproteins and glycopeptides. However, this type of analysis remains challenging due to the low abundance of glycopeptides in complex protein digests, the microheterogeneity at glycosylation sites, ion suppression effects and the competition for ionisation by co-eluting peptides. Specific sample preparation is necessary for comprehensive and site-specific glycosylation analyses using MS. Therefore, researchers continue to pursue new columns to broaden their applications. The current manuscript covers recent literature published from 2008 to 2013. The stationary phases containing various chemical bonding methods or ligands immobilisation strategies on solid supports that selectively enrich N-linked or sialylated N-glycopeptides are categorised with either physical or chemical modes of binding. These categories include lectin affinity, hydrophilic interactions, boronate affinity, titanium dioxide affinity, hydrazide chemistry and other separation techniques. This review should aid in better understanding the syntheses and physicochemical properties of each type of stationary phases for enriching glycoproteins and glycopeptides.

Synthesis, spectroscopic and radical scavenging studies of palladium(II)-hydrazide complexes

In present study, a series of palladium(II) complexes with biologically active hydrazide ligands have been synthesized, characterized and screened for their antioxidant (superoxide and DPPH radical scavenging) properties. Spectral studies (FT-IR, EI-mass, (13)C and (1)H NMR spectroscopy) and physico-chemical measurements including elemental analysis, magnetic susceptibility and conductivity measurements represented square planar structure for all complexes. Substituted and unsubstituted benzohydrazides (1-4) have shown monodentate behavior forming complexes of general formula [PdL2Cl2]. However, pyridinecarbohydrazides (5 and 6) were coordinated in bidentate fashion of [PdLCl2] general formula producing stable five-membered chelate ring. All palladium complexes were found to be considerably more potent inhibitors of DPPH free radical compared to free hydrazides. These complexes are even stronger DPPH scavengers than standard antioxidant propyl gallate. The complexes have also shown good superoxide scavenging ability compared to inactive free hydrazides, however complexes are weaker superoxide scavengers than ascorbic acid, a standard superoxide inhibitor. An interesting structure activity relationship has been evaluated.

Synthesis and analgesic activity of novel hydrazide and hydrazine derivatives

The uses of non-steroidal anti-inflammatory drugs (NSAIDs) are limited by a variety of side effects. So research on preparing new analgesic agents is important. According to some reports about the analgesic activity of hydrazide and hydrazine derivatives a new series of these compounds were synthesized in order to obtain new analgesic compounds. The final compounds 10a-10e and 15a-15d were prepared by condensation of corresponding hydrazides 7,8 and 11-14 with different aldehydes 9a-9e. The structures of all synthesized compounds were confirmed by means of FT-IR, 1H-NMR and Mass spectra. All compounds were evaluated for their analgesic activities by abdominal constriction test (writhing test). Most of the synthesized compounds induced significant reduction in the writhing response when compared to control and compound 15 was more potent than mefenamic acid in the writhing test.