Synthesis of stereochemical probes for new fluorogenic assays for yeast transketolase variants

For the screening of yeast transketolase (TK) variants with improved or new properties acquired by random mutagenesis, we report on the stereoselective synthesis of fluorogenic substrates as probes for measuring TK activity. Compound 1 (7-(2′,3′,5′-trihydroxy-4′-oxo-pentyl)oxycoumarine), prepared as previously described, [Tetrahedron Lett.2003, 44, 827-830] enabled us to evaluate wild type TK velocity in a simple, specific and reproducible way. To select TK mutants able to produce d-threo aldoses, we prepared compound 2 (dihydroxy-4-O-(2′-oxo-benzopyran-7′-yl-D-threose) from dimethyl tartrate. Starting from d-ribose, we successfully obtained compound 3 (7′-(2,3,5-trihydroxy-4-oxo-pentyl)oxycoumarine) as a probe for TK mutants able to produce l-erythro ketoses.     

Efficient synthesis of new azo-sulfonamide derivatives and investigation of their molecular docking and cytotoxicity results

The present study focused on the synthesis, introduction and investigation of the biological effects of sulfonamide-derived products as new azo-sulfonamides (samples 1–6). In this transformation, the amine sulfonamide is first converted to the corresponding diazonium salt, which is then attacked by a nucleophilic carbon of the aromatic ring in the playing medium. All products were obtained with reasonable yields and high purity. The structure of synthesized derivatives was determined using various analytical tools including FT-IR, ¹H NMR, ¹³C NMR and XRD spectroscopy, and the synthesized products were purified and identified. Biological properties of newly synthesized azo-compounds similar to SSZAD were also investigated. These compounds were tested in terms of biological effectiveness. The results of biochemical assays show that: the products have significant biological properties. MTT toxicity of compounds in breast cancer cells (MCF-7) for compounds 1–6 according to IC₅₀ compare to Vinblastine is Vin > 5 > 4 > 6 > 2 > 3 > 1. The biochemical results obtained were analyzed by molecular docking interaction studies and showed strong hydrogen bonding with the target receptor. The docking calculation has been invoked to reveal the type of interactions that synthesized compounds can establish with the residues forming the active sites of the target proteins, 1FDW the three higher scores molecules appears to be (6 > 1 > 2), 3FC2 (the three highest binding affinities are in the order of 1 > 3 > 6), and 5GWK (three highest binding affinities are 1 > 3 > 6). The results indicate the effective interaction of all products with the targets. The molecular dynamics simulation has been invoked to study the presence of a stable system of the interacting protein–ligand.     

Inhibitory Effect of Lithospermic Acid on the HIV-1 Nucleocapsid Protein

The HIV-1 nucleocapsid protein (NC) is a desirable target in antiretroviral therapy due to its high conservation among HIV-1 strains, and to its multiple and crucial roles in the HIV-1 replication cycle. Natural products represent a valuable source of NC inhibitors, with the catechol group being a privileged scaffold in NC inhibition. By coupling molecular modeling with NMR spectroscopy and fluorescence-based assays, we disclosed lithospermic acid, a catechol derivative extracted from Salvia miltiorrhizza, as a potent and chemically stable non-covalent inhibitor of the NC. Being different from other catechol derivative reported so far, lithospermic acid does not undergo spontaneous oxidation in physiological conditions, thus becoming a profitable starting point for the development of efficient NC inhibitors.     

Homogeneous Phosphodiesterase and Hybridization Assays Using Europium Cryptate: Oligonucleotide Conjugates

Upon conjugation to single-stranded oligonucleotides, a europium cryptate (Eu³⁺ tris-bipyridine) showed a marked increase in its fluorescence lifetime and was much less sensitive to fluorescence quenching by uric acid. This behavior was shown to be moderately dependent on the length and sequence of the oligonucleotide and all the single-stranded oligonucleotides studied displayed similar behavior. In contrast, a cryptate moiety attached to a double-stranded oligonucleotide did not display such an increase in its fluorescence lifetime and was quenched in presence of uric acid. Taking advantage of this unique behavior characterizing single-stranded K-ODN conjugates, a new concept of dosage based on the modulation of the cryptate fluorescence by a quencher was set up. This fluorescence quenching assay involving a single fluorescent label was applied to the monitoring of hybridization reactions and detection of a phosphodiesterase activity.     

Gold Nanoparticle–Fluorophore Complexes: Sensitive and Discerning “Noses” for Biosystems Sensing

Gold nanoparticles (NPs) efficiently quench adsorbed fluorophores. Upon disruption of such complexes by an analyte, fluorescence turn‐on is observed. By judicious choice of the functionalized NP and the fluorophore, these complexes display different responses to analytes, thus leading to versatile yet simple array‐based sensor platforms. Using this strategy, we can identify proteins in buffer and serum, distinguish between both different species and different strains of bacteria, and differentiate between healthy, cancerous, and metastatic human and murine cells.     

尾式水杨酸卟啉化合物的合成及其初步抗癌活性研究

随着卟啉类化合物的研究不断深入,并在对发病机理、抗癌、抗病毒机制不断深入了解的基础上进行治疗药物的分子设计,一定会研制出肿瘤特异性摄入率高、光敏活性高的合成单体和其它具有独特诊断与治疗作用的药物.     

Design,Synthesis and Antitumor Activity of a Novel Series of PAC-1 Analogues

A novel series of first procaspase activating compound(PAC-1) analogues was designed, synthesized and evaluated for antitumor activity towards two cell lines[human promyelocytic leukemia cell line(HL60) and human embryonic lung fibroblast cell line(HLF)] by the MTT[3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazo-liumromide] method in vitro. The structures of all the compounds were confirmed by ¹H NMR, MS and elemental analysis. Among the compounds synthesized,(E)-2-[(3-{[4-(tert-butyl)benzyl](methyl)amino}propyl)(methyl)amino]-N'-[4-(diethylamino)-2-hydroxybenzylidene]acetohydrazide(compound 6n) exhibits a good anti-proliferative activity to the majority of tumor cells tested, and selectively cleaves cancer cells. Thus, compound 6n was identified as promising lead compound for further structural modification.     

Chemical composition and antioxidant activity of aerial parts of Ferula longipes Coss. ex Bonnier and Maury

This is the first study on the phytochemistry and antioxidant activity of Ferula longipes Coss. ex Bonnier and Maury (Apiaceae). A new flavonoid quercetin-3-O-α-L-rhamnopyranoside-7-O-ß-D-[2-O-caffeoyl]-glucopyranoside (1), along with 10 known compounds kaempferol-3-O-α-L-rhamnopyranoside (2), quercetin-3-O-α-L-rhamnopyranoside (3), kaempferol-3-O-ß-D-glucopyranoside-7-O-α-L-rhamnopyranoside (4), isorhamnetin-3-O-α-L-rhamnopyranoside-7-O-ß-D-glucopyranoside (5), quercetin-3-O-α-L-rhamnopyranoside-7-O-ß-D-glucopyranoside (6), isorhamnetin-3,7-di-O-β-D-glucopyranoside (7), apigenin (8), apigenin-7-O-ß-D-glucopyranoside (9), 3,5-dicaffeoylquinic acid (10), deltoin (11) were isolated from the aerial parts of Ferula longipes Coss. Structures elucidation was performed by comprehensive 1D and 2D NMR analyses, mass spectrometry and by comparison with literature data. The compounds 1, 3, 4, 6, 7 and 10 were evaluated for their antioxidant activity, compound 1 exhibited the best antiradical activity potential and showed IC₅₀ and A_0.5 values 5.70, 7.25, 5.00, and 2.63 μg/mL towards DPPH free radical-scavenging, ABTS, CUPRAC, and reducing power assays, respectively compared with BHA, BHT and ascorbic acid which were used as positive controls.     

Comprehensive stability‐indicating high‐performance liquid chromatography coupled with diode array detection method for simultaneous determination of amprolium hydrochloride and ethopabate in powder dosage form for veterinary use

This research deals with the development of a stability‐indicating high‐performance liquid chromatography method for simultaneous determination of amprolium hydrochloride and ethopabate. To the best of our knowledge, no comprehensive stability‐indicating method has been reported for analysis of this mixture. Separation was achieved using Kromasil cyano column with gradient elution of the mobile phase composed of sodium hexane sulfonate solution and methanol. Quantification was based on measuring peak areas at 266 nm. Amprolium and ethopabate peaks eluted at retention times 10.42 and 18.53 min, respectively. The proposed procedure was validated with respect to system suitability, linearity, ranges, precision, accuracy, specificity, robustness, detection, and quantification limits. Linearity ranges for amprolium and ethopabate were 1.5–240 and 1–160 μg/mL, respectively. Analytes were subjected to stress conditions of hydrolysis, oxidation and thermal degradation. The proposed method enabled resolution of drugs from their forced‐degradation products and amprolium related substance (2‐picoline). Moreover, specificity was verified by resolution of the analytes from about 22 drugs used in antimicrobial veterinary products. The validated method was successfully applied to assay of the combined veterinary powder dosage form, additionally it was implemented in the accelerated stability study of the dosage form when stored for six months at 40°C and 75% relative humidity.     

In Vitro Evaluation of the Cytotoxic Effect of Streptococcus pyogenes Strains,Protegrin PG-1, Cathelicidin LL-37, Nerve Growth Factor and Chemotherapy on the C6 Glioma Cell Line

Brain cancer treatment, where glioblastoma represents up to 50% of all CNS malignancies, is one of the most challenging calls for neurooncologists. The major driver of this study was a search for new approaches for the treatment of glioblastoma. We tested live S. pyogenes, cathelicidin family peptides and NGF, assessing the oncolytic activity of these compounds as monotherapy or in combination with chemotherapeutics. For cytotoxicity evaluation, we used the MTT assay, trypan blue assay and the xCELLigence system. To evaluate the safety of the studied therapeutic approaches, we performed experiments on normal human fibroblasts. Streptococci and peptides demonstrated high antitumor efficiency against glioma C6 cells in all assays applied, surpassing the effect of chemotherapeutics (doxorubicin, carboplatin, cisplatin, etoposide). A real-time cytotoxicity analysis showed that the cell viability index dropped to 21% 2–5 h after S. pyogenes strain exposure. It was shown that LL-37, PG-1 and NGF also exhibited strong antitumor effects on C6 glioma cells when applied at less than 10⁻⁴ M. Synergistic effects for combinations of PG-1 with carboplatin and LL-37 with etoposide were shown. Combinations of S. pyogenes strain #7 with NGF or LL-37 demonstrated a cytotoxic effect (56.7% and 57.3%, accordingly) on C6 glioma cells after 3 h of exposure.