Design, Synthesis, and Functional Studies on Noscapine and Cotarnine Amino Acid Derivatives as Antitumor Agents.

Noscapine, a phthalide isoquinoline alkaloid isolated from the opium poppy, alongside cotarnine, a tetrahydroisoquinoline (THIQ) scaffold produced by the oxidative degradation of noscapine, has exhibited antitumor activities against several types of cancer. Although derivatization with amino acids is regarded as a promising strategy to improve chemotherapeutics' anticancer properties, amino acid conjugates of noscapine and cotarnine have been the least investigated. In the present study, 20 amino acid conjugated derivatives of noscapine and cotarnine at the 6-position were synthesized and evaluated for anticancer activity in both in vitro and in vivo conditions. Analysis of the antiproliferative activity against 4T1 mammary carcinoma tumor cells showed that compounds 6h (noscapine-phenylalanine), 6i (noscapine-tryptophan), and 10i (cotarnine-tryptophan) with IC50 values of 11.2, 16.3, and 54.5 µM, respectively, were found to be far more potent than noscapine (IC50 = 215.5 µM) and cotarnine (IC50 = 575.3 µM) and were consequently opted for further characterization. Annexin V and propidium iodide staining followed by flow cytometry demonstrated improved apoptotic activity of compounds 6h, 6i, and 10i compared to those of noscapine and cotarnine. In a murine model of 4T1 mammary carcinoma, noscapine-tryptophan inhibited tumor growth more effectively than noscapine and the other amino acid conjugates without adverse effects. Moreover, molecular docking studies conducted on tubulin as the intracellular target of noscapine suggested a good correlation with experimental observations. Based on these results, noscapine-tryptophan could be a promising candidate for further preclinical investigations.

A new chiral stationary phase based on noscapine: Synthesis, enantioseparation, and docking study.

Noscapine is an isolated compound from the opium poppy, with distinctive chiral structure and chemistry, interacts with other compounds due to having multiple π-acceptors, hydrogen bond acceptors, and ionic sites. Therefore, it has promising applicability for the enantioselective separation of a wide range of polar, acidic, basic, and neutral compounds. A new noscapine derivative chiral stationary phase (ND-CSP) has been synthesized by consecutive N-demethylation, reduction, and N-propargylation of noscapine followed by attachment of a solid epoxy-functionalized silica bed through the 1,3-dipolar Huisgen cycloaddition. The noscapine derivative-based stationary phase provides a considerable surface coverage, which is greater than some commercial CSPs and can validate better enantioresolution performance. The major advantages inherent to this chiral selector are stability, reproducibility after more than 200 tests, and substantial loading capacity. The characterization by Fourier transform infrared (FTIR) spectroscopy and elemental analysis indicated successful functionalization of the silica surface. Chromatographic method conditions like flow rate and mobile phase composition for enantioseparation of various compounds such as warfarin, propranolol, mandelic acid, and a sulfanilamide derivative were optimized. Comparing the experimental results with docking data revealed a clear correlation between the calculated binding energy of ND-CSP and each enantiomer with the resolution of enantiomer peaks.

Semi-Synthesis of New 1,2,3-Triazole Derivatives of 9-Bromonoscapine and their Anticancer Activities.

Novel 1,2,3-triazole-tethered 9-bromonoscapine derivatives were synthesized by the propargylation of N-nornoscapine followed by Huisgen's 1,3-dipolar cycloaddition of the terminal alkynes with different azides. Cytotoxicity of the products was studied by MTT assay against the MCF-7 breast cancer cell line. Most of the compounds revealed a better cytotoxicity than N-nornoscapine and 9-bromonornoscapine as the parent compounds. Among the synthesized compounds, those with a hydroxylated aliphatic side chain (5p, 5q, and 5r) showed the highest activities (IC50s: 47.2, 37.9, and 32.3 µg/mL, respectively). Molecular docking studies showed that these compounds also had the highest docking scores and effective interactions with binding sites equal to -8.074, -7.425 and -7.820 kcal/mol, respectively.

Identification of novel anti-cancer agents by the synthesis and cellular screening of a noscapine-based library.

Noscapine is a natural product first isolated from the opium poppy (Papaver somniferum L.) with anticancer properties. In this work, we report the synthesis and cellular screening of a noscapine-based library. A library of novel noscapine derivatives was synthesized with modifications in the isoquinoline and phthalide scaffolds. The so generated library, consisting of fifty-seven derivatives of the natural product noscapine, was tested against MDA-MB-231 breast cancer cells in a cellular proliferation assay (with a Z' > 0.7). The screening resulted in the identification of two novel noscapine derivatives as inhibitors of MDA cell growth with IC50 values of 5 µM and 1.5 µM, respectively. Both hit molecules have a five-fold and seventeen-fold higher potency, compared with that of lead compound noscapine (IC50 26 µM). The identified active derivatives retain the tubulin-binding ability of noscapine. Further testing of both hit molecules, alongside the natural product against additional cancer cell lines (HepG2, HeLa and PC3 cells) confirmed our initial findings. Both molecules have improved anti-proliferative properties when compared to the initial natural product, noscapine.

Discovery of noscapine derivatives as potential ß-tubulin inhibitors.

Twenty novel 1,2,3-triazole noscapine derivatives were synthesized starting from noscapine by consecutive N-demethylation, reduction of lactone ring, N-propargylation and Huisgen 1,3-dipolar cycloaddition reaction. In order to select the most promising molecules to subject to further biophysical and biological evaluation, a molecular docking analysis round was performed using noscapine as reference compound. The molecules featuring docking predicted binding affinity better than that of noscapine were then subjected to MTT assay against MCF7 cell line. The obtained results disclosed that all the selected triazole derivatives exhibited a remarkably lower cell viability compared to noscapine in the range of 20 µM in 48 h. In an attempt to correlate the biological activity with the ability to bind tubulin, the surface plasmon resonance (SPR) assay was employed. Compounds 8a, 8h, 9c, 9f and 9j were able to bind tubulin with affinity constant values in the nanomolar range and higher if compared to noscapine. Integrating computational predictions and experimental evaluation, two promising compounds (8h and 9c) were identified, whose relevant cytotoxicity was supposed to be correlated with tubulin binding affinity. These findings shed lights onto structural modifications of noscapine toward the identification of more potent cytotoxic agents targeting tubulin.

Synthesis, in-vitro antiprotozoal activity and molecular docking study of isothiocyanate derivatives.

Novel isothiocyanate derivatives were synthesized starting from noscapine, bile acids, amino acids, and some aromatic compounds. Antiparasitic activities of the synthesized derivatives were tested against four unicellular protozoa, i.e., Trypanosoma brucei rhodesiense, T. cruzi, Leishmania donovani, and Plasmodium falciparum. Interestingly, seven isothiocyanate analogues displayed promising antiparasitic activity against Leishmania donovani with IC50 values between 0.4 and 1.0 µM and selectivity index (SI) ranged from 7.8 to 18.4, comparable to the standard drug miltefosine (IC50 = 0.7 µM). Compound 7h demonstrated the best antileishmanial activity with an IC50 value of 0.4 µM. Seven products exhibited inhibition activity against T. brucei rhodesiense with IC50s below 2.0 µM and SI between 2.7 and 29.3. Four primary amine derivatives of noscapine and five isothiocyanate derivatives exhibited antiplasmodial activity with IC50s in the range of 1.1-2.7 µM and SI values between 1.1 and 14.5. The isothiocyanate derivative 7c showed against T. cruzi with an IC50 value of 1.9 µM and SI 4. Molecular docking and ADMET studies were performed to investigate the interaction between active ligands and T. brucei trypanothione reductase active site. The docking studies showed significant binding affinity of noscapine derivatives to enzyme active site and good compatibility with experimental data.

N-substituted noscapine derivatives as new antiprotozoal agents: Synthesis, antiparasitic activity and molecular docking study.

Novel N-substituted noscapine derivatives were synthesized by a three-component Strecker reaction of cyclic ether of N-nornoscapine with varied aldehydes, in the presence of cyanide ion. Moreover, the corresponding amides were synthesized by the oxidation of cyanide moieties in good yields. The in vitro antiprotozoal activity of the products was also investigated. Interestingly, some analogues did put on display promising antiparasitic activity against Trypanosoma brucei rhodesiense with IC50 values between 2.5 and 10.0 µM and selectivity index (SI) ranged from 0.8 to 13.2. Eight compounds exhibited activity against Plasmodium falciparum K1 strain with IC50 ranging 1.7-6.4 µM, and SI values between 2.8 and 10.5 against L6 rat myoblast cell lines. Molecular docking was carried out on trypanothione reductase (TbTR, PDB ID: 2WOW) and UDP-galactose 4' epimerase (TbUDPGE PDB: 1GY8) as targets for studying the envisaged mechanism of action. Compounds 6j2 and 6b2 displayed excellent docking scores with -8.59 and -8.86 kcal/mol for TbTR and TbUDPGE, respectively.

Synthesis of novel norsufentanil analogs via a four-component Ugi reaction and in vivo, docking, and QSAR studies of their analgesic activity.

Novel substituted amino acid tethered norsufentanil derivatives were synthesized by the four-component Ugi reaction. Norsufentanil was reacted with succinic anhydride to produce the corresponding carboxylic acid. The resulting carboxylic acid has undergone a multicomponent reaction with different aldehydes, amines, and isocyanides to produce a library of the desired compounds. In all cases, amide bond rotation was observed in the NMR spectra. In vivo analgesic activity of the synthesized compounds was evaluated by a tail flick test. Very encouraging results were obtained for a number of the synthesized products. Some of the synthesized compounds such as 5a, 5b, 5h, 5j, and 5r were found to be more potent than sufentanil, sufentanil citrate, and norsufentanil. Binding modes between the compounds and mu and delta-opioid receptors were studied by molecular docking method. The relationship between the molecular structural features and the analgesic activity was investigated by a quantitative structure-activity relationship model. The results of the molecular modeling studies and the in vivo analgesic activity suggested that the majority of the synthesized compounds were more potent than sufentanil and norsufentanil.

Determination of Bortezomib in API Samples Using HPLC: Assessment of Enantiomeric and Diastereomeric Impurities.

A new, normal phase high performance liquid chromatography (NP-HPLC) method was developed for separation of Bortezomib (BZB) enantiomers and quantitative determination of (1S,2R)-enantiomer of BZB in active pharmaceutical ingredient (API) samples. The developed method was validated based on International Conference on Harmonisation (ICH) guidelines and it was proved to be accurate, precise and robust. The obtained resolution (RS) between the enantiomers was more than 2. The calibration curve for (1S,2R)-enantiomer was found to be linear in the concentration range of 0.24-5.36 mg/L with regression coefficient (R2) of 0.9998. Additionally, the limit of detection (LOD) and limit of quantification (LOQ) were 0.052 and 0.16 mg/L, respectively. Also, in this study, a precise, sensitive and robust gradient reversed-phase HPLC (RP-HPLC) method was developed and validated for determination of BZB in API samples. The detector response was linear over the concentration range of 0.26-1110.5 mg/L. The values of R2, LOD and LOQ were 0.9999, 0.084 and 0.25 mg/L, respectively. For both NP-HPLC and RP-HPLC methods, all of the RSD (%) values obtained in the precision study were <1.0%. System suitability parameters in terms of tailing factor (TF), number of theoretical plates (N) and RS were TF < 2.0, N > 2,000 and RS > 2.0. The performance of two common integration methods of valley to valley and drop perpendicular for drawing the baseline between two adjacent peaks were investigated for the determination of diastereomeric impurity (Imp-D) in the BZB-API samples. The results showed that the valley to valley method outperform the drop perpendicular method for calculation of Imp-D peak areas. Therefore, valley to valley method was chosen for peak integration.

Synthesis and in Vitro Antibacterial Evaluation of Novel 4-Substituted 1-Menthyl-1,2,3-triazoles.

Menthyl 1,4-disubstituted 1,2,3-triazole derivatives of hydroxybenzaldehydes, phenols and bile acids were synthesized via click chemistry. The novel synthesized compounds were evaluated for their in vitro antibacterial activity against Enterococcus faecium, and Staphylococcus aureus as Gram-positive bacteria. Some derivatives illustrated strong inhibitory effect against E. faecium with the minimum inhibitory concentration (MIC) values ranged from 1-3 µM, where cefixime as a positive control revealed MIC value of 35 µM. The structures of the synthesized compounds were confirmed by different spectroscopic techniques including 1H-NMR, 13C-NMR, high resolution (HR)-MS, IR and X-ray crystallographic analysis.

One-pot synthesis of 1,2,3-triazole linked dihydropyrimidinones via Huisgen 1,3-dipolar/Biginelli cycloaddition.

The combination of the Biginelli reaction with click chemistry has been used for the one-pot synthesis of 1,2,3-triazole linked dihydropyrimidinones from azides, aromatic aldehydes containing a propargyl ether group, urea, and 1,3-dicarbonyl compounds using Cu(OAc)(2)/sodium ascorbate as catalyst in acetic acid under mild reaction conditions.

Novel and efficient one-pot five- and six-component reactions for the stereoselective synthesis of highly functionalized enaminones and dithiocarbamates.

Efficient methods for stereoselective synthesis of polyfunctional (E)-enaminones and (Z)-dithiocarbamates via one-pot five- and six-component sequential Ugi/Nucleophilic addition reactions are described. High yields and high bond forming efficiency, and simple operations are the advantages of this method.

Six-component reactions for the stereoselective synthesis of 3-arylidene-2-oxindoles via sequential one-pot Ugi/Heck carbocyclization/Sonogashira/nucleophilic addition.

An efficient palladium-catalyzed protocol for the synthesis of 3-arylidene-2-oxindoles has been developed. In this approach, a sequential one-pot six-component reaction via Ugi/Heck carbocyclization/Sonogashira/nucleophilic addition was used for the synthesis of the desired skeleton.