Novel Thiosemicarbazone Derivatives: In Vitro and In Silico Evaluation as Potential MAO-B Inhibitors

MAO-B inhibitors are frequently used in the treatment of neurodegenerative diseases such as Parkinson’s and Alzheimer’s. Due to the limited number of compounds available in this field, there is a need to develop new compounds. In the recent works, it was shown that various thiosemicarbazone derivatives show hMAO inhibitory activity in the range of micromolar concentration. It is thought that benzofuran and benzothiophene structures may mimic structures such as indane and indanone, which are frequently found in the structures of such inhibitors. Based on this view, new benzofuran/benzothiophene and thiosemicarbazone hybrid compounds were synthesized, characterized and screened for their hMAO-A and hMAO-B inhibitory activity by an in vitro fluorometric method. The compounds including methoxyethyl substituent (2b and 2h) were found to be the most effective agents in the series against MAO-B enzyme with the IC50 value of 0.042 ± 0.002 µM and 0.056 ± 0.002 µM, respectively. The mechanism of hMAO-B inhibition of compounds 2b and 2h was investigated by Lineweaver–Burk graphics. Compounds 2b and 2h were reversible and non-competitive inhibitors with similar inhibition features as the substrates. The Ki values of compounds 2b and 2h were calculated as 0.035 µM and 0.046 µM, respectively, with the help of secondary plots. The docking study of compound 2b and 2h revealed that there is a strong interaction between the active sites of hMAO-B and analyzed compound.

Validation of chicken-specific pro-angiogenic growth factors three-dimensional structures and analysis of their role in high molecular weight heparin-induced angiogenesis

Background - High-molecular weight heparin (HMWH), a molecule which is extensively in use as an anticoagulant shows concentration-dependent angiogenic and anti-angiogenic potential. Based on the concentration, HMWH can bind with both angiogenic and anti-angiogenic factors and exerts diverse effect. Our earlier data suggested that HMWH (15 kDa) can induce concentration-dependent neovascularization on chicken chorioallantoic membrane (CAM). The diffusion pattern of HMWH through various layers of CAM supports its internalized action with the various cellular components of angiogenesis. So far, no studies have reported the interactive potential of HMWH with various pro-angiogenic growth factors under physiological conditions. Hence, we aimed to find the transcription level interaction of HMWH with major pro-angiogenic growth factors. In connection to the research, for the first time, we validated the three-dimensional structures of chicken-specific pro-angiogenic growth factors such as FGF2, MMP2, MMP9, NOS3, VEGF A, and VEGF C to find the binding affinity of HMWH with the core-functional units of these growth factors. Methods - CAMs are incubated with 50, 100, and 150 µM concentration of HMWH. Changes in the transcription level of specified pro-angiogenic growth factors are analyzed by semi-PCR method. The functional aspects of these molecules are identified with zymogram and immunohistochemical approaches. Scanning electron microscopic technique is applied to find the morphological changes on CAM under HMWH incubation. Three-dimensional structure validation and molecular docking are performed using the SWISS-MODEL web server and AutoDock vina-PyRx software version 8.0. Results - HMWH can enhance the transcription level of major pro-angiogenic growth factors with a significant impact on FGF2 and MMP2 under 100 µM concentration. The in-silico analysis reveals that HMWH shows a higher binding affinity with FGF2 followed by MMP2, MMP9, NOS3, VEGF A, and VEGF C, respectively. Conclusion - The combined results from the experimental and in-silico analysis reveal that HMWH can interact with pro-angiogenic growth factors under micromolar concentration in physiological conditions while inducing angiogenesis. This observation further supports the therapeutic benefits of HMWH as an angiogenic factor under micromolar concentration.

New sulphonamide pyrolidine carboxamide derivatives: Synthesis, molecular docking, antiplasmodial and antioxidant activities

Carboxamides bearing sulphonamide functionality have been shown to exhibit significant lethal effect on Plasmodium falciparum, the causative agent of human malaria. Here we report the synthesis of thirty-two new drug-like sulphonamide pyrolidine carboxamide derivatives and their antiplasmodial and antioxidant capabilities. In addition, molecular docking was used to check their binding affinities for homology modelled P. falciparum N-myristoyltransferase, a confirmed drug target in the pathogen. Results revealed that sixteen new derivatives killed the parasite at single-digit micromolar concentration (IC50 = 2.40–8.30 μM) and compounds 10b, 10c, 10d, 10j and 10o scavenged DPPH radicals at IC50s (6.48, 8.49, 3.02, 6.44 and 4.32 μg/mL respectively) comparable with 1.06 μg/mL for ascorbic acid. Compound 10o emerged as the most active of the derivatives to bind to the PfNMT with theoretical inhibition constant (Ki = 0.09 μM) comparable to the reference ligand pyrazole-sulphonamide (Ki = 0.01 μM). This study identifies compound 10o, and this series in general, as potential antimalarial candidate with antioxidant activity which requires further attention to optimise activity.

Synthesis and Anticancer Activity of Novel Oxadiazole Functionalized Pyrazolo[3,4-b]pyridine Derivatives

A series of novel oxadiazole functionalized pyrazolo[3,4-b]pyridine derivatives (6a-n)was synthesized using 6-thiophenyl-4-(trifluoromethyl)-1H-pyrazolo[3,4-b]pyridin-3-amine (1) through reaction with 2-bromoethyl acetate, followed by hydrazine hydrate to afford hydrazide derivatives (5). These compounds were further treated with aromatic acids in the presence of phosphoryl chloride and obtained oxadiazole functionalized pyrazolo[3,4-b]pyridine derivatives (6a-n). All the synthesized compounds 6a-n were screened for anticancer activity against four cancer cell lines such as HeLa - cervical cancer (CCL-2); COLO 205-colon cancer (CCL-222); HepG2-liver cancer (HB-8065); MCF7-breast cancer (HTB-22). Compounds 6i, 6m and 6n were found to have more prominent anticancer activity at micromolar concentration.

Synthesis and Anticancer Activity of Novel Amide Tagged Trifluoromethyl Indole and Pyrimido Indole Derivatives

A series of novel amide tagged trifluoromethyl indole and pyrimido indole derivatives 4a-e & 5a-e and 6a-d & 7a-d were synthesized from 4-methyl-2-(methylamino)-6-(trifluoromethyl)isophthalonitrile (1) on reaction with bromoethyl acetate to obtain 2a and 2b isomers. Compound 2a treated with hydrazine hydrate followed by Schiff base reaction to get compounds 4a-e. In another way, compound 2a on reaction with aliphatic primary amine to get compounds 6a-d. For cyclization, compounds 4a-e & 6a-d treated with trifluoroacetic acid to obtain compounds 5a-e and 7a-d, respectively. All the synthesized compounds 4a-e & 5a-e and 6a-d & 7a-d were tested for anticancer activity against four human cancer cell lines such as A549-lung cancer (CCL-185), MCF7-breast cancer (HTB-22), DU145-prostate cancer (HTB-81) and HeLa-cervical cancer (CCL-2). Compounds 9e and 9f were found to have promising anticancer activity at micromolar concentration.

Enantioselective Sensing of Insect Pheromones in Water

An arrayed combination of water-soluble deep cavitands and cationic dyes has been shown to optically sense insect pheromones at micromolar concentration in water. Machine learning approaches were used to optimize...

Enhancement of Anticancer Activity of N(4)1-(2-Pyridyl)piperazinyl 5-Nitroisatin Thiosemicarbazone on Chelation with Copper(II)

5-Nitroisatin-4-(1-(2-pyridyl)piperazinyl)-3-thiosemicarbazone (Nitistpyrdlpz) and its Cu(II) complex were synthesized and characterized by CHN and thermal analysis and spectroscopic measurements viz. UV-vis, FTIR, 1H NMR, 13C NMR, ESI-HRMS, PXRD and EPR. In the complex, copper(II) ion is coordinated by terdentate thiosemicarbazone anion and one chloride ion in a distorted square planar geometry. The synthesized compounds against breast cancer cell lines; MCF-7 and MDA-MB-231 and epidermoid carcinoma; A431 showed that the complex contributed to reduce the percentage of cell viability toward all the tested cell lines but remarkable contribution toward MDA-MB-231 cell line. The IC50 of the complex and free ligand was found in the range of IC50 0.85-1.24 μM and IC50 3.28-3.53 μM, respectively. Among those cell lines, the complex may be the better anticancer agent toward MDA-MB-231 because of its action at micromolar concentration (IC50 0.85 μM).

Targeting Breast Cancer Cells with G4 PAMAM Dendrimers and Valproic Acid Derivative Complexes

Background: Our research group has developed some Valproic Acid (VPA) derivatives employed as anti-proliferative compounds targeting the HDAC8 enzyme. However, some of these compounds are poorly soluble in water. Objective: Employed the four generations of Polyamidoamine (G4 PAMAM) dendrimers as drug carriers of these compounds to increase their water solubility for further in vitro evaluation. Methods: VPA derivatives were subjected to Docking and Molecular Dynamics (MD) simulations to evaluate their affinity on G4 PAMAM. Then, HPLC-UV/VIS, 1H NMR, MALDI-TOF and atomic force microscopy were employed to establish the formation of the drug-G4 PAMAM complexes. Results: The docking results showed that the amide groups of VPA derivatives make polar interactions with G4 PAMAM, whereas MD simulations corroborated the stability of the complexes. HPLC UV/VIS experiments showed an increase in the drug water solubility which was found to be directly proportional to the amount of G4 PAMAM. 1H NMR showed a disappearance of the proton amine group signals, correlating with docking results. MALDI-TOF and atomic force microscopy suggested the drug-G4 PAMAM dendrimer complexes formation. Discussion: In vitro studies showed that G4 PAMAM has toxicity in the micromolar concentration in MDAMB- 231, MCF7, and 3T3-L1 cell lines. VPA CF-G4 PAMAM dendrimer complex showed anti-proliferative properties in the micromolar concentration in MCF-7 and 3T3-L1, and in the milimolar concentration in MDAMB- 231, whereas VPA MF-G4 PAMAM dendrimer complex didn’t show effects on the three cell lines employed. Conclusion: These results demonstrate that G4 PAMAM dendrimers are capableof transporting poorly watersoluble aryl-VPA derivate compounds to increase its cytotoxic activity against neoplastic cell lines.

Synthesis and Cytotoxic Activity of New Vindoline Derivatives Coupled to Natural and Synthetic Pharmacophores

New Vinca alkaloid derivatives were synthesized to improve the biological activity of the natural alkaloid vindoline. To this end, experiments were performed to link vindoline with various structural units, such as amino acids, a 1,2,3-triazole derivative, morpholine, piperazine and N-methylpiperazine. The structure of the new compounds was characterized by NMR spectroscopy and mass spectrometry (MS). Several compounds exhibited in vitro antiproliferative activity against human gynecological cancer cell lines with IC50 values in the low micromolar concentration range.