Synthesis of Novel 8-Hydroxyquinoline Derivatives through Mannich Reaction and their Biological Evaluation as Potential Immunomodulatory Agents.

BACKGROUND: In continuation of our work on Mannich reaction on 8-hydroxyquinoline, fifteen different combinations of aromatic aldehydes and aniline were subjected to Mannich reaction from which twelve products (eight Mannich bases, two imines and two intramolecularly cyclized products with benzofuranone skeleton) were obtained. Among them six compounds (1, 2, 6, 8, 9 and 12) are the new compounds. The structures of the compounds were characterized by UV, IR, MS and 1H NMR. METHODS: The compounds were tested for the inhibition of pro-inflammatory cytokines tumor necrosis factor-α (TNF-α) and Interleukin-1ß (IL-1ß) at a concentration of 25 µg/mL. The cytokines were produced by THP-1 cells differentiated with PMA for 24hrs and stimulated with LPS for 4 hrs and supernatant were analyzed through ELISA technique. RESULTS AND DISCUSSION: Compounds 1-5, 8 and 9 inhibited the production of TNF-α and IL-1ß. Compounds 1, 3, and 8 exerted potent inhibitions of TNF-α with 71%, 71%, and 83% inhibition, respectively. Compounds 1 and 8 significantly inhibited the production of IL-1ß with 64% and 78% inhibition, respectively. CONCLUSION: Compounds 1 and 8 significantly inhibited the production of IL-1ß with 64% and 78% inhibition, respectively. Notably compound 8 showed the most potent inhibition of these cytokines. Additionally, the effect of compounds on viability of THP-1 cells was also evaluated. Moreover, molecular docking was carried out to study the mechanism of inhibition of TNF-α production.

Discovering Novel Alternaria solani Succinate Dehydrogenase Inhibitors by in Silico Modeling and Virtual Screening Strategies to Combat Early Blight.

Alternaria blight is an important foliage disease caused by Alternaria solani. The enzyme Succinate dehydrogenase (SDH) is a potential drug target because of its role in tricarboxylic acid cycle. Hence targeting Alternaria solani SDH enzyme could be efficient tool to design novel fungicides against A. solani. We employed computational methodologies to design new SDH inhibitors using homology modeling; pharmacophore modeling and structure based virtual screening. The three dimensional SDH model showed good stereo-chemical and structural properties. Based on virtual screening results twelve commercially available compounds were purchased and tested in vitro and in vivo. The compounds were found to inhibit mycelial growth of A. solani. Moreover in vitro trials showed that inhibitory effects were enhanced with increase in concentrations. Similarly increased disease control was observed in pre-treated potato tubers. Hence the applied in silico strategy led us to identify novel fungicides.

Targeting Dengue Virus NS-3 Helicase by Ligand based Pharmacophore Modeling and Structure based Virtual Screening.

Dengue fever is an emerging public health concern, with several million viral infections occur annually, for which no effective therapy currently exist. Non-structural protein 3 (NS-3) Helicase encoded by the dengue virus (DENV) is considered as a potential drug target to design new and effective drugs against dengue. Helicase is involved in unwinding of dengue RNA. This study was conducted to design new NS-3 Helicase inhibitor by in silico ligand- and structure based approaches. Initially ligand-based pharmacophore model was generated that was used to screen a set of 1201474 compounds collected from ZINC Database. The compounds matched with the pharmacophore model were docked into the active site of NS-3 helicase. Based on docking scores and binding interactions, 25 compounds are suggested to be potential inhibitors of NS3 Helicase. The pharmacokinetic properties of these hits were predicted. The selected hits revealed acceptable ADMET properties. This study identified potential inhibitors of NS-3 Helicase in silico, and can be helpful in the treatment of Dengue.

The immunomodulation potential of the synthetic derivatives of benzothiazoles: Implications in immune system disorders through in vitro and in silico studies.

Benzothiazole and its natural or synthetic derivatives have been used as precursors for several pharmacological agents for neuroprotective, anti-bacterial, and anti-allergic activities. The objective of the present study was to evaluate effects of benzothiazole analogs (compounds 1-26) for their immunomodulatory activities. Eight compounds (2, 4, 5, 8-10, 12, and 18) showed potent inhibitory activity on PHA-activated peripheral blood mononuclear cells (PBMCs) with IC50 ranging from 3.7 to 11.9 µM compared to that of the standard drug, prednisolone <1.5 µM. Some compounds (2, 4, 8, and 18) were also found to have potent inhibitory activities on the production of IL-2 on PHA/PMA-stimulated PBMCs with IC50 values ranging between <4.0 and 12.8 µM. The binding interaction of these compounds was performed through silico molecular docking. Compounds 2, 8, 9, and 10 significantly suppressed oxidative burst ROS production in phagocytes with IC50 values between <4.0 and 15.2 µM. The lipopolysaccharide (LPS)-induced nitrites in murine macrophages cell line J774 were found to be inhibited by compounds 4, 8, 9, and 18 at a concentration of 25 µg/mL by 56%, 91%, 58%, and 78%, respectively. Furthermore, compounds 5, 8, 12, and 18 showed significant (P<0.05) suppressive activity on Th-2 cytokine, interleukin 4 (IL-4) with an IC50 range of <4.0 to 40.3 µM. Interestingly compound 4 has shown a selective inhibitory activity on IL-2 and T cell proliferation (naïve T cell proliferation stage) rather than on IL-4 cytokine, while compound 12 displayed an interference with T-cell proliferation and IL-4 generation. Moreover compound 8 and 18 exert non-selective inhibition on both IL-2 and IL-4 cytokines, indicating a better interference with stage leading to humoral immune response and hence possible application in autoimmune diseases.

Structure-based design, synthesis and biological evaluation of ß-glucuronidase inhibitors.

Using structure-based virtual screening approach, a coumarin derivative (1) was identified as ß-glucuronidase inhibitor. A focused library of coumarin derivatives was synthesized by eco-benign version of chemical reaction, and all synthetic compounds were characterized by using spectroscopy. These compounds were found to be inhibitor of ß-glucuronidase with IC50 values in a micromolar range. All synthetic compounds exhibited interesting inhibitory activity against ß-glucuronidase, however, their potency varied substantially from IC50 = 9.9-352.6 µM. Of twenty-one compounds, four exhibited a better inhibitory profile than the initial hit 1. Interestingly, compounds 1e, 1k, 1n and 1p exhibited more potency than the standard inhibitor with IC50 values 34.2, 21.4, 11.7, and 9.9 µM, respectively. We further studied their dose responses and also checked our results by using detergent Triton ×-100. We found that our results are true and not affected by detergent.

In silico and in vitro immunomodulatory studies on compounds of Lindelofia stylosa.

Lindolefia stylosa (Kar. and Kir.) is an important medicinal plant in Central and West Asia. Compounds 1 (ethyl lithospermate), 2 (methyl lithospermate), 3 (lithospermate B), 4 (rosmarinic acid), 5 (methyl rosmarinate), 6 (ethyl rosmarinate), 7 (3-O-feruloyl-6'-O-coumaroyl sucrose), 8 (3-O-feruloyl-6'-O-caffeoyl sucrose), 9 (3,6'-O-diferuloyl sucrose), 10 (3,6'-O-diferuloyl-1-kestose), 11 (3-O-feruloyl-6'-O-coumaroyl-1-kestose), 12 (3,6'-O-diferuloyl nystose), 13 (3-O-Feruloyl-6'-O-coumaroyl nystose), 14 (p-coumaric acid), 15 (ferulic acid), 16 (naphthalene glycoside (8-O-ß-D-glucopyranoside)), and 17 (4'-hydroxy-5-methoxy-6,7-methylenedioxyisoflavone), isolated from this plant, were evaluated for their ability to modulate the immune response. Studies included monitoring the effect on reactive oxygen species (ROS) production, T-lymphocyte proliferation, and inhibition of four cytokines (IL-2, TNFα, IL-1ß, and IL-4). These cytokines play a major role in immune response modulation. Molecular docking studies on selected compounds were also conducted, which predict a potent activity of compounds 5 and 6 and moderate activity of compounds 1 and 2 as inhibitors of IL-2. Correlation between the predicted binding scores and the experimental results was found to be valid. Compound 5 was identified as the most potent IL-2 inhibitor in the series.

Immunosuppressive activity of buxidin and E-buxenone from Buxus hyrcana.

Buxidin (1) and E-Buxenone (2), steroidal alkaloids from Buxus hyrcana, are found to possess potent immunosuppressive properties. The activity was tested in vitro on oxidative burst, chemotaxis, T-cell proliferation, and cytokine production. Both compounds showed a significant immunomodulatory activity with clear suppressive effect on oxidative burst and chemotaxis in a dose-dependent manner. They also exhibited suppressive effect on the phytohemagglutinin-stimulated T-cell proliferation. The immunomodulatory activity was further confirmed by the suppression of IL-2 and IL-4 production. Furthermore, molecular docking studies were performed to investigate the binding mode of Buxidin (1) and E-Buxenone (2) with IL-2. Despite the structural differences between Buxidin (1) and E-Buxenone (2), docking results revealed that they adopt a similar binding pattern at the active site of the IL-2. A good agreement between practical and theoretic results indicates that the current docking study could provide an alternate tool for the structural optimization of recently identified ligand as more potent IL-2 inhibitors.