72 results on '"Krishna VS"'
Search Results
2. Contemporary era of Three-dimensional printing in pediatric dentistry: An overview
- Author
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Sai Sankar, AJ, primary, Shaheen, ShaikRabiya, additional, Sridevi, E, additional, S Krishna, VS, additional, Sridhar, M, additional, and Sankar, KSiva, additional
- Published
- 2023
- Full Text
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3. RP-HPLC Method for Development and Validation of Dasatinib in Bulk, Tablets Applied in Nano suspension, Drug Entrapment Efficiency and Serum
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Krishna Vs and Alekhya Ch
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Drug ,Dasatinib ,Entrapment ,Chromatography ,Chemistry ,media_common.quotation_subject ,Nano ,medicine ,Suspension (vehicle) ,media_common ,medicine.drug - Published
- 2020
4. Characterization of spray deposited ternary ZnSxSe(1-x) thin films for solar cell buffers
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M.G. Mahesha and Ganesha Krishna Vs
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Materials science ,Band gap ,Analytical chemistry ,General Physics and Astronomy ,02 engineering and technology ,Surfaces and Interfaces ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Copper indium gallium selenide solar cells ,0104 chemical sciences ,Surfaces, Coatings and Films ,law.invention ,symbols.namesake ,Van der Pauw method ,Lattice constant ,Electrical resistance and conductance ,law ,Solar cell ,symbols ,Thin film ,0210 nano-technology ,Raman spectroscopy - Abstract
This paper reports on cadmium free, environment friendly, industrially beneficial, chemically sprayed ZnSxSe(1-x) (ZSS) thin films with tunable band gap which is suitable for various optoelectronic applications including buffer layer in solar cells. Chemically sprayed ZSS thin films with x ranging from 0 to 1 were studied extensively by adopting the characterization techniques like X-ray diffractometry (XRD), Scanning electron microscopy with energy dispersive spectroscopy (SEM-EDAX), Ultraviolet – visible (UV–VIS), Photoluminescence (PL) and Raman spectroscopies in order to assess the suitability of the formed thin film for the buffer layer applications. XRD analysis was done to determine various parameters like lattice constant, crystallite size, strain and dislocation density. From lattice constant, Vegard's law was also verified and compared the composition estimation with EDAX data. Refractive index was compared using Vandemme model with the values obtained using reflectance data. Photoluminescence and Raman spectra were analyzed to get an insight on structural defects, which have major role in deciding the electrical properties. Electrical properties were assessed by estimating carrier concentration, carrier mobility and electrical resistivity by adopting Van der Pauw technique. Based on structural, optical and electrical properties, sample with x = 0.4 is suggested for the buffer layer application in CIGS based solar cells, which produces minimum lattice mismatch with considerably high optical transmittance and electrical conductance.
- Published
- 2020
5. MIMO-WDM Visible Light Communications Based on Commercial RGBA LEDs
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Ivan B. Djordjevic and Rakesh Mohan Krishna Vs
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Computer science ,business.industry ,MIMO ,Visible light communication ,02 engineering and technology ,01 natural sciences ,law.invention ,010309 optics ,020210 optoelectronics & photonics ,Transmission (telecommunications) ,Modulation ,law ,Wavelength-division multiplexing ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Optoelectronics ,business ,Light-emitting diode - Abstract
This paper considers a multi-input multi-output visible light communication (MIMO-WDM VLC) system using commercial four-color Red-Green-Blue-Amber (RGBA) LEDs using discrete multi-tone (DMT) modulation. The proposed 2×2 MIMO-VLC system offers an aggregate data transmission of over 120 Mb/s using over transmission distance of over 80 cm with bit-error rates below 2×10−3.
- Published
- 2018
6. DMT visible light communication using commercial RGBA LEDs
- Author
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Ivan B. Djordjevic and Rakesh Mohan Krishna Vs
- Subjects
Transmission (telecommunications) ,Computer science ,Gigabit ,Electronic engineering ,Bit error rate ,Visible light communication ,Forward error correction ,Multiplexing ,Quadrature amplitude modulation ,Data transmission - Abstract
VLC systems using commercial light emitting diode (LED) offer provision of simultaneous data transmission and illumination. However, limited modulation bandwidth and non-linear distortions are the main challenges faced by VLC designs in achieving high transmission data rates. Wavelength-division multiplexing in VLC (WDM-VLC) can improve the data rates to meet gigabit/s data standards. In this paper, we study the VLC data transmission using a commercially available red-green-blue-amber (RGBA) LED model. With quadrature amplitude modulation based discrete multi-tone (QAM-DMT) transmission, we demonstrate that proposed VLC system can achieve aggregate transmission rate of 2.1 Gb/s at bit error rate (BER) well below 2×10-3, which is typical hard-decision forward error correction (FEC) threshold.
- Published
- 2018
7. Asymmetric-Pulse Shaping Technique Using Fiber Bragg Grating
- Author
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Krishna, VS Rakesh, primary and Shivaleela, E.S., additional
- Published
- 2017
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8. Bidirectional 64-QAM OFDM-over-fiber transmission on single carrier PON
- Author
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Krishna, VS Rakesh, primary, Singla, Nitin, additional, Balani, Lovena, additional, and Singhal, Rahul, additional
- Published
- 2015
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9. Original article. Unpredictable cyclosporin-fluconazole interaction in renal transplant recipients.
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Sud, K, Singh, B, Krishna, VS, Thennarasu, K, Kohli, HS, Jha, V, Gupta, KL, and Sakhuja, V
- Abstract
Background: Cyclosporin (CsA) is metabolized primarily in the liver by cytochrome P-450 enzymes. Concomitant use of fluconazole can increase CsA concentrations by inhibiting this enzyme system and the effect seems to be dose dependent, with no interaction noted when fluconazole is used in a dose of 100 mg/day. Two previous investigations studying this interaction while using higher doses of fluconazole have provided inconsistent results. Recommendations advising an empirical 50% CsA dosage reduction in these patients have not been tested in a prospective trial. [ABSTRACT FROM PUBLISHER]
- Published
- 1999
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10. Proportional sway-based electrotactile feedback improves lateral standing balance.
- Author
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Raghav Hari Krishna VS, Kim J, Chang SH, Choe Y, and Park H
- Abstract
Introduction: Plantar cutaneous augmentation is a promising approach in balance rehabilitation by enhancing motion-dependent sensory feedback. The effect of plantar cutaneous augmentation on balance has been mainly investigated in its passive form (e.g., textured insole) or on lower-limb amputees. In this study, we tested the effect of plantar cutaneous augmentation on balance in its active form (i.e., electrical stimulation) for individuals with intact limbs., Methods: Ten healthy subjects participated in the study and were instructed to maintain their balance as long as possible on the balance board, with or without electrotactile feedback evoked on the medial side of the heel, synched with the lateral board sway. Electrotactile feedback was given in two different modes: 1) Discrete-mode E-stim as the stimulation on/off by a predefined threshold of lateral board sway and 2) Proportional-mode E-stim as the stimulation frequency proportional to the amount of lateral board sway. All subjects were distracted from the balancing task by the n-back counting task, to test subjects' balancing capability with minimal cognitive involvement., Results: Proportional-mode E-stim, along with the n-back counting task, increased the balance time from 1.86 ± 0.03 s to 1.98 ± 0.04 s ( p = 0.010). However, discrete-mode E-stim did not change the balance time ( p = 0.669). Proportional-mode E-stim also increased the time duration per each swayed state ( p = 0.035) while discrete-mode E-stim did not ( p = 0.053)., Discussion: These results suggest that proportional-mode E-stim is more effective than discrete-mode E-stim on improving standing balance. It is perhaps because the proportional electrotactile feedback better mimics the natural tactile sensation of foot pressure than its discrete counterpart., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Raghav Hari Krishna, Kim, Chang, Choe and Park.)
- Published
- 2024
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11. Reusable Floating Spherical Hydrogel Evaporator for Solar Desalination with Salt Mitigation and Contaminant Elimination.
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Chaw Pattnayak B, Krishna VS, Sahu BK, and Mohapatra S
- Abstract
The generation of clean and drinkable fresh water from seawater and contaminated water holds great potential to mitigate water scarcity. Herein, a floating spherical hydrogel evaporator (SHE) is designed to achieve sunlight-driven desalination, self-salt cleaning, and removal of environmental contaminants. The spherical lightweight polystyrene is coated with a porous carbon-embedded sodium alginate/PVA/CMC photothermal hydrogel to generate a spherical hydrogel evaporator (SHE) that floats naturally. The SHE is very sensitive to the weight imbalance (500 mg) and can respond quickly to the accumulation of salt by rotation to the fresh evaporation surface, realizing excellent antisalt fouling performance. Remarkably, with energy localization by porous carbon, the spherical floating evaporator achieved a high evaporation rate of 2.65 kg m
-2 h-1 with an evaporation efficiency of 98%. At the same time, SHE is also capable of adsorbing both organic contaminants and heavy metal ions through functional groups of the hydrogel, attaining 99% removal efficiency. Overall, this low-cost spherical floating evaporator may offer solution for eco-friendly and sustainable production of fresh water on a large scale.- Published
- 2023
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12. A Radiohistographic Analysis of Growth Factor-Mediated Sinus Augmentation in Atrophic Maxillae: A 30-Month Follow-up Study.
- Author
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Gayatri PSD, Kumar ABT, Shah R, Gowda TM, and Krishna VS
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- Humans, Animals, Cattle, Follow-Up Studies, Maxilla diagnostic imaging, Maxilla surgery, Becaplermin, Bone Regeneration, Maxillary Sinus diagnostic imaging, Maxillary Sinus surgery, Bone Transplantation methods, Dental Implantation, Endosseous methods, Alveolar Ridge Augmentation methods, Sinus Floor Augmentation methods
- Abstract
A total of 20 atrophic maxillary sinuses were augmented with recombinant human platelet-derived growth factor BB (rhPDGF-BB), alloplast, and bovine xenograft using a direct approach. CBCT imaging was performed at baseline, immediately postoperatively, and at 6 and 30 months postoperatively. A histologic evaluation revealed the bone bridging and bone regenerative efficacy of the graft material. Radiographic evaluation determined the ridge height (H) and volume of the graft (V) to be as 3.02 ± 1.35 mm at baseline (H0), 15.18 ± 2.52 mm (H1) and 1,106.10 ± 398.84 mm3 (V1) immediately postoperatively, 14.79 ± 2.30 mm (H2) and 1,086.95 ± 396.86 mm3 (V2) at 6 months, and 1,058 ± 391.83 mm3 (V3) at 30 months, with a significant gain in the residual ridge height at 6 months and no significant loss or gain in sinus volume postoperatively.
- Published
- 2023
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13. Spatiotemporal visual statistics of aquatic environments in the natural habitats of zebrafish.
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Cai LT, Krishna VS, Hladnik TC, Guilbeault NC, Vijayakumar C, Arunachalam M, Juntti SA, Arrenberg AB, Thiele TR, and Cooper EA
- Subjects
- Animals, Visual Fields, Ecosystem, Brain, Zebrafish, Visual Perception
- Abstract
Animal sensory systems are tightly adapted to the demands of their environment. In the visual domain, research has shown that many species have circuits and systems that exploit statistical regularities in natural visual signals. The zebrafish is a popular model animal in visual neuroscience, but relatively little quantitative data is available about the visual properties of the aquatic habitats where zebrafish reside, as compared to terrestrial environments. Improving our understanding of the visual demands of the aquatic habitats of zebrafish can enhance the insights about sensory neuroscience yielded by this model system. We analyzed a video dataset of zebrafish habitats captured by a stationary camera and compared this dataset to videos of terrestrial scenes in the same geographic area. Our analysis of the spatiotemporal structure in these videos suggests that zebrafish habitats are characterized by low visual contrast and strong motion when compared to terrestrial environments. Similar to terrestrial environments, zebrafish habitats tended to be dominated by dark contrasts, particularly in the lower visual field. We discuss how these properties of the visual environment can inform the study of zebrafish visual behavior and neural processing and, by extension, can inform our understanding of the vertebrate brain., (© 2023. Crown.)
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- 2023
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14. Isoniazid Linked to Sulfonate Esters via Hydrazone Functionality: Design, Synthesis, and Evaluation of Antitubercular Activity.
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Koçak Aslan E, Han Mİ, Krishna VS, Tamhaev R, Dengiz C, Doğan ŞD, Lherbet C, Mourey L, Tønjum T, and Gündüz MG
- Abstract
Isoniazid (INH) is one of the key molecules employed in the treatment of tuberculosis (TB), the most deadly infectious disease worldwide. However, the efficacy of this cornerstone drug has seriously decreased due to emerging INH-resistant strains of Mycobacterium tuberculosis ( Mtb ). In the present study, we aimed to chemically tailor INH to overcome this resistance. We obtained thirteen novel compounds by linking INH to in-house synthesized sulfonate esters via a hydrazone bridge ( SIH1-SIH13 ). Following structural characterization by FTIR,
1 H NMR,13 C NMR, and HRMS, all compounds were screened for their antitubercular activity against Mtb H37Rv strain and INH-resistant clinical isolates carrying katG and inhA mutations. Additionally, the cytotoxic effects of SIH1-SIH13 were assessed on three different healthy host cell lines; HEK293, IMR-90, and BEAS-2B. Based on the obtained data, the synthesized compounds appeared as attractive antimycobacterial drug candidates with low cytotoxicity. Moreover, the stability of the hydrazone moiety in the chemical structure of the final compounds was confirmed by using UV/Vis spectroscopy in both aqueous medium and DMSO. Subsequently, the compounds were tested for their inhibitory activities against enoyl acyl carrier protein reductase (InhA), the primary target enzyme of INH. Although most of the synthesized compounds are hosted by the InhA binding pocket, SIH1-SIH13 do not primarily show their antitubercular activities by direct InhA inhibition. Finally, in silico determination of important physicochemical parameters of the molecules showed that SIH1-SIH13 adhered to Lipinski's rule of five. Overall, our study revealed a new strategy for modifying INH to cope with the emerging drug-resistant strains of Mtb .- Published
- 2022
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15. Urea derivatives carrying a thiophenylthiazole moiety: Design, synthesis, and evaluation of antitubercular and InhA inhibitory activities.
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Keleş Atıcı R, Doğan ŞD, Gündüz MG, Krishna VS, Chebaiki M, Homberset H, Lherbet C, Mourey L, and Tønjum T
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- Antitubercular Agents chemistry, Microbial Sensitivity Tests, Molecular Docking Simulation, Bacterial Proteins, Urea pharmacology
- Abstract
The recent emergence of drug-resistant strains of Mycobacterium tuberculosis (Mtb) has complicated and significantly slowed efforts to eradicate and/or reduce the worldwide incidence of life-threatening acute and chronic cases of tuberculosis. To overcome this setback, researchers have increased the intensity of their work to identify new small-molecule compounds that are expected to remain efficacious antimicrobials against Mtb. Here, we describe our effort to apply the principles of molecular hybridization to synthesize 16 compounds carrying thiophene and thiazole rings beside the core urea functionality (TTU1-TTU16). Following extensive structural characterization, the obtained compounds were initially evaluated for their antimycobacterial activity against Mtb H37Rv. Subsequently, three derivatives standing out with their anti-Mtb activity profiles and low cytotoxicity (TTU5, TTU6, and TTU12) were tested on isoniazid-resistant clinical isolates carrying katG and inhA mutations. Additionally, due to their pharmacophore similarities to the well-known InhA inhibitors, the molecules were screened for their enoyl acyl carrier protein reductase (InhA) inhibitory potentials. Molecular docking studies were performed to support the experimental enzyme inhibition data. Finally, drug-likeness of the selected compounds was established by theoretical calculations of physicochemical descriptors., (© 2022 Wiley Periodicals LLC.)
- Published
- 2022
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16. Design and characterisation of piperazine-benzofuran integrated dinitrobenzenesulfonamide as Mycobacterium tuberculosis H37Rv strain inhibitors.
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Murthy VS, Tamboli Y, Krishna VS, Sriram D, Akber Ansari S, Alarfaj AA, Hirad AH, and Vijayakumar V
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- Amides chemistry, Cell Line, Tumor, Drug Screening Assays, Antitumor, Humans, Microbial Sensitivity Tests, Molecular Docking Simulation, Spectrum Analysis methods, Antitubercular Agents chemistry, Antitubercular Agents pharmacology, Benzenesulfonates chemistry, Benzofurans chemistry, Drug Design, Mycobacterium tuberculosis drug effects, Piperazine chemistry
- Abstract
Molecular hybridisation of four bioactive fragments piperazine, substituted-benzofuran, amino acids, and 2,4-dinitrobenzenesulfonamide as single molecular architecture was designed. A series of new hybrids were synthesised and subjected to evaluation for their inhibitory activity against Mycobacterium tuberculosis ( Mtb ) H37Rv. 4d - f and 4o found to exhibit MIC as 1.56 µg/mL, equally active as ethambutol whereas 4a, 4c, 4j displayed MIC 0.78 µg/mL were superior to ethambutol. Tested compounds demonstrated an excellent safety profile with very low toxicity, good selectivity index, and antioxidant properties. All the newly synthesised compounds were thoroughly characterised by analytical methods. The result was further supported by molecular modelling studies on the crystal structure of Mycobacterium tuberculosis enoyl reductase.
- Published
- 2021
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17. Mimicking the Energy Funnel of the Photosynthetic Unit Using a Dendrimer-Dye Supramolecular Assembly.
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Rama Krishna VS, Adak S, Jana P, Bheemireddy V, and Bandyopadhyay S
- Abstract
Photosynthesis involves light-harvesting complexes where an array of antenna pigment channels the absorbed solar energy to the reaction centre of a photosystem. This work reports a supramolecular dendrimer-dye assembly that mimics the natural light-harvesting mechanism. A dendrimeric molecule based on two-fluorophores has been constructed with three coumarin units at the end of three long arms and a 7-diethylaminocoumarin unit at the interior. The molecule self-aggregates in water into spherical micelles, which can encapsulate a rose-bengal dye (RB). On excitation, peripheral coumarin units shuttled the energy to the loaded RB dye reaction center via a two-step cascade resonance energy transfer (RET). The energy absorbed in the periphery is funnelled efficiently, resulting in a strong emission from the dye that resembles an energy funnel. The energy transfer cascade has been studied with both steady-state and time-resolved fluorescence spectroscopy. Molecular dynamics simulations of the self-assembled aggregates in water were also in agreement with the experimental observations., (© 2021 Wiley-VCH GmbH.)
- Published
- 2021
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18. Synthesis and Biological Evaluation of Novel Benzhydrylpiperazine-Coupled Nitrobenzenesulfonamide Hybrids.
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Murthy VS, Tamboli Y, Krishna VS, Sriram D, Zhang FX, Zamponi GW, and Vijayakumar V
- Abstract
A series of novel benzhydryl piperazine-coupled nitrobenzenesulfonamide hybrids were synthesized with good to excellent yields. They were tested for in vitro inhibition of mycobacterial activity against the Mycobacterium tuberculosis H37Rv strain, in vitro cytotoxicity MTT (RAW 264.7cells) assay, nutrient starvation (H37Rv strain), and ability to block Cav3.2 T-type calcium channels. Novel hybrids did not inhibit T-type calcium channels, whereas they showed excellent antituberculosis (TB) activity and low cytotoxicity with a selectivity index of >30. A direct impact of the amino acid linker was not observed. Studied hybrids exhibited good inhibition activities, and the 2,4-dinitrobenzenesulfonamide group emerged as a promising scaffold for further drug design by hybridization approaches for anti-TB therapy., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)
- Published
- 2021
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19. Design and Synthesis of "Chloropicolinate Amides and Urea Derivatives" as Novel Inhibitors for Mycobacterium tuberculosis .
- Author
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Konduri S, Bhargavi D, Prashanth J, Krishna VS, Sriram D, and Rao KP
- Abstract
A series of 30 novel diamino phenyl chloropicolinate fettered carboxamides, urea, and thiourea derivatives were synthesized by coupling of methyl 4-amino-6-(2-aminophenyl)-3-chloropyridine-2-carboxylate with different acid chlorides, urea, and thiourea moieties, respectively. All of these compounds were characterized by
1 H and13 C nuclear magnetic resonance spectroscopy, CHN analysis, and high-resolution mass spectra for confirmation of the structures. Two compounds were also characterized by single-crystal X-ray diffraction analysis to confirm the structures obtained by spectral analysis. All these 30 compounds were tested for their in vitro antimycobacterial activity using the microplate alamar blue assay method against Mycobacterium tuberculosis . Five compounds have shown good minimum inhibitory concentration (MIC) values with low cytotoxicity when compared with the reference drugs. Moreover, some of the compounds have high MIC values compared with isoniazid, rifampicin, and so forth and also had shown good reign in the spread of bacteria by the nutrient starvation model. These antimycobacterial activity results have shown a good correlation with molecular docking model analysis with the inhibitors MurB by exhibiting strong interactions. Some of these compounds could be promising candidates against M. tuberculosis for future preclinical agent drug development., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)- Published
- 2021
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20. Synthesis and antimicrobial evaluation of new nitric oxide-donating fluoroquinolone/oxime hybrids.
- Author
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Aziz HA, Moustafa GAI, Abuo-Rahma GEA, Rabea SM, Hauk G, Krishna VS, Sriram D, Berger JM, and Abbas SH
- Subjects
- Anti-Bacterial Agents chemical synthesis, Anti-Bacterial Agents chemistry, Antitubercular Agents chemical synthesis, Antitubercular Agents chemistry, Antitubercular Agents pharmacology, Bacteria drug effects, Ciprofloxacin pharmacology, Fluoroquinolones chemical synthesis, Fluoroquinolones chemistry, Microbial Sensitivity Tests, Models, Molecular, Nitric Oxide metabolism, Nitric Oxide Donors chemical synthesis, Nitric Oxide Donors chemistry, Oximes chemical synthesis, Oximes chemistry, Structure-Activity Relationship, Anti-Bacterial Agents pharmacology, Fluoroquinolones pharmacology, Nitric Oxide Donors pharmacology, Oximes pharmacology
- Abstract
A new series of nitric oxide-donating fluoroquinolone/oximes was prepared in this study. The nitric oxide release from the prepared compounds was measured using a modified Griess colorimetric method. The antitubercular evaluation of the synthesized compounds indicated that ketone derivatives 2b and 2e and oximes 3b and 3d exhibited somewhat higher activity than their respective parent fluoroquinolones. Mycobacterial DNA cleavage studies and molecular modeling of Mycobacterium tuberculosis DNA gyrase were pursued to explain the observed bioactivity. More important, antibacterial evaluation showed that oximes 3c-e are highly potent against Klebsiella pneumoniae, with minimum inhibitory concentration (MIC) values of 0.06, 0.08, and 0.034 µM, respectively, whereas ketone 2c and oxime 4c are more active against Staphylococcus aureus than ciprofloxacin (MIC values: 0.7, 0.38, and 1.6 µM, respectively). Notably, the antipseudomonal activities of compounds 2a and 4c were much higher than those of their respective parent fluoroquinolones., (© 2020 Deutsche Pharmazeutische Gesellschaft.)
- Published
- 2021
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21. Design and synthesis of new indanol-1,2,3-triazole derivatives as potent antitubercular and antimicrobial agents.
- Author
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Phatak PS, Bakale RD, Kulkarni RS, Dhumal ST, Dixit PP, Krishna VS, Sriram D, Khedkar VM, and Haval KP
- Subjects
- Antitubercular Agents chemical synthesis, Antitubercular Agents chemistry, Dose-Response Relationship, Drug, HEK293 Cells, Humans, Microbial Sensitivity Tests, Molecular Structure, Structure-Activity Relationship, Triazoles chemical synthesis, Triazoles chemistry, Antitubercular Agents pharmacology, Drug Design, Mycobacterium tuberculosis drug effects, Triazoles pharmacology
- Abstract
In a search of new antitubercular agents, herein we have reported a series of new thirty-two indanol-1,2,3-triazole derivatives. The synthesized compounds were screened for their in vitro antitubercular and antimicrobial activities. Among the screened compounds, most of the compounds have displayed good antitubercular activity against Mycobacterium tuberculosis H37Rv. The compound 5g has been identified as potent antitubercular agent with MIC value 1.56 µM. The most active compounds of the series were further studied for their cytotoxicity against HEK 293 cells using MTT assay and found to be nontoxic. In addition, ten compounds were shown good antimicrobial activities against both antibacterial and antifungal pathogens. A molecular docking study against Mycobacterial enoyl-ACP-reductase (InhA) was performed to gain an insight into the molecular mechanism of antitubercular action. The pharmacokinetic parameters of these compounds were studied and displayed acceptable drug-likeness score., (Copyright © 2020 Elsevier Ltd. All rights reserved.)
- Published
- 2020
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22. Design and synthesis of purine connected piperazine derivatives as novel inhibitors of Mycobacterium tuberculosis.
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Konduri S, Prashanth J, Krishna VS, Sriram D, Behera JN, Siegel D, and Rao KP
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- Antitubercular Agents chemical synthesis, Antitubercular Agents chemistry, Dose-Response Relationship, Drug, Microbial Sensitivity Tests, Molecular Structure, Piperazine chemical synthesis, Piperazine chemistry, Purines chemical synthesis, Purines chemistry, Structure-Activity Relationship, Antitubercular Agents pharmacology, Drug Design, Mycobacterium tuberculosis drug effects, Piperazine pharmacology, Purines pharmacology
- Abstract
A series of novel purine linked piperazine derivatives were synthesized to identify new, potent inhibitors of Mycobacterium tuberculosis. The compounds were designed to target MurB disrupting the biosynthesis of the peptidoglycan and exert antiproliferative effects. The first series of purine-2,6-dione linked piperazine derivatives were synthesized using an advanced intermediate 1-(3,4-difluorobenzyl)-7-(but-2-ynyl)-3-methyl-8-(piperazin-1-yl)-1H-purine-2,6(3H,7H)-dione hydrochloride (6) which was coupled with varied carboxylic acid chloride derivatives. Following this piperazine linked derivatives were also synthesized from 6 using diverse isocyanate partners. The anti-mycobacterial activity of the analogues was tested againstMycobacterium tuberculosis H37Rv which revealed a cluster of six analogues (11, 24,27, 32, 33 and34), possessed promising activity. In comparison, a set of these new compounds possessed greater potencies relative to current drugs used in the clinic such as Ethambutol. These results were also correlated with computational molecular docking analysis, providing models for strong interactions of the inhibitors with MurB providing a template for the future development of preclinical agents against Mycobacterium tuberculosis., (Copyright © 2020 Elsevier Ltd. All rights reserved.)
- Published
- 2020
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23. 1,3-Disubstituted urea derivatives: Synthesis, antimicrobial activity evaluation and in silico studies.
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Gündüz MG, Uğur SB, Güney F, Özkul C, Krishna VS, Kaya S, Sriram D, and Doğan ŞD
- Subjects
- Anti-Bacterial Agents chemical synthesis, Anti-Bacterial Agents chemistry, Biofilms drug effects, Dose-Response Relationship, Drug, Microbial Sensitivity Tests, Molecular Structure, Structure-Activity Relationship, Urea analogs & derivatives, Urea chemistry, Anti-Bacterial Agents pharmacology, Candida albicans drug effects, Molecular Docking Simulation, Mycobacterium tuberculosis drug effects, Urea pharmacology
- Abstract
The development of new antimicrobial compounds is in high demand to overcome the emerging drug resistance against infectious microbial pathogens. In the present study, we carried out the extensive antimicrobial screening of disubstituted urea derivatives. In addition to the classical synthesis of urea compounds by the reaction of amines and isocyanates, we also applied a new route including bromination, oxidation and azidination reactions, respectively, to convert 2-amino-3-methylpyridine to 1,3-disubstituted urea derivatives using various amines. The evaluation of antimicrobial activities against various bacterial strains, Candida albicans as well as Mycobacterium tuberculosis resulted in the discovery of new active molecules. Among them, two compounds, which have the lowest MIC values on Pseudomonas aeruginosa, were further evaluated for their inhibition capacities of biofilm formation. In order to evaluate their potential mechanism of biofilm inhibition, these two compounds were docked into the active site of LasR, which is the transcriptional regulator of bacterial signaling mechanism known as quorum sensing. Finally, the theoretical parameters of the bioactive molecules were calculated to establish their drug-likeness properties., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)
- Published
- 2020
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24. Design and synthesis of thiourea-based derivatives as Mycobacterium tuberculosis growth and enoyl acyl carrier protein reductase (InhA) inhibitors.
- Author
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Doğan ŞD, Gündüz MG, Doğan H, Krishna VS, Lherbet C, and Sriram D
- Subjects
- Animals, Antitubercular Agents chemical synthesis, Antitubercular Agents chemistry, Bacterial Proteins metabolism, Cell Survival drug effects, Dose-Response Relationship, Drug, Enzyme Inhibitors chemical synthesis, Enzyme Inhibitors chemistry, Macrophages drug effects, Macrophages microbiology, Mice, Microbial Sensitivity Tests, Molecular Docking Simulation, Molecular Structure, Mycobacterium tuberculosis growth & development, Mycobacterium tuberculosis metabolism, Oxidoreductases metabolism, RAW 264.7 Cells, Structure-Activity Relationship, Thiourea chemical synthesis, Thiourea chemistry, Antitubercular Agents pharmacology, Bacterial Proteins antagonists & inhibitors, Drug Design, Enzyme Inhibitors pharmacology, Mycobacterium tuberculosis drug effects, Oxidoreductases antagonists & inhibitors, Thiourea pharmacology
- Abstract
Tuberculosis remains the most deadly infectious disease worldwide due to the emergence of drug-resistant strains of Mycobacterium tuberculosis. Hence, there is a great need for more efficient treatment regimens. Herein, we carried out rational molecular modifications on the chemical structure of the urea-based co-crystallized ligand of enoyl acyl carrier protein reductase (InhA) (PDB code: 5OIL). Although this compound fulfills all structural requirements to interact with InhA, it does not inhibit the enzyme effectively. With the aim of improving the inhibition value, we synthesized thiourea-based derivatives by one-pot reaction of the amines with corresponding isothiocyanates. After the structural characterization using
1 H NMR,13 C NMR, FTIR and HRMS, the obtained compounds were initially tested for their abilities to inhibit Mycobacterium tuberculosis growth. The results revealed that some compounds exhibited promising antitubercular activity, MIC values at 0.78 and 1.56 μg/mL, combined with low cytotoxicity. Moreover, the most active compounds were tested against latent as well as dormant forms of the bacteria utilizing nutrient starvation model and Mycobacterium tuberculosis infected macrophage assay. Enzyme inhibition assay against enoyl-acyl carrier protein reductase identified InhA as the important target of some compounds. Molecular docking studies were performed to correlate InhA inhibition data with in silico results. Finally, theoretical calculations were established to predict the physicochemical properties of the most active compounds., Competing Interests: Declaration of competing interest None of the authors declared any potential conflicts of interest., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)- Published
- 2020
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25. A rare case of Wilson disease associated with intracerebral hemorrhage.
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Singh S, Krishna VS, Gupta N, Taank P, and Marwah V
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- Adult, Humans, Male, Cerebral Hemorrhage complications, Cerebral Hemorrhage diagnostic imaging, Hepatolenticular Degeneration complications, Hepatolenticular Degeneration diagnostic imaging
- Published
- 2020
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26. The effect of 'THE MOTOR VEHICLES (AMENDMENT) ACT, 2019' on the clinico-epidemiological profile of road traffic accident patients presenting to a tertiary care trauma centre in Bhubaneswar.
- Author
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Sasmal PK, Mohanty CR, Jain M, Radhakrishnan RV, Sahoo S, Krishna VS, Doki SK, and Dungala RVMK
- Abstract
Context: Road traffic accidents (RTA) are a foremost rising cause of morbidity and mortality in developing countries like India. The Government of India enacted a new motor vehicle amendment act (MVA) on September 1
st 2019 that permits heavy penalties for traffic rule offenders., Aims: To find out the early impact of "THE MOTOR VEHICLES (AMENDMENT) ACT, 2019"., Settings and Design: A retrospective observational study was performed during the time period July to October 2019 on RTA patients admitted to the Trauma and Emergency department., Methods and Materials: Patients studied in two groups - One Pre MVA group ( n = 371) and one Post MVA group ( n = 415). The data were extracted from medical case records of the department and filled up in a structured format. Detailed demographic profile, including the use of safety measure and clinical variables such as the pattern of injury and injury severity scores, were recorded., Statistical Analysis Used: Statistical analysis was done by R version 3.6.1., Results: There is a 41% drop in RTA victims post MVA implementation. Polytrauma reduced (25% vs 45.5%) significantly ( P = 0.002) and so was Injury severity score (6.00 vs 13.00). More RTA victims were wearing helmets as compared to previous (42% vs 18%), and there was a steep decline in the alcohol driving (25% vs 10%) between the pre and post MVA group. A significant reduction noted in the under 18 yrs. Two-wheeler riders in the post MVA group compared to earlier ( P = 0.016)., Conclusions: The study reveals that there is a commendable reduction in the injury severity, violation of safety gears, alcohol use and rash driving following the implementation of MVA September 2019. Primary care and family physician can play a crucial role in creating public awareness about the personal safety measures, which will help in strengthening of this law to reduce the incidence of RTA and the associated mortality and morbidity., Competing Interests: There are no conflicts of interest., (Copyright: © 2020 Journal of Family Medicine and Primary Care.)- Published
- 2020
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27. Design, synthesis and biological evaluation of novel Pseudomonas aeruginosa DNA gyrase B inhibitors.
- Author
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Jogula S, Krishna VS, Meda N, Balraju V, and Sriram D
- Subjects
- Anti-Bacterial Agents chemical synthesis, Anti-Bacterial Agents chemistry, Anti-Bacterial Agents pharmacology, Bacterial Proteins antagonists & inhibitors, DNA Gyrase chemistry, Drug Design, Humans, Models, Molecular, Oxazoles chemical synthesis, Oxazoles chemistry, Oxazoles pharmacology, Pseudomonas Infections drug therapy, Pseudomonas Infections microbiology, Pseudomonas aeruginosa drug effects, Thiazoles chemical synthesis, Thiazoles chemistry, Thiazoles pharmacology, Topoisomerase II Inhibitors chemical synthesis, Bacterial Proteins metabolism, DNA Gyrase metabolism, Pseudomonas aeruginosa enzymology, Topoisomerase II Inhibitors chemistry, Topoisomerase II Inhibitors pharmacology
- Abstract
In the present study, we attempted to develop a novel class of compounds active against Pseudomonas aeruginosa (Pa) by exploring the pharmaceutically well exploited enzyme targets. Since, lack of Pa gyrase B crystal structures, Thermus thermophilus gyrase B in complex with novobiocin (1KIJ) was used as template to generate model structure by performing homology modeling. Further the best model was validated and used for high-throughput virtual screening, docking and dynamics simulations using the in-house database for identification of Pa DNA gyrase B inhibitors. This study led to an identification of three lead molecules with IC
50 values in range of 6.25-15.6 µM against Pa gyrase supercoiling assay. Lead-1 optimization and expansion resulted in 15 compounds. Among the synthesized compounds six compounds were shown good enzyme inhibition than Lead-1 (IC50 6.25 µM). Compound 13 emerged as the most potential compound exhibiting inhibition of Pa gyrase supercoiling with an IC50 of 2.2 µM; and in-vitro Pa activity with MIC of 8 µg/mL in presence of efflux pump inhibitor; hence could be further developed as novel inhibitor for Pa gyrase B., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)- Published
- 2020
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28. Regio- and diastereoselective synthesis of spiropyrroloquinoxaline grafted indole heterocyclic hybrids and evaluation of their anti- Mycobacterium tuberculosis activity.
- Author
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Arumugam N, Almansour AI, Kumar RS, Mohammad Ali Al-Aizari AJ, Alaqeel SI, Kansız S, Krishna VS, Sriram D, and Dege N
- Abstract
An efficient and eco compatible approach for the regio- and stereoselective synthesis of structurally diverse novel hybrid heterocycles comprising spiropyrrolidine, indenoquinoxaline and indole structural units in excellent yields, has been achieved through a one-pot multicomponent process involving 1,3-dipolar cycloaddition as a key step. The 1,3-dipolar component is the azomethine ylide generated in situ from indenoquinoxaline and l-tryptophan and reacts with various substituted β-nitrostyrenes affording the spiroheterocyclic hybrids. The ring system thus created possesses two C-C and three C-N bonds and four adjacent stereogenic carbons, one of which is quaternary and the reaction proceeded with full diastereomeric control. All the synthesized compounds were assayed for their in vitro activity against Mycobacterium tuberculosis H37Rv using MABA assay. Interestingly, the compound bearing a 2-fluoro substituent on the aryl ring displayed an equipotent activity (MIC 1.56 μg mL
-1 ) to ethambutol against Mycobacterium tuberculosis H37Rv., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)- Published
- 2020
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29. Benzimidazoquinazolines as new potent anti-TB chemotypes: Design, synthesis, and biological evaluation.
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Jadhavar PS, Patel KI, Dhameliya TM, Saha N, Vaja MD, Krishna VS, Sriram D, and Chakraborti AK
- Subjects
- Animals, Antitubercular Agents chemical synthesis, Antitubercular Agents chemistry, Benzimidazoles chemical synthesis, Benzimidazoles chemistry, Cell Survival drug effects, Dose-Response Relationship, Drug, Mice, Microbial Sensitivity Tests, Molecular Structure, Quinazolines chemical synthesis, Quinazolines chemistry, RAW 264.7 Cells, Structure-Activity Relationship, Tuberculosis microbiology, Antitubercular Agents pharmacology, Benzimidazoles pharmacology, Drug Design, Mycobacterium tuberculosis drug effects, Quinazolines pharmacology, Tuberculosis drug therapy
- Abstract
In search for new molecular entities as anti-TB agents, the benzimidazoquinazoline polyheterocyclic scaffold has been designed adopting the scaffold hopping strategy. Thirty-two compounds have been synthesized through an improved tandem decarboxylative nucleophilic addition cyclocondensation reaction of o-phenylenediamine with isatoic anhydride followed by further cyclocondensation of the intermediately formed 2-(o-aminoaryl)benzimidazole with trialkyl orthoformate/acetate. The resultant benzimidazoquinazolines were evaluated in vitro for anti-TB activity against M. tuberculosis H
37 Rv (ATCC27294 strain). Fourteen compounds exhibiting MIC values in the range of 0.4-6.25 µg/mL were subjected to cell viability test against RAW 264.7 cell lines and were found to be non-toxic (<30% inhibition at 50 µg/mL). The active compounds were further evaluated against INH resistant Mtb strains. The most active compound 6x [MIC (H37Rv) of 0.4 µg/mL] and the compound 6d [MIC (H37Rv) of 0.78 µg/mL] were also found to be active against INH resistant Mtb strain with MIC values of 12.5 and 0.78 µg/mL, respectively., Competing Interests: Declaration of Competing Interest The authors declare no competing financial interest., (Copyright © 2020 Elsevier Inc. All rights reserved.)- Published
- 2020
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30. Design and development of ((4-methoxyphenyl)carbamoyl) (5-(5-nitrothiophen-2-yl)-1,3,4-thiadiazol-2-yl)amide analogues as Mycobacterium tuberculosis ketol-acid reductoisomerase inhibitors.
- Author
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Krishna VS, Zheng S, Rekha EM, Nallangi R, Sai Prasad DV, George SE, Guddat LW, and Sriram D
- Subjects
- Amides chemical synthesis, Amides chemistry, Animals, Antitubercular Agents chemical synthesis, Antitubercular Agents chemistry, Biofilms drug effects, Cell Line, Dose-Response Relationship, Drug, Enzyme Inhibitors chemical synthesis, Enzyme Inhibitors chemistry, HEK293 Cells, Humans, Ketol-Acid Reductoisomerase metabolism, Macrophages drug effects, Macrophages microbiology, Mice, Microbial Sensitivity Tests, Models, Molecular, Molecular Structure, Mycobacterium tuberculosis enzymology, Structure-Activity Relationship, Amides pharmacology, Antitubercular Agents pharmacology, Drug Development, Enzyme Inhibitors pharmacology, Ketol-Acid Reductoisomerase antagonists & inhibitors, Mycobacterium tuberculosis drug effects
- Abstract
Based on our previous finding that the titled compound possesses anti-tuberculosis activity, a series of novel ((4-methoxyphenyl)carbamoyl) (5-(5-nitrothiophen-2-yl)-1,3,4-thiadiazol-2-yl)amide analogues have been synthesized. Amongst the 22 compounds synthesized and tested, 5b, 5c and 6c showed potent inhibitory activity with K
i values of 2.02, 5.48 and 4.72 μM for their target, Mycobacterium tuberculosis (Mt) ketol-acid reductoisomerase (KARI). In addition, these compounds have excellent in vitro activity against Mt H37Rv with MIC values as low as 1 μM. The mode of binding for these compounds to Mt KARI was investigated through molecular docking and dynamics simulations. Furthermore, these compounds were evaluated for their activity in Mt infected macrophages, and showed inhibitory activities with up to a 1.9-fold reduction in growth (at 10 μM concentration). They also inhibited Mt growth in a nutrient starved model by up to 2.5-fold. In addition, these compounds exhibited low toxicity against HEK 293T cell lines. Thus, these compounds are promising Mt KARI inhibitors that can be further optimized into anti-tuberculosis agents., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)- Published
- 2020
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31. Synthesis and efficacy of pyrvinium-inspired analogs against tuberculosis and malaria pathogens.
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Gaikwad VR, Karale UB, Govindarajalu G, Adhikari N, Krishna EV, Krishna VS, Misra S, Sriram D, Sijwali PS, and Rode HB
- Subjects
- Antimalarials chemical synthesis, Antimalarials chemistry, Antitubercular Agents chemical synthesis, Antitubercular Agents chemistry, Dose-Response Relationship, Drug, Malaria, Falciparum drug therapy, Malaria, Falciparum parasitology, Microbial Sensitivity Tests, Molecular Structure, Parasitic Sensitivity Tests, Pyrvinium Compounds chemical synthesis, Pyrvinium Compounds chemistry, Structure-Activity Relationship, Tuberculosis drug therapy, Tuberculosis microbiology, Antimalarials pharmacology, Antitubercular Agents pharmacology, Mycobacterium tuberculosis drug effects, Plasmodium falciparum drug effects, Pyrvinium Compounds pharmacology
- Abstract
Herein, we report the synthesis and evaluation of pyrvinium-based antimalarial and antitubercular compounds. Pyrvinium is an FDA approved drug for the treatment of pinworm infection, and it has been reported to have antiparasitic and antimicrobial activities. Pyrvinium contains quinoline core coupled with pyrrole. We replaced the pyrrole with various aryl or heteroaryl substituents to generate pyrvinium analogs. The profiling of these compounds against malaria parasite P. falciparum 3D7 revealed analogs with better antimalarial activity than pyrvinium pamoate. Compound 14 and 16 showed IC
50 of 23 nM and 60 nM against P. falciparum 3D7, respectively. These compounds were also effective against drug-resistant malaria parasite P. falciparum Dd2 with IC50 of 53 nM and 97 nM, respectively. The cytotoxicity against CHO-K1, HEK and NRK-49F cells revealed better selectivity index for these new analogs compared to pyrvinium. Additionally, this series of compounds showed activity against M. tuberculosis H37Rv; particularly compounds 10, 13, 14 and 16 showed equipotent antitubercular activity to that of pyrvinium pamoate. The compounds 14 and 16 should be taken forward as leads for further optimization., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)- Published
- 2020
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32. Synthesis, in vitro, and in vivo (Zebra fish) antitubercular activity of 7,8-dihydroquinolin-5(6H)-ylidenehydrazinecarbothioamides.
- Author
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Marvadi SK, Krishna VS, Surineni G, Srilakshmi Reshma R, Sridhar B, Sriram D, and Kantevari S
- Subjects
- Animals, Antitubercular Agents chemical synthesis, Disease Models, Animal, Drug Design, Humans, Hydrazines chemical synthesis, Microbial Sensitivity Tests, Molecular Docking Simulation, Quinolones chemical synthesis, Quinolones chemistry, Quinolones therapeutic use, Structure-Activity Relationship, Thioamides chemical synthesis, Zebrafish, Antitubercular Agents chemistry, Antitubercular Agents therapeutic use, Hydrazines chemistry, Hydrazines therapeutic use, Mycobacterium tuberculosis drug effects, Thioamides chemistry, Thioamides therapeutic use, Tuberculosis drug therapy
- Abstract
We, herein, describe the synthesis of a series of novel aryl tethered 7,8-dihydroquinolin-5(6H)-ylidenehydrazinecarbothioamides 4a-v, which showed in vitro and in vivo antimycobacterial activity against Mycobacterium tuberculosis (Mtb) H37Rv. The intermediates dihydro-6H-quinolin-5-ones 3a-v were synthesized from β-enaminones, reacting with cyclochexane-1,3-dione/5,5-dimethylcyclohexane-1,3-dione and ammonium acetate using a modified Bohlmann-Rahtz reaction conditions. They were further reacted with thiosemicarbazide to give the respective hydrazine carbothioamides 4a-v. All the new analogues 4a-v, were characterized by their NMR and mass spectral data analysis. Among the twenty-two compounds screened for in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv (ATCC27294), two compounds, 4e and 4j, exhibited the highest inhibition with an MIC of 0.39 µg/mL. Compounds 4a, 4g, and 4k were found to inhibit Mtb at an MIC of 0.78 µg/mL. Hydrazinecarbothioamides 4a-k, exhibited enhanced activity than dihydroquinolinones 3a-k. The observed increase in potency provides a clear evidence that hydrazinecarbothioamide is a potential pharmacophore, collectively imparting synergistic effect in enhancing antitubercular activity of the dihydroquinolinone core. The in vivo (Zebra fish) antimycobacterial screening of the in vitro active molecules led to the identification of a hit compound, 4j, with significant activity in the Mtb nutrient starvation model (2.2-fold reduction). Docking studies of 4j showed a hydrogen bond with the P156 residue of the protein., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)
- Published
- 2020
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33. Novel benzimidazole-acrylonitrile hybrids and their derivatives: Design, synthesis and antimycobacterial activity.
- Author
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Sirim MM, Krishna VS, Sriram D, and Unsal Tan O
- Subjects
- Acrylonitrile chemistry, Anti-Bacterial Agents chemical synthesis, Anti-Bacterial Agents chemistry, Benzimidazoles chemistry, Dose-Response Relationship, Drug, Microbial Sensitivity Tests, Molecular Structure, Structure-Activity Relationship, Acrylonitrile pharmacology, Anti-Bacterial Agents pharmacology, Benzimidazoles pharmacology, Drug Design, Mycobacterium tuberculosis drug effects
- Abstract
This paper reports the synthesis and evaluation of some benzimidazole-acrylonitrile hybrid derivatives for their in vitro antimycobacterial activities against Mycobacterium tuberculosis H37Rv. Among the derivatives studied, 3b was found to be the most active compound with MIC of 0.78 μg/mL against M. tuberculosis. This is a quite good activity compared with ethambutol (MIC = 1.56 μg/mL). Moreover, 3b showed 2.8 log fold reduction in bacterial count of dormant forms of mycobacterium which is more potent than first line drugs isoniazid, ciprofloxacin, rifampicin and moxifloxacin. Having activities against both active and dormant forms of M. tuberculosis,3b may be a useful candidate for the development of new drugs to treat tuberculosis., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)
- Published
- 2020
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34. Discovery of hydrazone containing thiadiazoles as Mycobacterium tuberculosis growth and enoyl acyl carrier protein reductase (InhA) inhibitors.
- Author
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Doğan H, Doğan ŞD, Gündüz MG, Krishna VS, Lherbet C, Sriram D, Şahin O, and Sarıpınar E
- Subjects
- Animals, Antitubercular Agents chemical synthesis, Antitubercular Agents chemistry, Bacterial Proteins metabolism, Cell Survival drug effects, Crystallography, X-Ray, Dose-Response Relationship, Drug, Enzyme Inhibitors chemical synthesis, Enzyme Inhibitors chemistry, Hydrazones chemistry, Mice, Microbial Sensitivity Tests, Molecular Docking Simulation, Molecular Structure, Mycobacterium tuberculosis enzymology, Mycobacterium tuberculosis growth & development, Oxidoreductases metabolism, RAW 264.7 Cells, Structure-Activity Relationship, Thiadiazoles chemical synthesis, Thiadiazoles chemistry, Antitubercular Agents pharmacology, Bacterial Proteins antagonists & inhibitors, Drug Discovery, Enzyme Inhibitors pharmacology, Hydrazones pharmacology, Mycobacterium tuberculosis drug effects, Oxidoreductases antagonists & inhibitors, Thiadiazoles pharmacology
- Abstract
Tuberculosis, caused by Mycobacterium tuberculosis, is a serious infectious disease and remains a global health problem. There is an increasing need for the discovery of novel therapeutic agents for its treatment due to the emerging multi-drug resistance. Herein, we present the rational design and the synthesis of eighteen new thiadiazolylhidrazones (TDHs) which were synthesized by intramolecular oxidative N-S bond formation reaction of 2-benzylidene-N-(phenylcarbamothioyl)hydrazine-1-carboximidamide derivatives by phenyliodine(III) bis(trifluoroacetate) (PIFA) under mild conditions. The compounds were characterized by various spectral techniques including FTIR,
1 H NMR,13 C NMR and HRMS. Furthermore, the proposed structure of TDH12 was resolved by single-crystal X-ray analysis. The compounds were evaluated for their in vitro antitubercular activity against M. tuberculosis H37Rv. Among them, some compounds exhibited remarkable antimycobacterial activity, MIC = 0.78-6.25 μg/mL, with low cytotoxicity. Additionally, the most active compounds were screened for their biological activities against M. tuberculosis in the nutrient starvation model. Enzyme inhibition assays and molecular docking studies revealed enoyl acyl carrier protein reductase (InhA) as the possible target enzyme of the compounds to show their antitubercular activities., Competing Interests: Declaration of competing interest The authors declared no potential conflicts of interest., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)- Published
- 2020
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35. 5-Chloro-2-thiophenyl-1,2,3-triazolylmethyldihydroquinolines as dual inhibitors of Mycobacterium tuberculosis and influenza virus: Synthesis and evaluation.
- Author
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Marvadi SK, Krishna VS, Sinegubova EO, Volobueva AS, Esaulkova YL, Muryleva AA, Tentler DG, Sriram D, Zarubaev VV, and Kantevari S
- Subjects
- Antitubercular Agents chemical synthesis, Antitubercular Agents chemistry, Antiviral Agents chemical synthesis, Antiviral Agents chemistry, Dose-Response Relationship, Drug, Microbial Sensitivity Tests, Molecular Structure, Structure-Activity Relationship, Antitubercular Agents pharmacology, Antiviral Agents pharmacology, Mycobacterium tuberculosis drug effects, Orthomyxoviridae drug effects
- Abstract
This study describes synthesis and evaluation of novel 5-Chloro-2-thiophenyl-1,2,3-triazolylmethyldihydroquinolines 7a-o as dual inhibitors of Mycobacterium tuberculosis and influenza virus. Huisgen's [3+2] dipolar cycloaddition of 6-(azidomethyl)-5-chloro-2-(thiophen-2-yl)-7,8-dihydroquinoline 5 with various alkynes 6a-o using sodium ascorbate and copper sulphate gave new dihydroquinoline-1,2,3-triazoles 7a-o in good to excellent yields. The new compounds were evaluated for in vitro antimycobacterial against M. tuberculosis H37Rv (Mtb) and antiviral activity against influenza virus A/Puerto Rico/8/34 (H1N1). Among the fifteen new analogs, compounds 7a (MIC: 3.12 µg/mL), 7j and 7k (MIC: 6.25 µg/mL) were identified as potent antitubercular agents. The virus-inhibiting activity of all the fifteen compounds was found to be moderate, and among them the compound 7l, bearing thiophene moiety appeared the most active with good selectivity index (IC
50 = 19.5 µg/mL; SI = 15). The results presented here will help developing newer dual inhibitors of tuberculosis and influenza virus., (Copyright © 2019 Elsevier Ltd. All rights reserved.)- Published
- 2019
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36. Synthesis and biological evaluation of 2,4,5-trisubstituted thiazoles as antituberculosis agents effective against drug-resistant tuberculosis.
- Author
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Karale UB, Krishna VS, Krishna EV, Choudhari AS, Shukla M, Gaikwad VR, Mahizhaveni B, Chopra S, Misra S, Sarkar D, Sriram D, Dusthackeer VNA, and Rode HB
- Subjects
- Antitubercular Agents chemical synthesis, Antitubercular Agents chemistry, Dose-Response Relationship, Drug, Humans, Microbial Sensitivity Tests, Molecular Structure, Structure-Activity Relationship, Thiazoles chemical synthesis, Thiazoles chemistry, Antitubercular Agents pharmacology, Mycobacterium tuberculosis drug effects, Thiazoles pharmacology, Tuberculosis, Multidrug-Resistant drug therapy
- Abstract
The dormant and resistant form of Mycobacterium tuberculosis presents a challenge in developing new anti-tubercular drugs. Herein, we report the synthesis and evaluation of trisubstituted thiazoles as antituberculosis agents. The SAR study has identified a requirement of hydrophobic substituent at C2, ester functionality at C4, and various groups with hydrogen bond acceptor character at C5 of thiazole scaffold. This has led to the identification of 13h and 13p as lead compounds. These compounds inhibited the dormant Mycobacterium tuberculosis H37Ra strain and M. tuberculosis H37Rv selectively. Importantly, 13h and 13p were non-toxic to CHO cells. The 13p showed activity against multidrug-resistant tuberculosis isolates., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)
- Published
- 2019
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- View/download PDF
37. New N -phenylacetamide-incorporated 1,2,3-triazoles: [Et 3 NH][OAc]-mediated efficient synthesis and biological evaluation.
- Author
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Akolkar SV, Nagargoje AA, Krishna VS, Sriram D, Sangshetti JN, Damale M, and Shingate BB
- Abstract
A facile, highly efficient, and greener method for the synthesis of new 1,4-disubstituted-1,2,3-triazoles was conducted using [Et
3 NH][OAc] as a medium by the implementation of ultrasound irradiation via click chemistry, affording excellent yields. The present synthetic method exhibited numerous advantages such as mild reaction conditions, excellent product yields, minimal chemical waste, operational simplicity, shorter reaction time, and a wide range of substrate scope. The synthesized compounds were further evaluated for in vitro antifungal activity against five fungal strains, and some of the compounds displayed equivalent or greater potency than the standard drug. A molecular docking study against the modelled three-dimensional structure of cytochrome P450 lanosterol 14α-demethylase was also performed to understand the binding affinity and binding interactions of the enzyme. Furthermore, the synthesized compounds were evaluated for DPPH radical scavenging activity and antitubercular activity against Mycobacterium tuberculosis H37Rv strain., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)- Published
- 2019
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38. Design, synthesis and molecular modeling studies on novel moxifloxacin derivatives as potential antibacterial and antituberculosis agents.
- Author
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Türe A, Kulabaş N, Dingiş Sİ, Birgül K, Bozdeveci A, Alpay Karaoğlu Ş, Krishna VS, Sriram D, and Küçükgüzel İ
- Subjects
- Animals, Anti-Bacterial Agents chemical synthesis, Anti-Bacterial Agents chemistry, Antifungal Agents chemical synthesis, Antifungal Agents chemistry, Cell Survival drug effects, Cells, Cultured, Crystallography, X-Ray, Dose-Response Relationship, Drug, Gram-Negative Bacteria drug effects, Gram-Positive Bacteria drug effects, Mice, Microbial Sensitivity Tests, Models, Molecular, Molecular Structure, Moxifloxacin chemical synthesis, Moxifloxacin chemistry, RAW 264.7 Cells, Saccharomyces cerevisiae drug effects, Structure-Activity Relationship, Anti-Bacterial Agents pharmacology, Antifungal Agents pharmacology, Drug Design, Moxifloxacin pharmacology
- Abstract
Twenty-one novel alkyl/acyl/sulfonyl substituted fluoroquinolone derivatives were designed, synthesized and evaluated for their anti-tuberculosis and antibacterial activity. The targeted compounds were synthesized by the introduction of alkyl, acyl or sulfonyl moieties to the basic secondary amine moiety of moxifloxacin. Structures of the compounds were enlightened by FT-IR,
1 H NMR,13 C NMR and HRMS data besides elemental analysis. Compounds were initially tested in vitro for their anti-mycobacterial activity against Mycobacterium tuberculosis H37Rv using microplate alamar blue assay. Minimal inhibitory concentration (MIC) values of all compounds were found between > 25.00-0.39 µg/mL while compounds 1, 2 and 13 revealed an outstanding activity against M. tuberculosis H37Rv with MIC values of 0.39 µg/mL. Activities of compounds 1-21 against to a number of Gram-positive and Gram-negative bacteria and fast growing mycobacterium strain were also investigated by agar well diffusion and microdilution methods. According to antimicrobial activity results, compound 13 was found the most potent derivative with a IC50 value of <1.23 μg/mL against Staphylococcus aureus and clinical strain of methicillin-resistant clinical strain of S. aureus., (Copyright © 2019 Elsevier Inc. All rights reserved.)- Published
- 2019
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39. Ultrasonication-ionic liquid synergy for the synthesis of new potent anti-tuberculosis 1,2,4-triazol-1-yl-pyrazole based spirooxindolopyrrolizidines.
- Author
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Pogaku V, Krishna VS, Sriram D, Rangan K, and Basavoju S
- Subjects
- Antitubercular Agents pharmacology, Humans, Structure-Activity Relationship, Antitubercular Agents therapeutic use, Ionic Liquids therapeutic use, Mycobacterium tuberculosis drug effects, Pyrazoles therapeutic use
- Abstract
The aim of the study is to design and synthesis of a new series of potent anti-TB 1,2,4-triazol-1-yl-pyrazole based spirooxindolopyrrolizidines with their safety profile. A synergetic effect of ultrasonication and ionic liquid was shown successfully as a green methodology for the synthesis of title compounds 6a-t. These derivatives were obtained in shorter reaction time with good yields and well characterized by various spectroscopic methods, single-crystal X-ray diffraction (6f). The in vitro anti-tuberculosis activity for newly-synthesized derivatives has been screened against Mycobacterium tuberculosis. Among all, six compounds 6e, 6k, 6l, 6n, 6q and 6r exhibited equal potent activity compared to standard drug ethambutol (MIC: 1.56 µg/mL) and another compound 6h exhibited outstanding activity (MIC: 0.78 µg/mL) than the standard drug ethambutol. Cytotoxic nature of the anti-TB active compounds was evaluated against RAW 264.7 cells. The 6h, 6e, 6k, 6l, 6n, 6q and 6r exhibited lower toxicity which could be promising hits for anti-tuberculosis., (Copyright © 2019. Published by Elsevier Ltd.)
- Published
- 2019
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40. Expansion of a novel lead targeting M. tuberculosis DHFR as antitubercular agents.
- Author
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Sharma K, Tanwar O, Deora GS, Ali S, Alam MM, Zaman MS, Krishna VS, Sriram D, and Akhter M
- Subjects
- Antitubercular Agents chemical synthesis, Antitubercular Agents chemistry, Dose-Response Relationship, Drug, Enzyme Inhibitors chemical synthesis, Enzyme Inhibitors chemistry, Humans, Indoles chemical synthesis, Indoles chemistry, Microbial Sensitivity Tests, Models, Molecular, Molecular Structure, Structure-Activity Relationship, Antitubercular Agents pharmacology, Enzyme Inhibitors pharmacology, Indoles pharmacology, Mycobacterium tuberculosis drug effects, Mycobacterium tuberculosis enzymology, Tetrahydrofolate Dehydrogenase metabolism
- Abstract
A series of 1-(1-benzyl-2-methyl-5-((1-phenyl-1H-1,2,3-triazol-4-yl)methoxy)-1H-indol-3-yl)ethanone and ethyl 1-benzyl-2-methyl-5-((1-phenyl-1H-1,2,3-triazol-4-yl)methoxy)-1H-indole-3-carboxylate derivatives were designed based on bioisosteric replacement of previously reported antitubercular agent (IND-07). Twenty ligands were successfully synthesized and some of them were found to have good in vitro activity (MIC < 10 μM) against the H
37 Rv strain of Mycobacterium tuberculosis. Among these compounds, KC-08 and KC-11 inhibited Mtb-DHFR with 4- and 18-fold selectivity for Mtb-DHFR over h-DHFR, respectively. Compound KC-11 display acceptable ADME, and better pharmacokinetic profiles than IND-07. Docking studies were performed to predict the binding mode of the compounds within the active site of Mtb-DHFR and h-DHFR. The results of our study suggest that compound KC-11 may serve as a valuable lead for the design and development of selective inhibitors of Mtb-DHFR with potential therapeutic application in tuberculosis., (Copyright © 2019 Elsevier Ltd. All rights reserved.)- Published
- 2019
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41. Discovery and evaluation of novel Mycobacterium tuberculosis ketol-acid reductoisomerase inhibitors as therapeutic drug leads.
- Author
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Krishna VS, Zheng S, Rekha EM, Guddat LW, and Sriram D
- Subjects
- Animals, Antitubercular Agents pharmacology, Catalytic Domain, Cell Survival, Computer Simulation, Databases, Chemical, Enzyme Inhibitors pharmacology, Kinetics, Mice, Mycobacterium tuberculosis drug effects, Protein Binding, RAW 264.7 Cells, Structure-Activity Relationship, Antitubercular Agents chemistry, Enzyme Inhibitors chemistry, Ketol-Acid Reductoisomerase antagonists & inhibitors, Molecular Docking Simulation methods, Mycobacterium tuberculosis enzymology
- Abstract
Tuberculosis (TB) remains a major threat to human health. This due to the fact that current drug treatments are less than optimal and the increasing occurrence of multi drug-resistant strains of etiological agent, Mycobacterium tuberculosis (Mt). Given the wide-spread significance of this disease, we have undertaken a design and evaluation program to discover new anti-TB drug leads. Here, we focused on ketol-acid reductoisomerase (KARI), the second enzyme in the branched-chain amino acid biosynthesis pathway. Importantly, this enzyme is present in bacteria but not in humans, making it an attractive proposition for drug discovery. In the present work, we used molecular docking to identify seventeen potential inhibitors of KARI using an in-house database. Compounds were selected based on docking scores, which were assigned as the result of favourable interactions between the compound and the active site of KARI. The inhibitory constant values for two leads, compounds 14 and 16 are 3.71 and 3.06 µM respectively. To assess the mode of binding, 100 ns molecular dynamics simulations for these two compounds in association with Mt KARI were performed and showed that the complex was stable with an average root mean square deviation of less than 3.5 Å for all atoms. Furthermore, compound 16 showed a minimum inhibitory concentration of 2.06 ± 0.91 µM and a 1.9 fold logarithmic reduction in the growth of Mt in an infected macrophage model. The two compounds exhibited low toxicity against RAW 264.7 cell lines. Thus, both compounds are promising candidates for development as an anti-TB drug leads.
- Published
- 2019
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42. Novel 1,3,4-oxadiazoles as antitubercular agents with limited activity against drug-resistant tuberculosis.
- Author
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Makane VB, Krishna VS, Krishna EV, Shukla M, Mahizhaveni B, Misra S, Chopra S, Sriram D, Azger Dusthackeer VN, and Rode HB
- Subjects
- Cell Line, Humans, Models, Molecular, Tuberculosis drug therapy, Antitubercular Agents chemistry, Antitubercular Agents pharmacology, Mycobacterium tuberculosis drug effects, Oxadiazoles chemistry, Oxadiazoles pharmacology, Tuberculosis, Multidrug-Resistant drug therapy
- Abstract
Aim: In recent times, heterocyclic chemotypes are being explored for the development of new antimycobacterials that target the drug-resistant tuberculosis. Here, we are disclosing the 5-substitued 2-mercapto-1,3,4-oxadiazoles as potent antitubercular agents., Methodology: A small library of 2-mercapto-1,3,4-oxadiazoles was synthesized using various acids. The compounds were evaluated for antituberculosis activity against M. tuberculosis H37Rv., Results: Compound 8j was identified as antitubercular lead with MIC of 0.6 μg/ml against M. tuberculosis H37Rv. This compound was nontoxic to CHO-K1 cells and showed selectivity index of 39. Of note, 8j showed antitubercular activity against pre-extensively drug-resistant clinical isolate of Mycobacterium with MIC of 2 μg/ml., Conclusion: This study provides potent antitubercular agent which can be further optimized to discover novel antibiotics.
- Published
- 2019
- Full Text
- View/download PDF
43. Synthesis of novel morpholine, thiomorpholine and N-substituted piperazine coupled 2-(thiophen-2-yl)dihydroquinolines as potent inhibitors of Mycobacterium tuberculosis.
- Author
-
Marvadi SK, Krishna VS, Sriram D, and Kantevari S
- Subjects
- Antitubercular Agents pharmacology, Humans, Magnetic Resonance Spectroscopy, Mass Spectrometry, Microbial Sensitivity Tests, Morpholines, Piperazine, Quinolines chemistry, Structure-Activity Relationship, Antitubercular Agents chemical synthesis, Mycobacterium tuberculosis drug effects, Quinolines chemical synthesis, Quinolines pharmacology
- Abstract
A series of novel morpholine, thiomorpholine and N-substituted piperazine coupled 2-(thiophen-2-yl)dihydroquinolines 7a-p was designed and synthesized from 2-acetyl thiophene in six step reaction sequence involving modified Bohlmann-Rahtz and Vilsmeier-Haack-Arnold reactions as key transformations. 2-(Thiophen-2-yl)dihydroquinoline was formylated and subsequently chlorinated using DMF-POCl
3 . The resulting aldehyde was reduced to give an alcohol and then converted to bromide using PBr3. Further coupling of bromide with morpholine, thiomorpholine and N-substituted piperazines resulted in the desired quinolines 7a-p in very good yields. All the new derivatives 7a-p were characterized by their NMR and mass spectral analysis. In vitro screening of new compounds for antimycobacterial activity against Mycobacterium tuberculosis H37Rv (MTB), resulted in two derivatives 7f and 7p as most potent antitubercular agents (MIC:1.56 μg/mL) with lower cytotoxicity profiles., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)- Published
- 2019
- Full Text
- View/download PDF
44. Synthesis and evaluation of novel substituted 1,2,3-triazolyldihydroquinolines as promising antitubercular agents.
- Author
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Marvadi SK, Krishna VS, Sriram D, and Kantevari S
- Subjects
- Microbial Sensitivity Tests, Mycobacterium tuberculosis drug effects, Quinolines chemistry, Antitubercular Agents chemical synthesis, Antitubercular Agents pharmacology, Quinolines chemical synthesis, Quinolines pharmacology, Triazoles chemistry
- Abstract
A series of novel substituted 1,2,3-triazolyldihydroquinolines 6a-o was designed and synthesized from 2-acetylthiophene in five-step reaction sequence involving modified Boltzmann-Rahtz reaction of β-Enaminone; Vilsmeier-Haack chloroformylation using DMF/POCl
3 ; Ohira-Bestmann homologation of aldehyde to alkyne as key steps. The reaction of alkyne 4 with various aryl azides in the presence of copper sulfate and sodium ascorbate resulted desired new 1,2,3-triazolyldihydroquinolines 6a-o in excellent yields. In vitro screening of new compounds for anti-mycobacterial activity against Mycobacterium tuberculosis H37Rv (Mtb), resulted in three derivatives 6a (MIC:1.56 µg/mL) and 6d, 6l (MIC:3.12 µg/mL) as promising antitubercular agents with lower cytotoxicity profiles., (Copyright © 2019 Elsevier Ltd. All rights reserved.)- Published
- 2019
- Full Text
- View/download PDF
45. Synthesis and evaluation of α-aminoacyl amides as antitubercular agents effective on drug resistant tuberculosis.
- Author
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Makane VB, Krishna VS, Krishna EV, Shukla M, Mahizhaveni B, Misra S, Chopra S, Sriram D, Dusthackeer VNA, and Rode HB
- Subjects
- Amides chemistry, Animals, Antitubercular Agents pharmacology, Cell Line, Humans, Microbial Sensitivity Tests, Mycobacterium tuberculosis drug effects, Amides pharmacology, Antitubercular Agents chemistry, Chemistry, Pharmaceutical methods, Tuberculosis, Multidrug-Resistant drug therapy
- Abstract
The development of an effective antitubercular agent is a challenge due to the complex nature of tuberculosis. Herein, we report the synthesis and evaluation of α-aminoacyl amides as antitubercular agents. The systematic medicinal chemistry approach led to identification of optimal substitutions required for the activity. Compound 11l was identified as antitubercular lead with drug like properties. Further, 11l selectively inhibited M. tuberculosis H37Rv with MIC value of 0.78 μM and was found to be non-toxic to CHOK1 cells. The lead compound inhibited multidrug resistant and Pre-Extensively drug resistant strains of Mycobacterium at 2 μg/mL and 8 μg/mL respectively., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)
- Published
- 2019
- Full Text
- View/download PDF
46. Rational design of coumarin derivatives as antituberculosis agents.
- Author
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Mali HM, Sabale SS, Degani MS, Borkute R, Choudhari AS, Sarkar D, Krishna VS, and Sriram D
- Subjects
- Antitubercular Agents adverse effects, Antitubercular Agents therapeutic use, Cell Survival drug effects, Coumarins adverse effects, Coumarins therapeutic use, Drug Design, HeLa Cells, Humans, MCF-7 Cells, Microbial Sensitivity Tests methods, Molecular Structure, Nitroimidazoles metabolism, Signal Transduction, Structure-Activity Relationship, THP-1 Cells, Antitubercular Agents chemical synthesis, Coumarins chemical synthesis, Mycobacterium tuberculosis drug effects
- Abstract
Aim: A series of coumarin derivatives was designed as potential antituberculosis agents., Results: The compounds were screened against active and dormant Mycobacterium tuberculosis (Mtb). Compounds 3k and 3n were found to have the most promising activity against replicating MtbH37Rv exhibiting minimum inhibitory concentration of 4.63 and 9.75 μM respectively. The compounds were also effective against dormant MtbH37Rv exhibiting more potency than the standard drugs, isoniazid and rifampicin. The compounds were found to be non-cytotoxic against human cell lines., Conclusion: This study provides promising antituberculosis agents that are effective against replicating as well as dormant Mtb and can thus act as potential leads for further development.
- Published
- 2018
- Full Text
- View/download PDF
47. Synthesis and biological evaluation of dihydroquinoline carboxamide derivatives as anti-tubercular agents.
- Author
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Kumar G, Sathe A, Krishna VS, Sriram D, and Jachak SM
- Subjects
- Animals, Antitubercular Agents chemical synthesis, Antitubercular Agents chemistry, Cell Survival drug effects, Dose-Response Relationship, Drug, Mice, Microbial Sensitivity Tests, Molecular Structure, Quinolines chemical synthesis, Quinolines chemistry, RAW 264.7 Cells, Structure-Activity Relationship, Antitubercular Agents pharmacology, Mycobacterium tuberculosis drug effects, Quinolines pharmacology
- Abstract
Sodium trifluoromethanesulfonate, and glacial acetic acid selectively catalyzed the synthesis of dihydroquinoline via Friedländer annulation. The synthesized dihydroquinoline analogues coupled with different amines by the use of coupling reagent gave dihydroquinoline carboxamide derivatives in moderate to good yields. All the synthesized novel compounds were evaluated for the anti-tubercular activity and cytotoxic activities in vitro. Among tested 30 compounds, two compounds, 8g and 8h showed MIC value of 0.39 and 0.78 μg/mL, respectively against Mycobacterium tuberculosis H37Rv and they were found to be non-toxic. Also these two compounds exhibited good pharmacological properties and oral absorption when studied using in-silico models., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)
- Published
- 2018
- Full Text
- View/download PDF
48. Synthesis of carbohydrazides and carboxamides as anti-tubercular agents.
- Author
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Kumar G, Krishna VS, Sriram D, and Jachak SM
- Subjects
- Caco-2 Cells, Drug Design, HEK293 Cells, Humans, Microbial Sensitivity Tests, Molecular Docking Simulation, Structure-Activity Relationship, Tuberculosis drug therapy, Tuberculosis microbiology, Antitubercular Agents chemistry, Antitubercular Agents pharmacology, Hydrazines chemistry, Hydrazines pharmacology, Mycobacterium tuberculosis drug effects
- Abstract
A novel series of furan/thiophene carbohydrazides and carboxamides were synthesized and evaluated for anti-TB and cytotoxic activities. All the synthesized compounds were characterized using
1 H and13 C NMR and mass spectral techniques. Among the 23 compounds tested for anti-tubercular activity, seven compounds (3e, 3g, 3h, 9b, 9c, 9e and 9h) showed minimum inhibitory concentration value less than 1 μg/mL against Mycobacterium tuberculosis H37Rv and they were found to be non-toxic. Molecular docking and dynamics simulation studies of these compounds with an enzyme enoyl ACP reductase revealed the probable mechanism of action, which is similar to isoniazid. Further, all these tested compounds exhibited good absorption, distribution, metabolism and excretion and drug-likeness in-silico and thus may be considered as potential leads for further drug development., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)- Published
- 2018
- Full Text
- View/download PDF
49. In silico design of small peptides antagonist against leptin receptor for the treatment of obesity and its associated immune-mediated diseases.
- Author
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Munikumar M, Krishna VS, Reddy VS, Rajeswari B, Sriram D, and Rao MV
- Subjects
- Amino Acid Sequence, Antibodies, Monoclonal chemistry, Antibodies, Monoclonal pharmacology, Humans, Molecular Docking Simulation, Molecular Dynamics Simulation, Obesity drug therapy, Peptides pharmacology, Protein Engineering methods, Quantitative Structure-Activity Relationship, Receptors, Leptin antagonists & inhibitors, Workflow, Drug Design, Models, Molecular, Peptides chemistry, Receptors, Leptin chemistry
- Abstract
Excess adiposity in obese inhibits negatively impacts immune function and host defence. Obesity is characterized by a state of low-grade, chronic inflammation in addition to disturbed levels of circulating nutrients and metabolic hormones. The impact of metabolic abnormalities on obesity-related co-morbidities has undergone intense scrutiny over the past decades. Thus, treatment of obesity and its associated immune-mediated diseases is challenging due to impaired function of leptin system. These disorders are managed through antibiotics and by cytokines replacement. However, the effectiveness of cytokines coupled to the complexity of the cytokine network leads to severe side-effects, which can still occur after careful preclinical evaluation. In addition, synthetic immunotherapeutics carry a degree of risk, time-consuming and expensive. Hence, the complexity of existing therapy and adverse effects emphasizes the need for an alternative approach for the management of immune dysfunction associated with obesity. Computer-aided small molecule antibody technology has been successful in the design of novel biologicals for the diagnosis of diseases and therapeutic interventions. In this study, the crystal structure of leptin receptor (LEPR) complex with monoclonal antibody (9F8 Fab) was explored to predict Ag-Ab interactions using bioinformatics tools. The LEPR of complementarity-determining region (CDR) loops were mutated with published positive control residues of Ser, Thr, Tyr, Trp, and Phe to design a set of 678 peptides which were evaluated through Ag-peptide docking, binding free-energies, and interaction energies. Thus, hypothesized novel peptides can be explored as clinically applicable antagonists for the treatment of obesity and associated immune-mediated diseases., (Copyright © 2018 Elsevier Inc. All rights reserved.)
- Published
- 2018
- Full Text
- View/download PDF
50. 1,2,3-Triazole-fused spirochromenes as potential anti-tubercular agents: synthesis and biological evaluation.
- Author
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Ashok D, Chiranjeevi P, Kumar AV, Sarasija M, Krishna VS, Sriram D, and Balasubramanian S
- Abstract
A facile and convenient approach has been designed for the synthesis of novel prototypes that possess the advantage of the two pharmacophores of chromene and 1,2,3-triazole in a single molecular backbone, were evaluated against Mycobacterium tuberculosis H37Rv strain. The new analogues 1,2,3-triazole-fused spirochromenes were accomplished in four step synthetic strategy utilizing click chemistry ([3 + 2] Huisgen cycloaddition) in the ultimate step. The synthesized compounds were established based on the spectral data and X-ray crystal structure for 7a. Among the compounds tested against Mycobacterium tuberculosis H37Rv strain, some products exhibited potent antimycobacterial activity with minimum inhibitory concentration (MIC) values ranging from 1.56 to 6.25 μg mL
-1 . Compounds exhibiting good in vitro potency in the MTB MIC assay were further examined for cytotoxicity in a RAW 264.7 cells. Compounds 7a, 7d, 7i (MIC: 1.56 μg mL-1 ) and 7k, 7m (MIC: 3.125 μg mL-1 ) exhibited promising hits., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)- Published
- 2018
- Full Text
- View/download PDF
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