Neeta Thapliyal - Academia.edu (original) (raw)
Papers by Neeta Thapliyal
Bioorganic & Medicinal Chemistry Letters, May 1, 2015
Troglitazone causes severe hepatic injury in certain individuals and multiple mechanisms related ... more Troglitazone causes severe hepatic injury in certain individuals and multiple mechanisms related to hepato-toxicity has been reported creating confusion. In the present study, the mechanism for the hepatic injury of glitazones was investigated by PASS. The results suggest that chromane containing glitazones are apoptic agonist (activating p53 by intrinsic pathway leading to the apoptosis) and those which do not contain the chromane are devoid of this. In case of hepatotoxicity by non-chromane glitazone and their metabolite such as M-3, RM-3, rosiglitazone and pioglitazone; PASS suggest that these chemicals are not apoptic agonist but they are the substrate for CYP enzyme (Phase-I Oxidative Enzyme) and Phase-II conjugating enzymes; interfering with bile acid metabolism rendering bile acid more toxic (cholestasis). This unmetabolised bile salt further initiates the process apoptosis via intrinsic and extrinsic pathway leading to the apoptosis. Immunoblot analysis further confirm our hypothesis that troglitazone (Chromane containing glitazone), but not rosiglitazone and pioglitazone (Non-chromane containing glitazone) increased the levels of p53 in a time-dependent manner. Hence our prediction related to the mechanism of hepato-toxicity by apoptosis and structural insight of glitazone can be helpful in improving the drug profile of this category.
Talanta, Sep 1, 2015
Dextromethorphan (DXM) and diphenhydramine (DPH) are two commonly used over-the-counter nonnarcot... more Dextromethorphan (DXM) and diphenhydramine (DPH) are two commonly used over-the-counter nonnarcotic antitussive drugs. Recent reports reveal the widespread abuse of DXM and DPH due to their euphoric and alcohol-like effects. Due to their medicinal importance as well as the apparent increase in their use as abused drugs, it has become critical to determine them in samples of biological, clinical and pharmaceutical interest. The electrochemical techniques for drug analysis have gathered considerable attention due to their pronounced selectivity, sensitivity and simplicity. The given review presents a compilation of published voltammetric and potentiometric methods developed for determination of DXM and DPH. It critically highlights the analytical performances, revealing the recent trends and progress in the specified approach for their analysis. The review forms a basis for further progress in this field and development of improved electrochemical sensors to determine the drug.
Anti-cancer Agents in Medicinal Chemistry, Aug 17, 2015
Overexpression of epidermal growth factor receptor (EGFR) is seen in a number of human tumors lik... more Overexpression of epidermal growth factor receptor (EGFR) is seen in a number of human tumors like prostate, colon, breast and ovarian. Their expression is correlated with vascularity and often difficult to diagnose. Though a number of active inhibitors and anticancer drugs against EGFR-tyrosine kinase are known, increase in resistance together with many side effects designate the need for new and improved treatments. Natural products and their analoges have significant contribution in the cancer drug discovery and development process. Therefore in the current review we mainly discuss design, synthesis and structural activity relationship of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors from the natural origin.
Electroanalysis, Jun 13, 2017
Mefloquine (MQ) is a quinoline based antimalarial drug, which is potent against multiple drug-res... more Mefloquine (MQ) is a quinoline based antimalarial drug, which is potent against multiple drug-resistant Plasmodium falciparum. It is widely prescribed for the prophylactic treatment of malaria. Due to extensive usage of MQ, constant monitoring of the drug level in human body is of paramount importancein order to ensure that optimum drug exposure is achieved. The present work describes a gold nanourchins (AuNUs) based electrochemical sensor for the determination of MQ.AuNUs were synthesized via seed-mediated method and characterized using ultraviolet-visible spectroscopy, energy-dispersive X-ray spectroscopy, field emission scanning electron microscopy, zeta-sizer and electrochemical techniques (electrochemical impedance spectroscopy and cyclic voltammetry). Fabrication of the sensor was done by drop-coating the synthesized AuNUs onto a glassy carbon electrode. The fabricated sensor exhibited enhanced voltammetric response, which was attributed to the excellent conductivity and high surface area of AuNUs. Under optimum square wave voltammetric conditions, the sensor displayed two linear response ranges (from 2.0 3 10 À9 to 1.0 3 10 À6 M and from 1.0 3 10 À6 to 1.0 3 10 À3 M) with a detection limit of 1.4 nM. The electrode demonstrated good reproducibility, stability and selectivity over common interferents. The utility of the sensor was successfully assessed for quantification of the drug in pharmaceutical preparation and spiked human urine sample. Thus, the present study demonstrates a promising approach for determination of MQ with practical utility in quality control and clinical analysis.
RSC Advances, 2015
Vascular endothelial growth factor receptor-2 (VEGFR-2) plays a crucial role in cancer angiogenes... more Vascular endothelial growth factor receptor-2 (VEGFR-2) plays a crucial role in cancer angiogenesis. A library of 6,7-dimethoxy quinazoline was prepared using ligand based drug design approach and passed through different filters of virtual screening such as docking study and Lipinski's rule. Twenty virtually screened compounds were synthesized and investigated against VEGFR-2 kinase and human umbilical vein endothelial cells (HUVEC) in vitro. Virtually screened compound 47 having 4-chlorophenyl-1,3,4-thiadiazole substitution at 3 rd position of 6,7-dimethoxy-2-phenylquinazolin-4(3H)-one exhibited the most promising activity, with IC 50 value of 3.8 nm and 5.5 nm against VEGFR-2 tyrosine kinase and HUVEC cell line. Docking simulation supported the initial pharmacophoric hypothesis and suggested a common mode of interaction at the ATP-binding site of VEGFR-2 demonstrating that compound 47 was a potential agent for cancer therapy that deserves further research.
Arabian Journal of Chemistry, Feb 1, 2018
Over expression of 11b-HSD 1 in key metabolic tissues is related to the development of type 2 dia... more Over expression of 11b-HSD 1 in key metabolic tissues is related to the development of type 2 diabetes, obesity, hypertension and metabolic syndrome. Nephrotoxicity of corosolic acid (selective inhibitor of 11b-HSD 1) is recently reported, which is one of the major drawback. Therefore, it is of great interest to find out the selective 11b-HSD 1 inhibitors without nephrotoxicity. Using crystal structures of 11b-HSD 1 in complex with inhibitors as a source of structural information, a combined structure-based virtual screening approach followed by PASS toxicity prediction, Lipinski's rule and ADME prediction was implemented to find out the potent and selective 11 b-HSD 1 analog of corosolic acid without nephrotoxicity. Two compounds with NCBI compound identification number CID59752459 (Genins of Asiatic acid) and CID 119034 (Asiatic acid) were found to be selective for the 11b-HSD 1 enzyme without nephrotoxicity which comply with
Mikrochimica Acta, Jan 16, 2019
Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for a number of life-threatenin... more Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for a number of life-threatening complications in humans. Mutations in the genetic sequence of S. aureus due to the presence of certain genes results in resistance against β-lactamases. Thus, there is an urgent need for developing highly sensitive techniques for the early detection of MRSA to counter the rise in resistant strains. This review (142 refs.) extensively covers literature reports on nanomaterial-based optical and electrochemical sensors from the year 1983 to date, with particularly emphasis on recent advances in electrochemical sensing (such as voltammetry and impedimetric) and optical sensing (such as colorimetry and fluorometry) techniques. Among the electrochemical methods, various nanomaterials were employed for the modification of electrodes. Whereas, in optical assays, formats such as enzyme linked immunosorbent assay, lateral flow assays or in optical fiber systems are common. In addition, novel sensing platforms are reported by applying advanced nanomaterials which include gold nanoparticles, nanotitania, graphene, grapheneoxide, cadmium telluride and related quantum dots, nanocomposites, upconversion nanoparticles and bacteriophages. Finally, closing remarks and an outlook conclude the review.
Electroanalysis, Aug 25, 2016
A novel, facile fabrication, based on electrochemically reduced graphene oxide (ErGO), grafted wi... more A novel, facile fabrication, based on electrochemically reduced graphene oxide (ErGO), grafted with Pt nanoparticles and Nafion hybrid nano‐composite (ErGO‐Pt/Nafion) on the surface of edge plane pyrolytic graphite (EPPG) has been reported. The fabricated sensor has been used for the sensitive and selective determination of efavirenz (EFZ), a well‐known drug for HIV infections. The ErGO‐Pt/Nafion film was characterized by Field Emission Scanning Electron Microscopy (FE‐SEM), Energy‐dispersive X‐ray spectrometry (EDS) and Electrochemical Impedance Spectroscopy (EIS). The experimental results reveal that the modified sensor displays an excellent electrocatalytic activity towards the oxidation of EFZ and exhibits a large linear dynamic relationship in the range of 0.05 μM to 150 μM, with a detection limit of 1.8 nM. Practical utility of the developed sensor has been demonstrated by determining the EFZ in biological fluids and pharmaceutical samples and a low detection limit with high sensitivity observed makes it valuable for the clinical diagnosis.
Materials Science and Engineering: C, Aug 1, 2017
A facile preparation strategy based on electrochemical technique for the fabrication of glycine (... more A facile preparation strategy based on electrochemical technique for the fabrication of glycine (Poly-Gly) and electrochemically reduced graphene oxide (ERGO) composite modified electrode was developed. The morphology of the developed composite (ERGO/Poly-Gly) was investigated using field emission scanning electron microscope (FE-SEM). The composite modified glassy carbon electrode (GCE) was characterized using fourier transform-infrared (FT-IR) spectroscopy, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The electrochemical characterization results revealed that ERGO/Poly-Gly modified GCE has excellent electrocatalytic activity. Further, it was employed for sensing of L-dopa in pH 5.5. Differential pulse voltammetry (DPV) was used for the quantification of L-dopa as well as for the simultaneous resolution of L-dopa and uric acid (UA). The LOD (S/N=3) was found to be 0.15 μM at the proposed composite modified electrode. Determination of L-dopa could also be achieved in the presence of potentially interfering substances. The sensor showed high sensitivity and selectivity with appreciable reliability and precision. The proposed sensor was also successfully applied for real sample analysis.
Analytica Chimica Acta, 2015
A review on the determination of antitubercular drugs is presented. Electrochemical methods explo... more A review on the determination of antitubercular drugs is presented. Electrochemical methods explored during 2006present for the determination are summarized. A comparison of electrochemical methods and chromatographic methods is presented.
![Research paper thumbnail of An insight on synthetic and medicinal aspects of pyrazolo[1,5-a]pyrimidine scaffold](https://attachments.academia-assets.com/109289960/thumbnails/1.jpg)
](European journal of medicinal chemistry, 2017
An insight on synthetic and medicinal aspects of pyrazolo[1,5a]pyrimidine scaffold
Journal of Pharmaceutical and Biomedical Analysis, Sep 1, 2021
This study emphases on electrochemical detection of ciprofloxacin in sheep serum and runoff water... more This study emphases on electrochemical detection of ciprofloxacin in sheep serum and runoff water using silver nanoparticle modified β-cyclodextrin (Ag-β-CD) composite. The Ag-β-CD composite was synthesized via a hydrothermal route, which resulted in a high product yield. Morphological and spectral characterizations of the Ag-β-CD composite were carried out. The Ag-β-CD composite was used to detect ciprofloxacin by employing differential pulse voltammetry (DPV) and cyclic voltammetry (CV). The Ag-β-CD modified electrode displayed excellent specificity towards the electro-oxidation of ciprofloxacin. Further, the sensor gave the best response towards the electro-oxidation of ciprofloxacin near the human physiological pH of 7.5. A linear response was obtained between the concentration range of 0.1 nM to 50 nM and the limit of detection (LOD) at 0.028 nM with high sensitivity and selectivity towards ciprofloxacin oxidation. The current work has a rationally synthesized and characterized nanocomposite with a very high potential for rapid and sensitive detection of ciprofloxacin in spiked sheep blood serum and domestic runoff water samples. High sensitivity and low LOD results illustrate good practicability for the detection of ciprofloxacin in such samples in the near future.
Materials Science and Engineering: C, Apr 1, 2019
A glassy carbon electrode modified with electrochemically polymerized methyl orange (PMO) and mul... more A glassy carbon electrode modified with electrochemically polymerized methyl orange (PMO) and multi-walled carbon nanotubes (MWCNT) was developed. The morphologies of the fabricating materials (PMO and MWCNT) were investigated by field-emission scanning electron microscopy (FE-SEM). The designed sensor was used for the sensitive determination of amodiaquine (AQ), an anti-malaria drug. AQ was developed as an alternative to chloroquine because of its activity against chloroquine-resistant Plasmodium falciparum (P. falciparum) parasites. The modified electrode was employed to study the electrochemical oxidation of AQ using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. Under optimal experimental conditions, DPV exhibited a linear response in the concentration range from 1.0 × 10-7 to 3.5 × 10-6 mol L-1 with a limit of detection (LOD) of 8.9 × 10-8 mol L-1. Furthermore, the number of electrons and protons involved in the electrochemical study of AQ was also calculated and a plausible mechanism for the electro-oxidation of AQ was deduced. The developed sensor demonstrated analytical applicability as it was successfully employed to determine the drug AQ in pharmaceutical formulations and human urine samples.
Anti-cancer Agents in Medicinal Chemistry, Aug 17, 2015
Anti-cancer Agents in Medicinal Chemistry, Aug 17, 2015
There is an ever-increasing need for the development of new drugs with safe and improved profile ... more There is an ever-increasing need for the development of new drugs with safe and improved profile for the treatment of cancer. From the time immemorial, nature has been considered as an abundant source of medicinal compounds having therapeutic properties. An enormous chemical diversity is present in thousands and millions of species of microorganisms, marine organisms, plants and animals that can act as potential therapeutic agents against various types of human cancer. Literature survey revealed that many alkaloids isolated from marine cyanobacteria, fungi, algae, sponges and tunicates displayed a wide range of anticancer properties like anti-proliferative, antiangiogenic, induction of apoptosis, promoting cytotoxicity by inhibition of topoisomerase activities and tubulin polymerization. In this context, bastadins derived from tyrosine-based alkaloids have been reported as one of the important class of anticancer agents. In particular bastadin 6 (24), seems to be a promising natural lead compound for the development of marine natural product-based anticancer therapeutic agents. This review mainly highlights the pharmacologically active scaffolds like purine, tyrosine and tryptophan containing marine alkaloids that exhibit biological activity, including anti-angiogenesis, cytotoxicity and anticancer activity.
Materials Science and Engineering: C, May 1, 2017
A gold nanourchins modified glassy carbon electrode (AuNu/GCE) was developed for the determinatio... more A gold nanourchins modified glassy carbon electrode (AuNu/GCE) was developed for the determination of antimalarial drug, primaquine (PQ). The surface of AuNu/GCE was characterized by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and cyclic voltammetry (CV). EIS results indicated that the electron transfer process at AuNu/GCE was faster as compared to the bare electrode. The SEM and TEM image confirmed the presence and uniform dispersion of gold nanourchins on the GCE surface. Upon investigating the electrochemical behavior of PQ at AuNu/GCE, the developed sensor was found to exhibit high electrocatalytic activity towards the oxidation of PQ. Under optimal experimental conditions, the sensor showed fast and sensitive current response to PQ over a linear concentration range of 0.01-1 μM and 0.001-1 μM with a detection limit of 3.5 nM and 0.9 nM using differential pulse voltammetry (DPV) and square wave voltammetry (SWV), respectively. The AuNu/GCE showed good selectivity, reproducibility and stability. Further, the developed sensor was successfully applied to determine the drug in human urine samples and pharmaceutical formulations demonstrating its analytical applicability in clinical analysis as well as quality control. The proposed method thus provides a promising alternative in routine sensing of PQ as well as promotes the application of gold nanourchins in electrochemical sensors.
Mikrochimica Acta, 2020
A copper(II) benzene-1,3,5-tricarboxylate (BTC) metal-organic framework (MOF) was modified with p... more A copper(II) benzene-1,3,5-tricarboxylate (BTC) metal-organic framework (MOF) was modified with poly(acrylic acid) (PAA) and then used in an electrochemical sensor for vancomycin. The MOF, synthesized via a single-pot method, has enhanced solubility and dispersibility in water as compared to HKUST-1 but without compromising its crystallinity and porosity. The MOF was placed on a glassy carbon electrode (GCE) where it shows enhanced electrocatalytic properties. This is assumed to be due to the presence of the poly(acrylic acid) that forms a network between various HKUST-1 crystals through dimer formation between the carboxy groups of BTC and PAA. This also led to better dispersion of the MOF and to improved interaction between MOF and vancomycin. The structural, spectral and electrochemical properties of the MOFs and their vancomycin complexes was characterized. The modified GCE is shown to be a viable tool for electrochemical determination (best at a working potential of 784 mV vs. Ag/AgCl) of the antibiotic vancomycin in spiked urine and serum samples. Response is linear in the 1-500 nM vancomycin concentration range, and the detection limit is 1 nM, with a relative standard deviation of ±4.3%.
RSC Advances, 2016
Aim: In this study, it was aimed to determine the reduced Glutathione (GSH) at the modified senso... more Aim: In this study, it was aimed to determine the reduced Glutathione (GSH) at the modified sensor with a simple and reliable electroanalytical method. Material and Method: Cyclic voltammetry and differential pulse voltammetry techniques were used for the determination of reduced-GSH. And the modified sensor was fabricated by dropping single-walled carbon nanotube (SWCNT) dispersion onto the surface of the glassy carbon electrode. Results: The determination of reduced-GSH was accomplished at SWCNT modified sensor. The relationship between the current responses of the sensor and the concentrations of the reduced-GSH (1.0 x 10-8-5.0 x 10-8 M) showed excellent linearity and the detection limit was calculated as 75 nM. Discussion: Determination of trace amounts of reduced-GSH in urine samples was successfully applied at the modified sensor. The results showed that modification of the glassy carbon electrode with SWCNT could provide a new strategy for determining the concentration of GSH in physiological solutions.
Arabian Journal of Chemistry, May 1, 2017
Hybrids of bromopyrrole alkaloids with aroyl hydrazone feature were synthesized and evaluated for... more Hybrids of bromopyrrole alkaloids with aroyl hydrazone feature were synthesized and evaluated for their anti-inflammatory activity using the carrageenan induced rat paw edema method. All the tested hybrids showed good anti-inflammatory activity with 64.78-86.03% inhibition of edema. Most active hybrids 4b and 4f were further investigated for antihistaminic H 1 [4b À8.09 lg/mL (18.5 lM); 4f À9.26 lg/mL (24.05 lM)] and anti-serotonergic 5-HT 3 [4b À7.01 lg/mL (16.04 lM); 4f À9.64 lg/mL (25.04 lM)] activities. Molecule 4f with anti-inflammatory, anti-histaminic and anti-serotonergic activities emerges as a potential anti-inflammatory lead form in this study.
Bioorganic & Medicinal Chemistry Letters, May 1, 2015
Troglitazone causes severe hepatic injury in certain individuals and multiple mechanisms related ... more Troglitazone causes severe hepatic injury in certain individuals and multiple mechanisms related to hepato-toxicity has been reported creating confusion. In the present study, the mechanism for the hepatic injury of glitazones was investigated by PASS. The results suggest that chromane containing glitazones are apoptic agonist (activating p53 by intrinsic pathway leading to the apoptosis) and those which do not contain the chromane are devoid of this. In case of hepatotoxicity by non-chromane glitazone and their metabolite such as M-3, RM-3, rosiglitazone and pioglitazone; PASS suggest that these chemicals are not apoptic agonist but they are the substrate for CYP enzyme (Phase-I Oxidative Enzyme) and Phase-II conjugating enzymes; interfering with bile acid metabolism rendering bile acid more toxic (cholestasis). This unmetabolised bile salt further initiates the process apoptosis via intrinsic and extrinsic pathway leading to the apoptosis. Immunoblot analysis further confirm our hypothesis that troglitazone (Chromane containing glitazone), but not rosiglitazone and pioglitazone (Non-chromane containing glitazone) increased the levels of p53 in a time-dependent manner. Hence our prediction related to the mechanism of hepato-toxicity by apoptosis and structural insight of glitazone can be helpful in improving the drug profile of this category.
Talanta, Sep 1, 2015
Dextromethorphan (DXM) and diphenhydramine (DPH) are two commonly used over-the-counter nonnarcot... more Dextromethorphan (DXM) and diphenhydramine (DPH) are two commonly used over-the-counter nonnarcotic antitussive drugs. Recent reports reveal the widespread abuse of DXM and DPH due to their euphoric and alcohol-like effects. Due to their medicinal importance as well as the apparent increase in their use as abused drugs, it has become critical to determine them in samples of biological, clinical and pharmaceutical interest. The electrochemical techniques for drug analysis have gathered considerable attention due to their pronounced selectivity, sensitivity and simplicity. The given review presents a compilation of published voltammetric and potentiometric methods developed for determination of DXM and DPH. It critically highlights the analytical performances, revealing the recent trends and progress in the specified approach for their analysis. The review forms a basis for further progress in this field and development of improved electrochemical sensors to determine the drug.
Anti-cancer Agents in Medicinal Chemistry, Aug 17, 2015
Overexpression of epidermal growth factor receptor (EGFR) is seen in a number of human tumors lik... more Overexpression of epidermal growth factor receptor (EGFR) is seen in a number of human tumors like prostate, colon, breast and ovarian. Their expression is correlated with vascularity and often difficult to diagnose. Though a number of active inhibitors and anticancer drugs against EGFR-tyrosine kinase are known, increase in resistance together with many side effects designate the need for new and improved treatments. Natural products and their analoges have significant contribution in the cancer drug discovery and development process. Therefore in the current review we mainly discuss design, synthesis and structural activity relationship of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors from the natural origin.
Electroanalysis, Jun 13, 2017
Mefloquine (MQ) is a quinoline based antimalarial drug, which is potent against multiple drug-res... more Mefloquine (MQ) is a quinoline based antimalarial drug, which is potent against multiple drug-resistant Plasmodium falciparum. It is widely prescribed for the prophylactic treatment of malaria. Due to extensive usage of MQ, constant monitoring of the drug level in human body is of paramount importancein order to ensure that optimum drug exposure is achieved. The present work describes a gold nanourchins (AuNUs) based electrochemical sensor for the determination of MQ.AuNUs were synthesized via seed-mediated method and characterized using ultraviolet-visible spectroscopy, energy-dispersive X-ray spectroscopy, field emission scanning electron microscopy, zeta-sizer and electrochemical techniques (electrochemical impedance spectroscopy and cyclic voltammetry). Fabrication of the sensor was done by drop-coating the synthesized AuNUs onto a glassy carbon electrode. The fabricated sensor exhibited enhanced voltammetric response, which was attributed to the excellent conductivity and high surface area of AuNUs. Under optimum square wave voltammetric conditions, the sensor displayed two linear response ranges (from 2.0 3 10 À9 to 1.0 3 10 À6 M and from 1.0 3 10 À6 to 1.0 3 10 À3 M) with a detection limit of 1.4 nM. The electrode demonstrated good reproducibility, stability and selectivity over common interferents. The utility of the sensor was successfully assessed for quantification of the drug in pharmaceutical preparation and spiked human urine sample. Thus, the present study demonstrates a promising approach for determination of MQ with practical utility in quality control and clinical analysis.
RSC Advances, 2015
Vascular endothelial growth factor receptor-2 (VEGFR-2) plays a crucial role in cancer angiogenes... more Vascular endothelial growth factor receptor-2 (VEGFR-2) plays a crucial role in cancer angiogenesis. A library of 6,7-dimethoxy quinazoline was prepared using ligand based drug design approach and passed through different filters of virtual screening such as docking study and Lipinski's rule. Twenty virtually screened compounds were synthesized and investigated against VEGFR-2 kinase and human umbilical vein endothelial cells (HUVEC) in vitro. Virtually screened compound 47 having 4-chlorophenyl-1,3,4-thiadiazole substitution at 3 rd position of 6,7-dimethoxy-2-phenylquinazolin-4(3H)-one exhibited the most promising activity, with IC 50 value of 3.8 nm and 5.5 nm against VEGFR-2 tyrosine kinase and HUVEC cell line. Docking simulation supported the initial pharmacophoric hypothesis and suggested a common mode of interaction at the ATP-binding site of VEGFR-2 demonstrating that compound 47 was a potential agent for cancer therapy that deserves further research.
Arabian Journal of Chemistry, Feb 1, 2018
Over expression of 11b-HSD 1 in key metabolic tissues is related to the development of type 2 dia... more Over expression of 11b-HSD 1 in key metabolic tissues is related to the development of type 2 diabetes, obesity, hypertension and metabolic syndrome. Nephrotoxicity of corosolic acid (selective inhibitor of 11b-HSD 1) is recently reported, which is one of the major drawback. Therefore, it is of great interest to find out the selective 11b-HSD 1 inhibitors without nephrotoxicity. Using crystal structures of 11b-HSD 1 in complex with inhibitors as a source of structural information, a combined structure-based virtual screening approach followed by PASS toxicity prediction, Lipinski's rule and ADME prediction was implemented to find out the potent and selective 11 b-HSD 1 analog of corosolic acid without nephrotoxicity. Two compounds with NCBI compound identification number CID59752459 (Genins of Asiatic acid) and CID 119034 (Asiatic acid) were found to be selective for the 11b-HSD 1 enzyme without nephrotoxicity which comply with
Mikrochimica Acta, Jan 16, 2019
Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for a number of life-threatenin... more Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for a number of life-threatening complications in humans. Mutations in the genetic sequence of S. aureus due to the presence of certain genes results in resistance against β-lactamases. Thus, there is an urgent need for developing highly sensitive techniques for the early detection of MRSA to counter the rise in resistant strains. This review (142 refs.) extensively covers literature reports on nanomaterial-based optical and electrochemical sensors from the year 1983 to date, with particularly emphasis on recent advances in electrochemical sensing (such as voltammetry and impedimetric) and optical sensing (such as colorimetry and fluorometry) techniques. Among the electrochemical methods, various nanomaterials were employed for the modification of electrodes. Whereas, in optical assays, formats such as enzyme linked immunosorbent assay, lateral flow assays or in optical fiber systems are common. In addition, novel sensing platforms are reported by applying advanced nanomaterials which include gold nanoparticles, nanotitania, graphene, grapheneoxide, cadmium telluride and related quantum dots, nanocomposites, upconversion nanoparticles and bacteriophages. Finally, closing remarks and an outlook conclude the review.
Electroanalysis, Aug 25, 2016
A novel, facile fabrication, based on electrochemically reduced graphene oxide (ErGO), grafted wi... more A novel, facile fabrication, based on electrochemically reduced graphene oxide (ErGO), grafted with Pt nanoparticles and Nafion hybrid nano‐composite (ErGO‐Pt/Nafion) on the surface of edge plane pyrolytic graphite (EPPG) has been reported. The fabricated sensor has been used for the sensitive and selective determination of efavirenz (EFZ), a well‐known drug for HIV infections. The ErGO‐Pt/Nafion film was characterized by Field Emission Scanning Electron Microscopy (FE‐SEM), Energy‐dispersive X‐ray spectrometry (EDS) and Electrochemical Impedance Spectroscopy (EIS). The experimental results reveal that the modified sensor displays an excellent electrocatalytic activity towards the oxidation of EFZ and exhibits a large linear dynamic relationship in the range of 0.05 μM to 150 μM, with a detection limit of 1.8 nM. Practical utility of the developed sensor has been demonstrated by determining the EFZ in biological fluids and pharmaceutical samples and a low detection limit with high sensitivity observed makes it valuable for the clinical diagnosis.
Materials Science and Engineering: C, Aug 1, 2017
A facile preparation strategy based on electrochemical technique for the fabrication of glycine (... more A facile preparation strategy based on electrochemical technique for the fabrication of glycine (Poly-Gly) and electrochemically reduced graphene oxide (ERGO) composite modified electrode was developed. The morphology of the developed composite (ERGO/Poly-Gly) was investigated using field emission scanning electron microscope (FE-SEM). The composite modified glassy carbon electrode (GCE) was characterized using fourier transform-infrared (FT-IR) spectroscopy, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The electrochemical characterization results revealed that ERGO/Poly-Gly modified GCE has excellent electrocatalytic activity. Further, it was employed for sensing of L-dopa in pH 5.5. Differential pulse voltammetry (DPV) was used for the quantification of L-dopa as well as for the simultaneous resolution of L-dopa and uric acid (UA). The LOD (S/N=3) was found to be 0.15 μM at the proposed composite modified electrode. Determination of L-dopa could also be achieved in the presence of potentially interfering substances. The sensor showed high sensitivity and selectivity with appreciable reliability and precision. The proposed sensor was also successfully applied for real sample analysis.
Analytica Chimica Acta, 2015
A review on the determination of antitubercular drugs is presented. Electrochemical methods explo... more A review on the determination of antitubercular drugs is presented. Electrochemical methods explored during 2006present for the determination are summarized. A comparison of electrochemical methods and chromatographic methods is presented.
European journal of medicinal chemistry, 2017
An insight on synthetic and medicinal aspects of pyrazolo[1,5a]pyrimidine scaffold
Journal of Pharmaceutical and Biomedical Analysis, Sep 1, 2021
This study emphases on electrochemical detection of ciprofloxacin in sheep serum and runoff water... more This study emphases on electrochemical detection of ciprofloxacin in sheep serum and runoff water using silver nanoparticle modified β-cyclodextrin (Ag-β-CD) composite. The Ag-β-CD composite was synthesized via a hydrothermal route, which resulted in a high product yield. Morphological and spectral characterizations of the Ag-β-CD composite were carried out. The Ag-β-CD composite was used to detect ciprofloxacin by employing differential pulse voltammetry (DPV) and cyclic voltammetry (CV). The Ag-β-CD modified electrode displayed excellent specificity towards the electro-oxidation of ciprofloxacin. Further, the sensor gave the best response towards the electro-oxidation of ciprofloxacin near the human physiological pH of 7.5. A linear response was obtained between the concentration range of 0.1 nM to 50 nM and the limit of detection (LOD) at 0.028 nM with high sensitivity and selectivity towards ciprofloxacin oxidation. The current work has a rationally synthesized and characterized nanocomposite with a very high potential for rapid and sensitive detection of ciprofloxacin in spiked sheep blood serum and domestic runoff water samples. High sensitivity and low LOD results illustrate good practicability for the detection of ciprofloxacin in such samples in the near future.
Materials Science and Engineering: C, Apr 1, 2019
A glassy carbon electrode modified with electrochemically polymerized methyl orange (PMO) and mul... more A glassy carbon electrode modified with electrochemically polymerized methyl orange (PMO) and multi-walled carbon nanotubes (MWCNT) was developed. The morphologies of the fabricating materials (PMO and MWCNT) were investigated by field-emission scanning electron microscopy (FE-SEM). The designed sensor was used for the sensitive determination of amodiaquine (AQ), an anti-malaria drug. AQ was developed as an alternative to chloroquine because of its activity against chloroquine-resistant Plasmodium falciparum (P. falciparum) parasites. The modified electrode was employed to study the electrochemical oxidation of AQ using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. Under optimal experimental conditions, DPV exhibited a linear response in the concentration range from 1.0 × 10-7 to 3.5 × 10-6 mol L-1 with a limit of detection (LOD) of 8.9 × 10-8 mol L-1. Furthermore, the number of electrons and protons involved in the electrochemical study of AQ was also calculated and a plausible mechanism for the electro-oxidation of AQ was deduced. The developed sensor demonstrated analytical applicability as it was successfully employed to determine the drug AQ in pharmaceutical formulations and human urine samples.
Anti-cancer Agents in Medicinal Chemistry, Aug 17, 2015
Anti-cancer Agents in Medicinal Chemistry, Aug 17, 2015
There is an ever-increasing need for the development of new drugs with safe and improved profile ... more There is an ever-increasing need for the development of new drugs with safe and improved profile for the treatment of cancer. From the time immemorial, nature has been considered as an abundant source of medicinal compounds having therapeutic properties. An enormous chemical diversity is present in thousands and millions of species of microorganisms, marine organisms, plants and animals that can act as potential therapeutic agents against various types of human cancer. Literature survey revealed that many alkaloids isolated from marine cyanobacteria, fungi, algae, sponges and tunicates displayed a wide range of anticancer properties like anti-proliferative, antiangiogenic, induction of apoptosis, promoting cytotoxicity by inhibition of topoisomerase activities and tubulin polymerization. In this context, bastadins derived from tyrosine-based alkaloids have been reported as one of the important class of anticancer agents. In particular bastadin 6 (24), seems to be a promising natural lead compound for the development of marine natural product-based anticancer therapeutic agents. This review mainly highlights the pharmacologically active scaffolds like purine, tyrosine and tryptophan containing marine alkaloids that exhibit biological activity, including anti-angiogenesis, cytotoxicity and anticancer activity.
Materials Science and Engineering: C, May 1, 2017
A gold nanourchins modified glassy carbon electrode (AuNu/GCE) was developed for the determinatio... more A gold nanourchins modified glassy carbon electrode (AuNu/GCE) was developed for the determination of antimalarial drug, primaquine (PQ). The surface of AuNu/GCE was characterized by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and cyclic voltammetry (CV). EIS results indicated that the electron transfer process at AuNu/GCE was faster as compared to the bare electrode. The SEM and TEM image confirmed the presence and uniform dispersion of gold nanourchins on the GCE surface. Upon investigating the electrochemical behavior of PQ at AuNu/GCE, the developed sensor was found to exhibit high electrocatalytic activity towards the oxidation of PQ. Under optimal experimental conditions, the sensor showed fast and sensitive current response to PQ over a linear concentration range of 0.01-1 μM and 0.001-1 μM with a detection limit of 3.5 nM and 0.9 nM using differential pulse voltammetry (DPV) and square wave voltammetry (SWV), respectively. The AuNu/GCE showed good selectivity, reproducibility and stability. Further, the developed sensor was successfully applied to determine the drug in human urine samples and pharmaceutical formulations demonstrating its analytical applicability in clinical analysis as well as quality control. The proposed method thus provides a promising alternative in routine sensing of PQ as well as promotes the application of gold nanourchins in electrochemical sensors.
Mikrochimica Acta, 2020
A copper(II) benzene-1,3,5-tricarboxylate (BTC) metal-organic framework (MOF) was modified with p... more A copper(II) benzene-1,3,5-tricarboxylate (BTC) metal-organic framework (MOF) was modified with poly(acrylic acid) (PAA) and then used in an electrochemical sensor for vancomycin. The MOF, synthesized via a single-pot method, has enhanced solubility and dispersibility in water as compared to HKUST-1 but without compromising its crystallinity and porosity. The MOF was placed on a glassy carbon electrode (GCE) where it shows enhanced electrocatalytic properties. This is assumed to be due to the presence of the poly(acrylic acid) that forms a network between various HKUST-1 crystals through dimer formation between the carboxy groups of BTC and PAA. This also led to better dispersion of the MOF and to improved interaction between MOF and vancomycin. The structural, spectral and electrochemical properties of the MOFs and their vancomycin complexes was characterized. The modified GCE is shown to be a viable tool for electrochemical determination (best at a working potential of 784 mV vs. Ag/AgCl) of the antibiotic vancomycin in spiked urine and serum samples. Response is linear in the 1-500 nM vancomycin concentration range, and the detection limit is 1 nM, with a relative standard deviation of ±4.3%.
RSC Advances, 2016
Aim: In this study, it was aimed to determine the reduced Glutathione (GSH) at the modified senso... more Aim: In this study, it was aimed to determine the reduced Glutathione (GSH) at the modified sensor with a simple and reliable electroanalytical method. Material and Method: Cyclic voltammetry and differential pulse voltammetry techniques were used for the determination of reduced-GSH. And the modified sensor was fabricated by dropping single-walled carbon nanotube (SWCNT) dispersion onto the surface of the glassy carbon electrode. Results: The determination of reduced-GSH was accomplished at SWCNT modified sensor. The relationship between the current responses of the sensor and the concentrations of the reduced-GSH (1.0 x 10-8-5.0 x 10-8 M) showed excellent linearity and the detection limit was calculated as 75 nM. Discussion: Determination of trace amounts of reduced-GSH in urine samples was successfully applied at the modified sensor. The results showed that modification of the glassy carbon electrode with SWCNT could provide a new strategy for determining the concentration of GSH in physiological solutions.
Arabian Journal of Chemistry, May 1, 2017
Hybrids of bromopyrrole alkaloids with aroyl hydrazone feature were synthesized and evaluated for... more Hybrids of bromopyrrole alkaloids with aroyl hydrazone feature were synthesized and evaluated for their anti-inflammatory activity using the carrageenan induced rat paw edema method. All the tested hybrids showed good anti-inflammatory activity with 64.78-86.03% inhibition of edema. Most active hybrids 4b and 4f were further investigated for antihistaminic H 1 [4b À8.09 lg/mL (18.5 lM); 4f À9.26 lg/mL (24.05 lM)] and anti-serotonergic 5-HT 3 [4b À7.01 lg/mL (16.04 lM); 4f À9.64 lg/mL (25.04 lM)] activities. Molecule 4f with anti-inflammatory, anti-histaminic and anti-serotonergic activities emerges as a potential anti-inflammatory lead form in this study.