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Ramírez-Lozano CM, Ochoa ME, Labra-Vázquez P, Jiménez-Sánchez A, Farfán N, Santillan R. Exploring the self-assembly dynamics of novel steroid-coumarin conjugates: a comprehensive spectroscopic and solid-state investigation. Org Biomol Chem 2024; 22:3314-3327. [PMID: 38578064 DOI: 10.1039/d4ob00192c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Abstract
The design, synthesis, and characterization of seven novel steroid-coumarin conjugates with diverse steroidal nuclei as lipophilic fluorescent materials for bioimaging applications are presented. The conjugates were synthesized through amidation, characterized using spectroscopic and spectrometric methods, and their main photophysical properties were determined. Dioxane : water titration experiments revealed their ability to self-assemble, forming J-aggregates as evidenced by new spectral bands at higher wavelengths. Monocrystal X-ray diffraction analysis disclosed distinctive aggregation patterns exhibiting J- or H-aggregates for selected compounds. Bioimaging studies demonstrated cell membrane localization for most conjugates, with some of them displaying an interesting selectivity for lipid droplets. Notably, the presence of the steroid fragments significantly influenced both the self-assembly patterns and the cellular localization of the fluorescent probes.
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Affiliation(s)
- Claudia M Ramírez-Lozano
- Departamento de Química, Centro de Investigación y de Estudios Avanzados del IPN, Apdo. Postal 14-740, 07000, Mexico.
| | - Ma Eugenia Ochoa
- Departamento de Química, Centro de Investigación y de Estudios Avanzados del IPN, Apdo. Postal 14-740, 07000, Mexico.
| | - Pablo Labra-Vázquez
- CIRIMAT, Université de Toulouse, CNRS, Université Toulouse 3 - Paul Sabatier, 118 Route de Narbonne, 31062, Toulouse, Cedex 9, France
| | - Arturo Jiménez-Sánchez
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, Coyoacán, Ciudad de México 04510, Mexico
| | - Norberto Farfán
- Facultad de Química, Departamento de Química Orgánica, Universidad Nacional Autónoma de México, 04510 CDMX, Mexico
| | - Rosa Santillan
- Departamento de Química, Centro de Investigación y de Estudios Avanzados del IPN, Apdo. Postal 14-740, 07000, Mexico.
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2
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Bhatta A, Upadhyaya J, Chamlagai D, Dkhar L, Phanrang PT, Rao Kollipara M, Mitra S. Exploring the impact of novel thiazole-pyrazole fused benzo-coumarin derivatives on human serum albumin: Synthesis, photophysical properties, anti-cholinergic activity, and interaction studies. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2024; 308:123669. [PMID: 38006865 DOI: 10.1016/j.saa.2023.123669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 11/18/2023] [Accepted: 11/18/2023] [Indexed: 11/27/2023]
Abstract
Derivatives of thiazole-pyrazole fused benzo-coumarin compounds were successfully synthesized and characterized, followed by a comprehensive spectroscopic investigation on various photophysical properties in different media. The multipronged approach using steady state and time resolved fluorescence spectroscopy pointed out the impact of substitution in the estimated spectroscopic and other physicochemical properties of the systems. Further, the evaluation of anti-acetylcholinesterase (anti-AChE) activity yielded significant insight into the therapeutic potential of the synthesized coumarinyl compounds for the treatment of Alzheimer's disease (AD). The findings revealed a non-competitive mode of inhibition mechanism, with an estimated IC50 value of 67.72 ± 2.00 nM observed for one of the investigated systems as AChE inhibitor. Notably, this value is even lower than that of an FDA-approved AD drug Donepezil (DON), indicating the enhanced potency of the coumarin derivatives in inhibiting AChE. Interestingly, significant diminution in inhibition was observed in presence of human serum albumin (HSA) as evidenced by the relative increase in IC50 value by 8 ∼ 39 % in different cases, which emphasized the role of albumin proteins to control therapeutic efficacies of potential medications. In-depth spectroscopic and in-silico analysis quantified the nature of interactions of the investigated systems with HSA and AChE. Overall, the outcomes of this study provide significant understanding into the biophysical characteristics of novel thiazole-pyrazole fused benzo-coumarin systems, which could aid in the development of new cholinergic agents for the treatment of AD and materials based on coumarin motifs.
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Affiliation(s)
- Anindita Bhatta
- Department of Chemistry, North-Eastern Hill University, Shillong 793 022, India
| | - Jahnabi Upadhyaya
- Department of Chemistry, North-Eastern Hill University, Shillong 793 022, India
| | - Dipak Chamlagai
- Department of Chemistry, North-Eastern Hill University, Shillong 793 022, India
| | - Lincoln Dkhar
- Department of Chemistry, North-Eastern Hill University, Shillong 793 022, India
| | | | - Mohan Rao Kollipara
- Department of Chemistry, North-Eastern Hill University, Shillong 793 022, India
| | - Sivaprasad Mitra
- Department of Chemistry, North-Eastern Hill University, Shillong 793 022, India.
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3
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Surya Prakash Rao H, Prabakaran M, Muthanna N. Synthesis of 7-hydroxydibenzopyran-6-ones via benzannulation of coumarins. Org Biomol Chem 2022; 20:6905-6914. [PMID: 35975610 DOI: 10.1039/d2ob01203k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have successfully demonstrated a facile synthesis of a variety of 7-hydroxydibenzopyran-6-ones via a two-step protocol from 3-acylcoumarins having a latent Nazarov dienone functionality. Condensation of 3-acylcoumarins and ethyl cyanoacetate under basic (wet K2CO3) and microwave irradiation conditions followed by decarboethoxylative aromatization with Br2 or DDQ furnished dibenzopyran-6-ones in high yields. The formation of ring C of the dibenzopyran-6-one motif critically depended on an active methylene compound and C7 substitution on coumarins. The Ar-Br or ArOTf substitution in dibenzopyran-6-ones was leveraged for the palladium-catalysed Suzuki coupling with diverse aryl boronic acids to increase the structural diversity. Reductive decyanation of C10 cyano dibenzopyran-6-ones furnished some of the isomers of urolithin A.
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Affiliation(s)
- H Surya Prakash Rao
- Department of Chemistry, Pondicherry University, Pondicherry - 605 014, India. .,Vasista Pharma Chem Pvt Limited, Gajularamaram, Hyderabad - 500 090, India
| | - M Prabakaran
- Department of Chemistry, Pondicherry University, Pondicherry - 605 014, India.
| | - Nandurka Muthanna
- Department of Chemistry, Pondicherry University, Pondicherry - 605 014, India.
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4
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Sarkar S, De S. Brij Niosomes as Carriers for Sustained Drug Delivery─A Fluorescence-Based Approach to Probe the Niosomal Microenvironment. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:4521-4537. [PMID: 35377656 DOI: 10.1021/acs.langmuir.1c02996] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Niosomes were prepared using a triad of polyoxyethylene alkyl ether surfactants. The focus was to elucidate the effects of varying alkyl chain length and varying hydrophilic headgroups on the structure of the niosomes, with an aim to design niosomes for efficient encapsulation and release of both hydrophobic and hydrophilic drugs. The phase transitions of the surfactants were ascertained by differential scanning calorimetry. It was found that the headgroup has a profound influence on the niosomal bilayer. Fluorescent probes Coumarin 153 (C-153) and 1,6-diphenyl-1,3,5-hexatriene were used to probe the structural integrity of the niosomal bilayer under stress conditions. Other aspects of the niosomes were probed by following the aggregation of the dyes fluorescein (FL) and Nile Red, red edge excitation shift, and fluorescence resonance energy transfer (FRET) between them. Fluorescence lifetime imaging microscopy provides proof of the exact location of the donor and acceptor dyes in the niosomes under FRET condition. It was also shown that the niosomes are efficient "carriers" for entrapment and controlled release of the chemotherapeutic drug 5-fluorouracil. It was found that a rigid niosomal bilayer leads to controlled drug release. The present work is relevant for the future use of these niosomes for cargo entrapment.
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Affiliation(s)
- Sudeshna Sarkar
- Department of Chemistry, University of Kalyani, Kalyani, West Bengal 741235, India
| | - Swati De
- Department of Chemistry, University of Kalyani, Kalyani, West Bengal 741235, India
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5
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Shoara AA, Churcher ZR, Steele TWJ, Johnson PE. Analysis of the role played by ligand-induced folding of the cocaine-binding aptamer in the photochrome aptamer switch assay. Talanta 2020; 217:121022. [PMID: 32498850 DOI: 10.1016/j.talanta.2020.121022] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 04/05/2020] [Accepted: 04/07/2020] [Indexed: 02/06/2023]
Abstract
The Photochrome Aptamer Switch Assay (PHASA) relies on ligand binding by an aptamer to alter the local environment of a stilbene compound covalently attached to the 5' end of the aptamer. We used the PHASA with both structure switching and non-structure switching versions of the cocaine-binding aptamer. We show that the largest change in fluorescence intensity and the lowest concentration limit of detection (CLooD) is obtained using the structure-switching cocaine-binding aptamer. Fluorescence anisotropy measurements were used to quantify the affinity of the conjugated aptamer to cocaine. We also used thermal melt analysis and Nuclear Magnetic Resonance (NMR) spectroscopy to show that the addition of the stilbene to the aptamer increases the melt temperature of the cocaine-bound structure-switching aptamer by (6.4 ± 0.3) °C compared to the unconjugated aptamer while the free form of the structure-switching aptamer-stilbene conjugate remains unfolded.
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Affiliation(s)
- Aron A Shoara
- Department of Chemistry & Centre for Research on Biomolecular Interactions, York University, 4700 Keele St., Toronto, Ontario, M3J 1P3, Canada
| | - Zachary R Churcher
- Department of Chemistry & Centre for Research on Biomolecular Interactions, York University, 4700 Keele St., Toronto, Ontario, M3J 1P3, Canada
| | - Terry W J Steele
- School of Materials Science and Engineering (MSE), Division of Materials Technology, Nanyang Technological University (NTU), Singapore, 639798, Singapore
| | - Philip E Johnson
- Department of Chemistry & Centre for Research on Biomolecular Interactions, York University, 4700 Keele St., Toronto, Ontario, M3J 1P3, Canada.
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Sahu S, Talele P, Patra B, Verma RS, Mishra AK. A Multiparametric Fluorescence Probe to Understand the Physicochemical Properties of Small Unilamellar Lipid Vesicles in Poly(ethylene glycol)-Water Medium. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:4842-4852. [PMID: 32283935 DOI: 10.1021/acs.langmuir.9b03902] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
FDAPT (2-formyl-5-(4'-N,N-dimethylaminophenyl)thiophene) efficiently senses the minimum alteration of lipid bilayer microenvironment with all six different fluorescence parameters namely emission wavelength, fluorescence intensity, steady-state anisotropy, and their corresponding time-dependent parameters (Sahu et al., J. Phys. Chem. B 2018, 122, 7308-7318). In the present work, the effect of poly(ethylene glycol) on the small unilamellar vesicle is demonstrated with the emission behavior of the FDAPT probe. A medium and a high molecular weight PEG were chosen to perturb the lipid vesicles. The alteration of the bilayer polarity, water content inside bilayer, lipid packing density in the perturbed vesicles reflect significant changes in different fluorescence parameters of FDAPT probe. The effect of PEG on the unilamellar vesicle was rationalized with the alteration of the emission behavior, fluorescence lifetime, steady-state anisotropy and anisotropy decay of the probe. The simple and convenient fluorescence measurements provide new insights into the effect of PEG on the packing density, water volume, micro polarity, and microviscosity of the small unilamellar vesicle. The physiological understanding was extended to rationalize the cryoprotecting behavior of PEG.
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Affiliation(s)
- Saugata Sahu
- Department of Chemistry, Indian Institute of Technology Madras, Sardar Patel Road, Adyar, Chennai-600036, Tamil Nadu India
| | - Paurnima Talele
- Department of Chemistry, Indian Institute of Technology Madras, Sardar Patel Road, Adyar, Chennai-600036, Tamil Nadu India
| | - Bamadeb Patra
- Department of Biotechnology, Indian Institute of Technology Madras, Sardar Patel Road, Adyar, Chennai-600036, Tamil Nadu India
| | - Rama Shanker Verma
- Department of Biotechnology, Indian Institute of Technology Madras, Sardar Patel Road, Adyar, Chennai-600036, Tamil Nadu India
| | - Ashok Kumar Mishra
- Department of Chemistry, Indian Institute of Technology Madras, Sardar Patel Road, Adyar, Chennai-600036, Tamil Nadu India
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Bhardwaj P, Tripathi P, Gupta R, Pandey S. Niosomes: A review on niosomal research in the last decade. J Drug Deliv Sci Technol 2020. [DOI: 10.1016/j.jddst.2020.101581] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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8
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Tripathi AK. Interaction of alkyl chain containing pyrene derivatives with different micellar media: Synthesis and photophysical study. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2020; 228:117806. [PMID: 31761543 DOI: 10.1016/j.saa.2019.117806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 11/10/2019] [Accepted: 11/14/2019] [Indexed: 06/10/2023]
Abstract
The present work describes the synthesis and photophysical studies of four newly synthesized alkyl chain containing pyrene derivatives and their applications in micellization process of different types of surfactants e.g. CTAB and SDS. The fluorescent properties of these pyrene derivatives were utilized to understand the micellization process of CTAB and SDS. The length of alkyl chain affects the hydrophobicity of pyrene fluorophore which also affects the sensitivity of fluorophore towards the micellization of CTAB and SDS surfactants. The longest alkyl tail containing, PBBU showed more sensitivity whereas moderate alkyl chain containing, PABU and PBME showed moderate sensitivity and finally PAME contained smallest alkyl tail, showed no sensitivity towards the micellization of CTAB and SDS. The alkyl tail of fluorophore make it more hydrophobic and it could easily bind with the hydrophobic inner core of micelles. In both surfactants, PBBU showed LE emission at ~400 nm and aggregate emission at ~470 nm, whereas, PABU and PBME showed LE emission band at ~400 nm. Before CMC, the aggregates band of PBBU increased with increasing the surfactant concentrations, but after CMC the individual PBBU present into the water medium could binds with the inner core of micelles. Thus PBBU senses the formation of premicellar aggregates of CTAB and SDS. The LE emission of the fluorophore gradually increases while increasing the CTAB and SDS concentrations. The change in fluorescence emission of PABU, PBME and PBBU with increasing concentration of CTAB and SDS were used to calculate the CMC of CTAB and SDS surfactants.
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Affiliation(s)
- Alok Kumar Tripathi
- Department of Chemistry, National Taiwan University, Taiwan, ROC; Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
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9
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Mani P, Pandey AK, Tripathi AK. Synthesis and Binding Affinity of Hydrophobic Tail Containing Naphthalene Derivatives with Different Type of Organized Media. ChemistrySelect 2020. [DOI: 10.1002/slct.201904460] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Pavnesh Mani
- Department of ChemistryUniversity of Delhi Delhi India
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10
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Singh A, Pati AK, Mishra AK. Photophysics and photoreactivity of cross-conjugated enediynyl aggregates: Applications to multi-parametric sensing of microheterogeneity and reversible fluorescence switching. Chem Phys 2020. [DOI: 10.1016/j.chemphys.2019.110579] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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11
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Imaging mitochondria and plasma membrane in live cells using solvatochromic styrylpyridines. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2019; 203:111732. [PMID: 31864089 DOI: 10.1016/j.jphotobiol.2019.111732] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 11/20/2019] [Accepted: 12/04/2019] [Indexed: 12/16/2022]
Abstract
Investigating the dynamics of different biomolecules in the cellular milieu through microscopic imaging has gained paramount importance in the last decade. Continuous developments in the field of microscopy are paralleled by the design and synthesis of fluorophores that target specific compartments within a cell. In this study, we have synthesized four fluorescent styrene derivatives, a neutral styrylpridine, three cationic styrylpyridinium probes with and without cholesterol tether, and investigated their absorption, emission, and cellular imaging properties. The fluorophores show solvatochromic emission attributed to intramolecular charge transfer from donor to acceptor with an emission range of 500-600 nm. The fluorescent cholesterol conjugate labels plasma membrane effectively while the fluorophores devoid of the cholesterol tether label mitochondria. Cholesterol conjugate also shows strong interaction with liposome membrane. Furthermore, the fluorophores alsotrack the mitochondria in live cells with high specificity. Cell viability assay showed overall non-toxic nature of the probes even at higher fluorophore concentrations. Through sidearm modifications, keeping the fluorescent core intact, we successfully targeted specific subcellular compartments of neuronal (N2a) and non-neuronal (HeLa) mammalian cell lines. This strategy of using a single molecular scaffold with subtle substitutions could be ideal in generating a variety of fluorophores targeting other subcellular compartments.
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Hydrophilic Silver Nanoparticles Loaded into Niosomes: Physical-Chemical Characterization in View of Biological Applications. NANOMATERIALS 2019; 9:nano9081177. [PMID: 31426465 PMCID: PMC6724070 DOI: 10.3390/nano9081177] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 08/02/2019] [Accepted: 08/15/2019] [Indexed: 12/11/2022]
Abstract
Silver nanoparticles (AgNPs) are widely used as antibacterial agents and anticancer drugs, but often their low stability limits their mass production and broad applications. The use of niosomes as a carrier to protect and envelop AgNPs gives a new perspective to solve these problems. In this study, AgNPs were functionalized with sodium 3-mercapto-1-propanesulfonate (3MPS) to induce hydrophilic behavior, improving loading in Tween 20 and Span 20 niosomes (NioTw20 and NioSp20, respectively). Entrapment efficiency was evaluated by UV analyses and is around 1–4%. Dimensions were investigated by means of dynamic light scattering (DLS) (<2RH> = 140 ± 4 nm and <2RH> = 251 ± 1 nm respectively for NioTw20 + AgNPs and NioSp20 + AgNPs) and were compared with those by atomic force microscopy (AFM) and small angle X ray scattering (SAXS) analyses. Stability was assessed in water up to 90 days, and both in bovine serum and human serum for up to 8 h. In order to characterize the local structure of niosomes, SAXS measurements have been performed on Tween 20 and Span 20 empty niosomes and loaded with AgNPs. The release profiles of hydrophilic probe calcein and lipophilic probe Nile Red were performed in HEPES buffer and in human serum. All these features contribute to conclude that the two systems, NioTw20 + AgNPs and NioSp20 + AgNPs, are suitable and promising in the field of biological applications.
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Chitosan Glutamate-Coated Niosomes: A Proposal for Nose-to-Brain Delivery. Pharmaceutics 2018; 10:pharmaceutics10020038. [PMID: 29565809 PMCID: PMC6027090 DOI: 10.3390/pharmaceutics10020038] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 03/17/2018] [Accepted: 03/19/2018] [Indexed: 12/24/2022] Open
Abstract
The aim of this in vitro study is to prepare and characterize drug free and pentamidine loaded chitosan glutamate coated niosomes for intranasal drug delivery to reach the brain through intranasal delivery. Mucoadhesive properties and stability testing in various environments were evaluated to examine the potential of these formulations to be effective drug delivery vehicles for intranasal delivery to the brain. Samples were prepared using thin film hydration method. Changes in size and ζ-potential of coated and uncoated niosomes with and without loading of pentamidine in various conditions were assessed by dynamic light scattering (DLS), while size and morphology were also studied by atomic force microscopy (AFM). Bilayer properties and mucoadhesive behavior were investigated by fluorescence studies and DLS analyses, respectively. Changes in vesicle size and ζ-potential values were shown after addition of chitosan glutamate to niosomes, and when in contact with mucin solution. In particular, interactions with mucin were observed in both drug free and pentamidine loaded niosomes regardless of the presence of the coating. The characteristics of the proposed systems, such as pentamidine entrapment and mucin interaction, show promising results to deliver pentamidine or other possible drugs to the brain via nasal administration.
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14
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Differential interaction behaviors of an alkaloid drug with DMPG liposome membrane as a function of the phase state of the lipid: Nonionic surfactant-induced solubilization of the lipid. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2017.12.152] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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15
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A Fluorescence Study on Binding Interaction of N-acetylated Dansylamide Conjugates with β-cyclodextrin, Tween-20 and DPPC Lipid Bilayer Membrane. J Fluoresc 2017; 28:409-417. [DOI: 10.1007/s10895-017-2202-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 12/07/2017] [Indexed: 12/24/2022]
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16
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Development of a thermal-stable structure-switching cocaine-binding aptamer. Biochimie 2017; 145:137-144. [PMID: 28838608 DOI: 10.1016/j.biochi.2017.08.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 08/18/2017] [Indexed: 12/17/2022]
Abstract
We have developed a new cocaine-binding aptamer variant that has a significantly higher melt temperature when bound to a ligand than the currently used sequence. Retained in this new construct is the ligand-induced structure-switching binding mechanism that is important in biosensing applications of the cocaine-binding aptamer. Isothermal titration calorimetry methods show that the binding affinity of this new sequence is slightly tighter than the existing cocaine-binding aptamer. The improved thermal performance, a Tm increase of 4 °C for the cocaine-bound aptamer and 9 °C for the quinine-bound aptamer, was achieved by optimizing the DNA sequence in stem 2 of the aptamer to have the highest stability based on the nearest neighbor thermodynamic parameters and confirmed by UV and fluorescence spectroscopy. The sequences in stem 1 and stem 3 were unchanged in order to retain the structure switching and ligand binding functions. The more favorable thermal stability characteristics of the OR3 aptamer should make it a useful construct for sensing applications employing the cocaine-binding aptamer system.
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17
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Sarkar I, Hemamalini A, Das TM, Mishra AK. Introduction of an α,β-unsaturated carbonyl conjugated pyrene–lactose hybrid as a fluorescent molecular probe for micro-scale anisotropic media. RSC Adv 2016. [DOI: 10.1039/c5ra26146e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A new fluorescent lactose molecule (pyd-lact) (E)-1-(galactose-β-(1→4)-β-d-glucopyranosyl)-4-(1-pyrene)-but-3-en-2-one, has been synthesized by attaching 1-pyrene-but-3-ene-2-one to lactose.
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Affiliation(s)
- Ivy Sarkar
- Department of Chemistry
- Indian Institute of Technology Madras
- Chennai – 600 036
- India
| | | | - Thangamuthu Mohan Das
- Department of Organic Chemistry
- University of Madras
- Chennai – 600 025
- India
- Department of Chemistry
| | - Ashok Kumar Mishra
- Department of Chemistry
- Indian Institute of Technology Madras
- Chennai – 600 036
- India
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18
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Sarkar I. Monitoring thermo-reversible dehydration of the pluronic microenvironment using 4-chloro-1-naphthol as an ESPT fluorescent molecular probe. NEW J CHEM 2016. [DOI: 10.1039/c5nj03354c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An ESPT fluorescent molecular probe, 4-chloro-1-naphthol, has been employed to study the thermo-reversible sol–gel transition, dehydration and micro-polarity of pluronics.
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Affiliation(s)
- Ivy Sarkar
- Department of Chemistry
- Indian Institute of Technology Madras
- Chennai – 600 036
- India
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19
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Rao HSP, Kamalraj M. Synthesis and Characterisation of Coumarins from H-Cardanol. JOURNAL OF CHEMICAL RESEARCH 2015. [DOI: 10.3184/174751915x14184667167559] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A facile conversion of H-cardanol (side-chain hydrogenated cardanol, 3-pentadecylphenol; renewable fine chemical from the cashew industry) into value added 3-acylcoumarins, including those incorporating (+) menthol or cholesterol, has been achieved. The H-cardanol coumarin hybrid compounds were low melting, lipophilic and soluble in hydrocarbon solvents. They exhibit UV characteristics typical of 7-alkyl-3-acylcoumarins.
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Affiliation(s)
| | - M. Kamalraj
- Department of Chemistry, Pondicherry University, Pondicherry 605014, India
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20
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Sarkar I, Malini H, Das TM, Mishra AK. Synthesis and evaluation of a glucose attached pyrene, as a fluorescent molecular probe in sugar and non-sugar based micro-heterogeneous media. RSC Adv 2015. [DOI: 10.1039/c5ra11481k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
A new fluorescent pyrene–glucose conjugate (pyd-glc), 1-(4,6-O-butylidene-β-d-glucopyranosyl)-4-(1-pyrene)-butan-2-one, has been synthesized by attaching a pyrene molecule to acetal (butylidene) protected glucose via a butane-2-one linker.
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Affiliation(s)
- Ivy Sarkar
- Department of Chemistry
- Indian Institute of Technology Madras
- Chennai – 600 036
- India
| | - Hema Malini
- Department of Organic Chemistry
- University of Madras
- Chennai – 600 025
- India
| | | | - Ashok Kumar Mishra
- Department of Chemistry
- Indian Institute of Technology Madras
- Chennai – 600 036
- India
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Agnihotri H, Vasu AK, Palakollu V, Kanvah S. Neutral and cationic pyridylbutadienes: solvatochromism and fluorescence response with sodium cholate. Photochem Photobiol Sci 2015; 14:2159-67. [DOI: 10.1039/c5pp00179j] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Characteristic ICT emission in solvents and enhanced emission intensity in presence of sodium cholate.
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Affiliation(s)
- Harsha Agnihotri
- Department of Chemistry
- Indian Institute of Technology Gandhinagar
- Ahmedabad 382 424
- India
| | - Anuji K. Vasu
- Department of Chemistry
- Indian Institute of Technology Gandhinagar
- Ahmedabad 382 424
- India
| | | | - Sriram Kanvah
- Department of Chemistry
- Indian Institute of Technology Gandhinagar
- Ahmedabad 382 424
- India
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22
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Sarkar I, Prakash Rao HS, Desai A, Mishra AK. Utilizing an aggregate forming microenvironment sensitive coumarin–cholesterol conjugate as a sensor of pluronic organization and micro-polarity. RSC Adv 2015. [DOI: 10.1039/c5ra16549k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
A new fluorescent cholesterol molecular probe, 3-acetyl-7-(diethylamino)-2H-chromen-2-one attached cholesterol (Cum–Chl), has recently been introduced as a reporter of micro-heterogeneous media.
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Affiliation(s)
- Ivy Sarkar
- Department of Chemistry
- Indian Institute of Technology Madras
- Chennai-600 036
- India
| | | | - Avinash Desai
- Department of Chemistry
- Pondicherry University
- Pondicherry-605 014
- India
| | - Ashok Kumar Mishra
- Department of Chemistry
- Indian Institute of Technology Madras
- Chennai-600 036
- India
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23
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Palakollu V, Kanvah S. Cholesterol-tethered AIEE fluorogens: formation of self-assembled nanostructures. RSC Adv 2015. [DOI: 10.1039/c5ra04417k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Design and synthesis of cholesterol conjugated chromophores exhibiting intramolecular charge transfer (ICT) and Aggregation Induced Enhanced Emission (AIEE) and their self-assembling behavior is described.
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Affiliation(s)
| | - Sriram Kanvah
- Department of Chemistry
- Indian Institute of Technology Gandhinagar
- Ahmedabad 382424
- India
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24
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Tripathi AK, Mohapatra M, Mishra AK. Fluorescence of N-acylated dansylamide with a long hydrophobic tail: sensitive response to premicellar aggregation of sodium deoxycholate. Phys Chem Chem Phys 2015; 17:29985-94. [DOI: 10.1039/c5cp04263a] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The present work describes the synthesis and photophysical studies of two fluorescent dansylamide derivatives, in which the amine group is acylated by a long hydrophobic chain (a part of a biologically relevant palmitic acid) and by a short hydrophobic tail (a part of acetic acid).
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Affiliation(s)
- Alok Kumar Tripathi
- Department of Chemistry
- Indian Institute of Technology Madras
- Chennai 600036
- India
| | - Monalisa Mohapatra
- Department of Chemistry
- Indian Institute of Technology Madras
- Chennai 600036
- India
| | - Ashok Kumar Mishra
- Department of Chemistry
- Indian Institute of Technology Madras
- Chennai 600036
- India
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