@article { ISI:000260429100023, title = {Synthesis and biological evaluation of bile acid dimers linked with 1,2,3-triazole and bis-beta-lactam}, journal = {Organic \& Biomolecular Chemistry}, volume = {6}, number = {20}, year = {2008}, month = {OCT}, pages = {3823-3830}, publisher = {ROYAL SOC CHEMISTRY}, type = {Article}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

We report herein the synthesis and biological evaluation of bile acid dimers 11-18 linked through 1,2,3-triazole and bis-beta-lactam. The dimers 11-18 were synthesized using 1,3-dipolar cycloaddition reaction of diazido bis-beta-lactams 3, 4 and terminal alkynes 7-10 derived from cholic acid/deoxycholic acid in the presence of Cu(I) catalyst (click chemistry). These novel molecules were evaluated in vitro for their antifungal and antibacterial activity. Most of the compounds exhibited significant antifungal as well as antibacterial activity against all the tested fungal and bacterial strains. Moreover, their in vitro cytotoxicities towards HEK-293 and MCF-7 cells were also established.

}, issn = {1477-0520}, doi = {10.1039/b809221d}, author = {Vatmurge, Namdev S. and Hazra, Braja G. and Pore, Vandana S. and Shirazi, Fazal and Deshpande, Mukund V. and Kadreppa, Sreenath and Chattopadhyay, Samit and Gonnade, Rajesh G.} } @article { ISI:000259972800039, title = {Synthesis of chimeric tetrapeptide-linked cholic acid derivatives: impending synergistic agents}, journal = {Bioorganic \& Medicinal Chemistry Letters}, volume = {18}, number = {20}, year = {2008}, month = {OCT}, pages = {5512-5517}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Tetrapeptides derived from glycine and beta-alanine were hooked at the C-3 beta position of the modified cholic acid to realize novel linear tetrapeptide-linked cholic acid derivatives. All the synthesized compounds were tested against a wide variety of microorganisms (Gram-negative bacteria, Gram-positive bacteria and fungi) and their cytotoxicity was evaluated against human embryonic kidney (HEK293) and human mammary adenocarcinoma (MCF-7) cell lines. While relatively inactive by themselves, these compounds interact synergistically with antibiotics such as fluconazole and erythromycin to inhibit growth of fungi and bacteria, respectively, at 1-24 mu g/mL. The synergistic effect shown by our novel compounds is due to their inherent amphiphilicity. The fractional inhibitory concentrations reported are comparable to those reported for Polymyxin B derivatives. (c) 2008 Elsevier Ltd. All rights reserved.

}, keywords = {Antimicrobial activity, Cholic acid, Cytotoxicity, Synergism, Tetrapeptide}, issn = {0960-894X}, doi = {10.1016/j.bmcl.2008.09.013}, author = {Bavikar, Sudhir N. and Salunke, Deepak B. and Hazra, Braja G. and Pore, Vandana S. and Dodd, Robert H. and Thierry, Josiane and Shirazi, Fazal and Deshpande, Mukund V. and Kadreppa, Sreenath and Chattopadhyay, Samit} } @article { ISI:000344244700034, title = {Specific probe for Hg2+ to delineate even H+ in pure aqueous buffer/Hct116 colon cancer cells: Hg(II)-eta(2)-arene pi-interaction and a TBET-based fluorescence response}, journal = {Chemical Communications}, volume = {50}, number = {92}, year = {2014}, month = {SEP}, pages = {14421-14424}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

A new molecular probe that demonstrates a distinct TBET process, induced by the Hg(II)-eta(2)-arene pi-interaction, in pure aqueous medium with a large pseudo-Stokes shift of 200 nm.

}, issn = {1359-7345}, doi = {10.1039/c4cc06740a}, author = {Reddy, Upendar G. and Ramu, Vadde and Roy, Sovan and Taye, Nandaraj and Chattopadhyay, Samit and Das, Amitava} } @article { ISI:000363068700007, title = {Specific reagent for Cr(III): imaging cellular uptake of Cr(III) in Hct116 cells and theoretical rationalization}, journal = {Journal of Physical Chemistry B}, volume = {119}, number = {41}, year = {2015}, month = {OCT}, pages = {13018-13026}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

A new rhodamine-based reagent (L-1), trapped inside the micellar structure of biologically benign Triton-X 100, could be used for specific recognition of Cr(III) in aqueous buffer medium having physiological pH. This visible light excitable reagent on selective binding to Cr(III) resulted in a strong fluorescence turn-on response with a maximum at similar to 583 nm and tail of that luminescence band extended until 650 nm, an optical response that is desired for avoiding the cellular autofluorescence. Interference studies confirm that other metal ions do not interfere with the detection process of Cr(III) in aqueous buffer medium having pH 7.2. To examine the nature of binding of Cr(III) to L-1, various spectroscopic studies are performed with the model reagent L-1 which tend to support Cr(III)-eta(2)-olefin pi-interactions involving two olefin bonds in molecular probe L-1. Computational studies are also performed with another model reagent L-M to examine the possibility of such Cr(III)-eta(2)-olefin pi-interactions. Presumably, polar functional groups of the model reagent L-M upon coordination to the Cr(III) center effectively reduce the formal charge on the metal ion and this is further substantiated by results of the theoretical studies. This assembly is found to be cell membrane permeable and shows insignificant toxicity toward live colon cancer cells (Hct116). Confocal laser scanning microscopic studies further revealed that the reagent L-1 could be used as an imaging reagent for detection of cellular uptake of Cr(III) in pure aqueous buffer medium by Hct116 cells. Examples of a specific reagent for paramagnetic Cr(III) with luminescence ON response are scanty in the contemporary literature. This ligand design helped us in achieving the turn on response by utilizing the conversion from spirolactam to an acyclic xanthene form on coordination to Cr(III).

}, issn = {1520-6106}, doi = {10.1021/acs.jpcb.5b07565}, author = {Ali, Firoj and Saha, Sukdeb and Maity, Arunava and Taye, Nandaraj and Si, Mrinal Kanti and Suresh, E. and Ganguly, Bishwajit and Chattopadhyay, Samit and Das, Amitava} } @article { ISI:000375346500029, title = {Specific receptor for hydrazine: mapping the in situ release of hydrazine in live cells and in an in vitro enzymatic assay}, journal = {Chemical Communications}, volume = {52}, number = {36}, year = {2016}, month = {MAR}, pages = {6166-6169}, publisher = {ROYAL SOC CHEMISTRY}, type = {Article}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

We report a new chemodosimetric reagent capable of detecting hydrazine in the presence of several other competing amine derivatives and ionic analytes of biological relevance. This reagent has been utilized for real time monitoring of in situ N2H4 release during the metabolism of a crucial tuberculosis drug, isoniazid, in live HepG2 cells. The fluorescence response of the reagent based on its specific reaction with N2H4 is used for developing an in vitro assay for aminoacylase-1.

}, issn = {1359-7345}, doi = {10.1039/c6cc01787h}, author = {Ali, Firoj and Anila, H. A. and Taye, Nandaraj and Mogare, Devraj G. and Chattopadhyay, Samit and Das, Amitava} } @article {43426, title = {Switch-on NIR probe for specific detection of Hg2+ ion in aqueous medium and in mitochondria}, journal = {Inorganic Chemistry}, volume = {55}, year = {2016}, month = {NOV}, pages = {12052-12060}, abstract = {A new 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-based probe molecule (L) is synthesized for specific binding to Hg2+ ion in physiological condition with an associated luminescence ON response in the near-IR region of the spectrum. Appropriate functionalization in the 5-position of each of two pyrrole moieties with styryl functionality in a BODIPY core helped us in achieving the extended conjugation and a facile intramolecular charge transfer transition with a narrow energy gap for frontier orbitals. This accounted for a poor emission quantum yield for the probe molecule L. Binding to. Hg2+ helped in interrupting the facile intramolecular charge transfer (ICT) process that was initially operational for L. This resulted in a hypsochromic shift of absorption band and a turn-on luminescence response with lambda(Em)(max) of 650 nm on specific binding to Hg2+. Observed spectral changes are rationalized based on quantum chemical calculations. Interestingly, this reagent is found to be localized preferentially in the mitochondria of the live human colon cancer (Hct116) cells. Mitochondria is one of the major targets for localization of He2+, which actually decreases the mitochondrial membrane potential and modifies various proteins having sulfudryl functionality(ies) to cause cell apoptosis. Considering these, ability of the present reagent to specifically recognize Hg2+] in the mitochondrial region of the live Hct116 cells has significance.}, doi = {10.1021/acs.inorgchem.6b02233}, author = {Agarwalla, Hrideshg and Mahajan, Pankaj S. and Sahu, Debashis and Taye, Nandaraj and Ganguly, Bishwajit and Mhaske, Santosh B. and Chattopadhyay, Samit and Das, Amitava} }