Tandeep Kaur

Highly Selective Fluorescence Turn-on Chemodosimeter Based on Rhodamine for Nanomolar Detection of Copper Ions

A highly selective fluorescent chemodosimeter based on rhodamine is synthesized which undergoes Cu(2+) driven hydrolysis in aqueous media to produce fluorescence turn-on changes with a detection limit up to the nanomolar range.

New Fluorogenic Sensors for Hg2+ Ions: Through-Bond Energy Transfer from Pentaquinone to Rhodamine

New pentaquinone derivatives 5 and 8 having rhodamine moieties have been designed and synthesized that undergo through-bond energy transfer (TBET) in the presence of Hg(2+) ions among the various cations (Cu(2+), Pb(2+), Fe(2+), Fe(3+), Zn(2+), Ni(2+), Cd(2+), Co(2+), Ag(+), Ba(2+), Mg(2+), K(+), Na(+), and Li(+)) tested in mixed aqueous media.

Recognition of adenosine monophosphate and H2PO4- using zinc ensemble of new hexaphenylbenzene derivative: potential bioprobe and multichannel keypad system.

Zinc ensemble of hexaphenylbenzene derivative 3 exhibits sensitive response toward adenosine monophosphate (AMP) and H(2)PO(4)(-) ions. Further, the application of derivative 3 as a multichannel molecular keypad could be realized in the presence of inputs of Zn(2+) ions, H(2)PO(4)(-) ions, and AMP.

Azide-alkyne cycloaddition en route to novel 1H-1,2,3-triazole tethered isatin conjugates with in vitro cytotoxic evaluation.

1H-1,2,3-triazole tethered isatin conjugates have been synthesized and evaluated for cytotoxicity on four human cancer cell lines. The results revealed 5a, 5c, 5e and 5n proved to be twice as potent as 5-fluorouracil on THP-1 cell line with 5a and 5c being most active exhibiting IC(50) values of <1 against all cell lines except Caco-2. Activity profiles showed dependence on the substituents on isatin rings with a preference for hydrogen while a strong electron withdrawing fluoro as well as nitro substituents on either ring decreased the anticancer activity.

Synthesis and anticancer activity of 2-benzylidene indanones through inhibiting tubulin polymerization.

In an attempt to discover a potent and selective anticancer agent, gallic acid has been modified to benzylidene indanones as tubulin polymerization inhibitors. These compounds were evaluated against several human cancer cell lines and also evaluated for inhibition of tubulin polymerase in in vitro assays. Three of the analogues exhibited strong cytotoxicity against human cancer cell lines IC(50)=10-880 nM and also showed tubulin polymerization inhibition (IC(50)=0.62-2.04 μM). Compound 9j, the best candidate of the series was found to be non-toxic in acute oral toxicity in Swiss-albino mice up to 1000 mg/kg dose.

A comparative study of proapoptotic potential of cyano analogues of boswellic acid and 11-keto-boswellic acid

Semi-synthetic analogues of β-boswellic acid (BA) and 11-keto-β-boswellic acid (KBA) were comparatively evaluated for in vitro cytotoxicity against human myeloid leukaemia (HL-60) and human cervical carcinoma (HeLa) cells. 2-Cyano analogues of both the triterpenes were observed to have significant cytotoxicity against both the cells, displaying cytotoxicity in HL-60 cells at low concentrations. Further investigations suggested the proapoptotic potential associated with the two molecules to induce cytotoxicity in HL-60 cells, where one of them showed early proapoptotic effect as evidenced by several biological end-points of the apoptosis such as annexinV binding, DNA fragmentation and increase in sub-G0 DNA fraction and apoptotic bodies formation (Hoechst 33258 staining and SEM studies).

Hg2+ induced hydrolysis of pentaquinone based Schiff base: a new chemodosimeter for Hg2+ ions in mixed aqueous media

A pentaquinone based compound 3 has been synthesized which works as a selective and sensitive chemodosimeter for mercury ions via Hg(2+) promoted hydrolysis of an imine linkage to generate a fluorescent change in mixed aqueous media.

2-Anilinonicotinyl linked 2-aminobenzothiazoles and [1,2,4]triazolo[1,5-b] [1,2,4]benzothiadiazine conjugates as potential mitochondrial apoptotic inducers

A series of N-(2-anilino-pyridyl) linked 2-amino benzothiazoles (4a-n) and [1,2,4]triazolo [1,5-b]benzothiadiazine conjugates (5a-j) have been designed, synthesized and evaluated for their antiproliferative activity. Some of these compounds (4h-k, 4n, and 5e) have exhibited potent cytotoxicity specifically against human leukemia HL-60 cell lines with IC(50) values in the range of 0.08-0.70 μM. All these compounds were tested for their effects on the cell cycle perturbations and induction of apoptosis. Morphological evidences of apoptosis, including fragmentation of nuclei and inter nucleosomal DNA laddering formation were clearly observed after 24h exposure to compound 4i. Flow cytometry analysis revealed that compound 4i showed drastic cell cycle perturbations due to concentration dependant increase in the sub-G0 region which comprises of both the apoptotic and debris fraction, thus implying the extent of cell death. These compounds trigger the mitochondrial apoptotic pathway that results in the loss of mitochondrial membrane potential through activation of multiple caspases followed by activation of caspase-3, and finally cleavage of PARP. Further the mechanism of cell death was analysed by fluorescent microscopic analysis and also by scanning electron microscopy. The cytotoxicity of 4i correlated with induction of apoptosis, caspases activation and DNA damage and thus indicating the apoptotic pathway of anticancer effect of these compounds.

Tubulin inhibitors from an endophytic fungus isolated from Cedrus deodara.

From an endophytic fungus, a close relative of Talaromyces sp., found in association with Cedrus deodara, four compounds including two new ones (2 and 4) were isolated and characterized. The structures of two compounds (1 and 4) were confirmed by X-ray crystallography. The compounds displayed a range of cytotoxicities against human cancer cell lines (HCT-116, A-549, HEP-1, THP-1, and PC-3). All the compounds were found to induce apoptosis in HL-60 cells, as evidenced by fluorescence and scanning electron microscopy studies. Also, the compounds caused significant microtubule inhibition in HL-60 cells.