Hardeep Kaur

Antibacterial activity of tea and coffee: their extracts and preparations.

Tea, Camellia sinensis (L) O. Kuntze (Theaceae) and coffee, Coffea arabica Linn. (Rubiaceae) possess antimicrobial activity in addition to various biological properties. In this study six strains of human pathogenic bacteria were assessed for their sensitivity to aqueous extracts of tea and coffee along with their preparations i.e. supplemented with milk and sugar. Antibacterial potential of the extracts has been compared with some of the commonly employed antibiotics. Bactericidal activity of the selected extracts was assessed by viable cell count method. Both tea and coffee inhibited bacteria to a variable extent and retained their antibacterial activity even after addition of milk and sugar. Equal effectiveness of tea/coffee extracts and their preparations justifies their potential as antibacterial agents.

Synthesis of 4-aminoquinoline-pyrimidine hybrids as potent antimalarials and their mode of action studies.

Abstract One of the most viable options to tackle the growing resistance to the antimalarial drugs such as artemisinin is to resort to synthetic drugs. The multi-target strategy involving the use of hybrid drugs has shown promise. In line with this, new hybrids of quinoline with pyrimidine have been synthesized and evaluated for their antiplasmodial activity against both CQS and CQR strains of Plasmodium falciparum. These depicted activity in nanomolar range and were found to bind to heme as well as AT rich pUC18 DNA.

A quinoline-based turn-off fluorescent cation sensor

A quinoline-based cation sensor shows turn-off fluorescent behavior in the presence of Hg2+, Fe3+ and Cu2+ over other cations and offers discrimination of these cations from each other on the basis of the extent of quenching. The observed electronic absorption perturbations are in good agreement with theoretical (DFT, TD-DFT) calculations.

Structure−Activity Relationship Studies of Indole-Based Compounds as Small Molecule HIV‑1 Fusion Inhibitors Targeting Glycoprotein 41

We previously described indole-containing compounds with the potential to inhibit HIV-1 fusion by targeting the hydrophobic pocket of transmembrane glycoprotein gp41. Here we report optimization and structure–activity relationship studies on the basic scaffold, defining the role of shape, contact surface area, and molecular properties. Thirty new compounds were evaluated in binding, cell–cell fusion, and viral replication assays. Below a 1 μM threshold, correlation between binding and biological activity was diminished, indicating an amphipathic requirement for activity in cells. The most active inhibitor 6j exhibited 0.6 μM binding affinity and 0.2 μM EC50 against cell–cell fusion and live virus replication and was active against T20 resistant strains. Twenty-two compounds with the same connectivity displayed a consensus pose in docking calculations, with rank order matching the biological activity. The work provides insight into requirements for small molecule inhibition of HIV-1 fusion and demonstrates a potent low molecular weight fusion inhibitor.

Swapped-Domain Constructs of the Glycoprotein-41 Ectodomain Are Potent Inhibitors of HIV Infection

The conformational rearrangement of N- and C-heptad repeats (NHR, CHR) of the HIV-1 glycoprotein-41 (gp41) ectodomain into a trimer of hairpins triggers virus-cell fusion by bringing together membrane-spanning N- and C-terminal domains. Peptides derived from the NHR and CHR inhibit fusion by targeting a prehairpin intermediate state of gp41. Typically, peptides derived from the CHR are low nanomolar inhibitors, whereas peptides derived from the NHR are low micromolar inhibitors. Here, we describe the inhibitory activity of swapped-domain gp41 mimics of the form CHR-loop-NHR, which were designed to form reverse hairpin trimers exposing NHR grooves. We observed low nanomolar inhibition of HIV fusion in constructs that possessed the following properties: an extended NHR C-terminus, an exposed conserved hydrophobic pocket on the NHR, high helical content, and trimer stability. Low nanomolar activity was independent of CHR length. CD studies in membrane mimetic dodecylphosphocholine micelles suggested that bioactivity could be related to the ability of the inhibitors to interact with a membrane-associated prehairpin intermediate. The swapped-domain design resolves the problem of unstable and weakly active NHR peptides and suggests a different mechanism of action from that of CHR peptides in inhibition of HIV-1 fusion.

Performance analysis of mobile WiMax for frequency selective fading channel models

During the last decade, wireless field has witnessed revolutionary technology developments. The need for high data rates to support various multimedia applications has increased many folds. 3G and 4G technologies like WiMax (Worldwide Interoperability for Microwave Access) and LTE (Long Term Evolution) etc. are providing solution for this requirement of high speed data and high bandwidth. This paper discuss about WiMax system which is a Broadband Wireless Access (BWA) technology and is being used in WMAN (Wireless Metropolitan Area Networks). In this simulation work, the mobile WiMax is analyzed in terms of Bit Error Rate (BER) for ITU-R and Cost-207 channel model conditions for Typical Urban (TU) Area and Typical Rural Area (RA).