Subramani Nagaraj

Stereoselective synthesis of hexahydro-3-methyl-1-arylchromeno[3,4-b]pyrrole and its annulated heterocycles as potent antimicrobial agents for human pathogens.

Synthesis of a series of novel hexahydrochromenopyrrole analogues has been accomplished through an intramolecular 1,3-dipolar cycloaddition (1,3-DC reaction) of azomethine ylides, generated by the aldehyde induced decarboxylation of secondary amino acids. These compounds were screened for antibacterial and antifungal activities against six human pathogenic bacteria and three human pathogenic fungi and found to have good antimicrobial properties against most of the microorganisms.

Synthesis and antioxidant properties of enone core based dendrimers with carbazole as surface group.

Synthesis of enone core based dendrimers with carbazole as surface group has been achieved. All the synthesized dendrimers showed excellent antioxidant behavior with commercially available 1,1-diphenyl-2-picryl hydrazyl (DPPH).

Synthesis and antibacterial activity of some novel imidazole-based dicationic quinolinophanes

Synthesis of novel quinoline based dicationic benzimidazolophanes and imidazolophanes incorporating various spacer units is described. Some of the quinolinophanes 1b, 3a,3b and 4a exhibit good antibacterial activity against most of the human pathogenic bacteria in the tested concentrations as compared to the other cyclophanes as well as the test control, streptomycin.

κ-Carrageenan: An effective drug carrier to deliver curcumin in cancer cells and to induce apoptosis

The current study is to develop a natural drug carrier with seaweed derived polymers namely κ-Carrageenan (κ-Car) for drug delivery applications. κ-Car is a natural polysaccharide which derived from edible red seaweeds, they are easily available, non-toxic, cost effective, biodegradable and biocompatible nature. Curcumin (Cur) is a yellow-orange polyphenol existing in turmeric, which is predominantly used as spice and food coloring agent. The ultimate use of polymeric composites, especially those composed of natural polymers, has become a very interesting approach in recent drug delivery applications, due to their non-toxicity and biological origin. In this study the primary approach which depends on the loading of Curcumin into κ-Carrageenan was accomplished, and which (κ-Car-Cur) an active drug carrier was developed for drug delivery against selected lung cancer cells (A549). Thus, the κ-Car-Cur was synthesized by solvent evaporation method followed by freeze drying, and it was further characterized. From this study, it has been reported that the high encapsulation efficiency, good stability, and successful release of Cur from the carrier (κ-Car) was achieved. The drug release was more active at acidic pH 5.0 with the cumulative release of 78%, which is the favorable condition present in tumor microenvironments. The in vitro cellular applications studies of κ-Car-Cur demonstrated that, κ-Car-Cur composites induced higher cytotoxicity against selected cancer cells than free Cur and effectively involved to trigger cellular apoptosis in A549 cancer cells. Further, it was also possessed that inhibition of cell growth and changes in metabolic activity of cancer cells are the unique characteristic features of cellular apoptosis, through reactive oxygen species (ROS) generation. It also observed that there was a decrease in mitochondrial membrane potential (ΔψmΔψm) which leads to a cellular apoptosis during treatment with κ-Car-Cur. Hence, the study outcomes may provide the potential outline for the use of κ-Car-Cur as a promising tool to deliver drugs at intracellular level.

Synthesis, photophysical, antibacterial and larvicidal studies on triazolophanes with 5-nitro isophthalate functionality at the intraannular position

1 : 1 and 2 : 2 oligomeric triazolophanes with 5-nitro isophthalate and triazolyl functionalities at the intraannular position have been synthesized by copper(I) catalyzed 1,3 dipolar cycloaddition of the corresponding propargylic esters with various phenyl substituted aliphatic azides under mild conditions through click methodology. The 1 : 1 oligomeric triazolophanes exhibit good target binding ability and better antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Salmonella typhi and Escherichia coli bacteria than the 2 : 2 oligomeric triazolophanes, supported by molecular docking studies, and triazolophanes T3, T4 and T5 show good larvicidal activity.

Bioactive potential and composition analysis of sulfated polysaccharide from Acanthophora spicifera (Vahl) Borgeson

Marine seaweeds contain a valuable source of functional bioactive polysaccharide and it plays main role for effective anticancer activity. The structural feature of SPs was studied through FT-IR and 1H NMR spectra analysis. The isolated SPs from A. spicifera contain 63.3% of total sugar, 21.9% of total sulfate and 12.6% of total uranic acid was found. The active F2 fraction molecular weight of SP was found to be 420 kDa. The sugar was composed of galactose (73.5%), xylose (9.2%), mannose (1.9%) and arabinose (10.9%). Further the SP showed DPPH free radical scavenging activity of 55.55% at 150 μg/mL and reducing power activity of 91.3% at 125 μg/mL. In the present study, the purified sulfated polysaccharide (fraction F2) were extracted, purified and characterized for red seaweed and evaluated for their potential anticancer activity of in A549 cell lines under in vitro condition. These polysaccharide fractions exhibited potential apoptotic effects on A549 cell lines.

Synthesis, Optical, and Antioxidant Studies of Anthraquinone-core-based Dendrimers with N-Phenylcarbazole as Surface Group

Synthesis of hyperbranched dendrimers up to third generation with N-phenylcarbazole as surface group and anthraquinone as the core unit has been achieved. The fluorescence decay studies of the dendrimers indicate that generation growth alters the relaxation time. The highly branched third-generation dendrimer has a longer relaxation time than the zero-, first-, and second-generation dendrimers. Similarly, higher-generation dendrimers show better antioxidant behaviour with 1,1-diphenyl-2-picryl hydrazyl than the lower-generation dendrimers.