Identification of Phytoconstituents of Tragia Involucrata leaf Extracts and Evaluate their Correlation with Anti-inflammatory & Antioxidant Properties.

AIMS: The present investigation was aimed at exploring the phytoconstituents using Gas Chromatography Mass Spectroscopy and to evaluate antioxidant and anti-inflammatory properties of the leaf extracts. MATERIALS AND METHODS: The extracts were obtained sequentially with petroleum ether, ethyl acetate and water using Soxhlet apparatus. The anti-inflammatory property of the identified compounds using GC- MS spectroscopy was evaluated in silico. The antioxidant activity was performed by DPPH and H2O2 method whereas anti-inflammatory study was carried out by HRBC membrane stabilization method. Terpenoids were found to be a major constituents in petroleum ether extract while, phenols and flavonoids were predominantly found in ethyl acetate extract. RESULTS AND DISCUSSION: The GC-MS analysis of the extract revealed six major molecules including Squalene, 19ß, 28-epoxyleanan-3-ol and 2-tu-Butyl-5-chloromethyl-3-methyl-4-oxoimidazolidine- 1-carboxylic acid. The ethyl acetate extract showed a significant antioxidant activity (P<0.01) in both DPPH method (70.87%) and H2O2 method (73.58%) at 200 µg mL-1. Increased membrane stabilization of petroleum ether extract was observed in the in vitro anti-inflammatory activity study. A strong relationship between the terpenoid content and anti-inflammatory activity was obtained from the correlation (0.971) and docking study. CONCLUSION: These results justify T. involucrata to be a rich source of terpenoids with potent anti- inflammatory property.

Effect of Different Intracanal Medicaments on Apical Sealing Ability of BioRoot RCS.

AIMS AND OBJECTIVES: The aim of the present study was to determine the effect of different intracanal medicaments on the apical seal of BioRoot root canal sealer (RCS). MATERIALS AND METHODS: One hundred permanent single-rooted teeth were used in this study. All the samples were decoronated at the cementoenamel junction and instrumented in a sequential order from 15 to 50 number k-file. The specimens were randomly divided into five groups containing 20 teeth each. Intracanal medicaments used in this study were Metapex, triple antibiotic paste, Metrogyl DG gel forte (metronidazole gel 1.5% w/w), and curenext gel. For control group following instrumentation, the roots were obturated with laterally compacted gutta-percha with BioRoot RCS. In medicament groups after the period of 14 days, the medicaments were removed. All the four groups were obturated with BioRoot RCS and gutta-percha cones using lateral compaction technique. All the specimens were coated with nail varnish and immersed in 2% methylene blue. Then the specimens were demineralized and diphanized. The cleared teeth were analyzed by means of a stereomicroscope under 10× magnification. All the data were analyzed in SPSS version 18 software (IBM, Chicago, IL, USA). RESULT: Among all the intracanal medicaments, triple antibiotic paste showed the highest microleakage. When Metpaex and Metrogyl DG gel forte were compared with Curcuma longa, differences were not statistically significant. CONCLUSION: Among all the intracanal medicaments, triple antibiotic paste showed the highest microleakage and least was Metapex. CLINICAL SIGNIFICANCE: Incomplete removal of medicaments prevents the penetration of sealer into the dentinal tubules and interferes with the normal setting reaction, thus affecting the seal of obturating material leading to microleakage and subsequent treatment failure. Hence, while placing an intracanal medicament, it is important to consider its effect on leakage of the root canal system.

Core-shell Fe3O4@Au nanocomposite as dual-functional optical probe and potential removal system for arsenic (III) from Water.

We report for the very first time, development of a dual functional nanocomposite to perform as an optical probe as well as removal system for As(III) from ground water. Upon suitable thiolation using dithiothreitol (DTT), the Fe3O4(core)-Au(shell) nanocomposite (DTT-Fe3O4@Au) has been fabricated that can detect As(III) in aqueous solution with significantly low limit of detection and holds potential for selective removal of As(III) from water owing to its magnetic core. Due to high affinity of -SH groups for As(III), the nanoparticles undergo aggregation in the presence of As(III), resulting in a significant decrease in absorbance, yielding the limit of detection (LOD) as 0.86 ppb, which is much lower than the World Health Organisation (WHO) recommended threshold value of 10 ppb. UV-vis spectroscopy in conjunction with dynamic light scattering and electron microscopy techniques have further elaborated the detailed interaction between As(III) and DTT-Fe3O4@Au nanocomposite regarding their size dynamics and solution behaviour during the interaction. Moreover, ca.70% removal of As(III) from aqueous solution by DTT-Fe3O4@Au has been observed by ICP-MS measurement strengthening the potential of this nanocomposite as a dual-functional probe and filter.

Phosphorescent Oxygen and Mechanosensitive Nanostructured Materials Based on Hard Elastic Polypropylene Films.

It is well known that sensitivity of quenched-phosphorescence O2 sensors can be tuned by changing the nature of indicator dye and host polymer acting as encapsulation and quenching mediums. Here, we describe a new type of sensor materials based on nanostructured hard elastic polymeric substrates. With the example of hard elastic polypropylene films impregnated with Pt-benzoporphyrin dye, we show that such substrates enable simple one-step fabrication of O2 sensors by standard and scalable polymer processing technologies. In addition, the resulting sensor materials show prominent response to tensile drawing via changes in phosphorescence intensity and lifetime and O2 quenching constant, Kq. The mechanosensitive response shows reversibility and hysteresis, which are related to macroscopic changes in the nanoporous structure of the polymer. Such multifunctional materials can find use as mechanically tunable O2 sensors, as well as strain/deformation sensors operating in a phosphorescence-lifetime-based detection mode.

An efficient green synthesis of 2-arylbenzothiazole analogues as potent antibacterial and anticancer agents.

We have demonstrated a novel and green approach for the synthesis of 2-substituted benzothiazole analogues. A number of 2-aryl and heteroaryl benzothiazole scaffolds were synthesized using Amberlite IR-120 resin under microwave irradiation. The catalytic role and reusability of the resin was well established here. 2-Substituted benzothiazole analogues (3a-l) were also tested against several bacterial strains (Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Salmonella) and cancer cell lines (MCF-7 and HeLa). The stability of compound 2-phenyl benzothiazole (3a) and 2-pyridin-2-yl-benzothiazole (3k) in GSH (0.01mM dissolved in DMSO) was measured by UV-Vis spectroscopy. Compound 3k also shows remarkable fluorescence in MeOH.

Supramolecular approach to enantioselective DNA recognition using enantiomerically resolved cationic 4-amino-1,8-naphthalimide-based Tröger's bases.

The synthesis and photophysical studies of two cationic Tröger's base (TB)-derived bis-naphthalimides 1 and 2 and the TB derivative 6, characterized by X-ray crystallography, are presented. The enantiomers of 1 and 2 are separated by cation-exchange chromatography on Sephadex C25 using sodium (-)-dibenzoyl-l-tartarate as the chiral mobile phase. The binding of enantiomers with salmon testes (st)-DNA and synthetic polynucleotides are studied by a variety of spectroscopic methods including UV/vis absorbance, circular dichroism, linear dichroism, and ethidium bromide displacement assays, which demonstrated binding of these compounds to the DNA grooves with very high affinity (K ∼ 10(6) M(-1)) and preferential binding of (-)-enantiomer. In all cases, binding to DNA resulted in a significant stabilization of the double-helical structure of DNA against thermal denaturation. Compound (±)-2 and its enantiomers possessed significantly higher binding affinity for double-stranded DNA compared to 1, possibly due to the presence of the methyl group, which allows favorable hydrophobic and van der Waals interactions with DNA. The TB derivatives exhibited marked preference for AT rich sequences, where the binding affinities follow the order (-)-enantiomer > (±) > (+)-enantiomer. The compounds exhibited significant photocleavage of plasmid DNA upon visible light irradiation and are rapidly internalized into malignant cell lines.

New Insights into the Mechanism of Visible Light Photocatalysis.

In recent years, the area of developing visible-light-active photocatalysts based on titanium dioxide has been enormously investigated due to its wide range of applications in energy and environment related fields. Various strategies have been designed to efficiently utilize the solar radiation and to enhance the efficiency of photocatalytic processes. Building on the fundamental strategies to improve the visible light activity of TiO2-based photocatalysts, this Perspective aims to give an insight into many contemporary developments in the field of visible-light-active photocatalysis. Various examples of advanced TiO2 composites have been discussed in relation to their visible light induced photoconversion efficiency, dynamics of electron-hole separation, and decomposition of organic and inorganic pollutants, which suggest the critical need for further development of these types of materials for energy conversion and environmental remediation purposes.

Synthesis, spectroscopic and biological studies of a fluorescent Pt(II) (terpy) based 1,8-naphthalimide conjugate as a DNA targeting agent.

The bi-functional complex [Pt(II)(terpy)(py-naphth)](NO3)2(), incorporating both 2,2':6',2''-terpyridine and 4-N,N'-dimethylamino-1,8-naphthalimide moieties, displays a high binding affinity for DNA as well as displaying cytotoxicity towards and inducing apoptosis in malignant cell lines.

The effect of the 4-amino functionality on the photophysical and DNA binding properties of alkyl-pyridinium derived 1,8-naphthalimides.

The synthesis and characterisation of two cationic pyridinium based 4-amino-1,8-naphthalimide derivatives (2 and 3) are described and compared to those of compound 1. The photophysical properties of 2 and 3 are shown to vary greatly with the solvent polarity and H-bonding ability. The dimethylamino substitution in 3 results in a weak quantum yield of fluorescence emission due to faster non-radiative deactivation of the excited singlet state than that seen for 2. As with 1, the fluorescence of 2 was found to be enhanced in its 1 : 1 complex with 5'-adenosine-monophosphate (5'-AMP) while it was partially quenched in its complex with 5'-guanosine-monophosphate (5'-GMP). In contrast, the fluorescence of 3 was enhanced ('switched on') in the presence of both adenine and guanine rich sequences. Linear and circular dichroism studies showed that each of 1, 2 and 3 binds to double-stranded DNA by intercalation. However, 2 and 3 do not show the preference for AT-rich DNA observed for 1. Comparative fluorescence studies with double stranded DNA show that the emission of was 16 times enhanced in its DNA bound form, suggesting potential use of this structure as a spectroscopic probe for studying nucleic acid structure.

Recent advances in the development of 1,8-naphthalimide based DNA targeting binders, anticancer and fluorescent cellular imaging agents.

The development of functional 1,8-naphthalimide derivatives as DNA targeting, anticancer and cellular imaging agents is a fast growing area and has resulted in several such derivatives entering into clinical trials. This review gives an overview of the many discoveries and the progression of the use of 1,8-naphthalimides as such agents and their applications to date; focusing mainly on mono-, bis-naphthalimide based structures, and their various derivatives (e.g. amines, polyamine conjugates, heterocyclic, oligonucleotide and peptide based, and those based on metal complexes). Their cytotoxicity, mode of action and cell-selectivity are discussed and compared. The rich photophysical properties of the naphthalimides (which are highly dependent on the nature and the substitution pattern of the aryl ring) make them prime candidates as probes as the changes in spectroscopic properties such as absorption, dichroism, and fluorescence can all be used to monitor their binding to biomolecules. This also makes them useful species for monitoring their uptake and location within cells without the use of co-staining. The photochemical properties of the compounds have also been exploited, for example, for photocleavage of nucleic acids and for the destruction of tumour cells.

Synthesis and photophysical evaluation of a pyridinium 4-amino-1,8-naphthalimide derivative that upon intercalation displays preference for AT-rich double-stranded DNA.

The synthesis, characterisation and solid state crystal structure of a cationic 4-amino-1,8-naphthalimide derivative (1) are described. The photophysical properties of 1 are shown to vary with the solvent polarity and H-bonding ability. The fluorescence of 1 is enhanced and blue-shifted in its 1:1 complex with 5'-adenosine-monophosphate while it is partially quenched and red-shifted in its complex with 5'-guanosine-monophosphate. Linear and circular dichroism measurements show that 1 binds to double-stranded DNA by intercalation. Comparative UV-visible and fluorescence studies with double stranded synthetic polynucleotides poly(dA-dT)(2) and poly(dG-dC)(2) show that 1 binds much more strongly to the AT polymer; 1 also has a strong preference for A-T rich sequences in natural DNA. Thermal denaturation measurements also reveal a much greater stabilisation of the double-stranded poly(dA-dT)(2) than of natural DNA.