Synergistic Excited State involved Catalytic Reduction of (NH3-trz)[Fe(dipic)2] Complex by SnO2/TiO2 Nanocomposite

The photocatalytic activity of well-fabricated, economical SnO2/TiO2 nanocomposite synthesized via hydrothermal route was validated using the (NH3-trz)[Fe(dipic)2] complex under ultra-violet illumination. The structural features of (NH3-trz)[Fe(dipic)2] complex was explored in detail. The catalysts were systematically examined with XRD, SEM, FT-IR UV-vis, PL, micro-Raman, VSM, AFM, HRTEM. The photoreactivity of the model compound (NH3-trz)[Fe(dipic)2] in water/binary solvent systems was investigated. The rate of photoreaction (k) of nanocomposite (0.1432 sec-1) is higher than the SnO2 (0.0373 sec-1) and TiO2 (0.1422 sec-1) in H2O:PriOH (70:30%) than the rest of the solvents system. The pathways, mechanistic feature of accumulated reactive species on nanocomposite to induce adherent [Fe(dipic)2]- anion and photo-reductive products were studied. The generation of hydroxyl radical on the surface of each catalyst can be identified as 7-hydroxycoumarin and discussed.

Utilization of Cellulose to Its Full Potential: A Review on Cellulose Dissolution, Regeneration, and Applications

As the most abundant natural polymer, cellulose is a prime candidate for the preparation of both sustainable and economically viable polymeric products hitherto predominantly produced from oil-based synthetic polymers. However, the utilization of cellulose to its full potential is constrained by its recalcitrance to chemical processing. Both fundamental and applied aspects of cellulose dissolution remain active areas of research and include mechanistic studies on solvent–cellulose interactions, the development of novel solvents and/or solvent systems, the optimization of dissolution conditions, and the preparation of various cellulose-based materials. In this review, we build on existing knowledge on cellulose dissolution, including the structural characteristics of the polymer that are important for dissolution (molecular weight, crystallinity, and effect of hydrophobic interactions), and evaluate widely used non-derivatizing solvents (sodium hydroxide (NaOH)-based systems, N,N-dimethylacetamide (DMAc)/lithium chloride (LiCl), N-methylmorpholine-N-oxide (NMMO), and ionic liquids). We also cover the subsequent regeneration of cellulose solutions from these solvents into various architectures (fibers, films, membranes, beads, aerogels, and hydrogels) and review uses of these materials in specific applications, such as biomedical, sorption, and energy uses.

PRE-FORMULATION PROFILING OF ACECLOFENAC AND DEVELOPMENT OF A SENSITIVE ANALYTICAL TECHNIQUE FOR ITS ASSESSMENT

Pre-formulation studies are an integral part of formulation development. For the successful development of the formulation, it is essential to perform all the pre-formulation studies. The present work was aimed at systematically investigating the physicochemical properties of aceclofenac, a non-steroidal anti- infl ammatory drug used for the management of rheumatoid arthritis, osteo arthritis and ankylosing spondylitis. The studies included pre-formulation profi ling of the drug in order to fi nalize the excipients for the development of its delivery. Drug characterization was carried out for solubility in different solvent systems, pKa determination, bulk characterization, melting point, dissolution. Further, and some other parameters RP-HPLC method for estimation of the drug was developed and validated. Earlier methods were developed using C18 column for the estimation of drug content. In the present research, an attempt was made to develop and validate an analytical method using HILIC column. The pre-formulation profi ling of the drug was successfully done and a sensitive analytical method was also developed.

Isolation of N-Ethyl-2-pyrrolidinone-Substituted Flavanols from White Tea Using Centrifugal Countercurrent Chromatography Off-Line ESI-MS Profiling and Semi-Preparative Liquid Chromatography

N-Ethyl-2-pyrrolidinone-substituted flavanols (EPSF) are marker compounds for long-term stored white teas. However, due to their low contents and diasteromeric configuration, EPSF compounds are challenging to isolate. In this study, two representative epimeric EPSF compounds, 5′′′R- and 5′′′S-epigallocatechin gallate-8-C N-ethyl-2-pyrrolidinone (R-EGCG-cThea and S-EGCG-cThea), were isolated from white tea using centrifugal partition chromatography (CPC). Two different biphasic solvent systems composed of 1. n-hexane – ethyl acetate – methanol – water (1:5:1:5, v/v/v/v) and 2. n-hexane – ethyl acetate – acetonitrile – water (0.7:3.0:1.3:5.0, v/v/v/v) were used for independent pre-fractionation experiments; 500 mg in each separation of white tea ethyl acetate partition were fractionated. The suitability of the two solvent systems was pre-evaluated by electrospray mass-spectrometry (ESI-MS/MS) analysis for metabolite distribution and compared to the results of the CPC experimental data using specific metabolite partition ratio KD values, selectivity factors α, and resolution factors RS. After size-exclusion and semi-preparative reversed-phase liquid chromatography, 6.4 mg of R-EGCG-cThea and 2.9 mg of S-EGCG-cThea were recovered with purities over 95%. Further bioactivity evaluation showed that R- and S-EGCG-cThea possessed in vitro inhibition effects on α-glucosidase with IC50 of 70.3 and 161.7 μM, respectively.

Preliminary Phytochemical analysis of Andrographis paniculata Leaf extract

Andrographis paniculata is a traditional medicinal plant widely used in Ayurveda and Siddha treatment. The extract from this plant is used to prevent and cure certain diseases. Phytochemical analysis of this leaf extract would identify the compounds in it and through this, new medicine could be formulated. In this study, three different solvent systems (Solvent A-100% aqueous, Solvent B-100% methanol and Solvent C- 50% aqueous and 50% methanol) were used to extract the compounds from leaves with three different time period of 24hrs, 48 hrs and 72 hrs. When compared to other conditions, the majority of the compounds were discovered in analyses with solvent C at 24hrs. The major compounds such as alkaloid, terpenoid, flavonoid, tannin and saponin were identified in the leaf extract. This study reveals that; with better extraction conditions, the presence of most of the phytochemicals from the leaf extract could pave a way to formulate new medication.