In vitro anti-acne activity of phytoactives from the stem bark of Artocarpus hirsutus Lam. and characterisation of pyranocycloartobiloxanthone A as a mixture of two anomers

This study is aimed to isolate the phytoactives from the stem bark of Artocarpus hirsutus and evaluate their in vitro anti-acne activity. The ethanolic stem bark extract of A. hirsutus provided two major phytoactive constituents: (i) pyranocycloartobiloxanthone A, (1) and (ii) Artonine E, (2) whose structures were determined by NMR and MS spectroscopic analysis. The present study is the first to report compound 1 as a mixture of two anomers (α and β), approximately 70:30 ratio. Both compounds 1 and 2 were isolated for the first time from this plant. In vitro anti-acne activity of compounds 1 and 2 were evaluated by agar well diffusion method and the minimum inhibition was determined by broth micro dilution method. The result of anti-microbial activity (MIC = 2.0 μg/mL each) is comparable to antibiotic, Clindamycin (MIC = 0.03 μg/mL) and clearly demonstrate their potential as anti-acne agents.     

Two new rearranged taxoids from Taxus wallichiana ZUCC

Two new rearranged taxane diterpenoids, 5alpha,7beta,10beta,13alpha-tetrahydroxy-2alpha,9alpha,15-triacetoxy-11(15-->1)-abeo-taxa-4(20), 11-diene (1) and 5alpha,9alpha,10beta,13alpha-tetraacetoxy-15-hydroxy-11(15-->1)-abeo-taxa-4(20), 11-diene (2) have been isolated from the barks of Taxus wallichiana. The structures of these compounds have been confirmed by modern spectroscopic techniques.     

Quantum chemical investigation on D-π-A-based phenothiazine organic chromophores with spacer and electron acceptor effects for DSSCs

Structural Chemistry - In this work, the newly designed phenothiazine-based organic dye (PT-BTBA, PT-EBTBA, and PT-EBTEBA) derivatives were screened and investigated for dye-sensitized solar cell...     

Comparative chemical fingerprinting of Oroxylum indicum and Scutellaria baicalensis using liquid chromatography and mass spectrometry

Introduction: Identification of Oroxylum indicum and Scutellaria baicalensis provides an interesting challenge in selection of biomarker compound to be used in routine analysis. Both plants have similar phytochemical profile and are rich sources of flavones and flavone glycosides. The objective of this study was to prepare the chemical fingerprinting of O. indicum bark and S. baicalensis roots using the liquid chromatography and mass spectroscopy in single chromatographic method. Materials and methods: Extracts prepared using various solvent systems (methanol, aqueous methanol, chloroform, hexane, and water) of both plants were analyzed using C18 reverse phase column with solvent system containing acetonitrile and 0.1% formic acid. Major flavonoids were identified based on mass spectra, fragmentation pattern, and UV spectra. Results: In this article, well-resolved high-performance liquid chromatographic (HPLC) separation in both plant extracts was obtained and chemical fingerprints for both plant extracts were established and flavonoids present (baicalin, oroxylin A-7-O-glucuronide, chrysin-7-O-glucuronide, baicalein, chrysin, oroxylin-A, wogonin, skullcap flavone II) were identified as possible biomarkers. Conclusion: Mass spectrometry coupled with HPLC can be a tool for fingerprinting of various natural products used in dietary supplement industry. The fingerprint developed in the article can be used for quality evaluation as well as identifying possible adulteration of extracts of both the plants.     

Tetra­butyl­bis(N‐phthaloyl­glycinato)­distannoxane dimer

The crystal structure of the title compound, [Sn₄(C₄H₉)₈(C₁₀H₆NO₄)₄O₂], contains centrosymmetric dimers. It contains a central Sn₂O₂ core with the O atoms bonded to two di­butyl­bis(N‐phthaloyl­glycinato)­tin units. The Sn atoms of the core are six‐coordinate in a skew trapezoidal bipyramidal geometry, while the exocyclic Sn atoms are essentially five‐coordinate in a distorted trigonal geometry. The Sn—C distances lie in a narrow range of 2.120 (5)–2.138 (4) Å.     

Analysis of chemically reactive species with mixed convection and Darcy–Forchheimer flow under activation energy: a novel application for geothermal reservoirs

Journal of Thermal Analysis and Calorimetry - In the present article, an analysis has been performed to discuss the impact of steady mixed convection with Darcy–Forchheimer flow towards...     

Supercritical CO2 drying of pure silica aerogels: effect of drying time on textural properties of nanoporous silica aerogels

Journal of Sol-Gel Science and Technology - Aerogel technologies provide high-performance lightweight materials with unique textural characteristics such as high specific surface area and open...     

Simplified Synthesis of Biomass-Derived Si/C Composites as Stable Anode Materials for Lithium-Ion Batteries

Synthesis of silicon/carbon (Si/C) composites from biomass resources could enable the effective utilization of agricultural products in the battery industry with economical as well as environmental benefits. Herein, a simplified process was developed to synthesize Si/C from biomass, by using a low-cost agricultural byproduct “rice husk (RH)” as a model. This process includes the calcination of RH for SiO₂/C and the reduction of SiO₂/C by Al in molten salts at a moderate temperature. This process does not need the removal of carbon before thermal reduction of SiO₂, which is thought to be necessary to avoid the formation of SiC at elevated temperatures. Thus, carbon derived from biomass can be directly used for Si/C composites for anode materials. The resultant Si/C shows a high reversible capacity of 1309 mAh g⁻¹ and long cycle life (300 cycles). This research advocates a new and simplified strategy for the synthesis of RH-based biomass-derived Si/C, which is beneficial for low-cost, environmentally friendly, and green energy storage applications.