New resveratrol oligomers in the stem bark of Vatica pauciflora

Five new resveratrol oligomers; pauciflorols A-C (1-3), isovaticanols B (6) and C (8), and three new oligostilbene glucosides; pauciflorosides A (11), B (13), C (14), were isolated from the stem bark of Vatica pauciflora (Dipterocarpaceae) together with known 17 resveratrol oligomers (4, 5, 7, 9, 10, 12 and 15-25) and bergenin (26). The structures of isolates were established on the basis of detailed spectroscopic analysis. The typical and characteristic spectral properties of some resveratrol oligomers were also discussed.     

Two New Spermidine Alkaloids from Chisocheton weinlandii

The investigation of the MeOH extract of the leaves of Chisocheton weinlandii Harms (Meliaceae) revealed two new open‐chain spermidine alkaloids, chisitine 1 ( 1 ) and chisitine 2 ( 2 ). Their structures were elucidated by NMR spectroscopy, tandem‐mass spectrometry, and independant syntheses (Scheme 3). Detailed MS/MS fragmentation pathways are discussed for both compounds based on H/D exchange and ¹⁸O‐labeling experiments (Schemes 1 and 2).     

Resveratrol oligomers and their O-glucosides from Cotylelobium lanceolatum

Three new resveratrol oligomers, cotylelophenol C (1) (resveratrol tetramer) and cotylelosides A (2) and B (3) (O-glucosides of resveratrol trimer), together with four known glucosides of resveratrol oligomers (vaticasides A, B, C, D) and piceid, were isolated from an acetone soluble part of stem of Cotylelobium lanceolatum (Dipterocarpaceae). The structures of new compounds were determined by spectral data analysis. The characteristic properties observed in the NMR spectra of 1 were also discussed.     

Flexible microfluidic cloth-based analytical devices using a low-cost wax patterning technique

This paper describes the fabrication of microfluidic cloth-based analytical devices (μCADs) using a simple wax patterning method on cotton cloth for performing colorimetric bioassays. Commercial cotton cloth fabric is proposed as a new inexpensive, lightweight, and flexible platform for fabricating two- (2D) and three-dimensional (3D) microfluidic systems. We demonstrated that the wicking property of the cotton microfluidic channel can be improved by scouring in soda ash (Na(2)CO(3)) solution which will remove the natural surface wax and expose the underlying texture of the cellulose fiber. After this treatment, we fabricated narrow hydrophilic channels with hydrophobic barriers made from patterned wax to define the 2D microfluidic devices. The designed pattern is carved on wax-impregnated paper, and subsequently transferred to attached cotton cloth by heat treatment. To further obtain 3D microfluidic devices having multiple layers of pattern, a single layer of wax patterned cloth can be folded along a predefined folding line and subsequently pressed using mechanical force. All the fabrication steps are simple and low cost since no special equipment is required. Diagnostic application of cloth-based devices is shown by the development of simple devices that wick and distribute microvolumes of simulated body fluids along the hydrophilic channels into reaction zones to react with analytical reagents. Colorimetric detection of bovine serum albumin (BSA) in artificial urine is carried out by direct visual observation of bromophenol blue (BPB) colour change in the reaction zones. Finally, we show the flexibility of the novel microfluidic platform by conducting a similar reaction in a bent pinned μCAD.     

Diamide derivatives and cycloartanes from the leaves of Aglaia elliptica

Chemical examination of the leaves of Aglaia elliptica led to the isolation of two new diamides, 10-O-acetylaglain B (1) and 4-epiaglain A (2), two known diamides, aglain A (3) and odorine (4), and three known cycloartanes (5-7). The structures of 1 and 2 were elucidated by interpretation of the spectral data.     

Stilbene derivatives from two species of Gnetaceae

Five new stilbene oligomers (gnemonols A, B and C, gnemonoside E and gnetal) were isolated together with 2b-hydroxyampelopsin F and gnetin E from Gnetum gnemon and G. gnemonoides. The structures of the compounds were elucidated on the basis of spectral evidence.     

Antimicrobial Treatment of Different Metal Oxide Nanoparticles: A Critical Review

Many nanomaterials can be used as metal oxides (Ti, Ag, Zn, Cu, Mg, Ca, Ce, Yt, Al). Metal oxide nanoparticles have strong antimicrobial properties. The oxides that play a large role as antimicrobial agents can be divided into two major groups based on their mechanism of action i.e., those that involve oxidation and those that inhibit the production of Reactive Oxygen Species (ROS). Previous studies have shown that, toxic metals like silver and titanium, and their metals oxides, employ the ROS‐mediated mechanism that leads to oxidative stress‐related cytotoxicity, cancer, and heart diseases. Oxidative stress further leads to increased ROS production and also delays the cellular processes involved in wound heal‐ ing. Other metal oxide nanoparticles, like Y₂O₃, CeO₂ and Al₂O₃ act as free radical scavengers. Out of these, aluminium oxide nanoparticles are more effective antimicrobial agents, than the other metal oxide nanoparticles. A combination of Al₂O₃ and other antimicrobial agents such as TiO₂ may act as ideal antimicrobial agents, along with possessing free radical scavenging activity. This critical review aims to study the antimicrobial properties of different metal oxide nanoparticles and the mechanism of action in‐ volved, besides comparing their efficacy to eliminate bacteria.     

Breakable Hybrid Organosilica Nanocapsules for Protein Delivery

The direct delivery of specific proteins to live cells promises a tremendous impact for biological and medical applications, from therapeutics to genetic engineering. However, the process mostly involves tedious techniques and often requires extensive alteration of the protein itself. Herein we report a straightforward approach to encapsulate native proteins by using breakable organosilica matrices that disintegrate upon exposure to a chemical stimulus. The biomolecule‐containing capsules were tested for the intracellular delivery of highly cytotoxic proteins into C6 glioma cells. We demonstrate that the shell is broken, the release of the active proteins occurs, and therefore our hybrid architecture is a promising strategy to deliver fragile biomacromolecules into living organisms.