CHEMICAL CONSTITUENTS OF HEDYOTIS PINIFOLIA WALL. COLLECTED IN THUA THIEN HUE

This study reports the chemical constituents from the whole plants Hedyotis pinifolia Wall. Ex G. Don (now accepted as Oldenlandia  pinifolia (Wall. Ex G. Don) Kuntze) collected  in Thua Thien Hue province. Thirteen compounds were isolated by chromatography method. Their structures were elucidated using MS and NMR analysis and compared with reported data. They contain three anthraquinones, a carotenoid, two triterpenes, four iridoid glucosides and three flavonoid glycosides. Four of them were found for the first time in this genus

Supporting Information from Green synthesis of <i>Piper chaudocanum</i> stem extract mediated silver nanoparticles for colorimetric detection of Hg²⁺ ions and antibacterial activity

A green synthetic approach to synthesize silver nanoparticles (AgNPs) using the stem extract of Piper chaudocanum for highly sensitive colorimetric detection of Hg2+ with a low limit of detection of 23 nM and easy colorimetric read-out has been reported. In addition, the biosynthesized AgNPs demonstrated efficient antibacterial activity against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. The morphology and structure of the as-synthesized AgNPs were examined using SEM, TEM, EDX, XRD and FT-IR analyses. The XRD and TEM results confirm the formation of AgNPs with an average particle size of 8–12 nm. The TLC, CC and HPLC revealed that four main compounds, pentacosanoic acid (1), piperine (2), β-sitosterol (3), and campesterol glucoside (4), isolated from P. chaudocanum extract act as reducing and stabilizing agents for AgNP formation, and piperine plays a vital role in green synthesis. The chemical structures of these compounds were determined by ESI MS, FTIR, and 1D, 2D NMR spectroscopic data analysis. This approach is an efficient, green, cost-effective, eco-friendly and promising technique for synthesizing AgNPs with applications in the colorimetric detection of Hg2+ and antibacterial activity

ZIF-67/g-C3N4-Modified Electrode for Simultaneous Voltammetric Determination of Uric Acid and Acetaminophen with Cetyltrimethylammonium Bromide as Discriminating Agent

In the present paper, the ZIF-67/g-C3N4 composite was synthesized and utilized as a modifier for a glassy carbon electrode for the simultaneous voltammetric determination of uric acid (URA) and acetaminophen (ACE) with cetyltrimethylammonium bromide (CTAB) as a discriminating agent. The composite was characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and nitrogen adsorption/desorption isotherms. The obtained ZIF-67/g-C3N4 composite exhibits good textural properties (specific surface area: 75 m2·g−1) and is stable in water with a pH range of 3 to 10. The ZIF-67/g-C3N4-modified electrode combined with CTAB as a discriminating agent possesses excellent catalytic electrochemistry towards URA and ACE with well-defined electrochemical responses. The electrochemical kinetics study is also addressed. The linear relation of the oxidation peak current of URA and ACE and the concentration ranging from 0.2 μM to 6.5 μM provide a detection limit of 0.052 μM for URA and 0.053 μM for ACE. The proposed method is well-suited to simultaneously analyze URA and ACE in human urine with comparable results with HPLC

Cu2O/Fe3O4/UiO-66 nanocomposite as an efficient fenton-like catalyst: Performance in organic pollutant degradation and influencing factors based machinelearning

The persistent presence of organic pollutants like dyes in water environment necessitates innovative approaches for efficient degradation. In this research, we developed an advanced hybrid catalyst by combining metal oxides (Cu2O, Fe3O4) with UiO-66, serving as a heterogeneous Fenton catalyst for for efficient RB19 breakdown in water with H2O2. The control factors to the catalytic behavior were also quantified by machine learning. Experimental results show that the catalytic performance was much better than its individual components (P < 0.05 &amp; non-zero 95% C.I). The improved catalytic efficiency was linked to the occurrence of active metal centers (Fe, Cu, and Zr), with Cu(I) from Cu2O playing a crucial role in promoting increased production of HO•. Also, UiO-66 served as a catalyst support, attracting pollutants to the reaction center, while magnetic Fe3O4 aids catalyst recovery. The optimal experimental parameters for best performance were pH at 7, catalyst loading of 1.6 g/L, H2O2 strength of 0.16 M, and reaction temperature of 25 °C. The catalyst can be magnetically separated and regenerated after five recycling times without significantly reducing catalytic activity. The reaction time and pH were ranked as the most influencing factors on catalytic efficiency via Random Forest and SHapley Additive exPlanations models. The findings show that developed catalyst is a suitable candidate to remove dyes in water by Fenton heterogeneous reaction

Electrochemical Determination of Uric Acid in Urine by Using Zeolite Imidazolate Framework-11 Modified Electrode

In the present article, the synthesis of zeolite imidazole framework-11 (ZIF-11) by ultrasonic-assisted hydrothermal process and its application as an electrode modifier for electrochemical determination of uric acid in urine are demonstrated. The obtained materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and nitrogen adsorption/desorption isotherms. It was found that the ZIF-11 with rhombic dodecahedron topology and high surface area (1066 m2.g-1) was synthesized in a certain temperature and found in around 25–40°C, and other crystalline phases of zinc benzimidazolate deferring from ZIF-11 phase were found in less 25°C or higher than 40°C. The ZIF-11 is stable in the pH range 6-10. The modification of glassy carbon electrode was performed with ZIF-67 using the drop-casting procedure. The present ZIF-11 modified electrode was employed to study the electrochemical behavior of uric acid (UA). UA oxidation is catalyzed by this electrode in aqueous buffer solution (pH 7) with a decrease of 70 mV in overpotential compared to glassy carbon electrode. With the differential pulse–anodic stripping voltammetry (DP-ASV) method, the oxidation current of UA versus its concentration shows good linearity in the range 20–540μM (R=0.998) with a detection limit of 0.48 μM (S/N=3). The obtained ZIF-11 modified electrode was applied in the detection of UA content in urine samples, and satisfied results were obtained

Chemical constituents of <i>Oldenlandia pinifolia</i> and their antiproliferative activities

<p>This study describes the chemical constituents of <i>Oldenlandia pinifolia</i> (Wall. Ex G. Don) Kuntze (synonym <i>Hedyotis pinifolia</i> Wall. Ex G. Don) and discusses their anti-proliferative activities. Thirteen compounds were isolated from the <i>n</i>-hexane, ethyl acetate and <i>n</i>-butanol extracts of whole plants <i>O</i>. <i>pinifolia</i> by chromatography method. Their structures were elucidated using MS and NMR analysis and compared with reported data. They are three anthraquinones, a carotenoid, two triterpenes, four iridoid glycosides and three flavonoid glycosides. Among them, 2-methyl-1,4,6-trihydroxy-anthraquinone is a new one, and three compounds were found for the first time in this genus. MTT assay resulted that the <i>n</i>-butanol extract and four isolated compounds inhibited the proliferation of chronic myelogenous leukaemia cells. The results from Hoechst 33343 staining and caspase 3-inducing exhibited that those four tested compounds induced apoptosis and activated caspase 3 (<i>p</i> < 0.05). One of them, isorhamnetin-3-<i>O</i>-<i>β</i>-rutinoside showed the most activity with IC₅₀ value of 394.68 ± 25.12 μM.</p

Voltammetric Determination of Rhodamine B Using a ZIF-67/Reduced Graphene Oxide Modified Electrode

In the present article, the synthesis of zeolite imidazolate framework-67/reduced graphene oxide (ZIF-67/rGO) and voltammetric determination of Rhodamine B (RhB) are demonstrated. The obtained materials were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and nitrogen adsorption/desorption isotherms. It was found that the ZIF-67/rGO composite consists of ZIF-67 nano-particles highly dispersed on the rGO matrix and possesses a high specific surface area. Because of the synergistic effect of good conductivity of rGO and high surface area of ZIF-67, the ZIF-67/rGO—modified glassy carbon electrode exhibits good electrochemical behavior toward Rhodamine B (RhB) oxidation. The use of this electrode to quantitate RhB with differential pulse voltammetric method was successful with a broad linear range, from 0.96 to 44.07 μg.L-1 of RhB and a low limit of detection of 1.79 μg.L-1. The procedure was able to be applied to quantitatively determine RhB content in several food samples with an exceptional recovery rate (98-103%). The quantitative results highly agreed with that provided by high-performance liquid chromatography, revealing that this material is promising in in situ monitoring of other illegal additives in food

Road traffic related mortality in Vietnam: evidence for policy from a national sample mortality surveillance system

Background: Road traffic injuries (RTIs) are among the leading causes of mortality in Vietnam. However, mortality data collection systems in Vietnam in general and for RTIs in particular, remain inconsistent and incomplete. Underlying distributions of external causes and body injuries are not available from routine data collection systems or from studies till date. This paper presents characteristics, user type pattern, seasonal distribution, and causes of 1,061 deaths attributable to road crashes ascertained from a national sample mortality surveillance system in Vietnam over a two-year period (2008 and 2009)