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Direct Solid Sample Analysis of Medicinal Herbs for Determination of Ba, Cu, Ni, V and Zn by EDXRF
In this work, an analytical method for determination of Ba, Cu, Ni, V, and Zn, in medicinal herbs, through direct solid sample analysis by energy dispersive X-ray fluorescence spectrometry (EDXRF), was applied. Accuracy and precision (intra and inter day) of the analytical method were confirmed through analysis of certified reference material, tomato leaves (CRM NIST 1573a). Principal component analysis (PCA) and hierarchical cluster analysis (HCA) allowed to observe the formation of two groups. Group I was composed by highest levels of Cu and Zn, and the group II with highest concentrations of Ba, V, and Zn. Group I also ...
Source: Journal of the Brazilian Chemical Society - January 20, 2021 Category: Chemistry Source Type: research

What to Expect for the New Year?
(Source: Journal of the Brazilian Chemical Society)
Source: Journal of the Brazilian Chemical Society - January 20, 2021 Category: Chemistry Source Type: research

Additions and Corrections
This work describes the isolation of pure bergenin from Peltophorum dubium roots with good yields and its further derivatization through Williamson synthesis. The alkyl derivatives of the bergenin were identified by nuclear magnetic resonance and mass spectrometry data analysis. Among them, three derivatives were reported for the first time herein, 8,10-dihexyl-bergenin, 8,10-didecyl-bergenin, and 8,10-ditetradecyl-bergenin, along with three previously reported ones (8,10-dimethylbergenin, 8-methylbergenin, 8,10-dioctyl-bergenin). Most derivatives of the bergenin displayed moderate cytotoxicity against Artemia salina, exce...
Source: Journal of the Brazilian Chemical Society - December 14, 2020 Category: Chemistry Source Type: research

Bergenin of Peltophorum dubium (Fabaceae) Roots and Its Bioactive Semi-Synthetic Derivatives
This work describes the isolation of pure bergenin from Peltophorum dubium roots with good yields and its further derivatization through Williamson synthesis. The alkyl derivatives of the bergenin were identified by nuclear magnetic resonance and mass spectrometry data analysis. Among them, three derivatives were reported for the first time herein, 8,10-dihexyl-bergenin, 8,10-didecyl-bergenin, and 8,10-ditetradecyl-bergenin, along with three previously reported ones (8,10-dimethylbergenin, 8-methylbergenin, 8,10-dioctyl-bergenin). Most derivatives of the bergenin displayed moderate cytotoxicity against Artemia salina, exce...
Source: Journal of the Brazilian Chemical Society - December 14, 2020 Category: Chemistry Source Type: research

Identification of Potential Inhibitors of Severe Acute Respiratory Syndrome-Related Coronavirus 2 (SARS-CoV-2) Main Protease from Non-Natural and Natural Sources: A Molecular Docking Study
So far, there is neither a vaccine nor a specific antiviral drug to prevent or treat COVID-19 (coronavirus disease) infection. Recent studies have been done to investigate the capacity of human immunodeficiency virus type 1 (HIV-1) protease inhibitors be used in the treatment of COVID-19 patients. Some of those drugs have shown to be promising. Natural chemical substances from plants provide a good source of chemicals for the development of potential novel antiviral drugs against viral pathogens including HIV-1. In January 2020, a new promising target useful for structure-based drug design was elucidated and stored in the ...
Source: Journal of the Brazilian Chemical Society - December 14, 2020 Category: Chemistry Source Type: research

Multifunctionality of βCD/Ofloxacin and HPβCD/Ofloxacin Complexes: Improvement of the Antimicrobial Activity and Apoptosis Induction on Lung Adenocarcinoma A549 Cells
The ofloxacin (OFLOX) is a second-generation synthetic antibiotic that can be classified as a multifunctional drug, but is a poorly soluble drug, which influences its efficiency. The inclusion complexes of OFLOX with β -cyclodextrin ( β CD) or hydroxypropyl- β -cyclodextrin (HP β CD) can improve the chemical characteristics of the drug; however, studies showing the biological activity of these inclusion complexes are still scarce. The present work aimed to investigate the multifunctionality of the OFLOX and their inclusion complexes. Thus, the 1:1 β CD/OFLOX or HP β CD/OFLOX were prepared and analyzed by Fourier tran...
Source: Journal of the Brazilian Chemical Society - December 14, 2020 Category: Chemistry Source Type: research

An Electrochemiluminescence Biosensor for the Determination of Mercury Ion via Dual-Amplification Strategy
A novel dual-signal amplificatory electrochemiluminescence (ECL) deoxyribonucleic acid (DNA) biosensor was designed for the determination of Hg2+. One amplification unit was gold nanoparticles (AuNPs) modified on a glassy carbon electrode, and the other was single-stranded DNA (ssDNA) (with amino at the 3 ’ terminal and thiol at the 5 ’ terminal) labeled with a carboxyl-functionalized Ru@SiO2 nanoparticles (Ru1@SiO2) as a nanoprobe. The ECL biosensor was obtained through a strong gold-sulfur bond between Au on AuNPs modified electrode and thiol in the nanoprobe. In the presence of Hg2+, the ECL signal reduced because...
Source: Journal of the Brazilian Chemical Society - December 14, 2020 Category: Chemistry Source Type: research

Activated Complex Approach to Describe Bovine Serum Albumin-Azure A and Bovine Serum Albumin-Azure B Intermolecular Interactions
Azure A (AZA) and azure B (AZB) phenothiazine dyes are used for clinical and medical purposes, and their functions can be altered via interactions with proteins. However, no kinetics information on the interactions between phenothiazine dyes and bovine serum albumin (BSA) is available. Surface plasmon resonance was used to determine the energetic and dynamic of the BSA-AZA and BSA-AZB complexes formation at pH 7.4. At temperature ≤ 16 °C, the formation of activated (DH ‡ a,12 °C,AZA= -310.57 kJ mol-1 and DH ‡ a,12 °C,AZB= -256.37 kJ mol-1) and thermodynamically stable (DH°12°C,AZA= -314.56 kJ mol-1 and DH°12°...
Source: Journal of the Brazilian Chemical Society - December 14, 2020 Category: Chemistry Source Type: research

Green Extraction Optimization of Bioactive Compounds from Rosemary (Rosmarinus officinalis L.) Using Response Surface Methodology
Rosemary (Rosmarinus officinalis L.) is known for its bioactive compounds with high antioxidant potential and pharmacological properties, such as antibacterial, antidepressant and anti-inflammatory. These properties are attributed to the presence of (poly)phenolic compounds. In the literature there is no extraction of these compounds with a totally non-toxic solvent, capable of applying the extract directly to the food. This work aimed to optimize the extraction conditions of bioactive compounds from the rosemary leaves using water as solvent. According to the analysis of variance parameters, a cubic model of high order of...
Source: Journal of the Brazilian Chemical Society - December 14, 2020 Category: Chemistry Source Type: research

Synthesis, in silico Study and Antimicrobial Activity of New Piperine Derivatives Containing Substituted δ-Esters
A series of fifteen new piperine-derived diesters was synthesized through the substitution reaction between the salt of piperic acid, obtained through piperine basic hydrolysis, with the δ -chloro-esters, obtained through the cleavage of tetrahydrofuran (THF) with acyl chlorides in the presence of ZnCl2. The final compounds were obtained with yields ranging from 50 to 84% and were characterized by infrared (IR) and 1H and 13C nuclear magnetic resonance spectroscopy (NMR). The new compounds were evaluated in silico in regard to their ADME (absorption, distribution, metabolism, and excretion) properties, and in vitro for th...
Source: Journal of the Brazilian Chemical Society - December 14, 2020 Category: Chemistry Source Type: research

Method for Cleaning Back-Produced Water from Polymer Flooding Operations to Determine Polymer Molar Mass Using Size-Exclusion Chromatography
One of the methods used by the oil industry to increase production is to inject water, containing polymer, into the reservoir. The viscosity of the aqueous solution is primarily responsible for the efficiency of this method, and is achieved using polymers with high molar mass. However, polymer degradation can occur during pumping and fluid displacement in the porous medium, reducing the efficiency of the polymer flooding method. Therefore, it is important to monitor the molar mass of the polymer in the produced water. Size-exclusion chromatography (SEC) is a powerful method for determining average molar mass of polymers, b...
Source: Journal of the Brazilian Chemical Society - December 14, 2020 Category: Chemistry Source Type: research

Synthesis and Antioxidant and Antimicrobial Properties of β-Hydroxy Sulfides, Sulfoxides, and Sulfones Derived from Cardanol and Glycerol Derivatives
This article reports the preparation of amphiphilic β -hydroxy sulfides, sulfoxides, and sulfones derived from cardanol and glycerol. Thiolysis of cardanol epoxide 3 with various thiols (4a-4j) in ethanol or water yielded the corresponding β -hydroxy sulfides 5a-5j (61-95%). Treatment with 30% H2O2 in acetic acid at ambient temperature completely converted these products into β -hydroxy sulfoxides 6a-6j and sulfones 7a, 7c-7f, 7h-7j. The synthesized compounds were characterized by 1H nuclear magnetic resonance (NMR), 13C NMR, high-resolution mass spectroscopy (HRMS) and performed the in vitro evaluation antimicrobial ac...
Source: Journal of the Brazilian Chemical Society - December 14, 2020 Category: Chemistry Source Type: research

Development of a First-Order Derivative UV Spectrophotometric Method for the Assay and Solubility Evaluation of Lamotrigine and Nicotinamide Cocrystals
This study demonstrated that the first-order derivative method is feasible for drug and coformer determination in cocrystals and is a suitable alternative to chromatographic methods. (Source: Journal of the Brazilian Chemical Society)
Source: Journal of the Brazilian Chemical Society - December 14, 2020 Category: Chemistry Source Type: research

Determining Mercury in Sediment Samples by Extraction Using a Novel-Chelating Reagent Dithiothreitol (DTT) Followed by Cold Vapor Atomic Fluorescence Spectrometry (CV-AFS)
A new analytical protocol has been developed for the determination of mercury in surface sediments using dithiothreitol (DTT) as a new chelating reagent for the extraction. This protocol requires a small sample mass (250 mg), 4.0 mL of a 0.1 M (pH = 9.0) aqueous DTT solution, and sonication for 30 min, followed by cold vapor atomic fluorescence spectrometry (CV-AFS). The limits of detection and quantification determined were 6 and 18 ng g − 1, respectively. The method was validated using three standard reference materials, SRM NIST 1646a, PACS-2, and MESS-3, with recoveries in the range of 102-124%. The new analytical pr...
Source: Journal of the Brazilian Chemical Society - December 14, 2020 Category: Chemistry Source Type: research

Identification of Flavonoids as Inhibitors of Plasmodium falciparum Enoyl-ACP Reductase by Hierarchical Virtual Screening
Malaria, a parasitic infection caused by Plasmodium falciparum, is a serious global public health problem. The enzyme enoyl-acyl carrier protein (ACP) reductase present in a limiting step in the biosynthesis of fatty acids type II was used to search for novel molecules with potential inhibitor by virtual screening techniques. A flavonoid library obtained in ChEMBL database (n = 4,008) was filtered through physico-chemical similarity using the Euclidean distance as a criterion. The selected molecules were subjected to molecular docking using the scoring function GridScore in the DOCK 6.5 software. The top 30 ranked molecule...
Source: Journal of the Brazilian Chemical Society - December 14, 2020 Category: Chemistry Source Type: research