NMR analysis, cytotoxic activity and theoretical study of a complex between SRPIN340 and -sulfonic acid calix[6]arene.

This study aimed to enhance the aqueous dissolution of SRPK inhibitor -(2-(piperidin-1-yl)-5-(trifluoromethyl)phenyl)isonicotinamide (SRPIN340). A complex with -sulfonic calix[6]arene (Host) and SRPIN340 (Guest) was prepared, studied via H nuclear magnetic resonance (NMR) and theoretical calculations and biologically evaluated on cancer cell lines. The 1:1 host (H)/guest (G) complex significantly enhanced the aqueous dissolution of SRPIN340, achieving 64.

Impact of different roasting conditions on the chemical composition, antioxidant activities, and color of and L. samples.

This work aimed to evaluate the physicochemical changes during the roasting process of Robusta and Arabica coffee. The highest content of total phenolics was detected in roasted coffee at temperatures of 135 °C/20.20 min, 210 °C/9.

Influence of spontaneous and inoculated fermentation of açai on simulated digestion, antioxidant capacity and cytotoxic activity.

This work describes the kinetic study of different types (spontaneous, lactic and alcoholic) of açai fermentation in terms of total phenolics and total anthocyanins, as well as antioxidant capacity, before and after simulated digestion (SD). Cytotoxicity (A549, HCT8 and IMR90 cells) and formation of reactive oxygen species (A549 cells) were also evaluated. The results revealed that spontaneous fermentation (SF) for 24 h, followed by SD, generated a product with greater bioaccessibility of phenolics (52.

Chemical composition of heartwood and sapwood of Tectona grandis characterized by CG/MS-PY.

Teak wood has chemical compounds that can be used for pharmaceutical and textile industries, in addition, this compounds are related to resistance to biodeterioration, color and modification processes. Heartwood and sapwood of T. grandis (teak), 15 years-old, were characterized by Py-CG/MS analysis and syringyl (S)/guaiacyl (G) ratio was evaluated.

Ketoconazole/calix[n]arenes-based compounds improve the antifungal activity against azole-resistant Candida isolates.

Ketoconazole (KTZ) is an antifungal agent; however, its bioavailability and therapeutic efficacy are reduced by the low aqueous solubility of the drug. Aiming at providing to improve the biopharmaceutical properties of KTZ, we studied the water-soluble different calix[n]arenes as carrier systems for KTZ. All calix[n]arene-KTZ tested showed in vitro antifungal activity superior or similar to free KTZ against Candida spp.

A color reaction for the determination of Cu in distilled beverages employing digital imaging.

In this work, we describe for the first time the synthesis of a thiocarbazone for the selective determination of Cu in distilled beverages. The method was based on the complexation reaction of Cu with the thiocarbazone, and the colored product was analyzed using a smartphone application. The thiocarbazone reacts with Cu to form a 1:1 (metal:ligand) complex.

Fast pyrolysis as a tool for obtaining levoglucosan after pretreatment of biomass with niobium catalysts.

Levoglucosan (LGA) is a promising chemical platform derived from the pyrolysis of biomass that offers access to a variety of value-added products. We report an efficient route to produce LGA via the pretreatment of biomass with niobium compounds (oxalate, chloride and oxide) followed by fast pyrolysis coupled with gas chromatography-mass spectrometry (Py-GC-MS) at temperatures of 350-600 °C. Catalytic pretreatment reduces the quantity of lignin in the biomass, concentrates the cellulose and enhance LGA formation during fast pyrolysis.

Combination of entomopathogenic nematodes with acaricides or essential oil of Lippia triplinervis against Rhipicephalus microplus (Acari: Ixodidae).

This study aimed to evaluate the combination effect of Heterorhabditis bacteriophora HP88 and H. indica LPP1, with the acaricides deltamethrin, amitraz and chlorfenvinphos, and the essential oil (EO) of Lippia triplinervis, against engorged females of Rhipicephalus microplus. In order to verify the effect of acaricides and EO, the adult immersion test was used, and in the groups treated only with entomopathogenic nematodes (EPNs), 150 infective juveniles were used per female.

Usnic acid enantiomers restore cognitive deficits and neurochemical alterations induced by Aβ in mice.

Alzheimer's disease (AD) is the most prevalent form of dementia with a complex pathophysiology not fully elucidated but with limited pharmacological treatment. The Usnic acid (UA) is a lichen secondary metabolite found in two enantiomeric forms: (R)-(+)-UA or (S)-(-)-UA, with antioxidant and anti-inflammatory potential. Thus, given the role of neuroinflammation and oxidative injury in the AD, this study aimed to investigate experimentally the cognitive enhancing and anti-neuroinflammatory effects of UA enantiomers.

Tetrahydroquinolines by the multicomponent Povarov reaction in water: calix[n]arene-catalysed cascade process and mechanistic insights.

The catalyst p-sulfonic acid calix[4]arene was effectively used in the three-component Povarov reaction between aromatic anilines and two equivalents of 2,3-dihydrofuran to obtain furano[3,2-c]-1,2,3,4-tetrahydroquinolines. These reactions proceeded efficiently using water as a green solvent and nontoxic catalysts that could be efficiently reused; the reactions were metal-free and used only inexpensive and easily available compounds. Together with a simple workup procedure, these advantages make this protocol a very efficient and green alternative to the traditional methods for constructing tetrahydroquinoline structures, through the formation of two new C-C bonds and one C-N bond.

Calix[n]arene-Catalyzed Three-Component Povarov Reaction: Microwave-Assisted Synthesis of Julolidines and Mechanistic Insights.

A new one-pot cascade reaction-based application of Povarov reactions with a p-sulfonic acid calix[4]arene catalyst for the synthesis of a series of 34 julolidine derivatives with substituents at C8 or C9 in good to excellent yields is reported. These microwave-assisted reactions proceeded efficiently, had short reaction times, were metal-free, were low cost, and used an inexpensive, easily available and nontoxic catalyst. These advantages, along with a simple workup procedure, make this protocol a very efficient and green alternative to the traditional methods for constructing these types of N-heterocyclic skeletons.

Quinolines: Microwave-assisted synthesis and their antifungal, anticancer and radical scavenger properties.

An efficient method for the synthesis of quinolines using microwave irradiation was developed providing 28 quinolines with good yields. The reaction procedures are environmentally friendly, convenient, mild and of easy work-up. Quinolines were evaluated for their antifungal, anticancer and antioxidant properties and exhibited high activities in all tests performed.

Chemical composition and acaricidal activity of the essential oil of Baccharis dracunculifolia De Candole (1836) and its constituents nerolidol and limonene on larvae and engorged females of Rhipicephalus microplus (Acari: Ixodidae).

Baccharis dracunculifolia DC (common name "alecrim-do-campo" in Brazil) is a plant with widespread distribution in South America that is the botanical origin of green propolis. The aim of this study was to evaluate the chemical composition and acaricidal activity of the essential oil of B. dracunculifolia and its constituents nerolidol and limonene on unengorged larvae and engorged females of Rhipicephalus microplus (Acari: Ixodidae).

Organocatalysis in the three-component Povarov reaction and investigation by mass spectrometry.

A diastereoselective three-component cascade reaction, catalyzed by p-sulfonic acid calix[4]arene, provides a unique method to access diverse julolidine derivatives in high yields. Additionally, the reaction was also monitored by mass spectrometry and the mechanistic pathway uncovered.

Calix[n]arenes as goldmines for the development of chemical entities of pharmaceutical interest.

Calix[n]arenes are macrocyclic cone-shaped compounds formed from phenolic units linked by methylene groups in the ortho position. Structural features make calix[n]arenes a versatile class of molecules that are of great interest, particularly in the pharmaceutical field. The cavity-like shape gives calix[n]arenes the ability to selectively encapsulate ions or neutral molecules, which can be used to generate carrier systems capable of increasing the solubility and diffusivity of chemical species.

Activity of essential oil of Lippia triplinervis Gardner (Verbenaceae) on Rhipicephalus microplus (Acari: Ixodidae).

The objective of this work was to characterize and investigate the acaricidal activity of the essential oil of the aerial parts of Lippia triplinervis at different concentrations on unengorged larvae and engorged females of Rhipicephalus microplus. The essential oil yielded 2.21 % (w/w to dry matter) and was composed mainly of carvacrol (31.

Yacon flour and Bifidobacterium longum modulate bone health in rats.

Yacon flour has been considered a food with prebiotic potential because of the high levels of fructooligosaccharides, which allows for its use in formulating synbiotic foods. The purpose of this study was to evaluate the effect of yacon flour and probiotic (Bifidobacterium longum) on the modulation of variables related to bone health. Thirty-two Wistar rats were divided into 4 groups: control, yacon flour, diet+B.

Proparacaine complexation with beta-cyclodextrin and p-sulfonic acid calix[6]arene, as evaluated by varied (1)H-NMR approaches.

This study focused on the use of NMR techniques as a tool for the investigation of complex formation between proparacaine and cyclodextrins (CDs) or p-sulfonic acid calix[6]arene. The pH dependence of the complexation of proparacaine with beta-CD and p-sulfonic acid calix[6]arene was studied and binding constants were determined by (1)H NMR spectroscopy [diffusion-ordered spectroscopy (DOSY)] for the charged and uncharged forms of the local anesthetic in beta-CD and p-sulfonic acid calix[6]arene. The stoichiometries of the complexes was determined and rotating frame Overhauser enhancement spectroscopy (ROESY) 1D experiments revealed details of the molecular insertion of proparacaine into the beta-CD and p-sulfonic acid calix[6]arene cavities.

Calixarenes as new platforms for drug design.

Calixarenes, macrocyclic compounds of phenolic units linked by methylene groups at the 2,6-positions, present some of the requirements to serve as platforms for the design and synthesis of biological active compounds. They are also interesting host molecules for chemical biology study purposes. Their basic molecular scaffold has potential ability for molecule recognition; it is promptly synthesized in large amounts, and might be easily modified for maximizing molecular interactions toward relevant guest molecules.

Topology of a ternary complex (proparacaine-beta-cyclodextrin-liposome) by STD NMR.

The topologies of proparacaine (PPC) in beta-cyclodextrin (beta-CD), PPC in egg phosphatidylcholine (EPC) liposomes and PPC in beta-CD in EPC were investigated using NMR experiments (1D ROESY and saturation transfer difference (STD)). This is the first description of the STD technique applied to PPC-EPC-beta-CD system, revealing that not only PPC was imbedded in EPC bilayer, but beta-CD was also interacting with liposome vesicles. These results are novel and were rationalized as the spontaneous formation of a ternary complex with some beta-CD molecules bound to external liposome vesicles surfaces.

'Non-covalent synthesis' of a chiral host of calix[6]arene and enantiomeric discrimination.

'Non-covalent synthesis' of novel chiral hosts (calix[6]arene-chiral amine complexes) and its application to enantiomeric discrimination was investigated by (1)H NMR spectroscopy. The topology of a ternary complex was proposed for the calix[6]arene-amine-sulfoxide to rationalize the chiral recognition.

Regioselectivity in aromatic Claisen rearrangements.

Theoretical calculations and the isomeric product composition for a series of eight meta-substituted allyl aryl ethers confirm the reliability of a new (1)H NMR methodology used to predict aromatic Claisen regioselectivity from ground-state conformational preference of the reactant allyloxy group. Frontier HOMO-LUMO intramolecular orbital interactions, a classical approach in predicting reactivity and selectivity for Claisen rearrangements of allyl vinyl ethers, is shown to fail to mimic transition-state orbital interactions for aromatic Claisen rearrangements of meta-substituted allyl aryl ethers. B3LYP/6-31G(d,p) calculations on reactants and transition states are shown, however, to correctly predict the outcome of such aromatic Claisen rearrangements from either the preferential reactant ground-state conformation (theoretical predictions that agree with the NMR measurements) or the less energetic transition state, or both.