Chemical Physical Characterization and Profile of Fruit Volatile Compounds from Different Accesses of Myrciaria floribunda (H. West Ex Wild.) O. Berg through Polyacrylate Fiber

Among the many species of native fruit of Brazil that have been little explored, there is Myrciaria floribunda (also known as rumberry, cambuizeiro, or guavaberry), a species with significant variability, which has fruits of different colors (orange, red, and purple) when ripe. The physical-chemical characteristics evaluated were fruit weight (FW), seed weight (SW), pulp weight (PW), number of seeds (NS), longitudinal diameter (LD), transverse diameter (TD), format (LD/TD), hydrogen potential (pH), soluble solids (SS), titratable acidity (TA), and ratio (SS/TA); further, the volatile organic compounds (VOCs) of nine accesses of rumberry orchards were identified. The averages of the variables FW, SW, PW, NS, LD, TD, shape, and firmness were 0.76 g, 0.22 g, 0.54 g, 1.45, 10.06 mm, 9.90 mm, 1.02, 2.96 N, respectively. LD/TD data showed that the fruits have a slightly rounded shape (LD/TD = 1). The averages for pH, SS, TA, and SS/TA were 3.74, 17.58 Brix, 4.31% citric acid, and 4.31, respectively. The evaluated parameters indicated that the fruits can be consumed both in natura and industrialized, with the red-colored fruits presenting a good balance of SS/TA, standards demanded by the processing industries. Thirty-six VOCs were identified, with emphasis on the sesquiterpenes. Caryophyllene (21.6% to 49.3%) and γ-selinene (11.3% to 16.3%) were the most predominant compounds in rumberry fruits.     

Characterization of magnetic nanoparticles modified with thiol functionalized PAMAM dendron for DNA recovery

Magnetic nanoparticles (MNPs) modified with the thiol functionalized polyamidoamine (PAMAM) dendron were synthesized to estimate their DNA recovery capabilities. Aminosilane-modified MNPs and MNPs surrounded by a phospholipid (distearoylphosphatidylethanolamine (DSPE)) bilayer were used as core particles. Cystamine-core PAMAM dendrimers were reduced by dithiothreitol to dendron thiols and chemically conjugated to the core particles. Characterization of the synthesis revealed an increase of the surface amine charge from generation 1 (G1) to G6, starting with an aminosilane initiator. Particle size distribution analysis indicated that G6 PAMAM-modified MNPs exhibited monodispersity in an aqueous solution. G6 PAMAM-MNPs and G6 PAMAM-PE-MNPs synthesized by the proposed method have equivalent DNA recovery abilities to PAMAM-MNPs prepared by the conventional divergent synthesis method. In optimized conditions, 96% of λDNA was recovered using G6 PAMAM-PE-MNPs. Therefore, the method for preparing PAMAM-MNPs and PAMAM-PE-MNPs proposed in this study will be a novel approach for producing DNA carriers for efficient DNA purification by magnetic separation.     

Controlled Radical Polymerization of 2,3‐Epithiopropyl Methacrylate

We report first results on the controlled radical polymerization of 2,3‐epithiopropyl methacrylate (ETMA) also known as thiiran‐2‐ylmethyl methacrylate. Reversible addition‐fragmentation chain transfer (RAFT) of ETMA was carried out in bulk and in solution, using AIBN as initiator and the chain transfer agents: cyanopropyl dithiobenzoate (CPDB) and cumyl dithiobenzoate (CDB). A linear increase of the number‐average molecular weight and decrease of the polydispersity with monomer conversion were observed using CPDB as transfer agent, indicating a controlled process. Atom transfer radical polymerization (ATRP) of ETMA was performed under different reaction conditions using copper bromide complexed by tertiary amine ligands and ethyl 2‐bromoisobutyrate (EBiB) or 2‐bromopropionitrile (BPN) as initiator. All experiments lead to a crosslinked polymer. Preliminary studies in the absence of initiator showed that the CuBr/ligand complex alone initiates the ring‐opening polymerization of thiirane leading to a poly(propylene sulfide) with pendant methacrylate groups.

     

Inclusion Complex between Local Anesthetic/2-hydroxypropyl-β-cyclodextrin in Stealth Liposome

The drugs delivery system in the treatment of diseases has advantages such as reduced toxicity, increased availability of the drug, etc. Therefore, studies of the supramolecular interactions between local anesthetics (LAs) butamben (BTB) or ropivacaine (RVC) complexed with 2-hydroxypropyl-β-cyclodextrin (HP-βCD) and carried in Stealth liposomal (SL) are performed. ¹H-NMR nuclear magnetic resonance (DOSY and STD) were used as the main tools. The displacements observed in the ¹H-NMR presented the complexion between LAs and HP-βCD. The diffusion coefficients of free BTB and RVC were 7.70 × 10⁻¹⁰ m² s⁻¹ and 4.07 × 10⁻¹⁰ m² s⁻¹, and in the complex with HP-βCD were 1.90 × 10⁻¹⁰ m² s⁻¹ and 3.64 × 10⁻¹⁰ m² s⁻¹, respectively, which indicate a strong interaction between the BTB molecule and HP-βCD (98.3% molar fraction and Ka = 72.279 L/mol). With STD-NMR, the encapsulation of the BTB/HP-βCD and RVC/HP-βCD in SL vesicles was proven. Beyond the saturation transfer to the LAs, there is the magnetization transfer to the hydrogens of HP-βCD. BTB and RVC have already been studied in normal liposome systems; however, little is known of their behavior in SL.     

Chemical Approach to the Optimization of Conditions Using HS-SPME/GC–MS for Characterization of Volatile Compounds in Eugenia brasiliensis Fruit

Grumixama (Eugenia brasiliensis Lam.) is a native fruit of the Brazilian Atlantic Forest, belonging to the Myrtaceae family, which designatesthe most significant number of species with food potential. It stands out due to its phytochemical characteristics because of the presence of polyphenols and volatile organic compounds. Volatile compounds are substances released by foods that give off an aroma and influence flavor. Solid-phase microextraction is a technique that allows for low-cost, fast, and solvent-free extraction, has an affinity for numerous analytes, and is easily coupled to gas chromatography. The objectives of this work were to evaluate the efficiency of different fibers of SPME (solid-phase microextraction) in the extraction of volatile organic compounds from grumixama pulp; optimize a method for extraction time, temperature, and sample weight; and to determine the characteristic volatile profile of this fruit. For the extraction of volatile compounds, three fibers of different polarities were used: polar polyacrylate (PA) fibers, divinylbenzene/carboxyne/polydimethylsiloxane (DVB/CAR/PDMS) semipolar fibers, and polydimethylsiloxane/divinylbenzene (PDMS/DVB). Fourteen volatile organic compounds (VOCs) were identified by DVB/CAR/PDMS, six by PA, and seven by PDMS/DVB through solid-phase microextraction in the headspace mode (SPME-HS). Considering the total number of compounds identified, regardless of the fiber used, and the optimization of the method, Eugenia brasiliensis presented sesquiterpene fractions (85.7%, 83.3%, and 85.7% of total VOCs) higher than the monoterpene fractions (14.3%, 16.7%, and 14.3%) for DVB/CAR/PDMS, PA, and PDMS/DVB, respectively in its composition. In addition, it was possible to verify that the fiber DVB/CAR/PDMS presented a better efficiency due to the larger chromatographic area observed when the grumixama pulp was subjected to conditions of 75 °C, 2.0 g, and an adsorption time of 20 min.     

Total synthesis of the (+)-antimycin A3 family: structure elucidation of (+)-antimycin A3a

(+)-Antimycin A_3a (AA_3a), one component of the natural antibiotic antimycin A₃, was synthesized using an asymmetric aza-Claisen rearrangement. The stereochemistry at the 2′ position on the acyloxy side chain of AA_3a was established as S-configuration by comparison of the synthetic AA_3a and the natural AA_3a.     

Antioxidant and Protective Effects of <Emphasis Type="Italic">Schinus terebinthifolius</Emphasis> Raddi Against Doxorubicin-Induced Toxicity

Doxorubicin is an anticancer drug whose toxic effects on non-cancer cells are associated with increased oxidative stress. This study investigated the chemical composition, antioxidant activity of the methanolic extract of Schinus terebinthifolius Raddi leaves (MESL) as well as effects against doxorubicin-induced toxicity in human erythrocytes, K562 human erythroleukemia cells, and mouse hearts. The chemical composition indicated the presence of phenolic compounds, flavonoids, tannins, and ascorbic acid. MESL showed antioxidant activity by scavenging free radicals and inhibiting hemolysis and lipid peroxidation in human erythrocytes incubated with an oxidizing agent, and was able to increase the enzymatic activity of superoxide dismutase and glutathione peroxidase in human erythrocytes, without influencing the activity of enzyme catalase. The increase of oxidative hemolysis and malondialdehyde levels in erythrocytes incubated with doxorubicin was reduced by treatment with MESL. The cytotoxic activity of doxorubicin in erythroleukemia cells treated with MESL was unmodified. Additionally, the extract protected mice against the doxorubicin-induced cardiotoxicity. In conclusion, the MESL exhibits antioxidant activity, reducing doxorubicin-induced oxidative stress without changing the anticancer action of the drug, and protects against doxorubicin-induced cardiotoxicity. Hence, these findings suggest that these effects are via anti-oxidative by inhibiting free radicals, decreased oxidative stress, and increased antioxidant enzyme activity.     

Picoline as ligand with antimony trichloride and triiodide adducts

Solid adducts SbX₃·L-pic (X=Cl, I and L=α-, β- and γ-picolines) were synthesized and characterized by elemental analysis, ¹H and ¹³C NMR, IR spectroscopy and thermal analysis. The infrared spectroscopy and the magnetic resonance for ¹H and ¹³C nuclei of these compounds suggest that the ligands coordinate through nitrogen atom. Kinetic studies were accomplished by means of thermogravimetric data, through isothermal and non-isothermal techniques. The best adjusting models for adducts thermal decomposition were R¹ for isothermal and R₁ and R₂ for the non-isothermal methods. The energy of activation values obtained by isothermal method indicate the following orders of thermal stability for adducts: i) SbCl₃·α-pic>SbCl₃·β-pic>SbCl₃·γ-pic and ii) SbI₃·β-pic>SbI₃·γ-pic>SbI₃·α-pic. The activation energy values obtained by non-isothermal were higher than those from isothermal methods, showing the order of stability:iii) SbCl₃·α-pic<SbCl₃·β-pic<SbCl₃·γ-pic and iv) SbI₃·β-pic>SbI₃·α-pic=SbI_3··γ-pic. These obtained data through R₁ model presented the kinetic compensation effect for trichloride adducts, which could be associated to both isothermal and non-isothermal processes. This revised version was published online in August 2006 with corrections to the Cover Date.