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Microwave Multicomponent Synthesis In the manner that very important research is often performed by multidisciplinary research teams, the applications of multicomponent reactions involving the combination of multiple starting materials with different functional groups leading to the higher efficiency and environmentally friendly construction of multifunctional/complex target molecules is growing in importance. This review will explore the advances and advantages in microwave multicomponent synthesis (MMS) that have been achieved over the last five years.
Springer Science and Business Media LLC - Tập 14 Số 12 - Trang 4936-4972
Neuroprotective Effects of Exogenous Activin A on Oxygen-Glucose Deprivation in PC12 Cells Ischemic cerebrovascular disease is one of the most common causes of death in the World. Exogenous activin A (ActA) protects neurons against toxicity and plays a central role in regulating the brain’s response to injury. In the present study, we investigated the mechanisms involved in the neuroprotective effects of ActA in a model of hypoxic-ischemic brain disease. We found that ActA could effectively increase the survival rate of PC12 cells and relieve oxygen-glucose deprivation (OGD) damage. To clarify the neuroprotective mechanisms of ActA, the effects of ActA on the ActA/Smad pathway and on the up-regulation of inducible nitric oxide synthase (NOS) and superoxide dismutase (SOD) were investigated using OGD in PC12 cells. The results showed that ActA could increase the expression of activin receptor IIA (ActRIIA), Smad3 and Smad4 and that 50 ng/mL and 100 ng/mL of ActA could reduce NO levels and increase SOD activity by 78.9% and 79.9%, respectively. These results suggested that the neuroprotective effects of ActA in ischemia could be related to the activation of the ActA/Smad signaling pathway and to its anti-oxidant activities.
Springer Science and Business Media LLC - Tập 17 Số 1 - Trang 315-327
Biodegradable and Biocompatible Polyhydroxy-alkanoates (PHA): Auspicious Microbial Macromolecules for Pharmaceutical and Therapeutic Applications Polyhydroxyalkanoates (PHA) are bio-based microbial biopolyesters; their stiffness, elasticity, crystallinity and degradability are tunable by the monomeric composition, selection of microbial production strain, substrates, process parameters during production, and post-synthetic processing; they display biological alternatives for diverse technomers of petrochemical origin. This, together with the fact that their monomeric and oligomeric in vivo degradation products do not exert any toxic or elsewhere negative effect to living cells or tissue of humans or animals, makes them highly stimulating for various applications in the medical field. This article provides an overview of PHA application in the therapeutic, surgical and tissue engineering area, and reviews strategies to produce PHA at purity levels high enough to be used in vivo. Tested applications of differently composed PHA and advanced follow-up products as carrier materials for controlled in vivo release of anti-cancer drugs or antibiotics, as scaffolds for tissue engineering, as guidance conduits for nerve repair or as enhanced sutures, implants or meshes are discussed from both a biotechnological and a material-scientific perspective. The article also describes the use of traditional processing techniques for production of PHA-based medical devices, such as melt-spinning, melt extrusion, or solvent evaporation, and emerging processing techniques like 3D-printing, computer-aided wet-spinning, laser perforation, and electrospinning.
Springer Science and Business Media LLC - Tập 23 Số 2 - Trang 362
Antimicrobial Activity of Sphingolipids Isolated from the Stems of Cucumber (Cucumis sativus L.) Three antimicrobial sphingolipids were separated by bioassay-guided isolation from the chloroform fraction of the crude methanol extract of cucumber (Cucumis sativus L.) stems and identified as (2S,3S,4R,10E)-2-[(2'R)-2-hydroxytetra-cosanoylamino]-1,3,4-octadecanetriol-10-ene (1), 1-O-β-D-glucopyranosyl(2S,3S,4R,10E)-2-[(2'R)-2-hydroxy-tetracosanoylamino]-1,3,4-octadecanetriol-10-ene (2) and soya-cerebroside I (3) by their physicochemical properties and spectroscopic analysis. They were evaluated to show antifungal and antibacterial activity on test microorganisms including four fungal and three bacterial species. Among them, compound 1, a relatively low polarity aglycone, exhibited stronger antimicrobial activity than its corresponding glycoside 2. The results indicated that sphingolipids could be the main antimicrobial compounds in the crude methanol extract of cucumber stems.
Springer Science and Business Media LLC - Tập 15 Số 12 - Trang 9288-9297
Phenolic and Lignan Glycosides from the Butanol Extract of Averrhoa carambola L. Root Fifteen compounds, which included six chiral lignans and nine phenolic glycosides, were separated from the butanol fraction of Averrhoa carambola L. root and identified. All of the compounds, namely 3,4,5-trimethoxyphenol-1-O-β-D-glucopyranoside (1), benzyl-1-O-β-D-glucopyranoside (2), (+)-5'-methoxyisolariciresinol 3α-O-β-D-gluco-pyranoside (3), (+)-isolariciresinol 3α-O-β-D-glucopyranoside (4), koaburaside (5), (+)-lyoniresinol 3α-O-β-D-glucopyranoside (6), (−)-lyoniresinol 3α-O-β-D-glucopyranoside (7), (−)-5'-methoxyisolariciresinol 3α-O-β-D-glucopyranoside (8), (−)-isolariciresinol 3α-O-β-D-glucopyranoside (9), 3,5-dimethoxy-4-hydroxyphenyl 1-O-β-apiofuranosyl (1''→6')-O-β-D-glucopyranoside (10), 3,4,5-trimethoxyphenyl 1-O-β-apiofuranosyl (1''→6')-β-gluco-pyranoside (11), methoxyhydroquinone-4-β-D-glucopyranoside (12), (2S)-2-O-β-D-gluco-pyranosyl-2-hydroxyphenylacetic acid (13), 3-hydroxy-4-methoxyphenol 1-O-β-D-apio-furanosyl-(1''→6')-O-β-D-glucopyranoside (14) and 4-hydroxy-3-methoxyphenol 1-O-β-D-apiofuranosyl-(1''→6')-O-β-D-glucopyranoside (15) were isolated from this plant for the first time.
Springer Science and Business Media LLC - Tập 17 Số 10 - Trang 12330-12340
Agarose and Its Derivatives as Supports for Enzyme Immobilization Agarose is a polysaccharide obtained from some seaweeds, with a quite particular structure that allows spontaneous gelation. Agarose-based beads are highly porous, mechanically resistant, chemically and physically inert, and sharply hydrophilic. These features—that could be further improved by means of covalent cross-linking—render them particularly suitable for enzyme immobilization with a wide range of derivatization methods taking advantage of chemical modification of a fraction of the polymer hydroxyls. The main properties of the polymer are described here, followed by a review of cross-linking and derivatization methods. Some recent, innovative procedures to optimize the catalytic activity and operational stability of the obtained preparations are also described, together with multi-enzyme immobilized systems and the main guidelines to exploit their performances.
Springer Science and Business Media LLC - Tập 21 Số 11 - Trang 1577
Immobilization of Moniliella spathulata R25L270 Lipase on Ionic, Hydrophobic and Covalent Supports: Functional Properties and Hydrolysis of Sardine Oil The oleaginous yeast Moniliella spathulata R25L270 was the first yeast able to grow and produce extracellular lipase using Macaúba (Acrocomia aculeate) cake as substrate. The novel lipase was recently identified, and presented promising features for biotechnological applications. The M. spathulata R25L270 lipase efficiently hydrolyzed vegetable and animal oils, and showed selectivity for generating cis-5,8,11,15,17-eicosapentaenoic acid from sardine oil. The enzyme can act in a wide range of temperatures (25–48 °C) and pH (6.5–8.4). The present study deals with the immobilization of M. spathulata R25L270 lipase on hydrophobic, covalent and ionic supports to select the most active biocatalyst capable to obtain omega-3 fatty acids (PUFA) from sardine oil. Nine immobilized agarose derivatives were prepared and biochemically characterized for thermostability, pH stability and catalytic properties (KM and Vmax). Ionic supports improved the enzyme–substrate affinity; however, it was not an effective strategy to increase the M. spathulata R25L270 lipase stability against pH and temperature. Covalent support resulted in a biocatalyst with decreased activity, but high thermostability. The enzyme was most stabilized when immobilized on hydrophobic supports, especially Octyl-Sepharose. Compared with the free enzyme, the half-life of the Octyl-Sepharose derivative at 60 °C increased 10-fold, and lipase stability under acidic conditions was achieved. The Octyl-Sepharose derivative was selected to obtain omega-3 fatty acids from sardine oil, and the maximal enzyme selectivity was achieved at pH 5.0.
Springer Science and Business Media LLC - Tập 22 Số 10 - Trang 1508
Phosphorylation of Guar Gum/Magnetite/Chitosan Nanocomposites for Uranium (VI) Sorption and Antibacterial Applications The development of new materials is needed to address the environmental challenges of wastewater treatment. The phosphorylation of guar gum combined with its association to chitosan allows preparing an efficient sorbent for the removal of U(VI) from slightly acidic solutions. The incorporation of magnetite nanoparticles enhances solid/liquid. Functional groups are characterized by FTIR spectroscopy while textural properties are qualified by N2 adsorption. The optimum pH is close to 4 (deprotonation of amine and phosphonate groups). Uptake kinetics are fast (60 min of contact), fitted by a pseudo-first order rate equation. Maximum sorption capacities are close to 1.28 and 1.16 mmol U g−1 (non-magnetic and magnetic, respectively), while the sorption isotherms are fitted by Langmuir equation. Uranyl desorption (using 0.2 M HCl solutions) is achieved within 20–30 min; the sorbents can be recycled for at least five cycles (5–6% loss in sorption performance, complete desorption). In multi-component solutions, the sorbents show marked preference for U(VI) and Nd(III) over alkali-earth metals and Si(IV). The zone of exclusion method shows that magnetic sorbent has antibacterial effects against both Gram+ and Gram- bacteria, contrary to non-magnetic material (only Gram+ bacteria). The magnetic composite is highly promising as antimicrobial support and for recovery of valuable metals.
Springer Science and Business Media LLC - Tập 26 Số 7 - Trang 1920
Lipophilicity as a Central Component of Drug-Like Properties of Chalchones and Flavonoid Derivatives Lipophilcity is an important physico-chemical parameter that influences membrane transport and binding ability to action. Migration distance following complete elution of compounds was used to calculate different lipophilicity-related parameters. The aim of this study is to show that lipophilicity is a central component of thiazole chalcones and flavonoid derivatives regarding their drug-like properties. Experimental and computational methods were used. This study considers 44 previously synthesized compounds (thiazole chalcones, flavanones, flavones, 3-hydroxyflavones, and their acetylated derivatives). The concerned compounds have shown antitumoral hallmarks and antibacterial activity in vitro. The experimental method used to determine compounds’ lipophilicity was the reverse-phase thin layer chromatography (RP-TLC). Lipophilicity related parameters—isocratic retention factor (RM), relative lipophily (RM0), slope (b), chromatographic hydrophobic index (φ0), scores of principal components (PC1/RM)—were determined based on reverse-phase chromatography results.
Springer Science and Business Media LLC - Tập 24 Số 8 - Trang 1505
Synthesis, Molecular Properties Prediction, and Anti-staphylococcal Activity of N-Acylhydrazones and New 1,3,4-Oxadiazole Derivatives Five new 1-(2-(5-nitrofuran-2-yl)-5-(aryl)-1,3,4-oxadiazol-3-(2H)-yl) ethanone compounds 5a–e were synthesized by cyclization of N-acylhydrazones 4a–e with acetic anhydride under reflux conditions. Their structures were fully characterized by IR, 1H-NMR, and 13C-NMR. Furthermore, evaluations of the antibacterial activity of the 1,3,4-oxadiazoles 5a–e and N-acylhydrazones 4a–e showed strong activity against several strains of Staphylococcus aureus, with MICs between 4 μg/mL to 32 μg/mL. In silico studies of the parameters of Lipinski’s Rule of Five, as well as the topological polar surface area (TPSA), absorption percentage (% ABS), drug likeness and drug score indicate that these compounds, especially 4a and 5d, have potential to be new drug candidates.
Springer Science and Business Media LLC - Tập 17 Số 5 - Trang 5095-5107
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