Production of phenolic-rich extracts from Brazilian plants using supercritical and subcritical fluid extraction: Experimental data and economic evaluation

Flame vine (Pyrostegia venusta) (FV), ice-cream-bean (Inga edulis) (IC), dog's knot (Heteropterys aphrodisiaca) (DK), and common bean (Phaseolus vulgaris L.) (BE) extracts were obtained by supercritical and subcritical fluid extraction (SFE) at 323 K and 35 MPa using pure carbon dioxide (CO2), carbon dioxide with ethanol (CO2 + EtOH) and carbon dioxide with water (CO2 + H2O). The extraction efficiency was evaluated by factoring in the solvent system and plant matrix influence in extraction yield (EY), antioxidant activity (AA), total phenolic content (TPC) and total flavonoid content (TFC). The manufacturing costs of crude extracts (COMEY) and phenolic-rich fractions (COMTPC) were also evaluated. The highest EY was achieved using CO2 + H2O, except for IC extracts. The BE extracts showed the highest TPC (338 mg GAE/g extract, dw), and the highest TFC was obtained for IC extracts using CO2 (260 mg CE/g extract, dw). AA achieved higher values for FV extracts using CO2 + EtOH (0.096 mL/mg). The lowest COMEY and COMTPC were obtained for FV and BE extracts using CO2 + H2O in a 0.5 m(3) extraction column13196109CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP140290/2009-5; 301301/2010-72008/10986-

Silk Fibroin Hydrogels Incorporated with the Antioxidant Extract of Stryphnodendron adstringens Bark

Barbatimão (Stryphnodendron adstringens) is a Brazilian medicinal plant known for its pharmacological properties, including healing activity related to its phenolic composition, which is chiefly given by tannins. In order to preserve its stability and bioactivity, barbatimão extracts can be incorporated into (bio-)polymeric matrixes, of which silk fibroin stands out due to its versatility and tunable properties. This work aimed to obtain barbatimão bark extract rich in phenolic compounds and evaluate its incorporation in fibroin hydrogels. From the extraction process, it was observed that the PG (propylene glycol) extract presented a higher global yield (X0) and phenolic compounds (TPC) than the ET (ethanol) extract. Furthermore, the antioxidant activity (ORAC and FRAP) was similar between both extracts. Regarding the hydrogels, morphological, chemical, thermal, and mechanical characterizations were performed to understand the influence of the barbatimão extract and the solvent on the fibroin hydrogel properties. As a result, the hydrogels containing the barbatimão PG extract (BT/PG hydrogels) showed the better physical–chemical and structural performance. Therefore, these hydrogels should be further investigated regarding their potential in medical and pharmaceutical applications, especially in wound healing

Structural and functional characterization of the Streptococcus pneumoniae RrgB pilus backbone D1 domain

Streptococcus pneumoniae expresses on its surface adhesive pili, involved in bacterial attachment to epithelial cells and virulence. The pneumococcal pilus is composed of three proteins, RrgA, RrgB, and RrgC, each stabilized by intramolecular isopeptide bonds and covalently polymerized by means of intermolecular isopeptide bonds to form an extended fiber. RrgB is the pilus scaffold subunit and is protective in vivo in mouse models of sepsis and pneumonia, thus representing a potential vaccine candidate. The crystal structure of a major RrgB C-terminal portion featured an organization into three independently folded protein domains (D2-D4), whereas the N-terminal D1 domain (D1) remained unsolved. We have tested the four single recombinant RrgB domains in active and passive immunization studies and show that D1 is the most effective, providing a level of protection comparable with that of the full-length protein. To elucidate the structural features of D1, we solved the solution structure of the recombinant domain by NMR spectroscopy. The spectra analysis revealed that D1 has many flexible regions, does not contain any intramolecular isopeptide bond, and shares with the other domains an Ig-like fold. In addition, we demonstrated, by site-directed mutagenesis and complementation in S. pneumoniae, that the D1 domain contains the Lys residue (Lys-183) involved in the formation of the intermolecular isopeptide bonds and pilus polymerization. Finally, we present a model of the RrgB protein architecture along with the mapping of two surface-exposed linear epitopes recognized by protective antisera

Radical oxygen species and bile secretion

Oxidative stress is a common feature in most hepatopathies. Accumulating evidences indicate that reactive oxygen species (ROS) induce a number of functional changes either deleterious or adaptive in the capability of the hepatocytes to produce bile and to secrete exogenous and endogenous compounds. This review is aimed to describe the mechanisms involved in these changes. For this purpose, we will summarize: 1. The current evidence that acutely induced oxidative stress is cholestatic, by describing the mechanisms underlying the hepatocyte secretory failure, including the disorganization of the actin cytoskeleton and its most noticeable consequences, that is, the impairment of tight-junctional structures and the endocytic internalization of canalicular transporters relevant to bile formation. 2. The role for oxidative-stress-activated signalling pathways in the pathomechanisms described above, particularly those involving Ca2+ elevation and its consequent activation via Ca2+ of “classical” and “novel” PKC isoforms. 3. The mechanisms involved in the adaptive response against oxidative stress mediated by ROS-responsive transcription factors, such as upregulation of GSH synthesis pathway, antioxidant enzymes, and hepatocellular efflux pumps. 4. The consequences on hepatocellular secretory function when this adaptive response can be surpassed by the sustained/high production of ROS. This deleterious effects include transcriptional and posttranscriptional changes in the expression of transporters relevant to bile formation, as has been shown to occur, for example, after long-term administration of aluminum to rats, in the Long-Evans Cinnamon rat (a model of chronic hepatic copper accumulation mimicking Wilson’s disease), and in ischemia-reperfusion injury.Fil: Basiglio, Cecilia Lorena. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Fisiología Experimental (IFISE‑CONICET); Argentina.Fil: Toledo, Flavia D. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Fisiología Experimental (IFISE‑CONICET); Argentina.Fil: Sánchez Pozzi, Enrique J. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Fisiología Experimental (IFISE‑CONICET); Argentina.Fil: Roma, Marcelo Gabriel. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Fisiología Experimental (IFISE‑CONICET); Argentina