Extraction, separation, and evaluation of antioxidant effect of the different fractions of polyphenols from cocoa beans / Extracción, separación y evaluación del efecto antioxidante de las diferentes fracciones de polifenoles de los granos de cacao / Extração, Separação e Avaliação do Efeito Antioxidante das Diferentes Frações de Polifenóis de Grãos de Cacau

Abstract Polyphenol Extracts (PE) hold antioxidant properties, which might be related to positive effects on human health. It has been stated that PE, obtained from cocoa beans, contain fractions of flavan-3-ols with different degrees of polymerization (DP). However, it is unknown which of the fractions or their mixture drives the best antioxidant activity. This paper reports the study conducted to elucidate the role of each fraction (with different DP) on Antioxidant Capacity (AC). First, the process of extraction and separation of polyphenols' fractions in cocoa beans was executed; afterward, AC was determined for each fraction individually and their combinations (monomers, dimers and oligomers). Solid-liquid extraction was made by using a 50% (v/v) ethanol solution and a mass:solvent ratio of 1:120 in an ultrasound bath. PE were separated into monomers, dimers, and oligomers by HPLC using a semipreparative column. The results obtained show that PE contain 95.35, 7.45, and 21.75 mg EE (epicatechin equivalents) / g ds of monomers, dimers, and oligomers, respectively. Finally, the AC of each fraction was evaluated using a complete cubic model mix design. According to the results, the best AC was obtained for dimers. However, when monomers, dimers and oligomers were mixed, an antagonistic effect on AC was observed.

Resumen Los extractos polifenólicos (PE) tienen propiedades antioxidantes positivas para la salud humana. Se conoce que los PE obtenidos del cacao contienen fracciones de flavan-3-ols con diferentes grados de polimerización (DP). Sin embargo, se desconoce qué fracción o mezcla de ellos posee mayor capacidad antioxidante. Este trabajo se realizó con el fin de evaluar la capacidad antioxidante (AC) de cada fracción polifenólica (con diferentes DP) extraída del cacao. Primero, se realizó un proceso de extracción y separación de las fracciones de polifenoles en los granos de cacao. Luego, se determinó la AC para cada fracción individual y combinada (monómeros, dímeros y oligómeros). La extracción sólido-líquido se realizó utilizando una solución de etanol en agua al 50 % (v/v) y una relación masa:solvente de 1:120 en un baño de ultrasonido. El extracto PE se separó en monómeros, dímeros y oligómeros por HPLC usando una columna semipreparativa. Los resultados obtenidos muestran que el extracto PE contiene 95,35, 7,45 y 21,75 mg EE (equivalentes de epicatequina) / g ds de monómeros, dímeros y oligómeros, respectivamente. Finalmente, se evaluó la CA de cada fracción utilizando un diseño de mezcla de modelo cúbico completo. Según los resultados, se obtuvo una mayor AC para dímeros; sin embargo, se observó un efecto antagonista de la AC cuando se mezclan monómeros, dímeros y oligómeros.

Resumo Os extratos de polifenóis (PE) possuem propriedades antioxidantes, que podem estar relacionadas a efeitos positivos para a saúde humana. Foi afirmado que o PE, obtido a partir de grãos de cacau, contém frações de flavan-3-ols com diferentes graus de polimerização (DP). No entanto, não se sabe qual fração ou mistura deles impulsiona a melhor atividade antioxidante. Este artigo relata os achados de um estudo realizado com o objetivo de elucidar o papel de cada fração (com DP diferente) na capacidade antioxidante (AC). Inicialmente, o processo de extração e separação de frações de polifenóis 'em grãos de cacau é descrito. Posteriormente, é determinada a AC para cada fração isolada e combinada (monômeros, dímeros e oligômeros). A extração sólido-líquido foi realizada utilizando uma solução de etanol a 50% (v/v) e uma razão massa: solvente de 1: 120 em um banho de ultrassom. O PE foi separado em monômeros, dímeros e oligômeros por HPLC usando uma coluna semi-preparativa. Os resultados obtidos mostram que o PE contém 95,35, 7,45 e 21,75 mg EE (equivalentes de epicatequina) / g ds de monômeros, dímeros e oligômeros, respectivamente. Finalmente, o efeito de cada fração na AC foi avaliado usando um modelo de mistura cúbica completo. De acordo com os resultados, a melhor AC foi obtida para os dímeros; no entanto, um efeito antagônico na AC foi observado quando monômeros, dímeros e oligômeros foram misturados.

Evaluación teórica de las propiedades electrónicas y estructurales que afectan a la conductividad eléctrica en copolímeros de furano-tiofeno / Theoretical evaluation of the electronic and structural properties that affect the electrical conductivity in furan-thiophene copolymers / Avaliação teórica das propriedades eletrônicas e estruturais que afetam à condutividade eléctrica em copolímeros de furano-tiofeno

Resumen Desde el punto de vista científico y tecnológico ha habido un gran interés en el uso de monosustituyentes de furano y tiofeno como polímeros conductores, debido a sus múltiples aplicaciones como OLED, amplificadores ópticos, nanotecnología, entre otros. Por ello, el propósito de este trabajo fue estudiar los aspectos teóricos que afectan las propiedades electroconductoras de este tipo de moléculas. Se determinaron teóricamente los aspectos estructurales y electrónicos que influyeron en la conductividad de copolímeros de furano-tiofeno monosustituidos, al utilizar grupos carboxilos, metilos, hidroxilos, ciano y fluoruros como sustituyentes en el carbono C3 y C10 de cada heterociclo. La diferencia de energía entre el LUMO y el HOMO (band gap, Eg) y el potencial de ionización (PI) fue calculada a partir de las geometrías optimizadas en DFT para el estado neutro, anión y catión. Los PI y la Eg de los copolímeros fueron obtenidos mediante la extrapolación de los valores del oligómero a (1/N) y de una cadena de longitud infinita (1/N=0), obteniéndose una correlación lineal (R=0,99), la cual se mantiene a lo largo de todos los modelos de ajuste de cada copolímero analizado en el estudio.

Abstract There has been great scientific and technological interest in the use of mono-substituents of furan and thiophene as conducting polymers due to their multiple applications such as OLED, optical amplifiers and nanotechnology, among others. For this, the purpose of this work was to study the theoretical aspects that affect the electroconductive properties of this type of molecules. The structural and electronic properties that influence the conductivity of mono substituted-furan-thiophene copolymers were determined theoretically. The effect of using carboxyl, methyl, hydroxyl, cyano, and fluoride groups as substituents on the carbon C3 and C10 of each heterocycle was observed. The energy difference between the LUMO and the HOMO (band gap, Eg) and the ionization potential (IP) were calculated from the geometries optimized in DFT for the neutral, anion and cation state. The PI and Eg of the copolymers were obtained by extrapolating the values of the oligomer a (1/N) and a chain of infinite length (1/N=0) for which a linear correlation was obtained (R=0.99). This correlation is maintained throughout all the adjustment models of each copolymer analyzed in the study.

Resumo Existe muito interesse os termos científicos e tecnológicos em utilizar substituintes mono-substituídos furano e tiofeno como polímeros condutores devido às suas múltiplas aplicações, tais como OLED, amplificadores ópticos e nanotecnologia, entre outros. O objetivo deste trabalho foi estudar os aspectos teóricos que afetam as propriedades eletrocondutoras deste tipo de moléculas. Neste contribuição os aspectos estruturais e electrónicas que influenciam a condutividade de copolímeros furano-tiofeno substituos mono teoricamente determinada observando o efeito do uso de grupos carboxilo, metilo, hidroxilo, ciano e fluoretos como substituintes em C3 e C10 de carbono de cada heterociclo. A diferença de energia entre o LUMO e o HOMO (intervalo de banda, Eg) e o potencial de ionização (IP) foram calculadas a partir das geometrias optimizadas de DFT para o estado neutro, anião e catião. O PI e o Eg dos copolímeros foram obtidos por extrapolação dos valores do oligómero (1/N) e extrapolando para uma cadeia de comprimento infinito (1/ N=0) para os quais uma correlação linear foi obtida (R=0,99), que é mantido ao longo de todos os modelos de ajuste de cada copolímero analisados no estudo.

Effects of chaperone-mediated autophagy on the level of α-synuclein oligomers in Parkinson's disease cell model / 上海交通大学学报（医学版）

Objective • To investigate the effects of chaperone-mediated autophagy (CMA) on α-synuclein oligomers level in the Parkinson's disease (PD) cell model with impaired ubiquitin proteasome system (UPS). Methods • The PD cell model was established by adding the proteasome inhibitor lactacystin in the SK-N-SH cell line stably transfected with wild type α-synuclein. The levels of α-synuclein oligomers, lysosome-associated membrane protein type 2A (LAMP2A) and 70 kDa heat shock homologous protein (HSC70) were detected using Western blotting. CMA function was inhibited with LAMP2A siRNA, and its effects on α-synuclein oligomers and cell viability were detected. Furthermore, the interaction of LAMP2A with α-synuclein oligomers was detected by immunoprecipitation. Results • In the PD cell model, the levels of α-synuclein oligomers, and CMA related proteins, i.e. LAMP2A and HSC70, were increased. Inhibiting the expression of LAMP2A further increased α-synuclein oligomers level, while it decreased cell viability. Furthermore, LAMP2A could interact with α-synuclein oligomers. Conclusion • In the PD cell model, CMA is one of the pathways regulating α-synuclein oligomers level. Inhibiting CMA function can further increase the α-synuclein oligomers level and deteriorate cell survival.

Structural insights into Plasmodium falciparum nicotinamide mononucleotide adenylyltransferase: oligomeric assembly

The biochemical pathways involved in nicotinamide adenine dinucleotide (NAD) biosynthesis converge at the enzymatic step catalysed by nicotinamide mononucleotide adenylyltransferase (NMNAT, EC: 2.7.7.1). The majority of NMNATs are assembled into homo-oligomeric states that comprise 2-6 subunits. Recently, the NMNAT of Plasmodium falciparum (PfNMNAT) has been identified as a pharmacological target. The enzymatic characterisation, cellular location, and tertiary structure of the PfNMNAT protein have been reported. Nonetheless, its quaternary structure remains to be explored. The present study describes the oligomeric assembly of the 6 x His-PfNMNAT recombinant protein using immobilised metal affinity chromatography coupled with size exclusion chromatography (SEC) and native protein electrophoresis combined with Ferguson plot graphing. These chromatographic approaches resulted in the elution of an active monomer from the SEC column, whereas the Ferguson plot indicated a dimeric assembly of the 6 x His-PfNMNAT protein.

Aspidosperma subincanum II. Usefulness of uleine and ribonucleic fragments in the treatment of AIDS patients

Aids patients were treated during a year with three different food supplements commercially available: para-pau-aspido (Aspidosperma subincanum Mart. ex A. DC., Apocynaceae); 2Leid (nucleic acids and cytokines); and Para Immuno (propolis, pollen and royal jelly). All foods, given either alone or in combination, proved useful to all AIDS patients who received the supplements, be these under tri-therapy (Triomine: stavudine, lamivudine, névirapine) or left unattended.

In vitro evaluation of anti-Alzheimer effects of dry ginger (Zingiber officinale Roscoe) extract.

As the disease modifying therapies against Alzheimer’s disease (AD) continue to exist as a major challenge of this century, the search for newer drug leads with lesser side effects is on the rise. A large number of plant extracts and phytocompounds are being actively pursued for their anti-Alzheimer effects. In the present study, the antioxidant activity, cholinesterase inhibition, anti-amyloidogenic potential and neuroprotective properties of methanolic extract of dry ginger (GE) have been evaluated. The extract contained 18±0.6 mg/g gallic acid equivalents of total phenolic content and 4.18±0.69 mg quercetin equivalents/g of dry material. GE expressed high antioxidant activity with an IC50 value of 70±0.304 µg/mL in DPPH assay and 845.4±56.62 μM Fe(II) equivalents/g dry weight in FRAP assay respectively. In Ellman’s assay for the cholinesterase inhibitory activity, GE had an IC50 value of 41±1.2 µg/mL and 52±2 µg/mL for inhibition of acetyl- and butyrylcholinesterase respectively. Also, GE increased the cell survival against amyloid β (Aβ) induced toxicity in primary adult rat hippocampal cell culture. Aggregation experiments with the thioflavin T binding studies showed that GE effectively prevented the formation of Aβ oligomers and dissociated the preformed oligomers. These findings suggest that methanolic GE influences multiple therapeutic molecular targets of AD and can be considered as an effective nontoxic neutraceutical supplement for AD.

Amyloid-beta oligomers regulate the properties of human neural stem cells through GSK-3beta signaling

Alzheimer's disease (AD) is the most common cause of age-related dementia. The neuropathological hallmarks of AD include extracellular deposition of amyloid-beta peptides and neurofibrillary tangles that lead to intracellular hyperphosphorylated tau in the brain. Soluble amyloid-beta oligomers are the primary pathogenic factor leading to cognitive impairment in AD. Neural stem cells (NSCs) are able to self-renew and give rise to multiple neural cell lineages in both developing and adult central nervous systems. To explore the relationship between AD-related pathology and the behaviors of NSCs that enable neuroregeneration, a number of studies have used animal and in vitro models to investigate the role of amyloid-beta on NSCs derived from various brain regions at different developmental stages. However, the Abeta effects on NSCs remain poorly understood because of conflicting results. To investigate the effects of amyloid-beta oligomers on human NSCs, we established amyloid precursor protein Swedish mutant-expressing cells and identified cell-derived amyloid-beta oligomers in the culture media. Human NSCs were isolated from an aborted fetal telencephalon at 13 weeks of gestation and expanded in culture as neurospheres. Human NSCs exposure to cell-derived amyloid-beta oligomers decreased dividing potential resulting from senescence through telomere attrition, impaired neurogenesis and promoted gliogenesis, and attenuated mobility. These amyloid-beta oligomers modulated the proliferation, differentiation and migration patterns of human NSCs via a glycogen synthase kinase-3beta-mediated signaling pathway. These findings contribute to the development of human NSC-based therapy for AD by elucidating the effects of Abeta oligomers on human NSCs.

Progress in Molecular Mechanisms of ?-amyloid Peptides in Alzheimer's Disease / 生物化学与生物物理进展

The pathological presentation of Alzheimer disease (AD), the leading cause of senile dementia, involves regionalized neuronal death and an accumulation of intraneuronal and extracellular filaments termed neurofibrillary tangles and senile plaques, respectively. One of the ?-amyloid peptides (A?), the A?1-42 form, is primarily responsible for neuronal damage and cell death that is the main component in the senile plaques. Over the past twenty years, the amyloid hypothesis has been strongly supported by a wealth of evidence, including data from genetic studies of Alzheimer disease. Amyloid cascade hypothesis states that the accumulation and deposition of fibrillar A? is the primary driver of neurodegeneration and cognitive decline leading to dementia. AD is a clinicopathological syndrome in which different gene defects can lead--directly or indirectly--to alter APP expression or proteolytic processing as such to change A? stability or aggregation. These result in a chronic imbalance between A? production and clearance. Gradual accumulation of aggregated A? initiates a complex, multistep cascade that includes gliosis, inflammatory changes, neuritic/synaptic change, tangles and transmitter loss. The evidence that links A? to the pathogenesis of AD is substantial, but the means by which these peptides exert their toxic effects, and where in neuronal cells they act, is far from clear. The up-to-date proceeding in the molecular mechanism of ?-amyloid peptides is overviewed.

Progress in soluble A? oligomers in Alzheimer's disease and drugs targeting A? oligomers / 中国药理学通报

A? plays a crucial role in Alzheimer's Disease and the soluble A? oligomers have been recognized as the emerging neurotoxins,which ultimately cause memory impairment and neuronal loss through different mechanisms.The development of novel drugs targeting A? oligomers indicates new and promising therapy approaches for AD.The pathological roles as the proximal toxins in AD and the compounds,targeting soluble A? oligomers,which are currently in preclinical and early clinical development,are reviewed.

PREPARATION OF CHITIN/CHITOSAN OLIGOMERS / 中国海洋药物

Chitin/Chitosan oligomers were prepared by the concentrated hydrochloric acid or enzymatic hydrolysis with chitinase and chitosanase and its transglycosylation reaction. Their preparation,isolation and analytical methods are reviewed.

Interaction of aromatic ionen oligomers with DNA.

A novel polycationic ionen was synthesized and fractionated on carboxymethyl- Sephadex using a salt gradient in 7M urea. A series of oligomers of discrete length were characterised by ultraviolet spectra. The ultraviolet spectra of oligomers revealed a new band centred at 232.5 nm which was probably due to exciton splitting. Thermal denaturation studies indicated both stabilization of the helix conformation and a higher degree of cooperativity in the melting of DNA (oligomers)n complex as compared to native calf thymus DNA. Ionen oligomers exhibited large extrinsic Cotton effect at 232.5 nm which could be attributed to exciton interaction.