Evaluation of cross-linkers in the design of immobilized multi isomerase cascade for the preparation of rare sugars.

The cascade of sugar isomerases is one of the most practical methods for producing rare sugars, and enzyme immobilization endows it with high economic efficiency, operational convenience and reusability. However, the most employed cross-linker glutaraldehyde (GA) has the disadvantages of enzyme deactivation and limitation of substrate binding. Herein, three compounds, glyoxal, GA, and 2,5-furandicarboxaldehyde (DFF) were evaluated within a previously developed cascade comprising ribose-5-phosphate isomerase and D-tagatose-3-epimerase to prepare D-ribulose form D-xylose.

Mitochondria in Neuroprotection by Phytochemicals: Bioactive Polyphenols Modulate Mitochondrial Apoptosis System, Function and Structure.

In aging and neurodegenerative diseases, loss of distinct type of neurons characterizes disease-specific pathological and clinical features, and mitochondria play a pivotal role in neuronal survival and death. Mitochondria are now considered as the organelle to modulate cellular signal pathways and functions, not only to produce energy and reactive oxygen species. Oxidative stress, deficit of neurotrophic factors, and multiple other factors impair mitochondrial function and induce cell death.

Rapid on-site dual optical system to measure specific reactive oxygen species (O2-• and OCl-) in a tiny droplet of whole blood.

Oxidative stress has been implicated in various disorders and controlling it would be important for healthy life. We have developed a new optical system for easily and accurately measuring oxidative stress in whole blood. It is optimized for simultaneously detecting reactive oxygen species (ROS) and highly reactive ROS (hROS), elicited mostly by white blood cells in a few microliters of blood.

Phytochemicals prevent mitochondrial membrane permeabilization and protect SH-SY5Y cells against apoptosis induced by PK11195, a ligand for outer membrane translocator protein.

Epidemiological studies present the beneficial effects of dietary habits on prevention of aging-associated decline of brain function. Phytochemicals, the second metabolites of food, protect neuronal cells from cell death in cellular models of neurodegenerative disorders, and the neuroprotective activity has been ascribed to the anti-oxidant and anti-inflammatory functions. In this paper, the cellular mechanism of neuroprotection by phytochemicals was investigated, using the cellular model of mitochondrial apoptosis induced by PK11195, a ligand of outer membrane translocator protein, in SH-SY5Y cells.

Rasagiline prevents cyclosporine A-sensitive superoxide flashes induced by PK11195, the initial signal of mitochondrial membrane permeabilization and apoptosis.

Rasagiline, a neuroprotective inhibitor of type B monoamine oxidase, prevented PK111195-induced apoptosis in SH-SY5Y cells through inhibition of mitochondrial apoptosis signaling (J Neural Transm 120:1539-1551, 2013, J Neural Transm 122:1399-1407, 2015). This paper presents that PK11195 induced superoxide flashes, the transit production burst, mediated by cyclosporine A-sensitive membrane permeability transition. Rasagiline prevented superoxide flashes, calcium efflux, and cell death by PK11195.

Kopsiyunnanines J1 and J2, new strychnos-type homo-monoterpenoid indole alkaloids from Kopsia arborea.

Two new indole alkaloids, kopsiyunnanines J1 and J2, were isolated from Yunnan Kopsia arborea, and their structures were determined by spectroscopic analyses. Kopsiyunnanines J1 and J2 are unprecedented Strychnos-type indole alkaloids having an additional C1 unit in the secologanin moiety of the molecule.

Rasagiline and selegiline suppress calcium efflux from mitochondria by PK11195-induced opening of mitochondrial permeability transition pore: a novel anti-apoptotic function for neuroprotection.

Rasagiline and selegiline, inhibitors of type B monoamine oxidase (MAO-B), protect neurons from cell death in cellular and animal models. Suppression of mitochondrial membrane permeabilization and subsequent activation of apoptosis cascade, and induction of anti-apoptotic, pro-survival genes are proposed to contribute the anti-apoptotic function. Rasagiline suppresses neurotoxin- and oxidative stress-induced membrane permeabilization in isolated mitochondria, but the mechanism has been not fully clarified.

Asymmetric total synthesis of novel pentacyclic indole alkaloid, kopsiyunnanine E, isolated from Kopsia arborea.

A new pentacyclic indole alkaloid, kopsiyunnanine E, was isolated from Yunnan Kopsia arborea, and its structure, which was inferred from spectroscopic data, was established by a 16-step asymmetric total synthesis that proved that the natural alkaloid was not enantiomerically pure.

Genetic and chemical characterization of white and red peony root derived from Paeonia lactiflora.

Two kinds of peony roots--white peony root (WPR) and red peony root (RPR)--are used for different remedies in traditional Chinese medicine; however, most of them are derived from the same botanical origin, Paeonia lactiflora. The difference between WPR and RPR has been debated for a long time. This study attempted to clarify the genetic and chemical characteristics of WPR and RPR in order to provide a scientific dataset for their identification and effective use.

Two new aspidosperma indole alkaloids from Yunnan Kopsia arborea.

Two new indole alkaloids, kopsiyunnanines G (1) and H (2), possessing the Aspidosperma skeleton were isolated from the aerial part of Yunnan Kopsia arborea BLUME (Apocynaceae). Their structures and stereochemistry were elucidated by means of MS and 2D NMR analyses.

Kopsiyunnanines F and isocondylocarpines: new tubotaiwine-type alkaloids from Yunnan Kopsia arborea.

Five new alkaloids, including three 19,20-epoxytubotaiwine stereoisomers, viz. kopsiyunnanines F1 (1), F2 (2), and F3 (3), (Z)-isocondylocarpine (4), and (Z)-isocondylocarpine N-oxide (5), along with five known tubotaiwine-type indole alkaloids were isolated from the aerial part of Yunnan Kopsia arborea Blume (Apocynaceae). Their structures including absolute configurations were elucidated by spectroscopic and chemical means.

Rhazinilam and quebrachamine derivatives from Yunnan Kopsia arborea.

Three new rhazinilam-derived alkaloids, kopsiyunnanines C1, C2, and C3, and a new quebrachamine-type alkaloid, kopsiyunnanine D, which possess an unusual methoxymethyl or ethoxymethyl function, were isolated from the aerial parts of Yunnan Kopsia arborea. This is the first report of the presence of these functions in natural alkaloids. The structures and absolute configurations of the alkaloids were determined by spectroscopic methods and confirmed by semisynthesis.