Extraction, rapid preparation and neuroprotective effect of texasin, a main active constituent from Caragana jubata (Pall.) Poir.

Searching for new anti-ischemic stroke (anti-IS) drugs has always been a hot topic in the pharmaceutical industry. Natural products are an important source of discovering anti-IS drugs. The aim of the present study is to extract, rapidly prepare and explore the neuroprotective effect of texasin, a main active constituent from Caragana jubata (Pall.) Poir., which is a kind of Tibetan medicine with a clear anti-IS effect. The results showed that 95% ethanol was the optimal extraction solvent. A three-step rapid preparation method for texasin was successfully established, with a purity of 99.2%. Texasin at the concentration of 25-100 µM had no effect on the viability of normal cultured PC12 cells; 12.5 and 25 µM texasin could enhance the viability of PC12 cells damaged by oxygen and glucose deprivation/reoxygenation (OGD/R), and their effects are comparable to the positive drug edaravone at the concentration of 50 µM. Compared with the normal group, the expression of Bcl-2 protein in OGD/R-injured PC12 cells was downregulated (p < 0.01), and that of PERK, eIF2α, ATF4, CHOP, Bax and Cleaved caspase-3 proteins were upregulated (p < 0.01, p < 0.001). Compared with the OGD/R group, 25 µM texasin could upregulate the expression of Bcl-2 protein (p < 0.01), and downregulate that of PERK, eIF2α, ATF4, CHOP, Bax and Cleaved caspase-3 proteins (p < 0.01, p < 0.001). The 7-OH and 1-O of texasin formed H-bonds with residues Cys891 of the hinge ß-strand of PERK, which is crucial for kinase inhibitors. The above results suggest that the method established in the present study achieved rapid preparation of high-purity texasin. Texasin might inhibit neuronal apoptosis via the regulation of endoplasmic reticulum stress PERK/eIF2α/ATF4/CHOP signalling pathway to exert a protective effect on OGD/R-injured PC12 cells. Aiding by molecular docking, texasin was assumed to be a potential PERK inhibitor.

Comparative Study of the Oxidation Stability of High Oleic Oils and Palm Oil during Thermal Treatment.

For the controversy still existed about the oxidation stability of the high oleic oils compared with palm oil (PO), this study was aimed to explore the possible reason causing the controversies. Total polar compounds (TPC) was used to evaluate the oxidation stability of oils. Results showed there exist two kinds of lineal changes about the content of total polar compounds (TPC) in each oil, which were closely linked with the fatty acid composition and the tocochromanols content. The possible influence of the initial quality of oils also should be considered. The TPC of high oleic peanut oil (HOPO), high oleic sunflower oil (HOSO), high oleic rapeseed oil (HORO) and PO increased slowly at the initial period mainly owing to the antioxidation of tocochromanols, then sharply after 24, 48, 36 and 72 h respectively, when tocochromanols in each oil almost reduced below the detection limit. After that, the major factor would be fatty acids, particularly PUFA. It showed that the major tocochromanols in different oils (e.g. α, γ-tocotrienols in PO, α, γ-tocopherols in HORO and HOPO, and α-tocopherols in HOSO), could impose the main effects of inhibiting the TPC generation in the initial thermal treatment. The TPC in HORO significantly increased after 84 hours of heat process, which might be caused by the higher content of the polyunsaturated fatty acids (PUFA) (i.e. C18:2 and C18:3). However, the content of the saturated fatty acid (SFA) did not show statistically significant change during the thermal treatment.

Facile Separation of 5-O-Galloylquinic Acid from Chinese Green Tea Extract using Mesoporous Zirconium Phosphate.

INTRODUCTION: 5-O-Galloylquinic acid from green tea and other plants is attracting increasing attention for its antioxidant and antileishmanial bioactivities. It is always isolated using a silica column, a Sephadex column and high-performance liquid chromatography (HPLC) methods, which are either laborious or instrument dependent. OBJECTIVE: To develop a new method to easily separate 5-O-galloylquinic acid. METHODOLOGY: Mesoporous zirconium phosphate (m-ZrP) was prepared to conveniently separate 5-O-galloylquinic acid from Chinese green tea extract, and the target compound was easily obtained by simple steps of adsorption, washing and desorption. The effects of the green tea extraction conditions, extract concentrations, and m-ZrP adsorption/desorption dynamics on the 5-O-galloylquinic acid separation were evaluated. RESULTS: 5-O-Galloylquinic acid that was separated from a 70% ethanol extract of green tea was of moderate HPLC purity (92%) and recovery (88%), and an increased non-specific binding of epigallocatechin gallate (EGCG) on m-ZrP was observed in the diluted tea extract. The times for maximal adsorption of 5-O-galloylquinic acid in 70% ethanol extract and maximal desorption of 5-O-galloylquinic acid in 0.4% phosphoric acid solution were confirmed as 7 h and 5 h, respectively. CONCLUSION: A facile method to separate 5-O-galloylquinic acid from Chinese green tea extract using m-ZrP was established. Copyright © 2016 John Wiley & Sons, Ltd.