High efficiency preparation of standard grade γ-tocopherol in plant-scale and its antioxidant activity

Natural standard grade γ-tocopherol are of great interest due to its good antioxidant activity and special pharmacological functions. This study separated and purified γ-tocopherol from mixed tocopherols using eco-friendly and low toxicity solvents. 0.28 g γ-tocopherol was obtained per performance with a purity of 98.89 ± 0.68% and a recovery yield of 93.23 ± 0.89%. The purification conditions were as follows: elution solvent n-hexane/ethyl acetate 94.5:5.5 (v/v), sample load size 0.5 g, a column height to diameter ratio of 16:1 and an elution rate of 2 mL/min. The purity and structure of γ-tocopherol was confirmed by HPLC, GC/MS and NMR. The adsorption isotherm of γ-tocopherol on silica gel (200-300 mesh) fitted the Langmuir isotherm model well. The antioxidant activity analysis showed that γ-tocopherol had the strongest antioxidant activity followed by δ-tocopherol and α-tocopherol. This study provides an economically attractive solution for the production of natural standard grade γ-tocopherol.

Extraction and Purification of Anthocyanins from Sorbus Pohuashanensis Fruits

The aim of this study was to isolate anthocyanins from Sorbus pohuashanensis. Anthocyanins were extracted from Sorbus pohuashanensis using enzyme hydrolysis and were further purified using macroporous resins. The optimal extraction con�ditions were investigated using single-factor experiments and an orthogonal experiment, respectively. The extraction yield was 15.33 � 0.05% under optimal conditions of pH 3.0, pectinase 0.15%, 50�C and 2.5 h. Subsequently, three types of macroporous resins, namely D101, D201, D301R, were in turn applied to purify anthocyanins by adsorption and elution. The D101 resin showed an adsorption rate of 93.75% and an elution rate of 45.33%. The best elution parameters were at 25�C, 85% ethanol, and pH 4.0 to achieve a purity of 61.93%. This study provided an efficient, sustainable, low-cost anthocyanin extraction method.

Nicotinic acid in nanocontainers. Encapsulation and release from ion exchangers

The paper is devoted to the study of the ion exchange encapsulation of nicotinic acid in nanocontainers on polymer matrices. Dowex-50 cation exchanger, sulphonated polymer based on metacyclophanoctol, polymer zirconium phosphate, and strongly basic Dowex-1 anion exchanger are used as polymer matrices. It was confirmed that commercial ion exchangers can encapsulate up to 0.64 g of nicotinic acid per gram of polymer. The high elution rate of nicotinic acid from nanocontainers via the ion exchange mechanism makes it possible to achieve the desired pharmacokinetics of drug release in vivo.

Evaluation of Elution Behavior of Silver Ions from Silver-Containing Carbonate Hydroxyapatite Composites

Infection related to orthopedic implant surgeries is one of the significant postoperative complications. Recently, many studies have been conducted on silver-containing hydroxyapatite (AgHA) composites as antibacterial and osteoconductive biomaterials to prevent postoperative infection. In this study, we prepared 1 and 10 wt% Ag-containing carbonate hydroxyapatite composites (1AgCHA and 10AgCHA, respectively) by solid-phase reaction, and investigated the relation between the elution rate of Ag ions from the composites and the chemical or physical states of Ag in AgCHA. X-ray diffraction (XRD) and scanning electron microscopy (SEM) results indicated that metallic Ag particles disappeared in 1AgCHA heated at 800°C, whereas they were distributed in 10AgCHA heated at all temperatures. The amount of A-type CO32-group in AgCHA structure drastically increased at 800°C, but decreased with increasing amount of Ag. The lattice constant (a-axis) of hydroxyapatite expanded drastically when heated at 800°C, and with increasing Ag content, the extent of expansion of a-axis decreased as well as amount of A-type CO32-in CHA. Moreover, after the 48-h elution test, the concentration of Ag+released from 10AgCHA heated at 800°C was less than 0.1% of total Ag amounts, while 1AgCHA heated at 800°C released over 0.8% of total Ag amounts. The results indicate that Ag+and CO32-were substituted competitively into the Ca2+and OH-sites of HA, respectively, after heating at 800°C, and that the elution rate of Ag+from the sites of Ag+-substituted CHA was faster than that from metallic Ag particles. A better understating of the elution behavior of Ag from AgCHA is important for controlling the physical and chemical states of Ag in composites.