A protocol using trifluoroacetic acid at a temperature of 60 °C is developed for the adequate removal of the stationary phase of reversed-phase liquid chromatography (RPLC) columns. This procedure allows for studying the same column first under RPLC and subsequently under hydrophilic-interaction liquid chromatography (HILIC) conditions to isolate intrinsic differences between mass transfer properties in HILIC and RPLC from differences in packing quality. The established procedure allows for a complete removal of the stationary phase (confirmed by retention studies and thermogravimetry analyses) while leaving the structure of the packing unaffected (witnessed by an unchanged external porosity and pressure drop). Accurate plate height analysis comparing compounds at the same zone retention factor indicates a significant difference in reduced c-term (typically 40-80% larger under HILIC conditions), despite the columns otherwise being identical. Correcting for the known contributions of longitudinal diffusion (b-term) and mass transfer (cm- and cs-term) to focus on band broadening originating from eddy dispersion, similar strong differences are observed (differences of some h = 0.3 up to 1.2). These findings show that the interior structure and retention mechanism of the particles have a very strong effect on the observed eddy dispersion, a factor typically ascribed to phenomena occurring outside the particles. This also implies that comparing the quality of packings of different particle types is virtually impossible without the availability of a sound model to correct for the intraparticle effect on the observed eddy dispersion.

Evaluation of the Kinetic Performance Differences between Hydrophilic-Interaction Liquid Chromatography and Reversed-Phase Liquid Chromatography under Conditions of Identical Packing Structure

Egg yolk phosphatidylcholine: Extraction, purification and its potential neuroprotective effect on PC12 cells

Although phosphatidylethanolamine (PE) is an important functional phospholipid, there have been very few reports on its antioxidant activity and corresponding molecular composition. Crude PE was extracted from egg yolk with various solvents, and response surface modeling was carried out to determine the optimum extraction conditions for PE, under which the PE content in extracts reached 58.94 µg/mL. The crude PE was purified using silica gel-based column chromatography. High-purity PE (98%), identified by high-performance liquid chromatography-evaporative light-scattering detector, was obtained using isocratic elution with a mixed solvent (chloroform: methanol: acetic acid = 18:5:1) eluent. PE purified from egg yolk exhibited high radical-scavenging activity, determined by electron paramagnetic resonance (EPR). The result was attributed to the high unsaturated fatty acids (83.10%) content in egg yolk PE, and the unsaturated fatty acids were identified as PE-16:0/18:1Δ9 , PE-16:0/18:2Δ9,12 , PE-16:0/20:4Δ5,8,11,14 , PE-18:0/18:1Δ9 , PE-18:0/18:2Δ9,12 , and PE-18:0/20:4Δ5,8,11,14 by MALDI-TOF MS combined with gas chromatography mass spectrometry. PRACTICAL APPLICATION: In this work, an attempt has been made to explore the antioxidant activity of PE that extracted and purified from egg yolk and its corresponding molecular composition. Owing to its plentiful unsaturated fatty acids (83.10%), purified PE from egg yolk exhibited a high radical-scavenging activity that indicated that egg-yolk PE had a strong antioxidant activity, and it might exert possible beneficial effects on the human health.; © 2019 Institute of Food Technologists®.

Egg Yolk Phosphatidylethanolamine: Extraction Optimization, Antioxidative Activity, and Molecular Structure Profiling.

Vaccinium uliginosum L. is a wild fruit tree, mainly distributed in the extremely cold climate region of China, such as the Greater Khingan Mountains, Lesser Khingan Mountains, and Changbai Mountains. Most fruit trees are largely unsustainable in these regions, but wild V. uliginosum thrives in the region. Therefore, it is necessary to protect the precious wild V. uliginosum resources. With the effect of global warming, the suitable habitat of V. uliginosum has also changed. A total of 287 pieces of data with 22 environmental variables were collected on the geographical distribution of wild V. uliginosum. The Maxent model was applied to predict the potential distribution of V. uliginosum in China under different climate scenarios (Socioeconomic Pathways 1-2.6 (SSP1-2.6), SSP2-4.5, SSP3-7.0 and SSP5-8.5) in the current and future two periods (the 2050s and 2070s). The predicted results show that the distribution and area of the suitable area-change range is small. The results show that the cumulative contribution rates of BIO07 (annual temperature range), BIO12 (annual precipitation), and BIO10 (mean temperature of warmest quarter) reach 74.1%, indicating that temperature and precipitation are the key factors affecting the distribution of V. uliginosum. This study can provide a reference for relevant departments to take conservation measures with respect to climate change and the adaptation of V. uliginosum to habitat changes.

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Prediction of the Potential Distribution of Vaccinium uliginosum in China Based on the Maxent Niche Model

Introduction Medicinal plants have been considered as potential source of therapeutics or as starting materials in drugs formulation. Methods The current study aims to shed light on the therapeutic potential of the Amomum subulatom and Amomum xanthioides Fruits by analyzing the phytochemical composition of their seeds and fruits using gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC) techniques to determine the presence of bioactive components such as flavonoids, phenols, vitamins, steroids, and essential oils. Results and Discussion The protein content is usually higher than the total lipids in both species except the fruit of A. subulatum which contain more lipids than proteins. The total protein contents for A. subulatum were 235.03 ± 21.49 and 227.49 ± 25.82 mg/g dry weight while for A. xanthioides were 201.9 ± 37.79 and 294.99 ± 37.93 mg/g dry weight for seeds and fruit, respectively. The Carvacrol levels in A. subulatum is 20 times higher than that in A. xanthioides. Lower levels of α-Thujene, Phyllanderenes, Ascaridole, and Pinocarvone were also observed in both species. According to DPPH (2,2-diphenylpicrylhydrazyl) assay, seed the extract of A. subulatum exhibited the highest antioxidant activity (78.26±9.27 %) followed by the seed extract of A. xanthioides (68.21±2.56 %). Similarly, FRAP (Ferric Reducing Antioxidant Power) assay showed that the highest antioxidant activity was exhibited by the seed extract of the two species; 20.14±1.11 and 21.18±1.04 µmol trolox g−1 DW for A. subulatum and A. xanthioides, respectively. In terms of anti-lipid peroxidation, relatively higher values were obtained for the fruit extract of A. subulatum (6.08±0.35) and the seed extract of A. xanthioides (6.11±0.55). Ethanolic seed extracts of A. subulatum had the highest efficiency against four Gram-negative bacterial species which causes serious human diseases, namely Pseudomonas aeruginosa, Proteus vulgaris, Enterobacter aerogenes, and Salmonella typhimurium. In addition, P. aeruginosa was also inhibited by the fruit extract of both A. subulatum and A. xanthioides. For the seed extract of A. xanthioides, large inhibition zones were formed against P. vulgaris and the fungus Candida albicans. Finally, we have in silico explored the mode of action of these plants by performing detailed molecular modeling studies and showed that the antimicrobial activities of these plants could be attributed to the high binding affinity of their bioactive compounds to bind to the active sites of the sterol 14-alpha demethylase and the transcriptional regulator MvfR. Conclusion These findings demonstrate the two species extracts possess high biological activities and therapeutical values, which increases their potential value in a number of therapeutic applications.

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Insight into the phytochemical profile and antimicrobial activities of Amomum subulatum and Amomum xanthioides: an in vitro and in silico study

Crude phosphatidylcholine (PC) was extracted with ethanol from egg yolk, and an L9(34) orthogonal array experimental design was set up to optimize the solvent extraction conditions. Subsequently, semipreparative hydrophilic interaction liquid chromatography (HILIC) was explored to purify the crude extract on a homemade silica column. The purity of PC prepared in this way can reach up to 93.96%, with rapid separation.

Jia-Huan Wang

Papers

Isolation and Purification of Phosphatidylcholine from Egg Yolk by Semipreparative Hydrophilic Interaction Liquid Chromatography

The possible future changes in potential suitable habitats of Tetrastigma hemsleyanum (Vitaceae) in China predicted by an ensemble model