Yawei Fan

Isolation and purification of three flavonoid glycosides from the leaves of Nelumbo nucifera (Lotus) by high-speed counter-current chromatography.

Semi-preparative high-speed counter-current chromatography (HSCCC) was successfully used for isolation and purification of flavonoid glycosides from the leaves of Nelumbo nucifera (Lotus) by using a two-phase-solvent system composed of n-hexane-ethyl acetate-methanol-water (1:5:1:5, v/v/v/v). The targeted compounds isolated, collected and purified by HSCCC were analyzed by high performance liquid chromatography (HPLC). A total of 4.6 mg of isoquercitrin, 9.1 mg of hyperoside and 3.0 mg of astragalin with the purity of 95.8%, 97.5% and 98.3%, respectively, were obtained in one-step separation and less than 6 h from 80 mg of crude extract from the leaves of N. nucifera. The chemical structures of all the three compounds were identified by MS, (1)H NMR, (13)C NMR. Astragalin was obtained from N. nucifera for the first time.

Evaluating and Predicting the Oxidative Stability of Vegetable Oils with Different Fatty Acid Compositions

The aim of this research was to evaluate the oxidative stabilities and qualities of different vegetable oils (almond, blend 1-8, camellia, corn, palm, peanut, rapeseed, sesame, soybean, sunflower, and zanthoxylum oil) based on peroxide value (PV), vitamin E content, free fatty acid, and fatty acid composition. The vegetable oils with different initial fatty acid compositions were studied under accelerated oxidation condition. It showed that PV and n-3 polyunsaturated fatty acid (PUFA) changed significantly during 21 d accelerated oxidation storage. Based on the changes of PV and fatty acid composition during the oxidation process, mathematical models were hypothesized and the models were simulated by Matlab to generate the proposed equations. These equations were established on the basis of the different PUFA contents as 10% to 28%, 28% to 46%, and 46% to 64%, respectively. The simulated models were proven to be validated and valuable for assessing the degree of oxidation and predicting the shelf life of vegetable oils.

Qualitative and Quantitative Analysis of Phenolics in Tetrastigma hemsleyanum and Their Antioxidant and Antiproliferative Activities

The phenolic profiles of Tetrastigma hemsleyanum leaf extracts by different solvents (80% methanol, ethyl acetate and hexane) and their antioxidant and antiproliferative activities were investigated. Thirteen phenolic compounds (3-caffeoylquinic acid, 5-caffeoylquinic acid, 1-caffeoylquinic acid, 5-p-coumaroylquinic acid, isoorientin-2″-O-rhamnoside, isoorientin, orientin-2″-O-rhamnoside, orientin, 1-p-coumaroylquinic acid, vitexin-2″-O-rhamnoside, isovitexin-2″-O-rhamnoside, vitexin and isovitexin) were identified in T. hemsleyanum leaves for the first time, and six of them were quantified using a combination of LC-QTOF-MS and LC-QqQ-MS techniques. It was found that 80% methanol extract exhibited the highest antioxidant activities (DPPH, 3.32 mmol of Trolox/g DW; ABTS, 1.38 mmol of Trolox/g DW; FRAP, 1.85 mmol of FeSO4/g DW), while the hexane extract had the lowest (1.23, 0.43 and 0.13, respectively). Total phenolic contents (TPC) of various extracts of T. hemsleyanum leaves ranged from 28.95 to 275.71 mg of GAE/g DW. Also, total antioxidant activities as evaluated by ABTS, FRAP and DPPH assays were correlated well with TPC. In addition, 80% methanol extract provided antiproliferative activity on HepG2 cells (IC50 = 524 μg/mL). This paper provides a complete picture of phenolics in T. hemsleyanum leaves and relates them to their antioxidant and antiproliferative activities.

Stereospecific Analysis of Triacylglycerol and Phospholipid Fractions of Five Wild Freshwater Fish from Poyang Lake

The fatty acids (FA) compositions and positional distributions in triacylglycerols (TAG) and phospholipids (PL) of five wild freshwater fish (Squaliobarbus curriculus, Erythroculter ilishaeformis, Pseudobagrus fulvidraco, Bostrichthys sinensis, and Siniperca kneri Garman) from Poyang Lake (the largest freshwater lake of China) were studied. For TAG, S. kneri German had the highest content (13.59%) of n - 3 polyunsaturated fatty acids (PUFA) and E. ilishaeformis had the lowest ratio of (n - 6)/(n - 3) (0.65). PL had a high content of PUFA, which declined in the order of phosphatidylethanolamine (PE) > phosphatidylcholine (PC) > TAG. 9c11t-18:2 accounted for 6.38-50.77% of total conjugated linoleic acids (CLA). The highest level of odd-branched chain fatty acids (OBCFA) was 26.7% in B. sinensis. The study revealed that the distribution of FA among the sn positions was not random: monounsaturated fatty acids (MUFA) and PUFA preferred positions 1 and 3 and saturated fatty acids (SFA) position 2 of TAG, while SFA and MUFA predominated over sn-1-PL and PUFA over sn-2-PL.

Characterization of Medium-Chain Triacylglycerol (MCT)-Enriched Seed Oil from Cinnamomum camphora (Lauraceae) and Its Oxidative Stability

Medium-chain triacylglycerol (MCT)-enriched oil was extracted by supercritical fluid extraction of carbon dioxide (SFE-CO(2)) from Cinnamomum camphora seeds. The SFE-CO(2) process was optimized using the Box-Behnken design (BBD). The maximum oil yield (42.82%) was obtained under the optimal SFE-CO(2) conditions: extraction pressure, 21.16 MPa; extraction temperature, 45.67 °C; and extraction time, 2.38 h. Subsequently, the physicochemical characteristics, fatty acid composition, triacylglycerol (TAG) composition, tocopherol content, and DSC profile as well as oxidative stabilities of C. camphora seed oil (CCSO) were studied. Results showed that CCSO contained two major medium-chain fatty acids, capric acid (53.27%) and lauric acid (39.93%). The predominant TAG species in CCSO was LaCC/CLaC (ECN 32, 79.29%). Meanwhile, it can be found that CCSO had much higher oxidative stabilities than coconut oil due to the higher content of tocopherols in CCSO (α-tocopherol, 8.67 ± 0.51 mg/100 g; γ-tocopherol, 22.6 ± 1.02 mg/100 g; δ-tocopherol, 8.38 ± 0.47 mg/100 g). Conclusively, CCSO with such a high level of MCTs and high oxidative stabilities could be potentially applied in special food for specific persons such as weak patients and overweight persons because oils enriched in MCTs can be rapidly absorbed into body to provide energy without fat accumulation.

Novel approach to evaluate the oxidation state of vegetable oils using characteristic oxidation indicators.

Four vegetable oils with typical fatty acid compositions were chosen to determine their indicators of lipid oxidation under the conditions of accelerated oxidation. Good linear correlations were observed between the total nonpolar carbonyl amount and the total oxidation value (TOTOX, R(2) = 0.89-0.97) or peroxide value (POV, R(2) = 0.92-0.97) during 35 days of accelerated oxidation. Additionally, nonanal in camellia oil (oleic acid mainly) increased significantly, and correlated linearly with TOTOX (21.6 TOTOX - 595, R(2) = 0.92); propanal increased significantly in perilla oil (linolenic acid mainly) and correlated linearly with TOTOX (8.10 TOTOX + 75.0, R(2) = 0.90). Hexanal (9.56 TOTOX + 913, R(2) = 0.90, and 7.10 TOTOX + 342, R(2) = 0.78, respectively) and nonenal (10.5 TOTOX + 691, R(2) = 0.95, and 6.65 TOTOX + 276, R(2) = 0.84, respectively) in sunflower oil (linoleic acid mainly) and palm oil (palmitic and oleic acids mainly) also had good linear correlations with TOTOX. Considering the change patterns of these four aldehydes, it was found that the oxidation stability was in the order sunflower oil < camellia oil < perilla oil < palm oil, which was same as POV, TOTOX, and total nonpolar carbonyls. It was concluded that the four aldehydes nonanal, propanal, hexanal, and nonenal could be used as oxidation indicators for the four types of oils.

Predictable effects of dietary lipid sources on the fatty acids compositions of four 1-year-old wild freshwater fish from Poyang Lake.

The descriptors linking dietary and fish fatty acids (FAs) compositions in four 1-year-old wild freshwater fish, Mylopharyngodon piceus, Ctenopharyngodon idella, Hypophthalmichthys molitrix, and Hypophthalmichthys nobilis, from Poyang Lake were studied. M. piceus mainly feeding on crustaceans had the highest relation of polyunsaturated fatty acids (PUFAs; r = 0.812) and odd-branched chain fatty acids (OBCFAs; r = 0.742) with spiral shells. Correlations between C. idella (herbivore) and aquatic plants (PUFAs, r = 0.995; OBCFAs, r = 0.783) were higher than other diet sources. The strongest correlation for PUFAs (r = 0.972) between H. molitrix (filter feeder with phytoplankton-feeding preference) and phytoplanktons was observed, followed by zooplanktons, whereas H. nobilis (filter feeder with zooplankton-feeding preference) showed the highest association with zooplanktons for PUFAs (r = 0.895). The high retainment of dietary FAs in fish body highlighted the potential for tailoring cultured fish FAs. The preferential distributions of n-3 long-chain PUFAs in sn-2-triacylglycerols and sn-2-phospholipids made fish an alternative for inland people supplementing n-3 PUFAs.

Lipid Rafts and Fas/FasL Pathway May Involve in Elaidic Acid-Induced Apoptosis of Human Umbilical Vein Endothelial Cells

Our previous study showed that trans-fatty acids can cause apoptosis of endothelial cells through the caspase pathway and the mitochondrial pathway. The objective of this study was to explore how trans-fatty acids activate the caspase pathway, whether there exist specific receptors induced apoptosis by comparing normal cells and non-rafts cells treated with elaidic acid (9t18:1) and oleic acid (9c18:1), respectively. Compared to normal cells treated with 9t18:1, the cell viability increased by 13% and the number of apoptotic cells decreased by 3% in non-rafts cells treated with 9t18:1 (p < 0.05), and the expression levels of pro-apoptotic proteins such as caspase-3, -8, -9, Bax, and Bid decreased, and expression of antiapoptotic protein Bcl-2 increased (p < 0.05). In addition, Fas/FasL expression in cell membrane decreased significantly (p < 0.05). In conclusion, the lipid rafts and Fas/FasL pathway may involve in 9t18:1-induced apoptosis of human umbilical vein endothelial cells.

Separation of Phospholipids from Hen Egg Yolk by Short Packed Silica Gel Column Chromatography

Short packed silica gel column chromatography has been performed to optimize the production of phosphatidylethanolamine (PE) and phosphatidylcholine (PC) from hen egg yolk with very low or no toxic solvents. The effects of silica type, sample loading amount, dimension of the glass chromatotube, and mobile phase compositions were investigated and high separation efficiency was achieved: gradient elution as 200 mL ethanol followed by 300 mL 95% ethanol to fractionate PE and PC after neutral lipids (NL) removed by 120 mL ethyl acetate, 40 mm silica gel (54 to 74 μm) bed height of the chromatotube with 22 mm inner dia (ID), and 0.25 g sample loading amount. By this procedure, 3.69 g PE and 2.88 g PC per 100 g egg yolk lipids were obtained, respectively. The refined PE and PC were identified by high-performance liquid chromatography/ultraviolet detector (HPLC-UV) with purity over 96%. The fatty acids in egg yolk revealed that PE and PC characterized higher ratios of n- 6/n- 3 (PE, 7.41; PC, 8.99). 18:2 n- 6 of PC (15.21%) predominated over PE (10.29%), whereas the level of 20:4 n- 6 of PC (8.78%) was lower than PE (15.67%).

Preparation and crystal structure of genistein benzenesulfonate prodrugs

In order to improve bioavailability and anticancer activity of genistein, a series of novel sulfonic acid ester prodrugs of the isoflavone genistein were synthesised in high yield with excellent regioselectivity. Their structures were characterised by IR, MS, elemental analysis and 1H NMR spectra. The crystal structure was examined by X-ray diffraction. X-ray structure determination revealed that all the aromatic rings in the compound are not coplanar. In the crystal structure, molecules are linked through intermolecular C-H···O hydrogen bonds, forming layers parallel to the ab plane.