Fangling Du

Screening natural antioxidants in peanut shell using DPPH-HPLC-DAD-TOF/MS methods.

Peanut shell, a byproduct in oil production, is rich in natural antioxidants. Here, a rapid and efficient method using DPPH-HPLC-DAD-TOF/MS was used for the first time to screen antioxidants in peanut shell. The method is based on the hypothesis that upon reaction with 1, 1-diphenyl-2-picrylhydrazyl (DPPH), the peak areas of compounds with potential antioxidant activities in the HPLC chromatogram will be significantly reduced or disappeared, and the identity confirmation could be achieved by HPLC-DAD-TOF/MS technique. With this method, three compounds possessing potential antioxidant activities were found abundantly in the methanolic extract of peanut shell. They were identified as 5,7-dihydroxychromone, eriodictyol, and luteolin. The contents of these compounds were 0.59, 0.92, and 2.36 mg/g, respectively, and luteolin possessed the strongest radical scavenging capacity. DPPH-HPLC-DAD-TOF/MS assay facilitated rapid identification and determination of natural antioxidants in peanut shell, which may be helpful for value-added utilization of peanut processing byproducts.

A novel method: ionic liquid-based ultrasound-assisted extraction of polyphenols from Chinese purple yam

Abstract Chinese purple yam is famous for therapeutic and nutritional values in lowering blood glucose, blood pressure and even preventing and treating cardiovascular diseases. However, traditional extraction techniques for the functional polyphenolic compounds mostly utilise unfriendly organic solvent and easily cause degradation of polyphenols. In this study, a novel ionic liquid-based ultrasound-assisted extraction (IL-UAE) technique was utilised to obtain polyphenols. The optimal extraction condition included: solid–liquid ratio (0.05 g/mL), ionic liquid concentration (1.05 M), extraction temperature (67°C) and ultrasonic time (37 min). The maximum free radical scavenging activity (86.21%) and total antioxidant activity (2.21 mM) were achieved and matched well with the predicted values, superior to that of the extract from regular ethanol-based UAE. IL-UAE could be a rapid and green technique for efficient extraction of polyphenols from purple yam with low solvent consumption and few structural deterioration, exhibiting application potential in food and pharmaceutical industries.

Comparative Proteomics Analysis Reveals Trans Fatty Acid Isomers Activates Different Pathways in Human Umbilical Vein Endothelial Cell.

Trans fatty acid (TFA), a group of unsaturated fats with at least one double bond in the trans configuration, plays a role in lipid metabolism, the structure of the cell membrane phospholipids, and apoptosis. Previous studies demonstrated that TFA was associated with coronary heart disease, obesity, and insulin resistance. Herein, a quantitative proteomics approach estimated the relative abundance of proteins in human umbilical vein endothelial cells treated with TFA (two different TFA structural isomers: 9t-18:1 and 9t,12t-18:2). The results revealed that 174 identified proteins were significantly altered with respect to expression. Furthermore, based on the cutoff values, 35 proteins were differentially expressed in the 9t-18:1 group as compared to the control group, 69 proteins were differentially expressed in 9t,12t-18:2 group as compared to the control group, and 120 proteins were differentially expressed in the 9t,12t-18:2 group as compared to the 9t-18:1 group. Based on the bioinformatics analysis, we found that TFA could alter the structural constitution of the cytoskeleton through protein interactions, localization into the cell membrane, and incorporation into the phospholipid of the cell. In addition, 17 differential apoptosis-related proteins, including cell division cycle 42, superoxide dismutase 1, glyoxalase I, and macrophage migration inhibitory factor were also identified. Together, these results might emphasize the need for studying TFA-induced biological processes.

Rat Small Intestinal Mucosal Epithelial Cells Absorb Dietary 1,3-Diacylglycerol Via Phosphatidic Acid Pathways.

Compared with triacylglycerol (TAG), dietary 1,3-diacylglycerol (1,3-DAG) is associated with reduced serum lipid and glucose levels. We investigated the metabolism of 1,3-DAG by assaying its intermediate metabolites during digestion and absorption in the rat small intestine. After gavage with TAG emulsion, TAG was digested mainly to 2-monoacylglycerol (2-MAG) and unesterified fatty acid (FFA) in the rat small intestinal lumen. 2-MAG was directly absorbed into the small intestinal epithelial cells and esterified to 1,2(2,3)-DAG, and further esterified to TAG. After gavage with 1,3-DAG emulsion, 1,3-DAG was digested mainly to 1(3)-MAG and FFA in the rat small intestinal lumen with subsequent significant increase of 1-MAG and 1,3-DAG concentrations in small intestinal mucosal epithelial cells, and the 2-MAG, 1,2(2,3)-DAG, and TAG concentrations in mucosal epithelial cells were not significantly different after 1,3-DAG than after TAG gavage, suggesting that the metabolic pathway of 1,3-DAG is different from that of TAG. In intestinal mucosal epithelial cells, we further assayed enzyme levels and gene expression of proteins in the phosphatidic acid (PtdOH) pathway. The glycerol kinase, phosphatidate phosphatase, and diacylglycerol acyltransferase-2 expression and the relative expression of mRNA of enzymes were significantly increased in the 1,3-DAG group compared with the TAG group, suggesting that TAG synthesis from dietary 1,3-DAG was mainly via PtdOH pathways, which may partially account for the effect of dietary DAG on postprandial serum TAG.

Biological effects of trans fatty acids and their possible roles in the lipid rafts in apoptosis regulation: Modulatory mechanism of lipid rafts induced by TFA

A large number of recent studies are focused on evaluating the mechanism of action of trans fatty acids (TFAs) on the progression of apoptosis. A strong positive association has been reported between TFA and coronary heart disease (CHD), obesity and nonalcoholic steatohepatitis and so on. The present study reviewed the biological effects of trans fatty acids (TFA) and their possible roles in lipid rafts in regulating apoptosis. The following aspects of TFA were included: the research about TFA and diseases affecting serum lipid levels, inducing system inflammation and immune response, and the correlation between TFA and apoptosis. The primary purpose of the review article was to comprehensively evaluate the potential correlation between lipid rafts and apoptosis induced by different structures of TFA and provide some new research progress and future directions about it.

Nephroprotective effects of diacylglycerol on diabetic nephropathy in type 2 diabetic rats

Diacylglycerol (DAG) has been reported to reduce the serum lipid and glucose levels more effectively compared with triacylglycerol (TAG). The present study examined the long-term effects of dietary DAG on rats with type 2 diabetic nephropathy (DN). The type 2 DN model was established by administering a high-fat and high-calorie diet along with an intraperitoneal injection of 35 mg/kg body weight streptozocin, and the disease developed over the following 8 weeks. Sprague-Dawley rats were then randomly divided into the control, TAG, low-dose DAG (Low-DAG) and high-dose DAG (High-DAG) groups. Blood glucose (BG), lipid levels and renal function parameters were then measured. The results revealed that the body weight in the High-DAG group was significantly reduced compared with the TAG group, while there was no significant difference in the food intake between TAG and DAG groups. BG, advanced glycation end products (AGEs), TAG, low-density lipoprotein cholesterol, urine protein and urine albumin levels were significantly reduced, while high-density lipoprotein cholesterol levels were significantly increased in the two DAG groups. In addition, hematoxylin-eosin stained glomeruli presented decreased glomerular enlargement and mesangial expansion in the DAG groups. Immunohistochemical detection revealed that the levels of transforming growth factor-β1 and connective tissue growth factor in renal tissues of the DAG groups were also significantly reduced compared with the TAG group. These findings indicate that DAG oils can significantly reduce BG levels and the deposition of AGEs in renal tissue, as well as regulate the levels of transforming growth factor-β1 and connective tissue growth factor, thus delaying the progression of nephropathy.