Nano-LC and conventional HPLC techniques were applied for the analysis of anthocyanins present in commercial fruit juices using a capillary column of 100 μm id and a 2.1 mm id narrow-bore C(18) column. Analytes were detected by UV-Vis at 518 nm and ESI-ion trap MS with HPLC and nano-LC, respectively. Commercial blueberry juice (14 anthocyanins detected) was used to optimize chromatographic separation of analytes and other analysis parameters. Qualitative identification of anthocyanins was performed by comparing the recorded mass spectral data with those of published papers. The use of the same mobile phase composition in both techniques revealed that the miniaturized method exhibited shorter analysis time and higher sensitivity than narrow-bore chromatography. Good intra-day and day-to-day precision of retention time was obtained in both methods with values of RSD less than 3.4 and 0.8% for nano-LC and HPLC, respectively. Quantitative analysis was performed by external standard curve calibration of cyanidin-3-O-glucoside standard. Calibration curves were linear in the concentration ranges studied, 0.1-50 and 6-50 μg/mL for HPLC-UV/Vis and nano-LC-MS, respectively. LOD and LOQ values were good for both methods. In addition to commercial blueberry juice, qualitative and quantitative analysis of other juices (e.g. raspberry, sweet cherry and pomegranate) was performed. The optimized nano-LC-MS method allowed an easy and selective identification and quantification of anthocyanins in commercial fruit juices; it offered good results, shorter analysis time and reduced mobile phase volume with respect to narrow-bore HPLC.

A correct function of adipocytes in connection with cellular fatty acid loading and release is a vital aspect of energy homeostasis; dysregulation of these reactions can result in obesity and type 2 diabetes mellitus. In addition, adipocytes have been proposed to play a major role in preventing lipotoxicity by removing excess fatty acids from the circulation and converting them into triglycerides and thus decreasing the exposure of other cells to their potentially harmful effects. We report here that the addition of α-tocopheryl phosphate (but not α-tocopherol) to NIH3T3-L1 preadipocytes transcriptionally activates a set of genes TRB3 (Tribbles Homolog 3), Sestrin-2 (SESN2), and Insulin-Induced Gene 1 (INSIG1)] potentially preventing fat accumulation in these cells. In contrast, in differentiated adipocytes, α-tocopheryl phosphate is responsible for the transcriptional inhibition of the same genes, possibly facilitating fat uptake and storage. In conclusion, it appears that in proliferating preadipocytes α-tocopheryl phosphate foils fat accumulation, whereas in adipocytes it enhances it. These processes may be relevant in the regulation of excess fat accumulation and in prevention of lipotoxicity.

Adipocytes play an important role in lipid and energy homeostasis and dysregulation of these processes contributes to obesity and type 2 diabetes mellitus. In addition, adipocytes influence inflammation and play a major role in preventing lipotoxicity by removing excess fatty acids from the circulation and storing them as triglycerides and thus reducing exposure of other cells to their potentially harmful effects. Although the many aspects of metabolic disorders associated with lipotoxicity and obesity cannot be fully clarified with cultured cells, the NIH3T3‐L1 preadipocytes/adipocytes differentiation model has been useful to study the molecular processes involved. In this model, several vitamins and phytochemicals have been shown to influence proliferation and differentiation. Here, we report by using quantitative RT‐PCR that in NIH3T3‐L1 pre‐adipocytes, α‐tocopheryl phosphate (αTP) (but not α‐tocopherol (αT)) activates a set of genes [TRB3 (Tribbles Homolog 3), Sestrin‐2, and Insulin Induced Gene 1 (INSIG)] potentially preventing lipids accumulation. In contrast, in differentiated adipocytes, αTP inhibits transcriptional expression of the same genes, potentially facilitating lipid uptake and storage. Thus, in proliferating pre‐adipocytes αTP foils lipid accumulation, whereas in adipocytes it enhances lipid accumulation. Supported by USDA Contract #58–1950‐0–014.