Metabolomic profiling of the nutritional components of chicory leaves following heat processing.

Chicory (Cichorium intybus L.; witloof) is a crisp bitter leafy vegetable, popularly used in western cuisine in salads and soups (leaves) and as an alternative to coffee (roasted roots). In this study, we explored the effect of heat processing under various temperatures and for different durations on the nutritional composition of chicory leaves using gas chromatography-mass spectrometry (GC/MS) and principal component analysis (PCA). "Vintor" chicory leaves were processed and homogenized to obtain lyophilized samples, and their moisture content and pH were measured. Heat processing was conducted at 4, 30, 60, and 100°C. Metabolites were extracted and analyzed using GC/MS. The results were statistically analyzed using multiple t-tests and Tukey-Kramer method. A PCA was conducted using standardized data. A lower temperature (≤60°C) positively influenced the concentrations of nutritional components (sugars, free amino acids, and organic acids), branched-chain amino acids (which reportedly improve exercise performance), and γ-aminobutyric acid (which exerts antihypertensive effects). Whereas, a higher temperature (100°C) and microwave processing induced the generation of low-molecular-weight sugars from polysaccharides and glycosides, decreased free amino acid concentrations, and caused heat-induced aminocarbonyl reactions. This study provides valuable information for enhancing the flavor profiles and potential health benefits of chicory leaves by identifying the optimal heat processing parameters for preserving the desired nutritional value. PRACTICAL APPLICATION: The palatability, nutritional content, and health benefits of chicory have been evaluated based on its inherent constituents, but changes in these parameters during food processing remain unclear. Heating at 30 and 60°C activated secondary metabolism in chicory, increasing the amino acid and organic acid concentrations, whereas heating at 100°C and microwave processing increased the sugar concentrations in chicory. Thus, the nutritional value and potential health benefits of chicory could be enhanced by processing it under controlled temperatures; the findings are valuable for both consumers and food processing industry.

Near-Physiological Concentrations of Extracellular Pyruvate Stimulated Glucose Utilization along with Triglyceride Accumulation and Mitochondrial Activity in HepG2 Cells.

Pyruvate, a key intermediate in energy and nutrient metabolism, probably plays important roles in these regulations. In previous reports using cell lines, extracellular pyruvate of supraphysiological concentrations inhibited the glucose uptake by myotubes while being stimulated by adipocytes. As the effect of pyruvate on the glucose utilization is unclear in cultured hepatocytes. We have investigated the effects of extracellular pyruvate on the glucose utilization and the subsequent metabolic changes using the cell line HepG2. In a 24 h culture, pyruvate enhanced the glucose consumption more potently than 1 µM insulin, and this enhancement was detectable at a near-physiological concentrations of ≤1 mM. For metabolic changes following glucose consumption, the conversion ratio of glucose and pyruvate to extracellular lactate was approximately 1.0 without extracellular pyruvate. The addition of pyruvate decreased the conversion ratio to approximately 0.7, indicating that the glycolytic reaction switched from being an anaerobic to a partially aerobic feature. Consistent with this finding, pyruvate increased the accumulation of intracellular triglycerides which are produced through substrate supply from the mitochondria. Furthermore, pyruvate stimulated mitochondria activity as evidenced by increases in ATP content, mitochondrial DNA copy number, enhanced mitochondria-specific functional imaging and oxygen consumption. Interestingly, 1 mM pyruvate increased oxygen consumption immediately after addition. In this study, we found that near-physiological concentrations of extracellular pyruvate exerted various changes in metabolic events, including glucose influx, lactate conversion rations, TG accumulation, and mitochondrial activity in HepG2 cells.

Application to Butterbur Products of a Suggested Daily Intake-Based Safety Evaluation of Individual Herbal Supplements with Cytochrome P450 Expression as a Major Index.

The present paper first proposes a method for ensuring the safety of commercial herbal supplements, termed the suggested daily intake-based safety evaluation (SDI-based safety evaluation). This new method was inspired as a backward analog of the acceptable daily intake (ADI) derivation from the no observed adverse effect level (NOAEL), the basis of food additive risk analysis; namely, rats are dosed with individual herbal supplement products at the SDI for human use multiplied by 100 (the usual uncertainty factor value) per body weight for 8 d. The primary endpoint is the sign of adverse effects on liver, especially gene expression of cytochrome P450 (CYP) isoforms. The proposed method was then applied to three butterbur (Petasites hybridus) products without pyrrolizidine alkaloids but lacking clear safety information. Results showed that two oily products markedly enhanced the mRNA expression of CYP2B (>10-fold) and moderately enhanced that of CYP3A1 (<4-fold) with liver enlargement. These products also caused the renal accumulation of alpha 2-microglobulin. One powdery product showed no significant effect on liver and kidney. The large difference in effects of products was due to the difference in chemical composition revealed by liquid chromatography-mass spectroscopy. The oily and the powdery products required attention in terms of safety and effectiveness, respectively. Finally, the results from the SDI-based safety evaluation of butterbur and other herbal supplement products were grouped into four categories and cautionary notes were discussed. The SDI-based safety evaluation of their products by herbal supplement operators would contribute to safe and secure use by consumers.