Ionic liquid-based carbon dots as highly biocompatible and sensitive fluorescent probe for the determination of vitamin P in fruit samples

Vitamin P (VP) known as rutin is one of the common flavonoids, which widely exists in fruits and vegetables and often used as a dietary additive. The rapid and accurate detection of VP in food matrices is critical for evaluating food quality and guiding diet. Herein, a rapid, accurate, and selective detection scheme for VP in fruit samples was proposed for the first time using ionic liquid-based carbon dots (IL-CDs). The synthesized IL-CDs exhibited great biocompatibility and excellent optical properties including high fluorescence intensity, high quantum yield, and good fluorescence stability. Through an internal filtering effect (IFE), VP could greatly reduce the fluorescence of these CDs. In the present study, this probe demonstrated good sensitivity and excellent selectivity toward VP with a low detection limit of 60.0 nmol/L. Moreover, this approach was effectively applied to detect VP in food samples with a recovery range of 97 % to 119 %. More interestingly, the results of cell imaging suggested that IL-CDs were expected to be promising material for bioimaging.

Do Certain Flavonoid IMPS Have a Vital Function?

Flavonoids are a vast group of metabolites that are essential for vascular plant physiology and, thus, occur ubiquitously in plant-based/-derived foods. The solitary designation of thousands of known flavonoids hides the fact that their metabolomes are structurally highly diverse, consist of disparate subgroups, yet undergo a certain degree of metabolic interconversion. Unsurprisingly, flavonoids have been an important theme in nutrition research. Already in the 1930s, it was discovered that the ability of synthetic Vitamin C to treat scurvy was inferior to that of plant extracts containing Vitamin C. Subsequent experimental evidence led to the proposal of Vitamin P (permeability) as an essential phytochemical nutrient. However, attempts to isolate and characterize Vitamin P gave confusing and sometimes irreproducible results, which today can be interpreted as rooted in the unrecognized (residual) complexity of the intervention materials. Over the years, primarily flavonoids (and some coumarins) were known as having Vitamin P-like activity. More recently, in a NAPRALERT meta-analysis, essentially all of these Vitamin P candidates were identified as IMPs (Invalid/Improbable/Interfering Metabolic Panaceas). While the historic inability to define a single compound and specific mode of action led to general skepticism about the Vitamin P proposition for "bioflavonoids," the more logical conclusion is that several abundant and metabolically labile plant constituents fill this essential role in human nutrition at the interface of vitamins, cofactors, and micronutrients. Reviewing 100+ years of the multilingual Vitamin P and C literature provides the rationales for this conclusion and new perspectives for future research.

Rutin promotes activation and reduces apoptosis of primordial follicles by regulating Akt phosphorylation after in vitro culture of ovine ovarian tissue

The aims of this study were to analyze the effects of different concentrations of rutin on primordial follicle survival and development after in vitro culture of sheep ovarian tissue, and to verify the possible involvement of the phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt) pathway in the rutin actions. Ovarian fragments were fixed for histological analysis (fresh control) or cultured in α-minimum essential medium alone (α-MEM⁺: control medium) or in α-MEM⁺supplemented with different concentrations of rutin (0.1; 1 or 10 μg/mL) for 7 days. Inhibition of the PI3K activity was performed in fragments cultured with 50 μM LY294002. Thereafter, immunohistochemistry was performed to evaluate the expression of cleaved caspase-3 (apoptosis) and Akt phosphorylation (p-Akt). The results showed that 1 μg/mL rutin has a greater percentage of normal follicles (P < 0.05) than those of α-MEM⁺ and other rutin treatments. In addition, 1 μg/mL rutin maintained the follicular apoptosis similar (P > 0.05) to that of the fresh control and lower than α-MEM⁺ and 10 μg/mL rutin. All rutin concentrations increased (P < 0.05) follicular activation compared to fresh control and α-MEM⁺. Furthermore, follicular and oocyte diameters increased (P < 0.05) only after culture with 1 μg/mL rutin. After PI3K inhibition, there was a reduction (P < 0.05) of rutin follicular effects. In conclusion, rutin at 1 μg/mL reduces apoptosis, promotes activation and growth of sheep primordial follicles through the modulation of the PI3K/Akt signaling pathway after in vitro culture of ovine ovarian tissue.

Rutin improves glutamate uptake and inhibits glutamate excitotoxicity in rat brain slices

Rutin is an important flavonoid consumed in the daily diet. It is also known as vitamin P and has been extensively investigated due to its pharmacological properties. On the other hand, neuronal death induced by glutamate excitotoxicity is present in several diseases including neurodegenerative diseases. The neuroprotective properties of rutin have been under investigation, although its mechanism of action is still poorly understood. We hypothesized that the mechanisms of neuroprotection of rutin are associated with the increase in glutamate metabolism in astrocytes. This study aimed to evaluate the protective effects of rutin with a focus on the modulation of glutamate detoxification. We used brain organotypic cultures from post-natal Wistar rats (P7-P9) treated with rutin to evaluate neural cell protection and levels of proteins involved in the glutamate metabolism. Moreover, we used cerebral cortex slices from adult Wistar rats to evaluate glutamate uptake. We showed that rutin inhibited the cell death and loss of glutamine synthetase (GS) induced by glutamate that was associated with an increase in glutamate-aspartate transporter (GLAST) in brain organotypic cultures from post-natal Wistar rats. Additionally, it was observed that rutin increased the glutamate uptake in cerebral cortex slices from adult Wistar rats. We conclude that rutin is a neuroprotective agent that prevents glutamate excitotoxicity and thereof suggest that this effect involves the regulation of astrocytic metabolism.