Comprehensive dietary exposure assessment of the Chinese population to organophosphate esters (OPEs): Results of the sixth China total diet study.

Organophosphate esters (OPEs) are emerging pollutants, while data on their occurrence in foods and human dietary intake are limited. Based on the 6th China total diet study conducted in 2016-2019, this study implemented a comprehensive survey of OPEs in plant-derived foods of cereals, potatoes, legumes, fruits, vegetables, and further assessed dietary exposure from both plant- and animal-derived food. The sum concentrations of 15 OPEs in the plant-derived samples ranged from 0.567 to 106 ng/g ww. 2-Ethylhexyl diphenyl phosphate (EHDPP) (median: 1.14 ng/g ww) had the highest level in plant-derived foods, with a proportion of 35.6% in the total median OPEs. Regional distribution analysis showed a higher contamination of OPEs in plant-derived food from northern area of China. Estimated dietary intakes (EDIs) of ∑OPEs for Chinese population were from 109 ng/kg bw/day in Beijing to 1164 ng/kg bw/day in Gansu province, with mean and median of 296 and 222 ng/kg bw/day, respectively. Although animal-derived foods had higher levels of OPEs, plant-derived foods, specifically cereals, was the major source of dietary OPE intake. The EDIs were much lower than reference doses, which suggested the intakes of OPEs via food consumption could not cause significant health risks to the Chinese population at present.

A chemometric-assisted method for automatic, rapid and non-targeted detection of multi-pesticides in plant-derived foods by gas chromatography-mass spectrometry.

An automatic, rapid and non-targeted detection method for multi-pesticides in plant-derived foods was developed by gas chromatography-mass spectrometry and chemometrics. In this method, a novel algorithm named moving window iterative target transformation factor analysis was proposed. Although there are challenges of peak overlapping and background interference, the retention time and corrected mass spectra of unknown pesticides can be automatically obtained through iteration calculation in the 'moving window' with reference to the pesticide mass spectral library. One mixed pesticide standard and nine varieties of plant-derived foods were investigated with the proposed method. By contrast, a fast temperature programme was used to shorten detection time compared to the standard temperature programme. For the mixed standard, the mass spectra and retention times of all 39 pesticides were successfully obtained from the overlapping signal. Furthermore, all spiked pesticides were successfully detected in plant-derived foods within 10 min using a fast temperature programme.

Phytochemical-based nanodrugs going beyond the state-of-the-art in cancer management-Targeting cancer stem cells in the framework of predictive, preventive, personalized medicine.

Cancer causes many deaths worldwide each year, especially due to tumor heterogeneity leading to disease progression and treatment failure. Targeted treatment of heterogeneous population of cells - cancer stem cells is still an issue in protecting affected individuals against associated multidrug resistance and disease progression. Nanotherapeutic agents have the potential to go beyond state-of-the-art approaches in overall cancer management. Specially assembled nanoparticles act as carriers for targeted drug delivery. Several nanodrugs have already been approved by the US Food and Drug Administration (FDA) for treating different cancer types. Phytochemicals isolated from plants demonstrate considerable potential for nanomedical applications in oncology thanks to their antioxidant, anti-inflammatory, anti-proliferative, and other health benefits. Phytochemical-based NPs can enhance anticancer therapeutic effects, improve cellular uptake of therapeutic agents, and mitigate the side effects of toxic anticancer treatments. Per evidence, phytochemical-based NPs can specifically target CSCs decreasing risks of tumor relapse and metastatic disease manifestation. Therefore, this review focuses on current outlook of phytochemical-based NPs and their potential targeting CSCs in cancer research studies and their consideration in the framework of predictive, preventive, and personalized medicine (3PM).

[Determination of dazomet and its metabolite methyl isothiocyanate residues in plant-derived foods by gas chromatography-triple quadrupole mass spectrometry].

Dazomet is a kind of crystal solid that is stable at room temperature and acts as a fumigant. It is commonly used to control soil fungi, as an insecticide, and in sterilization and weeding. It can effectively kill root-knot nematodes, soil pests, weeds, and many soil-borne disease-causing organisms, to provide clean and healthy soil. Dazomet slowly decomposes and releases methyl isothiocyanate, methylamine, carbon disulfide, and hydrogen sulfide in acidic soil, and diffuses upward through the spaces in the soil to kill contact organisms. When agricultural crops are planted in soil treated with cotton wool, the residues in the grown crop can cause harm to human body when consumed. To ensure the quality and safety of food crops, it is important to develop a detection method for dazomet and its metabolites in plant-derived foods. Hence, in this study, a rapid and simultaneous determination method was developed for dazomet and its metabolite methyl isothiocyanate residues in plant-derived foods by gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS). The sample pretreatment and chromatographic conditions were optimized in the experiment. Subsequently, dazomet and its metabolite methyl isothiocyanate residues in vegetables, fruits, grains, nuts, tea, and spices were extracted with ethyl acetate, and purified using graphitized carbon, a primary-secondary amine, stearyl-bonded silica gel, and anhydrous magnesium sulfate as dispersive solid-phase extraction sorbents. After centrifugation and filtration, the target compounds were analyzed in the multiple reaction monitoring (MRM) mode by GC-MS/MS, and quantified by matrix matching external standard method. The matrix effects of the samples were also evaluated. The matrix effect was found to be in the range of 2.5% to 13.6% for methyl isothiocyanate in 16 matrices. As this matrix effect was weak, there was no need for compensatory measures. In contrast, the matrix effect of dazomet in 16 matrices was in the range of 240.3% to 331.2%. This matrix effect was strong and required compensation. Finally, a matrix matching calibration method was used to compensate the matrix effects. The relative matrix effects of other tested substrates were analyzed using lettuce as the representative substrate; it was found that all showed weak matrix effects. Therefore, the use of lettuce as a representative matrix to prepare a matrix standard curve can effectively correct the matrix effects of dazomet and methyl isothiocyanate in other substrates. Under the optimal conditions, the calibration curves were linear in the range of 0.005-1 mg/L with correlation coefficients higher than 0.99. Recovery tests were conducted by adding mixed standards to blank samples at four levels. The recoveries were in the range of 74.2%-117.2% with relative standard deviations (RSDs, n=6) of 2.8%-9.0%. The limits of quantification (LOQs) of dazomet and methyl isothiocyanate were 0.01 mg/kg. The accuracy and precision of this method met the requirements of pesticide residue determination. The established method was used to detect dazomet and its metabolite methyl isothiocyanate residues in six samples of Chinese cabbage, Chinese chives, cowpea, lettuce, eggplant, ginger, celery, potato, orange, kiwifruit, tomato, chili, rice, tea, almond, and Cuminum cyminum L. in the laboratory, and nothing was detected. The method is simple, rapid, and sensitive; overcomes the shortcomings of existing methods that require two pretreatment steps and two sets of equipment; and meets the requirements for the detection of dazomet and its metabolite methyl isothiocyanate residues in plant-derived foods.

Plant guttation provides nutrient-rich food for insects.

Plant guttation is a fluid from xylem and phloem sap secreted at the margins of leaves from many plant species. All previous studies have considered guttation as a water source for insects. Here, we hypothesized that plant guttation serves as a reliable and nutrient-rich food source for insects with effects on their communities. Using highbush blueberries as a study system, we demonstrate that guttation droplets contain carbohydrates and proteins. Insects from three feeding lifestyles, a herbivore, a parasitic wasp and a predator, increased their longevity and fecundity when fed on these guttation droplets compared to those fed on control water. Our results also show that guttation droplets, unlike nectar, are present on leaves during the entire growing season and are visited by numerous insects of different orders. In exclusion-field experiments, the presence of guttation modified the insect community by increasing the number of predators and parasitic wasps that visited the plants. Overall, our results demonstrate that plant guttation is highly reliable, compared to other plant-derived food sources such as nectar, and that it increases the communities and fitness of insects. Therefore, guttation represents an important plant trait with profound implications on multi-trophic insect-plant interactions.

[Determination of 34 pesticide residues in plant-derived foods by automated QuEChERS sample preparation system combined with high performance liquid chromatography-tandem mass spectrometry].

An analytical method for the determination of 34 pesticide residues in plant-derived foods was established using an automated QuEChERS sample preparation system combined with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The sample extraction and dispersive solid-phase extraction in the manual QuEChERS method were combined using the vortex vibration and centrifugation functions of the automated QuEChERS sample preparation system. The operating parameters and pretreatment steps were optimized, and the analytes were detected in the multiple reaction monitoring (MRM) mode. The quantification analysis was performed by the matrix-matched external standard method. The automated and the manual QuEChERS methods were compared from the methodological verification standpoint. The calibration curves showed good linearity in a certain range, and the correlation coefficients (R2) were greater than 0.99. The limits of detection and limits of quantification were 0.76-3.60 µg/kg and 2.28-10.80 µg/kg, respectively. Moreover, the recoveries ranged from 53.0% to 125.2%, and the relative standard deviations (RSDs) were less than 1.59% (n=5). The results obtained by the manual QuEChERS method were not significantly different from those obtained by the automated QuEChERS method. This method can effectively reduce the labor intensity and probability of error in the determination of pesticide residues.

A fast and sensitive ultra-high-performance liquid chromatography-tandem mass spectrometry method for determining mefentrifluconazole in plant- and animal-derived foods.

A rapid and sensitive ultra-high-performance liquid chromatography-tandem mass spectrometry method, in conjunction with multiwalled carbon nanotube purification, was developed to determine the mefentrifluconazole levels in grapes, cucumbers, tomatoes, peppers, wheat, maize, eggs, milk, pork, chicken, and fish. After purification, tandem mass spectrometry of mefentrifluconazole required <3.0 min. Matrix-matched external standard curves were used to quantify the residual mefentrifluconazole. The method meets the requirements of the European Union Document SANTE/11813/2017. Quantification was linear between 5 and 500 µg/kg (R2 ≥ 0.9988), and both the intra- and interday relative standard deviations were ≤13.7%. Analyte recovery ranged from 81.5% to 107.6%. The limit of mefentrifluconazole quantification was 5 µg/kg for all matrices. The method successfully detected and quantified mefentrifluconazole that had been applied to cucumbers and tomatoes grown in a test field. These results imply that the proposed method is effective and reliable for detecting mefentrifluconazole residues in plant- and animal-derived foods.

Dietary Phytochemicals Targeting Cancer Stem Cells.

There is an increasing awareness of the importance of a diet rich in fruits and vegetables for human health. Cancer stem cells (CSCs) are characterized as a subpopulation of cancer cells with aberrant regulation of self-renewal, proliferation or apoptosis leading to cancer progression, invasiveness, metastasis formation, and therapy resistance. Anticancer effects of phytochemicals are also directed to target CSCs. Here we provide a comprehensive review of dietary phytochemicals targeting CSCs. Moreover, we evaluate and summarize studies dealing with effects of dietary phytochemicals on CSCs of various malignancies in preclinical and clinical research. Dietary phytochemicals have a significant impact on CSCs which may be applied in cancer prevention and treatment. However, anticancer effects of plant derived compounds have not yet been fully investigated in clinical research.

A rapid fluorometric method for determination of aflatoxin B1 in plant-derived food by using a thioflavin T-based aptasensor.

A fluorometric aptamer-based method is described for the determination of aflatoxin B1 (AFB1). The fluorescent dye thioflavin T (ThT) forms a complex with the aptamer against AFB1 (aptamer/ThT), and the fluorescence of the complex is strongly enhanced. On addition of AFB1, it will bind to the aptamer and release ThT. The fluorescence of free ThT is much weaker. The fluorescence of the system, best measured at excitation/emission wavelengths of 440/487 nm, drops gradually in the AFB1 concentration range from 0.2 to 200 ng·mL-1, exhibiting good linearity. The detection limits are 0.2 ng·mL-1 in buffer solution, and 1 ng·mL-1 when applied to plant-derived food. The recovery of AFB1 from spiked foodstuff ranges from 74.7% to 121%. The assay can be performed within 20 min. Graphical abstract Schematic presentation of label-free thioflavin T (ThT)-based fluorescence aptasensor using aflatoxin B1(AFB1) aptamer/ThT G-quadruplex complex and the AFB1 aptamer/AFB1 complex fluorescent signal system for the rapid and sensitive detection of AFB1 in soy sauce, spirits, rice, corn and peanuts.

Dietary phytochemicals in breast cancer research: anticancer effects and potential utility for effective chemoprevention.

Cancerous tissue transformation developing usually over years or even decades of life is a highly complex process involving strong stressors damaging DNA, chronic inflammation, comprehensive interaction between relevant molecular pathways, and cellular cross-talk within the neighboring tissues. Only the minor part of all cancer cases are caused by inborn predisposition; the absolute majority carry a sporadic character based on modifiable risk factors which play a central role in cancer prevention. Amongst most promising candidates for dietary supplements are bioactive phytochemicals demonstrating strong anticancer effects. Abundant evidence has been collected for beneficial effects of flavonoids, carotenoids, phenolic acids, and organosulfur compounds affecting a number of cancer-related pathways. Phytochemicals may positively affect processes of cell signaling, cell cycle regulation, oxidative stress response, and inflammation. They can modulate non-coding RNAs, upregulate tumor suppressive miRNAs, and downregulate oncogenic miRNAs that synergically inhibits cancer cell growth and cancer stem cell self-renewal. Potential clinical utility of the phytochemicals is discussed providing examples for chemoprevention against and therapy for human breast cancer. Expert recommendations are provided in the context of preventive medicine.

Determination of cyanamide residue in 21 plant-derived foods by liquid chromatography-tandem mass spectrometry.

Cyanamide is widely used in agriculture, and has a modest toxicity in humans. In the present study, a simple, sensitive, and widely applicable method for detecting cyanamide in 21 plant-derived foods was developed. In the proposed method, after the samples were homogenized and extracted, the method employs clean-up with multi-walled carbon nanotubes (MWCNTs) and derivatization with dansyl chloride. The derivatized sample extracts were quantified with liquid chromatography-tandem mass spectrometry (LC-MS/MS). The mean recoveries were in the range of 67.4%-107.1%, and the RSDs were between 1.0% and 17.8%. The quantification limit in shiitake‬, green tea and chinese pepper was 0.05mg/kg, and in others 18 plant-derived foods was 0.01mg/kg. Among the data of 5 different laboratories, the repeatability limits (r) ranged from 0.0010 to 0.0941, and the reproducibility limits (R) ranged from 0.0031 to 0.2667. Moreover, the repeatability among different testing personnels in the same laboratory also has been examined.