Abstract:Heavy metals, such as cadmium, copper, lead, chromium and mercury, are important environmental pollutants, particularly in areas with high anthropogenic pressure. Their presence in the atmosphere, soil and water, even in traces can cause serious problems to all organisms, and heavy metal bioaccumulation in the food chain especially can be highly dangerous to human health. Heavy metals enter the human body mainly through two routes namely: inhalation and ingestion, ingestion being the main route of exposure to these elements in human population. Heavy metals intake by human populations through food chain has been reported in many countries. Soil threshold for heavy metal toxicity is an important factor affecting soil environmental capacity of heavy metal and determines heavy metal cumulative loading limits. For soil-plant system, heavy metal toxicity threshold is the highest permissible content in the soil (total or bioavailable concentration) that does not pose any phytotoxic effects or heavy metals in the edible parts of the crops does not exceed food hygiene standards. Factors affecting the thresholds of dietary toxicity of heavy metal in soil-crop system include: soil type which includes soil pH, organic matter content, clay mineral and other soil chemical and biochemical properties; and crop species or cultivars regulated by genetic basis for heavy metal transport and accumulation in plants. In addition, the interactions of soil-plant root-microbes play important roles in regulating heavy metal movement from soil to the edible parts of crops. Agronomic practices such as fertilizer and water managements as well as crop rotation system can affect bioavailability and crop accumulation of heavy metals, thus influencing the thresholds for assessing dietary toxicity of heavy metals in the food chain. This paper reviews the phytotoxic effects and bioaccumulation of heavy metals in vegetables and food crops and assesses soil heavy metal thresholds for potential dietary toxicity.

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Severe hypoglycemia has a detrimental impact on the cerebrovasculature, but the molecular events that lead to the disruption of the integrity of the tight junctions remain unclear. Here, we report that the microvessel integrity was dramatically compromised (59.41% of wild‐type mice) in TP53‐induced glycolysis and apoptosis regulator (TIGAR) transgenic mice stressed by hypoglycemia. Melatonin, a potent antioxidant, protects against hypoglycemic stress‐induced brain endothelial tight junction injury in the dosage of 400 nmol/L in vitro. FRET (fluorescence resonance energy transfer) imaging data of endothelial cells stressed by low glucose revealed that TIGAR couples with calmodulin to promote TIGAR tyrosine nitration. A tyrosine 92 mutation interferes with the TIGAR‐dependent NADPH generation (55.60% decreased) and abolishes its protective effect on tight junctions in human brain microvascular endothelial cells. We further demonstrate that the low‐glucose‐induced disruption of occludin and Caludin5 as well as activation of autophagy was abrogated by melatonin‐mediated blockade of nitrosative stress in vitro. Collectively, we provide information on the detailed molecular mechanisms for the protective actions of melatonin on brain endothelial tight junctions and suggest that this indole has translational potential for severe hypoglycemia‐induced neurovascular damage.

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These data disclose novel findings about the therapeutic potential of DY-9836, and its encapsulated nanodrug delivery system significantly enhanced the cognitive function via inhibitory effect on nitrosative stress and NLRP3 signaling in VaD mice.

Bromocriptine is a sympatholytic dopamine D2 receptor agonist with remarkable bioactivities. It has been used clinically as a prescription drug for more than 30 years to treat hyperprolactinemia associated conditions, Parkinson's disease, acromegaly, prolactinomas and other pituitary hormone dependent adenomas and recently, diabetes mellitus as well as various other disorders. Long‐term treatment with bromocriptine has minimal or no harmful effects on renal, hepatic, cardiac or hematologic functions. This review article was planned to study the hypothetical and proposed mechanism of action as well as provide a brief discussion about its safety issues and tolerability. Bromocriptine represents an attractive option with high efficacy and safety profile for hyperprolactinemia‐associated conditions, acromegaly, parkinsonism, type 2 diabetes mellitus and various other diseases in a variety of dosage forms for best possible beneficial effects. It appeared to be an effective and safe addition to the pharmacopoeia of drugs for the treatment of a vast variety of diseases as monotherapy or in combination with other drugs.