Comparison of accumulation of four metalloids in Allium sativum

Natural Dietary Compounds in the Treatment of Arsenic Toxicity

Chronic exposure to arsenic (As) compounds leads to its accumulation in the body, with skin lesions and cancer being the most typical outcomes. Treating As-induced diseases continues to be challenging as there is no specific, safe, and efficacious therapeutic management. Therapeutic and preventive measures available to combat As toxicity refer to chelation therapy, antioxidant therapy, and the intake of natural dietary compounds. Although chelation therapy is the most commonly used method for detoxifying As, it has several side effects resulting in various toxicities such as hepatotoxicity, neurotoxicity, and other adverse consequences. Drugs of plant origin and natural dietary compounds show efficient and progressive relief from As-mediated toxicity without any particular side effects. These natural compounds have also been found to aid the elimination of As from the body and, therefore, can be more effective than conventional therapeutic agents in ameliorating As toxicity. This review provides an overview of the recently updated knowledge on treating As poisoning through natural dietary compounds. This updated information may serve as a basis for defining novel prophylactic and therapeutic formulations.

Elucidation of tellurium biogenic nanoparticles in garlic, Allium sativum, by inductively coupled plasma-mass spectrometry

BACKGROUND

Biosynthesis of Te nanoparticles may occur in higher plants exposed to Te, as reported on microorganisms. However, unambiguous observations of the biogenic nanoparticles (BgNPs) of Te in plants are lacking. Hence, in this study, we investigated the formation of insoluble BgNPs of Te in garlic (Allium sativum) as a model plant.

METHOD

We performed elemental analysis based on inductively coupled plasma-mass spectrometry (ICP-MS) technique, and obtained Te concentration and distribution in various parts of garlic. In addition, insoluble Te particles were detected by fast time-resolved ICP-MS. Direct observation of the insoluble Te particle was also conducted by scanning electron microscope (SEM) and transmission electron microscope (TEM).

RESULTS

A part of the roots and clove from Te-exposed garlic showed black coloration. Te concentrations in the black-colored parts were significantly increased compared with the non-colored parts. Transient signals of Te unique to nanoparticles were detected from the insoluble fractions of the black-colored parts. Finally, rod-shaped biogenic Te nanoparticles consisting of highly crystalline elemental Te was observed by SEM and TEM.

CONCLUSION

Our data provide new insights to the metabolic pathway of Te in higher plants for the formation of insoluble biogenic nanoparticles, which is extremely important for the detoxification of Te.

The Effect of Environmental Factors on Total Arsenic Accumulation in Sarcodia suiae, Rhodophyta

Little is known about the effects of environmental factors on total arsenic (TAs) accumulation in marine Rhodophyta. The effects of five environmental factors (temperature, light intensity, pH, exposure duration, and phosphate) at various As(III) concentrations were investigated in Sarcodia suiae. The highest TAs accumulations were recorded at 25°C, a luminance of 80 µmol photons m^-2 s^-1, and a pH of 8. TAs uptake increased significantly over time. However, a higher phosphate concentration reduced TAs accumulation. These data show that the extent of TAs accumulation depends on various environmental factors. Hence, our results suggest a potential in arsenic recovery process in wastewater treatments. S. suiae may provide a new means of reducing levels of arsenic in contaminated water and may be used as a potential Rhodophyta model for investigating other types of heavy metal pollution in future.

Arsenic-induced stress activates sulfur metabolism in different organs of garlic (Allium sativum L.) plants accompanied by a general decline of the NADPH-generating systems in roots

Arsenic (As) contamination is a major environmental problem which affects most living organisms from plants to animals. This metalloid poses a health risk for humans through its accumulation in crops and water. Using garlic (Allium sativum L.) plants as model crop exposed to 200μM arsenate, a comparative study among their main organs (roots and shoots) was made. The analysis of arsenic, glutathione (GSH), phytochelatins (PCs) and lipid peroxidation contents with the activities of antioxidant enzymes (catalase, superoxide dismutase, ascorbate-glutathione cycle), and the main components of the NADPH-generating system, including glucose-6-phosphate dehydrogenase (G6PDH), 6-phosphogluconate dehydrogenase (6PGDH), NADP-malic enzyme (NADP-ME) and NADP-isocitrate dehydrogenase (NADP-ICDH) was carried out. Data showed a correlation among arsenic accumulation in the different organs, PCs content and the antioxidative response, with a general decline of the NADPH-generating systems in roots. Overall, our results demonstrate that there are clear connections between arsenic uptake, increase of their As-chelating capacity in roots and a decline of antioxidative enzyme activities (catalase and the ascorbate peroxidase) whose alteration provoked As-induced oxidative stress. Thus, the data suggest that roots act as barrier of arsenic mediated by a prominent sulfur metabolism which is characterized by the biosynthesis of high amount of PCs.