Aquatic Nanotoxicology

Diabetes mellitus is a metabolic disorder widespread in developing and well-developed countries. It is the sixth leading cause of death in upper middle-income countries in 2015. Many of the synthetic medicine such as sulfonylureas, biguanides, alpha-glucosidase inhibitor and thiazolidinediones are the diabetic agents currently available to control the hyperglycemic condition. Due to the limitations of the drugs, it is required to find a natural alternative for the control of Diabetes Mellitus. Safe and effective antidiabetic agents can be extracted/separated from the traditional medicinal plants. 80% of the population around the Globe depends on traditional medicine. About 350 plants were traditionally used to treat diabetes mellitus. Medicinal plants were assessed for their antidiabetic activity, but these plants were not scientifically evaluated for the presence of an antidiabetic agent. Identification of anti-hyperglycemic agent without any side effects is the need of the hour. WHO has reported tremendous increase of 433million adults with Diabetes Mellitus in 2014, the prevalence of diabetes mellitus in India increased to 7.8% in India. The review focuses on the commonly available and traditionally used medicinal plants of North TamilNadu, India and their role in the control of diabetes mellitus. Introduction Diabetes Mellitus (DM) is a metabolic disorder. It was first described clinically by the Greek physician Aretaeus Cappadocia in 1500 BC " as a condition where Flesh and Bones run together and are siphoned into the urine ". Diabetes mellitus is characterized by hyperglycemic condition along with impaired metabolic functions. Two major types of DM exist; the first type is characterized by insufficient production of insulin and in the other type the target cells do not respond to insulin. The chronic hyperglycemic condition leads to long term damage and failure of target organs. The first WHO global report on diabetes demonstrates that the number of adult living with diabetes has almost quadrupled since 1980 and to 422 million adults in 2014; type 2 diabetes and associated factors such as overweight and obesity were the reason for the dramatic increase. Prevalence of diabetes in India accounts for 7.8% of the adult population [1] Over the past, three decades, the rise in the occurrence of diabetes was dramatic and grows very rapidly in low and middle income countries. The prevalence of diabetes in Tamil Nadu accounts to 13.7% in urban and 7.8% in rural areas in the year 2011 [2]. The synthetic drugs used lead to side effects as well as persistence of hyperglycemic conditions for a longer period of time resulting in serious complications and damages to the heart, blood vessels eyes, kidney and nerves, moreover, increases the risk of heart diseases and stroke [3]. Progressive reduction in β-cell function made it difficult to maintain glycemic control among many diabetic patients [4]. Polytherapy with many hypoglycemic agents to attain better glucose control is a common practice [5]. Many plants have been found to be useful in managing diabetes mellitus. Plants are the major source of drug and are available in the market as extracts directly or indirectly from the plant sources [6]. For the purpose of preventive and curative reasons plants were used as medicine in various parts of the world. Medicinal herbs were used to treat diabetes in large proportion all over the Globe because of the easy availability and affordability [7]. Plant medicines show a potential hypoglycemic activity in diabetes-induced animals. Further, the metabolites from the plant were formulated and were administered to control diabetes mellitus. Novel compounds with antihyperglycemic potential have to be isolated from the plant sources. Studies reveal the role of crude extracts of plants with potential antidiabetic activity in alloxan and streptozotocin-induced diabetic animals. It is required to isolate, purify and characterize the specific compounds with the efficacy to control by reducing blood glucose level and by means of regenerating the damaged β cells of the pancreatic islets for the normal secretion of insulin. The objective of the review is to collect and elucidate the antidiabetic properties of the medicinal plants used by the traditional healers to manage diabetes mellitus.

The aim of this study was comparing the toxic effects of zinc oxide nanoparticles (ZnO NPs) versus zinc ions (Zn2+) at a high non-lethal (500µg/L) and a low environmental relevant (0.05µg/L) concentrations on gills of rainbow trout (Oncorhynchus mykiss) following 14 days of waterborne exposure. Structural alterations, histopathological anomalies, and zinc bioaccumulation were investigated in the gills using field emission scanning electron microscopy (FESEM), hematoxylin and eosin staining (H&E), and graphite furnace atomic absorption spectrophotometry (GFAAS) respectively. Some damages such as shortening and fusion of secondary lamellae, surface epithelium hypertrophy, and hyperplasia of the primary lamellae were observed in the gill tissue. Histopathological alterations of gills were minimum in both none exposed (control) fish and fish exposed to 0.05µg/L Zn2+. The severity of gill damages were higher in fish exposed to 500µg/L ZnO NPs compared to 500µg/L Zn2+ and 0.05µg/L ZnO NPs. The Zn accumulation in the gills was concentration-dependent such that bioaccumulation order was as 500µg/L Zn2+> 500µg/L ZnO NPs ≈ 0.05µg/L Zn2+> 0.05µg/L ZnO NPs> control. In summary, the results of present study showed that although the accumulation capability of Zn2+ was higher than ZnO NPs, but NPs cause more structural damages to gills compare to ions.

http://www.trjfas.org/abstract.php?lang=en&id=1215

Increasing production and utilization of silver nanoparticles can lead to their release into aquatic ecosystems and tend to toxic effects on aquatics. It is not yet clearly specified whether observed toxic effect following exposure of aquatic organisms to colloidal nano-silver is caused by silver nanoparticles contained in the colloid, by free silver ions, or by a combination of both. In this study, acute toxicity of "nanosilver colloid" (containing free ionic silver and silver nanoparticles) compared to the toxicity of "silver nanoparticles" separated from colloidal nanosilver (without free Ag+ ions) were investigated in zebra fish, Danio rerio. Acute toxicity tests were planned and performed according to standards of Organization for Economic Cooperation and Development. The results showed that No Observed Effect Concentrations (NOECs), Lowest Observed Effect Concentrations (LOECs), Maximum Acceptable Toxicant Concentrations (MATCs), and Median Lethal Concentrations (LC50s) of "nano-silver colloid" were 250, 240, 248.90, and 300.64 times less than those of "silver nanoparticles", respectively. Therefore, toxicity of colloidal nanosilver is mostly due to the free silver ions (Ag+) rather than silver nanoparticles present in it. In general "nano-silver colloid" and "silver nanoparticles" are respectively classified as "highly toxic" and "toxic” chemicals for aquatics and the release of these substances into the environment should be prevented.

The objective of the present study was to know the effect of Silver nanoparticle on antioxidant enzymatic activities in selected tissues of the Zebrafish, Danio rerio. For the chronic toxicity study adult fish, Danio rerio were divided in to two groups. First group was experimental group in which fish were consecutively treated with a graded series of 0.3, 0.6, 0.9 mg/l an average 60 nm PVP coated AgNPs. Treatment was given for 21 days at the end of experimental period. Superoxide Dismutase (SOD), Catalase (CAT) and Glutathione Peroxidase (GPx) in gill, liver and muscle tissues were assayed. The levels of Catalase (CAT), was found to be decreased were as the Superoxide Dismutase (SOD) and Glutathione Peroxidase (GPx) were found to be increased significantly in gill, liver and muscle tissue of AgNPs treated fish.

This study was conducted to measure the bioconcentration of silver nanoparticles (AgNPs) in artemia brine shrimp (Artemia salina) and its transfer to zebrafish (Danio rerio), in order to: (1) determine the uptake of AgNPs by artemia from water, and (2) evaluate trophic transfer potential of AgNPs from artemia to zebrafish under controlled conditions. The artemia exposed to 0.5, 1.0, and 2.0 mgL AgNPs for 24 h and then were administrated to zebrafish for 14 days. Silver body burden was assayed using a Phoenix 886 flame atomic absorption spectrophotometer both in artemia and zebrafish. The results of this study showed that the uptake of AgNPs in artemia was higher than zebrafish (p < 0.05). The accumulation of AgNPs in zebrafish was dose dependent, with greater accumulation observed at higher AgNPs concentrations. Moreover, the results of this study indicated that the trophic transfer factor (BMF) of AgNPs was lower than 1 (< 1), and this nanoparticle was not potential of trophi...

This study aims to evaluate the potential toxic effects of ZnO nanoparticles on Artemia franciscana nauplii. The ZnO NPs suspension was characterized by TEM, EDS and DLS techniques. Acute toxicity was investigated by exposure of nauplii to concentrations of 1, 5, 7.5, 10, 15, 20, 25 and 30 mg/L of ZnO NPs for 48 h and 96 h. The 96-h EC10 and EC50 values of ZnO NPs were found to be 1.39 mg/L and 4.86 mg/L respectively. The ZnO NPs suspensions did not cause any significant acute toxicity after 48 h of exposure, but the immobilization rate increase significantly compare to control group after 96 h (P < 0.05). The results showed that the uptake, accumulation, and elimination of NPs in nauplii depends on the concentration of NPs and time. The elimination rates of 46.66% and 83.85% were recorded at 1 and 10 mg/L of NPs after 24 h of depuration period, respectively.

This study was conducted to measure the bioconcentration of silver nanoparticles (AgNPs) in artemia brine shrimp (Artemia salina) and its transfer to zebrafish (Danio rerio), in order to: (1) determine the uptake of AgNPs by artemia from water, and (2) evaluate trophic transfer potential of AgNPs from artemia to zebrafish under controlled conditions. The artemia exposed to 0.5, 1.0, and 2.0 mgL-1 AgNPs for 24 h and then were administrated to zebrafish for 14 days. Silver body burden was assayed using a Phoenix 886 flame atomic absorption spectrophotometer both in artemia and zebrafish. The results of this study showed that the uptake of AgNPs in artemia was higher than zebrafish (p < 0.05). The accumulation of AgNPs in zebrafish was dose dependent, with greater accumulation observed at higher AgNPs concentrations. Moreover, the results of this study indicated that the trophic transfer factor (BMF) of AgNPs was lower than 1 (< 1), and this nanoparticle was not potential of trophic transfer from artemia to zebrafish.

Environmental context The increased use of nanomaterials in industrial and consumer products requires robust strategies to identify risks when they are released into the environment. Aquatic toxicologists are beginning to possess a clearer understanding of the chemical and physical properties of nanomaterials in solution, and which of the properties potentially affect the health of aquatic organisms. This review highlights the main challenges encountered in aquatic nanotoxicity testing, provides recommendations for overcoming these challenges, and discusses recent studies that have advanced our understanding of the toxicity of three important OECD nanomaterials, titanium dioxide, zinc oxide and silver nanomaterials. Aquatic nanotoxicologists and ecotoxicologists have begun to identify the unique properties of the nanomaterials (NMs) that potentially affect the health of wildlife. In this review the scientific aims are to discuss the main challenges nanotoxicologists currently face i...