Selenoneine ameliorates peroxide-induced oxidative stress in C. elegans

Emerging evidence on selenoneine and its public health relevance in coastal populations: a review and case study of dietary Se among Inuit populations in the Canadian Arctic

Selenium is an essential mineral yet both deficiency and excess are associated with adverse health effects. Dietary intake of Se in humans varies greatly between populations due to food availability, dietary preferences, and local geological and ecosystem processes impacting Se accumulation into agricultural products and animal populations. We argue there is a need to evaluate and reconsider the relevance of public health recommendations on Se given recent evidence, including the metabolic pathways and health implications of Se. This argument is particularly pertinent for Inuit populations in Northern Canada, who often exceed dietary tolerable upper intake levels and exhibit very high whole blood Se concentrations due to their dependence on local country foods high in the newly discovered Se compound, selenoneine. Since selenoneine appears to have lower toxicity compared to other Se species and does not contribute to the circulating pools of Se for selenoprotein synthesis, we argue that total dietary Se or total Se in plasma or whole blood are poor indicators of Se adequacy for human health in these populations. Overall, this review provides an overview of the current evidence of Se speciation, deficiency, adequacy, and excess and implications for human health and dietary recommendations, with particular reference to Inuit populations in the Canadian Arctic and other coastal populations consuming marine foods.

Synthesis, cytotoxicity, antioxidant activity and molecular modeling of new NSAIDs-EBS derivatives

Two series of NSAIDs-EBS derivatives (5a-j and 9a-i) based on the hybridization of nonsteroidal anti-inflammatory drugs (NSAIDs) skeleton and Ebselen moiety were synthesized. Their cytotoxicity was evaluated against five types of human cancer cell lines, BGC-823 (human gastric cancer cell line), SW480 (human colon adenocarcinoma cells), MCF-7 (human breast adenocarcinoma cells), HeLa (human cervical cancer cells), A549 (human lung carcinoma cells). Moreover, the most active compound 5j showed IC50 values below 3 μM in all cancer cell lines and with remarkable anticancer activity against MCF-7 (1.5 μM) and HeLa (1.7 μM). The redox properties of the NSAIDs-EBS derivatives prepared herein were conducted by 2, 2-didiphenyl-1-picrylhydrazyl (DPPH), bleomycin dependent DNA damage and glutathione peroxidase (GPx)-like assays. Finally, TrxR1 inhibition activity assay and molecular docking study revealed NSAIDs-EBS derivatives could serve as potential TrxR1 inhibitor.

Ergothioneine, Ovothiol A, and Selenoneine-Histidine-Derived, Biologically Significant, Trace Global Alkaloids

The history, chemistry, biology, and biosynthesis of the globally occurring histidine-derived alkaloids ergothioneine (10), ovothiol A (11), and selenoneine (12) are reviewed comparatively and their significance to human well-being is discussed.

Protective effects of pretreatment with Fe2+, Cu2+, and Rb+ on phoxim poisoning in silkworm, Bombyx mori

BACKGROUND

Phoxim is a widely used organophosphorus pesticide in agriculture. People are paying more and more attention to its toxicity. At present, there is no appropriate way to solve the phoxim poisoning of silkworm, which severely affected the development of sericulture. Fe²⁺, Cu²⁺, Rb⁺ exerted their biological effects through various forms in vivo.

METHODS

To evaluate the effect of Fe²⁺/Cu²⁺/Rb⁺ on phoxim poisoning in silkworm, Bombyx mori were treated with fresh mulberry leaves soaked in 2.5 mg/L phoxim for 2 min with 50 mg/L FeCl₂, 150 mg/L CuCl₂, or 0.5 mg/L RbCl from 5 days of the fifth-instar silkworm.

RESULTS

Fe²⁺, Cu²⁺, and Rb⁺ pretreatments significantly inhibited the phoxim-induced reduction of survival rate and alleviated the phoxim-induced poisoning symptoms. The protective effects of Fe²⁺, Cu²⁺, and Rb⁺ on phoxim poisoning might be due to their enhancement of superoxide dismutase (SOD), catalase (CAT), and carboxylesterase (CarE) in the hemolymph and fat body of silkworm. This enhancement might reduce reactive oxygen species (ROS) accumulation and oxidative stress (OS) caused by phoxim poisoning. Thereby it reduced the damage to silkworm tissues and cells.

CONCLUSIONS

These results showed that Fe²⁺, Cu²⁺, and Rb⁺ treatments protected the silkworm from phoxim poisoning by directly enhancing the activity of SOD, CAT, and CarE enzymes and reducing oxidative stress, but not dependent on the high expression of CYP genes. The use of Fe²⁺, Cu²⁺, and Rb⁺ to enhance the activity of SOD, CAT, and CarE enzymes may be an underlying effective way to solve phoxim poisoning in the silkworm industry.

New organoselenides (NSAIDs-Se derivatives) as potential anticancer agents: Synthesis, biological evaluation and in silico calculations

Herein we reported the synthesis of twenty new organoselenium compounds (2a-2j and 3a-3j) based on the hybridization of nonsteroidal antiinflammatory drugs (NSAIDs) skeleton and organoselenium motif (-SeCN and -SeCF₃), the anticancer activity was evaluated against four types of cancer cell lines, Caco-2 (human colon adenocarcinoma cells), BGC-823 (human gastric cancer cells), MCF-7 (human breast adenocarcinoma cells), PC-3 (human prostatic cancer cells). Interestingly, the introduction of the -SeCN or -SeCF₃ moiety in corresponding parent NSAIDs results in the significant effect on cancer cell lines. Moreover, the most active compound 3a showed IC₅₀ values lower than 5 μM against the four cancer cell lines, particularly to BGC-823 and MCF-7 with IC₅₀ values of 2.5 and 2.7 μM, respectively. Furthermore, three compounds 3a, 3g and 3i were selected to investigate their ability to induce apoptosis in BGC-823 cells via modulating the expression of anti-apoptotic Bcl-2 protein, pro-inflammatory cytokines (IL-2) and proapoptotic caspase-8 protein. The redox properties of the NSAIDs-Se derivatives prepared herein were conducted by 2, 2-didiphenyl-1-picrylhydrazyl (DPPH), bleomycin dependent DNA damage and glutathione peroxidase (GPx)-like assays. Finally, molecular docking study revealed that an interaction with the active site of thioredoxin reductase 1 (TrxR1) and predicted the anticancer activity of the synthesized candidates. Overall, these results could serve a promising launch point for further design of NSAIDs-Se derivatives as potential anticancer agents.

Selenoneine Ameliorates Hepatocellular Injury and Hepatic Steatosis in a Mouse Model of NAFLD

Selenoneine is a novel organic selenium compound markedly found in the blood, muscles, and other tissues of fish. This study aimed to determine whether selenoneine attenuates hepatocellular injury and hepatic steatosis in a mouse model of non-alcoholic fatty liver disease (NAFLD). Mice lacking farnesoid X receptor (FXR) were used as a model for fatty liver disease, because they exhibited hepatomegaly, hepatic steatosis, and hepatic inflammation. Fxr-null mice were fed a 0.3 mg Se/kg selenoneine-containing diet for four months. Significant decreases in the levels of hepatomegaly, hepatic damage-associated diagnostic markers, hepatic triglycerides, and total bile acids were found in Fxr-null mice fed with a selenoneine-rich diet. Hepatic and blood clot total selenium concentrations were 1.7 and 1.9 times higher in the selenoneine group than in the control group. A marked accumulation of selenoneine was found in the liver and blood clot of the selenoneine group. The expression levels of oxidative stress-related genes (heme oxygenase 1 (Hmox1), glutathione S-transferase alpha 1 (Gsta1), and Gsta2), fatty acid synthetic genes (stearoyl CoA desaturase 1(Scd1) and acetyl-CoA carboxylase 1 (Acc1)), and selenoprotein (glutathione peroxidase 1 (Gpx1) and selenoprotein P (Selenop)) were significantly decreased in the selenoneine group. These results suggest that selenoneine attenuates hepatic steatosis and hepatocellular injury in an NAFLD mouse model.

The antioxidant capacity evaluation of polysaccharide hydrolyzates from pumpkin using Caenorhabditis elegans model

Our previous study has optimized the acid hydrolysis process of pumpkin polysaccharides (PPe) with scavenging ability based on central composite design. The aim of this study was to explore the in vivo-antioxidant ability of PPe and pumpkin polysaccharides acid-hydrolysis (PPe-S) using Caenorhabditis elegans. In composition analysis, the constituents of total sugar, protein, uronic acid, and sulfur groups in PPe-S were 87.03 ± 1.21%, 1.25 ± 0.78%, 37.61 ± 0.97%, and 0.14 ± 0.04%, respectively. Besides, results of antioxidant ability showed that PPe and PPe-S could reduce the oxidative stress (OS) induced by methyl viologen, extend lifespan of worms, and reduce reactive oxygen species (ROS) level under oxidative conditions significantly (p < .05). Furthermore, PPe and PPe-S could enhance the stress-resistance related antioxidant enzymes including catalase (CAT) and superoxide dismutase (SOD) significantly (p < .05). Moreover, the antioxidant effect of PPe-S was superior to PPe at the concentration of 4.0 mg/ml. In summary, this study demonstrated that the derived hydrolyzates from PPe had protective effects on the damage induced by the generation of intracellular free radical agents. PRACTICAL APPLICATIONS: OS plays an important role in the pathogenesis of metabolic diseases, including type 2 diabetes. It is widely acknowledged that diabetes and its complications pose a threat to human's health, and the number of people with diabetes will expand to 640 million in the 2040 year. Current studies have shown that all diabetes drugs have a kind of side effects. Fortunately, researchers have found and confirmed that plant-derived polysaccharide had a notable hypoglycemic effect via reducing the OS level in cell and tissue, and could decrease the diabetes symptoms as well. In this study, we proved that the polysaccharide derived from pumpkin could effectively ameliorate the OS level in C. elegans, including decreasing the damage of biofilm and ROS level. Therefore, our study shows that there is a high potential for pumpkin-derived polysaccharide and its hydrolyzates to be a bioactive component to prevent diabetes. In other words, this research can be applied to diabetes prevention and other diseases induced by OS.

Selenocysteine as a Substrate, an Inhibitor and a Mechanistic Probe for Bacterial and Fungal Iron-Dependent Sulfoxide Synthases

Sulfoxide synthases are non-heme iron enzymes that participate in the biosynthesis of thiohistidines, such as ergothioneine and ovothiol A. The sulfoxide synthase EgtB from Chloracidobacterium thermophilum (CthEgtB) catalyzes oxidative coupling between the side chains of N-α-trimethyl histidine (TMH) and cysteine (Cys) in a reaction that entails complete reduction of molecular oxygen, carbon-sulfur (C-S) and sulfur-oxygen (S-O) bond formation as well as carbon-hydrogen (C-H) bond cleavage. In this report, we show that CthEgtB and other bacterial sulfoxide synthases cannot efficiently accept selenocysteine (SeCys) as a substrate in place of cysteine. In contrast, the sulfoxide synthase from the filamentous fungus Chaetomium thermophilum (CthEgt1) catalyzes C-S and C-Se bond formation at almost equal efficiency. We discuss evidence suggesting that this functional difference between bacterial and fungal sulfoxide synthases emerges from different modes of oxygen activation.