Comparative toxicity of physiological and biochemical parameters in Euglena gracilis to short-term exposure to potassium sorbate

Oral administration of tartrazine (E102) accelerates the incidence and the development of 7,12-dimethylbenz(a) anthracene (DMBA)-induced breast cancer in rats

BACKGROUND

Despite the considerable advances made in the treatment of cancer, it remains a global threat. Tartrazine (E102) is a synthetic dye widely used in food industries; it has recently been shown to induce oxidative stress (a well known risk factor of cancer) in rat tissues. The present work therefore aimed to assess the impact of a regular consumption of tartrazine on the incidence of breast cancer in rats.

METHODS

Forty (40) Wistar rats aged 55 to 60 days were randomly assigned into 5 groups (n = 8) including two groups serving as normal controls and receiving distilled water (NOR) or tartrazine (NOR + TARZ). The three remaining groups were exposed to the carcinogen DMBA (50 mg/kg) and treated for 20 weeks with either distilled water (DMBA), tartrazine 50 mg/kg (DMBA + TARZ) or a natural dye (DMBA + COL). The parameters evaluated were the incidence, morphology and some biomarkers (CA 15-3, estradiol and α-fetoprotein) of breast cancer. The oxidative status and histomorphology of the tumors were also assessed.

RESULTS

A regular intake of tartrazine led to an early incidence of tumors (100% in rats that received TARZ only vs 80% in rats that received DMBA only), with significantly larger tumors (p < 0.001) (mass = 3500 mg/kg and volume = 4 cm3). The invasive breast carcinoma observed on the histological sections of the animals of the DMBA + TARZ group was more developed than those of the DMBA group. The increase in serum α-fetoprotein (p < 0.05) and CA 15-3 (p < 0.01) levels corroborate the changes observed in tumors. The presence of oxidative activity in animals of the DMBA + TARZ group was confirmed by a significant decrease (p < 0.001) in the activity of antioxidant enzymes (SOD and catalase) as well as the level of GSH and increase in the level of MDA compared to the rats of the DMBA and NOR groups.

CONCLUSION

Tartrazine therefore appears to be a promoter of DMBA-induced breast tumorigenesis in rats through its oxidative potential. This work encourages further studies on the mechanisms of action of tartrazine (E102) and its limits of use.

Aquatic plants and ecotoxicological assessment in freshwater ecosystems: a review

This paper reviews the current state-of-the-art, limitations, critical issues, and new directions in freshwater plant ecotoxicology. We selected peer-reviewed studies using relevant databases and for each (1) publication year, (2) test plant species, (3) reference plant group (microalgae, macroalgae, bryophytes, pteridophytes, flowering plants), (4) toxicant tested (heavy metal, pharmaceutical product, hydrocarbon, pesticide, surfactant, plastic), (5) experiment site (laboratory, field), and (6) toxicant exposure duration. Although aquatic plant organisms play a key role in the functioning of freshwater ecosystems, mainly linked to their primary productivity, their use as biological models in ecotoxicological tests was limited if compared to animals. Also, toxicant effects on freshwater plants were scarcely investigated and limited to studies on microalgae (80%), or only to a certain number of recurrent species (Pseudokirchneriella subcapitata, Chlorella vulgaris, Lemna minor, Myriophyllum spicatum). The most widely tested toxicants on plants were heavy metals (74%), followed by pharmaceutical products and hydrocarbons (7%), while the most commonly utilized endpoints in tests were plant growth inhibition, variations in dry or fresh weight, morpho-structural alterations, chlorosis, and/or necrosis. The main critical issues emerged from plant-based ecotoxicological tests were the narrow range of species and endpoints considered, the lack of environmental relevance, the excessively short exposure times, and the culture media potentially reacting with toxicants. Proposals to overcome these issues are discussed.

Anthracene phytotoxicity in the freshwater flagellate alga Euglena agilis Carter

The freshwater flagellate alga Euglena agilis Carter was exposed to the polycyclic aromatic hydrocarbon (PAH) anthracene for 96 h under optimal photosynthetically active radiation (PAR), and responses of growth, photosynthetic pigment production, and photosynthetic efficiency were assessed. Anthracene reduced the growth rate (μ) and levels of chlorophyll a (Chl a), chlorophyll b (Chl b), and total carotenoids. The growth rate was more sensitive than photosynthetic parameters, with a median effective concentration (EC₅₀) of 4.28 mg L^-1. Between 5 and 15 mg L^-1, anthracene inhibited the maximum quantum yield (F_v/F_m) of photosystem II (PSII) and the maximum photosynthetic electron transport rate through PSII (rETR_max) with EC₅₀ values of 14.88 and 11.8 mg L^-1, respectively. At all anthracene concentrations, intracellular reactive oxygen species (ROS) were elevated, indicating increased oxidative stress. Anthracene presumably reduced the PSII efficiency of photochemical energy regulation and altered the photochemistry through intracellular ROS formation. Acute exposure to PAHs may induce severe physiological changes in phytoplankton cells, which may influence vital ecological processes within the aquatic environments. Additionally, growth and Chl a content may serve as sensitive risk assessment parameters of anthracene toxicity in water management since EC₅₀ values for both overlap with anthracene levels (8.3 mg L^-1) permitted by the US Environmental Protection Agency (USEPA).

Acute and 28-day repeated dose oral toxicity study of caraway oil in rats

Background Caraway oil (CO) obtained from the fruits of Carum carvi L. (Apiaceae) is used in traditional systems of medicine for various diseases. The present study was designed to evaluate the safety profile of CO by acute and repeated dose oral toxicity as per the Organisation for Economic Co-operation and Development guidelines 423 and 407, respectively. Methods In an acute toxicity study, a single dose of CO (300 and 2000 mg/kg) was given to female Wistar rats, and the animals were observed for signs of behavioral alterations, morbidity and mortality for 14 days. Repeated dose toxicity was performed at doses of 50, 100 and 200 mg/kg for 28 days in Wistar rats. The effects of CO on food and water intake, body weight, relative organ weight, clinical biochemistry, hematological parameters and urine parameters were studied. Gross necropsy and histopathology of vital organs were carried out. Results A single oral dose at 300 mg/kg CO did not show any signs of toxicity and mortality, while a dose of 2000 mg/kg showed signs of mortality in one animal and some signs of toxicity in another two animals. In the repeated dose toxicity study, CO at selected dose levels did not show any significant alterations in food and water intake, body weight and relative organ weight. Administration of CO did not show any significant changes in hematological, biochemical and urine parameters and histopathology study when compared with normal control animals. Conclusions The CO was found to be safe at all selected dose levels in the repeated dose toxicity study in rats.

Potassium sorbate suppresses intestinal microbial activity and triggers immune regulation in zebrafish (Danio rerio)

Potassium sorbate (PS) is a class of bacteriostatic antiseptic agent widely used in the food industry; the effects of its intake on host health are currently unclear.