Background: The leaf of Telfairia occidentalis Hook f. (Cucurbitaceae) is consumed in different parts of Nigeria because of the numerous nutritional and medicinal attributes ascribed to it. The sub-chronic toxicity of the hydroethanolic leaf extract of Telfairia occidentalis (TO) was investigated in this study. Methods: Rats in different groups were separately administered 80, 400 and 2000 mg/kg TO p.o. for 60 days. Animals were sacrificed and blood samples collected for haematological and biochemical analysis. Vital organs were harvested and evaluated for in vivo antioxidants and histopathological changes. Results: Results showed no significant changes in the weight of vital organs except in respect of the testes of the group treated with 2000 mg/kg extract which showed a significant (p<0.05) reduction in weight compared to the control group. There was a significant (p<0.01) increase in sperm motility and count of the group administered 80 mg/kg extract and a significant (p<0.001) reduction was observed at 2000 mg/kg. There were significant increases in the level of Hb and PCV at 80 and 2000 mg/kg of the extract. In respect of liver function parameters, a significant decrease in AST and ALT levels at doses of 400 and 2000 mg/kg relative to control was observed. A significant reduction (p<0.05) in the level of total cholesterol (400 mg/kg) and increase (p<0.05) in level of HDL (80-2000 mg/kg) compared to control was observed. There was also significant (p<0.05) increase in the level of MDA and significant (p<0.05) decrease in SOD level in the testes at 2000 mg/kg. Histopathological assessment of the testes revealed abnormality at this dose. These effects were reversed after 30 days of cessation of administration of TO. Conclusions: The findings showed that the hydroethanolic leaf extract of Telfairia occidentalis is relatively non-toxic on acute and sub-chronic exposure, with potential to elicit anti-anaemic effect, reduce the risk of atherosclerosis and cardiovascular disease, and enhance antioxidant status in the brain and liver. Although possibly beneficial at low dose, the extract could be harmful to the testes on prolonged oral exposure at high dose.

Stable suspensions of metal/metalloid oxide nanoparticles (Me-NPs) obtained by laser ablation of 99.99% pure elemental aluminum, titanium or silicon under a layer of deionized water were used separately, or in three binary combinations, or in a ternary combination to induce subchronic intoxications in rats. To this end, the Me-NPs were repeatedly injected intraperitoneally (i.p.) 18 times during 6 weeks before measuring a large number of functional, biochemical, morphological and cytological indices for the organism’s status. In many respects, the Al₂O₃-NP was found to be the most toxic species alone and the most dangerous component of the combinations studied. Mathematical modeling with the help of the Response Surface Methodology showed that, as well as in the case of any other binary toxic combinations previously investigated by us, the organism’s response to a simultaneous exposure to any two of the Me-NP species under study was characterized by a complex interaction between all possible types of combined toxicity (additivity, subadditivity or superadditivity of unidirectional action and different variants of opposite effects) depending on which outcome a given type was estimated for and on effect and dose levels. With any third MeO-NP species acting in the background, the type of combined toxicity displayed by the other two remained virtually the same or changed significantly, becoming either more or less unfavorable. Various harmful effects produced by the [Al₂O₃-NP+TiO₂-NP+SiO₂-NP]-combination, including its genotoxicity, were substantially attenuated by giving the rats per os during the entire exposure period a complex of innocuous bioactive substances expected to increase the organism’s antitoxic resistance.

Engineered nanomaterials (ENMs) are of significant relevance due to their unique properties, which have been exploited for widespread applications. Cerium oxide nanoparticles (CeO2-NPs) are one of most exploited ENM in the industry due to their excellent catalytic and multi-enzyme mimetic properties. Thus, toxicological effects of these ENMs should be further studied. Acute and subchronic toxicity of CeO2-NPs were assessed. First an in vitro multi-dose short-term (24h) toxicological assessment was performed in three different cell lines: A549 and Calu3, representing the lung tissue, and 3T3 as an interstitial tissue model. After that, a sub-chronic toxicity assessment (90 days) of these NPs was carried out on a realistic and well stablished reconstituted primary human airway epithelial model (MucilAir™), cultured at the Air-Liquid Interface (ALI), to study long-term effects of these particles. Results showed minor toxicity of CeO2-NPs in acute exposures. However, in subchronic exposures, cytotoxic and inflammatory responses were observed in the human airway epithelial model after 60 days of exposure to CeO2-NPs. These results suggest that acute toxicity approaches may underestimate the toxicological effect of some ENM, highlighting the need of subchronic toxicological studies in order to accurately assess the toxicity of ENM and their cumulative effects in the organism.