Current Chemical Biology - Volume 19, Issue 2, 2025

Freshwater bivalves are considered effective biomarkers for pollution in aquatic ecosystems. Despite advances in the use of zinc oxide nanoproducts in several sectors, such as food, industry, and medicine, paying attention to their environmental impacts is crucial. The objective of the study was to investigate the mechanisms of zinc oxide-chitosan nanocomposites (ZnO-CS NCs) ecotoxic in freshwater environments using freshwater bivalves Coelatora aegyptica as a sensitive indicator.

After preparing and characterizing ZnO NPs and ZnO-CS NCs with transmission electron microscopy, ultraviolet spectroscopy, and X-ray diffraction, we exposed the bivalve to three different doses of ZnO NPs and ZnO-CS NCs (12.5, 25, and 50 mg/L) for 7 days.

ZnO-CS NCs concentrations significantly increased malondialdehyde and nitric oxide levels, whereas glutathione and catalase levels decreased in investigated organs. Furthermore, histological changes were detected in the tissues of the gills and mantle.

The bivalve organs had varying quantities of MDA, NO, GSH, and CAT. This could be related to the accumulation pattern of heavy metals in each organ, their close interaction with water, or the removal rates.

We concluded from our findings that the toxicity of ZnO-CS NCs on freshwater bivalves causes histological alterations and an oxidative stress response. Moreover, Coelatura aegyptiaca was proposed as a highly sensitive bioindicator to monitor water contamination induced by diverse nanoparticles because it can accumulate and concentrate most pollutants, even at low concentrations. As a result, we recommend conducting additional studies with fresh bivalves to evaluate the aquatic ecosystem well and reduce water contamination at both local and worldwide levels.

Essential oils are widely recognized for their antioxidant properties, including their ability to neutralize free radicals and protect cells from oxidative stress, a key factor in cell death associated with neurodegenerative diseases.

The aim of this study was to analyze the chemical composition of essential oil extracted from the leaves and flowers of Xanthium italicum and to evaluate its antioxidant activity using the DPPH test and the Ferric Antioxidant Power Reduction Test (FRAP), as well as its hemolytic properties.

Leaf and fruit chemical composition was determined by gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC-MS). Antioxidant properties were evaluated using DPPH and FRAP methods. A suspension of human blood erythrocytes was used to determine the hemolytic effect of essential oils.

Thirty-five compounds were identified in the essential oil extracted from the leaves of Xanthium italicum. The main compounds were limonene (41.5%) and germacrene D (14.2%). For fruit essential oil, twenty-five compounds were identified, with α-bisabolol (62.2%), α-humulene (8.1%), and limonene (5.2%) as the main constituents. In-vitro antioxidant activity tests showed that the essential oil of Xanthium italicum fruits is a powerful antioxidant (0.038 mg/mL), surpassing even ascorbic acid (0.048 mg/mL). Human erythrocyte toxicity tests showed that the essential oil of Xanthium italicum leaves and fruits have a relatively low hemolytic effect, with hemolysis rates of 15.3% and 8.1%, respectively, even at high concentrations of 1000 μg/mL.

The essential oils of Xanthium italicum show a strong antioxidant activity, especially in fruits, and a low hemolytic effect on human erythrocytes. This could be a safe and effective natural antioxidant.