Free radical generation from an aniline derivative in HepG2 cells: a possible captodative effect

Cd2+ enhancing the bromination of bisphenol A in Brassica chinensis L.: Pathways and mechanisms

Traditional heavy metal pollution, such as cadmium, impacts the transformation and risks of bisphenol pollutants (like bisphenol A, BPA), in plants, especially due to the ubiquitous presence of bromide ion. Although it has been discovered that the bromination of phenolic pollutants occurs in plants, thereby increasing the associated risks, the influence and mechanisms of bromination under complex contamination conditions involving both heavy metals and phenolic compounds remain poorly understood. This study addresses the issue by exposing Brassica chinensis L. to cadmium ion (Cd2+, 25-100 μM), with the hydroponic solution containing BPA (15 mg/L) and bromide ion (0.5 mM) in this work. It was observed that Cd2+ primarily enhanced the bromination of BPA by elevating the levels of reactive oxygen species (ROS) and the activity of peroxidase (POD) in Brassica chinensis L. The variety of bromination products within Brassica chinensis L. increased as the concentration of Cd2+ rose from 25 to 100 μM. The substitution positions of bromine were determined using Gaussian calculations and mass spectrometry analysis. The toxicity of bromination products derived from BPA was observed to increase based on Ecological Structure-Activity Relationships analysis and HepG2 cytotoxicity assays. This study provides new insights into the risks and health hazards associated with cadmium pollution, particularly its role in enhancing the bromination of bisphenol pollutants in plants.

Dissipation of Chlorpyrifos in Bottled Tea Beverages and the Effects of (-)-Epigallocatechin-3-Gallate

ABSTRACT

Bottled tea beverages (BTB) are popular for the health benefits and convenience. Because chlorpyrifos (CP) is commonly used as a biomarker for exposure, as well as a pesticide in the field, it is important to determine the dynamics of CP dissipation in BTB to better perform risk assessments. This study focused on the dynamic behavior of CP for 22 days by fortifying bottled green tea, dark tea, and oolong tea beverages with the parent chemical and analyzing the degradation products. Photoinduction was used to generate the two transient intermediates: the reactive oxygen species from H2O2 and the triplet excited state of CP from the parent chemical in water were designed to observe the effects of (-)-epigallocatechin-3-gallate (EGCG) on the dissipation and transformation of CP. The results indicated that the CP degraded in BTB and the main products were detected. The half-life values of CP illustrated that EGCG increased the dissipation of CP by combination with CP and inhibited the generation of CP-oxon by scavenging the emerged oxidant, the reactive oxygen species, and interfering with the transformation of the triplet excited state of CP. This work suggests EGCG could play various roles in the dissipation and transformation of CP. Thus, a comprehensive identification of CP degradation should be performed when assessing the exposure risk in drinking BTB.

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