Study transport of hesperidin based on the DPPC lipid model and the BSA transport model.

Hesperidin (HE), a significant flavonoid polyphenolic compound present in citrus plants, exhibits diverse pharmacological effects. Considering the crucial involvement of biological membranes and transporter proteins in the transportation and biological processes of HE, it becomes essential to comprehend the potential mechanisms through which HE interacts with membranes and transporter proteins. In order to simulate the process of active molecule transport, a cell membrane model consisting of 1,2-dipalmitoyl-n-glycero-3-phosphatidylcholine (DPPC) and a transporter protein model of bovine serum albumin (BSA) were employed for investigation. The present study aimed to investigate the mechanism of action of hesperidin (HE) in DPPC and BSA using fluorescence quenching, Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). The localization and interaction of HE within liposomes were also elucidated. Furthermore, the binding of BSA and HE was analyzed through UV/Vis absorption spectroscopy, fluorescence spectroscopy, infrared spectroscopy, and computational biology techniques. Computational biology analysis revealed that the binding between HE and BSA primarily occurred via hydrogen bonding and hydrophobic interactions. This study aimed to investigate the role and mechanism of HE in the DPPC cell membrane model and the BSA transporter protein model, thereby offering novel insights into the action of HE in DPPC and BSA.

Acrylamide induces ferroptosis in HSC-T6 cells by causing antioxidant imbalance of the XCT-GSH-GPX4 signaling and mitochondrial dysfunction.

Acrylamide (AA) is a heat-induced food contaminant, mainly metabolized by the liver. Increasing evidences have proved that ferroptosis is linked to the pathogenesis of liver disease. In the current study, the underlying mechanism of AA-induced rat hepatic stellate (HSC-T6) cells ferroptosis was investigated by detecting changes in iron levels, expressions of ferroptosis-related proteins and indicators of mitochondrial dysfunction. The results showed that AA treatment led to iron levels increased and expressions of long-chain acyl-CoA synthase 4 (ACSL4), cyclooxygenase 2 (COX2) and ferritin heavy chain 1 (FTH1) proteins in HSC-T6 cells were all altered. Treatment with the ferroptosis inhibitor ferrostatin-1 (Fer-1) markedly reversed the impact of AA, suggesting that AA induced ferroptosis in HSC-T6 cells. Mechanistically, AA induced the onset of ferroptosis by affecting XCT-GSH-GPX4 antioxidant signaling. Moreover, AA created a peroxidative environment for ferroptosis by inducing oxidative stress in HSC-T6 cells through mitochondrial dysfunction, as evidenced by increased mitochondrial ROS (mtROS) release, mitochondrial membrane potential (MMP) depolarization, and decreased mitochondrial ATP. Our results indicated that AA resulted in mitochondrial dysfunction and ferroptosis, and dysregulation of XCT-GSH-GPX4 antioxidant signaling was a key factor in AA-induced ferroptosis.

Derivates variation of phenylalanine as a model disinfection by-product precursor during long term chlorination and chloramination.

Dissolved nitrogenous organic matter in water can contain precursors of disinfection by-products (DBPs), especially nitrogenous DBPs (N-DBPs). Amino acids are ubiquitous as dissolved nitrogenous organic matter in source water and can pass through drinking water treatment processes to react with disinfectants in finished water and in the distribution system. Phenylalanine (Phe) was selected as a model amino acid precursor to investigate its derived DBPs and their variations during a chlorination regime that simulated water distribution with residue chlorine. The 7-day DBPs formation potential (DBPsFP) test with chlorine revealed chlorination by-products of phenylalanine including trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs), and halonitromethanes (HNMs), but not trichloronitromethane (TCNM) which was a significant N-DBP detected during the first 48 h of chlorine contact. The formation of most carbonaceous DBPs (C-DBPs) increased with chlorination time; however N-DBPs and non-chlorinated byproducts of phenylacetonitrile and phenylacetaldehyde reached their highest concentration after 2 h of reaction, and then gradually decreased until below detection after 7 days. The chlorination influencing factors indicated that light enhanced the peak yield of DBPs; the pH value showed different influences associated with corresponding DBPs; and the presence of bromide ions (Br-) generated a variety of bromine-containing DBPs. The DBPsFP test with chloramine reduced C-DBPs generation to about 1/3 of the level observed for chlorine disinfection and caused an increase in dichloroacetonitrile. Surveillance of DBPs during drinking water distribution to consumers should consider the varying contact times with disinfectants to accurately profile the types and concentrations of C-DBPs and N-DBPs present in drinking water.

Investigation of internal pollutant loading for a tide-influenced waterbody.

Based on laboratory experiments and field investigations, the relationship between internal pollutant release intensity and water velocity was determined for Neijiang, a representative waterbody. A two-dimension, unsteady hydrodynamic water quality model coupled with internal pollutant release was established and validated to assess Neijiang in different, typical years and at different tidal cycles. The internal-to-external pollutant loading ratio (IEPLR) was proposed in this paper for the first time to identify the temporal distribution of the effect induced by internal pollutant loading on the water environment. It was found that the annual internally released amounts of total nitrogen, total phosphorous, and chemical oxygen demand (COD) in the high-water year (1998) was 484.0 Mg, 405.3 Mg, and 1928.3 Mg, respectively, which was 27% greater than levels found in the typical-water year (2001) and the dry-water year (2004). Internal pollutant loading in the three typical years showed marked temporal variation; the high-water year displayed the most asymmetrical distribution. Internally released total nitrogen, total phosphorus, and COD during the tidal cycle of flood season was 1.374 Mg, 1.059 Mg, and 4.456 Mg, respectively, which was approximately 55.9% higher than dry season. External pollutant loading on Neijiang was the significant factor influencing water quality because the mean IEPLRs in the three typical years and the tidal cycles were less than one. However, because of the enhanced intensity of internal pollutant release, there were still 124 d in 1998, 22 d in 2001, and 38 d in 2004 when IEPLRs were greater than one; during these days a sudden algae bloom or water quality saltation might occur in Neijiang.