Inhibitory interaction of flavonoids with organic anion transporter 3 and their structure-activity relationships for predicting nephroprotective effects.

The organic anion transporter 3 (OAT3), an important renal uptake transporter, is associated with drug-induced acute kidney injury (AKI). Screening and identifying potent OAT3 inhibitors with little toxicity in natural products, especially flavonoids, in reducing OAT3-mediated AKI is of great value. The five strongest OAT3 inhibitors from the 97 flavonoids markedly decreased aristolochic acid I-induced cytotoxicity and alleviated methotrexate-induced nephrotoxicity. The pharmacophore model clarified hydrogen bond acceptors and hydrophobic groups are the critical pharmacophores. These findings would provide valuable information in predicting the potential risks of flavonoid-containing food/herb-drug interactions and optimizing flavonoid structure to alleviate OAT3-related AKI.

Multifold enhanced synergistic removal of nickel and phosphate by a (N,Fe)-dual-functional bio-sorbent: Mechanism and application.

A novel (N,Fe)-dual-functional biosorbent (N/Fe-DB) capable of efficient synergistic removal of Ni(II) and H2PO4- from aqueous solution was synthesized. The adsorption capacities of Ni(II) and H2PO4- were both remarkably enhanced over 3 times compared with those in single systems. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy confirmed that complexation of amino groups and ligand exchange of hydrous ferric oxide in N/Fe-DB played dominant roles. The electric double layer compressing and chelating ligand of deprotonated H2PO4- accounted for the enhanced removal of Ni(II) in binary system, while cation bridge interaction promoted uptake of H2PO4-. Furthermore, the coadsorbates were sequentially recovered, with the ratios of more than 99.0%. Besides, the recovered N/Fe-DB remained stable and applicable to the treatment of real electroplating wastewater even after six adsorption-regeneration cycles. Since the electroplating industry is springing up, effective control of heavy metals and phosphate has attracted global concerns. Based on the enhanced coremoval properties and superb regenerability, N/Fe-DB is potentially applicable to practical production.

Synthesis of heavy metal chelating agent with four chelating groups of N1,N2,N4,N5-tetrakis(2-mercaptoethyl)benzene-1,2,4,5-tetracarboxamide (TMBTCA) and its application for Cu-containing wastewater.

A novel heavy metal chelating agent, N(1),N(2),N(4),N(5)-tetrakis(2-mercaptoethyl) benzene-1,2,4,5-tetracarboxamide (TMBTCA), was designed with four chelating groups, and a facile one-step synthetic procedure was developed with pyromellitic dianhydride (PMDA) and cysteamine hydrochloride (CHC) as raw materials by aqueous acylation. The effects of mole ratio of reactants (CHC/PMDA), reaction temperature, and reaction time on the yield of TMBTCA were studied. Its application for Cu-containing wastewater was investigated. The experimental results showed that the maximum yield of TMBTCA was 75.92%, as the mole ratio of CHC/PMDA reached 4.8, reaction temperature was 5°C, and reaction time was 6h. It was observed that TMBTCA could effectively remove Cu(2+) and CuEDTA to much lower than 0.5 mg/L (the discharge limit of copper ions in China). Furthermore, TMBTCA showed more affinity for cadmium and copper than some traditional commercial precipitants, such as DTC, TBA and TMT, via comparison of their ability for heavy metal removal, and the precipitates of Cu-TMBTCA and Cd-TMBTCA presented good stability in leaching tests. The results can provide a reference for design and further research on new kind of heavy metal chelating agent with more bonding sites, especially for heavy metal precipitation in PCB wastewater treatment.