A high-affinity fluorescent probe for human uridine-disphosphate glucuronosyltransferase 1A9 function monitoring under environmental pollutant exposure.

Uridine-disphosphate glucuronosyltransferase 1A9 (UGT1A9), an important detoxification and inactivation enzyme for toxicants, regulates the exposure level of environmental pollutants in the human body and induces various toxicological consequences. However, an effective tool for high-throughput monitoring of UGT1A9 function under exposure to environmental pollutants is still lacking. In this study, 1,3-dichloro-7-hydroxy-9,9-dimethylacridin-2(9H)-one (DDAO) was found to exhibit excellent specificity and high affinity towards human UGT1A9. Remarkable changes in absorption and fluorescence signals after reacting with UGT1A9 were observed, due to the intramolecular charge transfer (ICT) mechanism. Importantly, DDAO was successfully applied to monitor the biological functions of UGT1A9 in response to environmental pollutant exposure not only in microsome samples, but also in living cells by using a high-throughput screening method. Meanwhile, the identified pollutants that disturb UGT1A9 functions were found to significantly influence the exposure level and retention time of bisphenol S/bisphenol A in living cells. Furthermore, the molecular mechanism underlying the inhibition of UGT1A9 by these pollutant-derived disruptors was elucidated by molecular docking and molecular dynamics simulations. Collectively, a fluorescent probe to characterize the responses of UGT1A9 towards environmental pollutants was developed, which was beneficial for elucidating the health hazards of environmental pollutants from a new perspective.

An electrochemical sensing platform based on a new copper complex for the determination of hydrogen peroxide and nitrite.

A new copper(II) complex [Cu(C12H23N3)4Br2·2H2O] was synthesized and its structure was characterized by x-ray crystallography and elemental analysis. The copper atom had a distorted octahedron coordination involving two bromide anions and four nitrogen atoms from the 1-decyl-1H-[1,2,4]triazole ligands. Moreover, the electrochemical behavior and electrocatalysis of the carbon paste electrode (Cu-CPE) bulk-modified by the complex have been studied in detail. The Cu-CPE showed excellent electrocatalytic activities toward the reduction of hydrogen peroxide and nitrite, and the detection limit was much lower than that mentioned in earlier reports. This bulk-modified CPE has good reproducibility, long-term stability and surface renewability, which appear promising for constructing chemical sensors.

1,2-Di-2-furylethane-1,2-dione.

The title compound, C(10)H(6)O(4), lies across a twofold rotation axis through the midpoint of the C-C bond between the two carbonyl groups. The furan ring plane and the plane through all atoms are inclined at 23.88 (1)°. In the crystal structure, weak C-H⋯O hydrogen bonds form sheets in the bc plane and columns down the c axis.

2,3-Bis(4-bromo-phen-yl)quinoxaline.

The title compound, C(20)H(12)Br(2)N(2), was prepared by the reaction of 1-(3-bromo-phen-yl)-2-(4-bromo-phen-yl)ethane-1,2-dione with o-phenyl-enediamine in refluxing ethanol. In the mol-ecule, all bond lengths and angles are within normal ranges. The dihedral angle between the two benzene rings is 34.89 (1)°. The dihedral angles between the benzene rings and the quinoxaline system are 57.23 (1) and 36.75 (1)°. The crystal packing is stabilized by van der Waals forces.

(6E)-N-[(4Z)-2,5-Dimethyl-4-(p-tolyl-imino)cyclo-hexa-2,5-dienyl-idene]-4-methyl-aniline.

The title compound, C(22)H(22)N(2), was prepared by the reaction of 4-amino-toluene with sodium carbonate, sodium hydroxide and potassium permanganate. The mol-ecule is disposed about a crystallographic inversion centre with one half-mol-ecule comprising the asymmetric unit. The dihedral angle between the terminal and central benzene rings is 88.05 (1)°. The crystal packing is stabilized by van der Waals forces.