Rapid structural characterization of in vivo and in vitro metabolites of tinoridine using UHPLC-QTOF-MS/MS and in silico toxicological screening of its metabolites

Tinoridine is a nonsteroidal anti-inflammatory drug and also has potent radical scavenger and antiperoxidative activity. However, metabolism of tinoridine has not been thoroughly investigated. To identify in vivo metabolites, the drug was administered to Sprague-Dawley rats (n = 5) at a dose of 20 mg kg(-1), and blood, urine and feces were collected at different time points up to 24 h. In vitro metabolism was delved by incubating the drug with rat liver microsomes and human liver microsomes. The metabolites were enriched by optimized sample preparation involving protein precipitation using acetonitrile, followed by solid-phase extraction. Data processes were carried out using multiple mass defects filters to eliminate false-positive ions. A total of 11 metabolites have been identified in urine samples including hydroxyl, dealkylated, acetylated and glucuronide metabolites; among them, some were also observed in plasma and feces samples. Only two major metabolites were formed using liver microsomal incubations. These metabolites were also observed in vivo. All the 11 metabolites, which are hitherto unknown and novel, were characterized by using ultrahigh-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry in combination with accurate mass measurements. Finally, in silico toxicological screening of all metabolites was evaluated, and two metabolites were proposed to show a certain degree of lung or liver toxicity.

Aminodi(hetero)arylamines in the thieno[3,2-b]pyridine series: synthesis, effects in human tumor cells growth, cell cycle analysis, apoptosis and evaluation of toxicity using non-tumor cells

Three aminodi(hetero)arylamines were prepared via a palladium-catalyzed C-N Buchwald-Hartwig coupling of methyl 3-aminothieno[3,2-b]pyridine-2-carboxylate with different bromonitrobenzenes, followed by reduction of the nitro groups of the coupling products to the corresponding amino compounds. The aminodi(hetero)arylamines thus obtained were evaluated for their growth inhibitory effect on four human tumor cell lines MCF-7 (breast adenocarcinoma), A375-C5 (melanoma), NCI-H460 (non-small cell lung cancer) and HepG₂ (hepatocellular carcinoma). The toxicity to non-tumor cells was also evaluated using a porcine liver primary cell culture (PLP1), established by us. The aminodi(hetero)arylamine with the NH₂ group in the ortho position and an OMe group in the para position to the NH of the di(hetero)arylamine, is the most promising compound giving the lowest GI₅₀ values (1.30–1.63 µM) in all the tested human tumor cell lines, presenting no toxicity to PLP1 at those concentrations. The effect of this compound on the cell cycle and induction of apoptosis was analyzed in the NCI-H460 cell line. It was observed that it altered the cell cycle profile causing a decrease in the percentage of cells in the G0/G1 phase and an increase of the apoptosis levels.