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Toxicological effects of 25H-NBOMe and 25H-NBOH recreational drugs on zebrafish embryos and larvae at the end of 96 h exposure period were demonstrated. 25H-NBOH and 25H-NBOMe caused high embryo mortality at 80 and 100 µg mL−1, respectively. According to the decrease in the concentration tested, lethality decreased while non-lethal effects were predominant up to 10 and 50 µg mL−1 of 25H-NBOH and 25H-NBOMe, respectively, including spine malformation, egg hatching delay, body malformation, otolith malformation, pericardial edema, and blood clotting. We can disclose that these drugs have an affinity for DNA in vitro using biophysical spectroscopic assays and molecular modeling methods. The experiments demonstrated that 25H-NBOH and 25H-NBOMe bind to the unclassical major groove of ctDNA with a binding constant of 27.00 × 104 M−1 and 5.27 × 104 M−1, respectively. Furthermore, these interactions lead to conformational changes in the DNA structure. Therefore, the results observed in the zebrafish embryos and DNA may be correlated.

Twenty chromenes were synthesized with good to excellent yields (70–96%). From the series of chromenes herein tested, compounds 14, 12, 15, 16, 17, 18, and 20 were the most potent throughout the cancer human cell lines tested. In general, the para-position electron-withdrawing substituents on the phenyl ring are favored towards potency and selectivity for cancer cells. Biophysical studies were performed with eight chromene derivatives (13-20) and ctDNA to evaluate possible biological targets. The molecular fluorescence verified that compound 16 presented a higher binding constant (Kb) with the ctDNA, agreeing with in vitro biological results and that evaluated chromenes derivatives interact preferentially via intercalation. Finally, an inverse linear correlation (logKb vs. GI50) was observed for six human carcinogenic cell lines; hence, the mechanism of action of these compounds may be related to DNA interaction.

Background: The pharmacological effects of propolis have mainly been investigated in various fields of medicine as an essential resource for the prevention and treatment of diseases. Purpose: This study examined the cardioprotective effect of hydroalcoholic extract of Brazilian red propolis (BRPHE) against isoproterenol (ISO)-induced myocardial infarction in rats. Methods: Rats were pretreated with BRPHE (50, 75, and 150 mg/kg) for 30 days, with concurrent administration of ISO (85 mg/kg) during the last two days. The hemodynamic, biochemical, histological, and morphometric changes were monitored from control and experimental groups at the end of the experiment, i.e., on the 31st day. Phytochemical compounds were determinated by the UV–Vis spectrophotometric and UPLC-DAD-UV–Vis methods. Results: ISO-induced myocardial infarcted rats showed an increase in cardiac marker enzymes, i.e., in creatine kinase-NAC (CK-NAC) and CK-MB, tachycardia, myocardium necrosis, edema, hemorrhagic areas, infiltration of inflammatory cells like lymphocytes, and increased myocardial infarct size. However, pretreatment of ischemic rats with BRPHE significantly inhibited these effects of ISO. Thus, histopathological findings obtained for the myocardium further confirmed the biochemical findings. Flavonoids and phenols were identified in BRPHE. Conclusion: Our results suggested that BRPHE pretreatment ameliorated myocardial injury in ISO-induced myocardial infarcted rats and exhibited cardioprotective activity.

Purpose: Quercetin is a flavonoid known for its therapeutic properties and for forming complexes. Although the antimony-quercetin (SbQ) complex has been produced before, no previous exploration of its characteristics has been published in literature. Thus, this study aimed to characterize this complex, assess its stability and investigate its complexation site through its antibacterial activity. Methods: The SbQ complex was synthetized using Sb(III) potassium tartrate trihydrate and quercetin anhydrous (1:1) (v/v) as a solution and dried using three methods: rotaevaporation, lyophilization and spray drying. The material, in solution, was analyzed by UV-vis and fluorimetry; and, in the powder, by X-ray diffraction (XRD), both scanning electronic and fluorescence microscopy and infrared spectroscopy (FT-IR). Antimicrobial activity was evaluated via broth microdilution. Results: UV-vis exhibited a shoulder peak at 291 nm indicating metal chelation at C-ring of quercetin and confirmed 1:1 stoichiometry. Spectrofluorimetry showed an increase of intensity with the complex formation with an emission band (525 nm). After drying, XRD and SEM indicated loss of crystallinity and a difference in shape and size of the complex compared to its precursors. FT-IR suggested by a shift of frequency of the carbonyl group (1661 cm-1) that the quercetin bond to antimony by the C-3, followed by positions C-5 and C-4 carbonyl, which has been confirmed by MIC through the structure-activity relationship of the antibacterial activity of quercetin. Conclusion: These results provided a characterization of SbQ complex with the confirmation of its binding site, working as a guide for future studies involving this complex.

AbstractMany well-established methods for determining the antioxidant capacities in several samples have been described in literature. However, DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)) are the main two methods that utilize radicals as spectrophotometric probes for analysis. Nevertheless, these methods have certain limitations because of their slower kinetics, solvent polarity effects, the hydrophilicity and lipophilicity of the compounds, chemical costs, etc. In this study, a spectrophotometric method for determining the antioxidant capacity in beverages was developed based on an exploration of the cation radical derived from DEPD. This method was based on the oxidation of aromatic amines with Fe(III) ions at pH 4.0, which leads to their corresponding purple cation radicals (DEPD•+) with λmax values at 500 and 540 nm. The addition of an antioxidant after the formation of the radical leads to a reduction in color intensity that is proportional to the antioxidant concentration in the medium. Results obtained using this method were compared with the Folin-Ciocalteau, ABTS and DPPH methods in terms of applications in wines, teas, and infusions samples. Linear correlation analysis at a 95% confidence level was employed to compare the results, which were in good agreement with a correlation coefficient of r > 0.9000. Thus, the developed method was simple, accurate, and consistent with other assays for the determination of the total amount of phenolic compounds and antioxidant capacity.

A multi-commuted flow system was developed to determine propylthiouracil (PTU) based on the reaction of its thiol form with iminoquinone radical generated by the oxidation of N,N-dimethyl-p-phenylenediamine in an alkaline medium. PTU can be found in tautomeric forms and the tautomeric equilibrium was displaced to enhance the thiol form. However, the reaction product is unstable and its residence time in the flow path was carefully investigated. The proposed procedure showed good precision (< 1.5%) and a limit of detection (3s) of 0.11 mg L-1. High recoveries were obtained in the validation test. The procedure was employed for propylthiouracil determination in medications.

A multi-commuted flow system was developed to determine propylthiouracil (PTU) based on the reaction of its thiol form with iminoquinone radical generated by the oxidation of N,N-dimethyl-p-phenylenediamine in an alkaline medium. PTU can be found in tautomeric forms and the tautomeric equilibrium was displaced to enhance the thiol form. However, the reaction product is unstable and its residence time in the flow path was carefully investigated. The proposed procedure showed good precision (< 1.5%) and a limit of detection (3s) of 0.11 mg L-1. High recoveries were obtained in the validation test. The procedure was employed for propylthiouracil determination in medications.