Background and PurposeLeaves of Jacaranda decurrens are used in traditional Brazilian medicine to treat metabolic diseases related to increased reactive oxygen species. The present study evaluated the antioxidant and cytotoxic potential of hydroethanolic extract from the leaves of Jacaranda decurrens subsp. symmetrifoliolata.Experimental ApproachPhenolic compounds, flavonoids and saponins were evaluated in an ethanol∶water (80∶20, v/v) extract from the leaves of Jacaranda decurrens subsp. symmetrifoliolata (E-Jds). The antioxidant activity of E-Jds was investigated by assessing the following: 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity; protection against 2,2′-azobis (2-amidinopropane) dihydrochloride (AAPH)-induced hemolysis of erythrocytes; in vitro and in vivo malondialdehyde dosage; and the ability to activate antioxidant enzymes. K562 leukemia cells were used for the cytotoxic evaluation of E-Jds and for the assessment of the cell death profile through flow cytometry.Key ResultsPhenolic and flavonoid compounds were quantified as 14.38% and 2.15%, respectively, of E-Jds. These phenolic and flavonoid compounds proved to be able to scavenge DPPH free radicals with an IC50 of 9.3±3.3 µg/mL, to protect up to 50% of erythrocytes against AAPH-induced hemolysis and to reduce in vitro and in vivo malondialdehyde levels up to 84% and 22%, respectively. E-Jds also increased glutathione peroxidase enzyme activity, with a concomitant decrease in superoxide dismutase and catalase activity, and exhibited dose-dependent cytotoxic activity on K562 erythroleukemia cells with cell death occurring via both late apoptosis and necrosis.ConclusionsE-Jds exhibits in vitro and in vivo antioxidant potential, which may be the mechanism mediating the metabolic activities reported in folk medicine. Furthermore, the cytotoxic activity identified in this study contributes with the knowledge of antiproliferative activities that have been described in the literature for the genus Jacaranda.

Background. Obesity is a growing epidemic with limited effective treatments and an important risk factor for several diseases such as metabolic syndrome (MetS). In this study, we aimed to investigate the effect of 3-amino-1,2,4-triazole (ATZ), an inhibitor of catalase and heme synthesis, in a murine model for MetS. Methods. Male C57BL/6 mice with high-fat diet-induced MetS received ATZ (500 mg·kg-1·24 h-1) for 12 weeks. Results. The HFD group showed increased blood pressure and body weight, enhanced fat deposition accompanied by an increase in adipocyte diameter, and decreased lipolysis in white adipose tissue (WAT). The expression of genes related to inflammation was increased in WAT of the HFD group. Concurrently, these mice exhibited an increase in leptin, nonesterified fatty acid (NEFA), insulin, and glucose in plasma, coupled with glucose intolerance and insulin resistance. Strikingly, ATZ prevented the increase in blood pressure and the HFD-induced obesity as observed by lower body weight, WAT index, triglycerides, NEFA, and leptin in plasma. ATZ treatment also prevented the HFD-induced increase in adipocyte diameter and even induced marked atrophy and the accumulation of macrophages in this tissue. ATZ treatment also improved glucose metabolism by increasing glucose tolerance and insulin sensitivity, GLUT4 mRNA expression in WAT in parallel to decreased insulin levels. Conclusions. In the context of HFD-induced obesity and metabolic syndrome, the fat loss induced by ATZ is probably due to heme synthesis inhibition, which blocks adipogenesis by probably decreased RevErbα activity, leading to apoptosis of adipocytes and the recruitment of macrophages. As a consequence of fat loss, ATZ elicits a beneficial systemic antiobesity effect and improves the metabolic status.