Effects of hydroxyurea on cytotoxicity, inflammation and oxidative stress markers in neutrophils of patients with sickle cell anemia: dose-effect relationship

ABSTRACT Introduction: Although the efficacy of hydroxyurea (HU) in inhibiting erythrocyte sickling has been well demonstrated, the action of this drug on human neutrophils and the mechanism by which it improves the manifestations of the disease have not been studied thoroughly. We aimed to investigate the cell viability, along with inflammatory and oxidative markers in the neutrophils of sickle cell anemia (SCA) patients and the effects of HU therapy on these cells, by evaluating the dose-responsiveness. Methods: In the present study, 101 patients (45 men and 56 women, aged 18-69 years) with SCA were divided into groups according to the use or not of HU: the SS group (without HU treatment, n = 47) and the SSHU group (under HU treatment, n = 54). The SSHU group was further stratified into subgroups according to the daily dose of the drug that patients already used: SSHU - 0.5 g (n = 19); SSHU - 1 g (n = 26) and SSHU - 1.5-2 g (n = 9). A control group (AA) comprised 50 healthy individuals. Neutrophils isolated from whole blood were analyzed using Trypan Blue, monoiodotyrosine (MTT) and lactate dehydrogenase (LDH) toxicity assays. Myeloperoxidase (MPO), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activities and concentrations of interleukin 10 (IL-10), tumor necrosis factor alpha (TNF-α) and malonaldehyde (MDA) were also measured. Results: Neutrophils from SCA patients showed membrane fragility and a significant decrease in cell viability when analyzed by Trypan Blue (p < 0.05), MTT (p < 0.001) and LDH (p = 0.011), compared to the AA group. Levels of inflammatory (MPO, TNF-α, and IL-10) and oxidative markers (SOD, GSH-Px, and MDA) were also altered (p < 0.05) in these cells, showing a significant difference in the SSHU-1g and SSHU - 1.5-2 g groups, compared to the SS group. Treatment with HU reverted the levels of all markers to concentrations similar to those in healthy individuals in a positive dose-effect relationship. Conclusion: The HU did not generate a cytotoxic effect on neutrophils in SCA patients, but it modulated their oxidative and inflammatory mechanisms, promoting cytoprotection with a positive dose-effect.

Influence of process conditions on the physicochemical characteristics of cumaru (Amburana cearensis) powder produced by spray drying

The aim of the work was to study the spray-drying of ethanolic extract from Amburana cearensis (Allemão) A.C. Sm., Fabaceae, in order to obtain powders with better pharmacological and technological properties for herbal medicine. A 2³ fractional factorial statistical design was used to find adequate spray-drying operating conditions (inlet air temperature; feed flow rate and air flow rate) to produce A. cearensis powder with adequate concentration of active principles (amburoside and coumarin), low moisture content and high process yield. The HPLC analyses showed that the spray-drying powder of A. cearensis production did not cause alterations in the chromatographic profile when related to the fluid extract. The most significant factor that affected the amburoside concentration was air flow rate, while the concentration of coumarin, a thermolabile molecule, was influenced mainly by inlet air temperature. The moisture content of the spray-drying powder of A. cearensis varied from 3.72 to 5.85% (w/w), while the maximal process yield was 41.1% (w/w). The present study demonstrates for the first time the best operating conditions to produce A. cearensis extract powder that were adequate when related to the coumarin and amburoside concentrations and moisture content. However, additional studies are still needed to improve mainly it technological characteristics.

Anti-inflammatory activities of the hydroalcoholic extracts from Erythrina velutina and E. mulungu in mice

This work studied the anti-inflammatory activities of the hydroalcoholic extracts (HAEs) from Erythrina velutina Willd. (Ev) and E. mulungu Mart. ex Benth. (Em) in the carrageenan- and dextran-induced mice hind paw edema models. These medicinal plants belonging to the Fabaceae family are used in some Brazilian communities to treat pain, inflammation, insomnia and disorders of the central nervous system. In the present work, the extracts were administered orally in male mice at the doses of 200 or 400 mg/kg. In the carrageenan-induced test, only Em showed anti-inflammatory activity, decreasing the paw edema, at the doses of 200 and 400 mg/kg. No effect was observed with Ev in this model. On the other hand, in the dextran model, Ev demonstrated anti-inflammatory effect, showing decrease of the paw edema at the 1, 2, 3, 4 and 24th h. Em (200 or 400 mg/kg) presented anti-inflammatory effect at the 2, 3 and 4th h after administration of dextran, as compared to control. In conclusion, the work showed that Ev and Em present anti-edematous actions, which possibly occurs by distinct mechanisms. While Ev seems to interfere especially in inflammatory processes in which mast cells have an important role, Em exerts greater activity in the inflammatory process that depends mainly on polymorphonuclear leucocytes. However, further studies are needed to determine the exact mechanism of action of the species investigated.