Electrochemical behavior and determination of major phenolic antioxidants in selected coffee samples.

The redox behavior of commercial roasted coffee products were evaluated by electroanalysis, whereas high performance liquid chromatography (HPLC) was used for determination of cinnamic acid markers, the total phenolic content (TPC) was achieved by Folin-Ciocalteu assay, and the traditional DPPH (1-diphenyl-2-picrylhydrazyl) method for antioxidant power determination. In turn, an optimized electrochemical index was proposed to estimate the antioxidant power of different samples and it was found a great correlation between all methods. The voltammetric profile of all coffee samples was quite similar, presenting the same number of peaks at the same potential values. Minor differences on current levels were in agreement with the total phenolic and major markers content, as well as, to the antioxidant power. Therefore, the electrochemical methods showed to be practical, low cost and very useful to evaluate the antioxidant properties of coffee samples, which is a relevant quality parameter of this widely consumed beverage.

Blocking the L-type Ca2+ channel (Cav 1.2) is the key mechanism for the vascular relaxing effect of Pterodon spp. and its isolated diterpene methyl-6α-acetoxy-7ß-hydroxyvouacapan-17ß-oate.

Pterodon spp. Vogel (Fabaceae), popularly known as "sucupira", has ethnopharmacological application which is described as having antispasmodic and relaxant effects. Hence, it was hypothesized that sucupira oil-resin (SOR) could induce smooth muscle relaxation. So, this study investigated the mechanisms involved in the vasorelaxant effect of SOR and its isolated diterpene (methyl-6α-acetoxy-7ß-hydroxyvouacapan-17ß-oate). Vascular reactivity experiments were performed using rat aortic rings (n=5-8) with (E+) or without endothelium (E-) in an isolated bath organ. The SOR (0-56 µg/mL) relaxed phenylephrine (E+: 86.7±7.1%; E-: 92.3±4.7%) and KCl contracted rings (E-: 97.1±2.8%). In the same way, diterpene (0-48 µg/mL) also relaxed phenylephrine (E+: 94.5±3.6%; E-: 92.2±3.4%) and KCl contracted rings (E-: 99.7±0.2%). The pre-incubation of arterial rings with cyclopiazonic acid (reticular Ca2+-ATPase inhibitor), tetraethylammonium (K+ channels blocker) or MDL-12,330A (adenylyl cyclesinhibitor) did not modify either SOR- or diterpeneinduced vasorelaxation. However, ODQ (guanylyl cyclase inhibitor) impaired only diterpene-induced vasorelaxation. SOR and diterpene significantly reduced CaCl2-induced contraction stimulated by Bay K8644 (1 µM), phenylephrine (0.1 µM) or KCl solution (40 mM). Computational molecular docking studies demonstrated that the vasodilator effect of diterpene relies on blocking the Cav 1.2 channel, and patch clamp results showed that diterpene substantially decreased the ionic current through Cav 1.2 in freshly dissociated vascular smooth muscle cells. These findings suggest that SOR and its isolated diterpene induce endothelium-independent vascular relaxation by blocking the L-type Ca2+ channel (Cav 1.2).

Diuretic effects and urinary electrolyte excretion induced by Aspidosperma subincanum Mart. and the involvement of prostaglandins in such effects.

ETHNOPHARMACOLOGICAL RELEVANCE: Aspidosperma subincanum Mart. is a medicinal herb known for its diuretic properties and used for the treatment of cardiovascular-related illnesses. Although our earlier study has shown that the ethanol extract of Aspidosperma subincanum (EEAS) induces hypotension and vasodilation, no scientific data have been recorded to evaluate the diuretic effects of this Brazilian medicinal plant. The aim of this study was to evaluate the diuretic activity of EEAS, and possible mechanism of action, using Wistar rats. MATERIAL AND METHODS: EEAS (60 and 120mg/kg), furosemide (20mg/kg) or saline (control) were orally administered to rats individually held in metabolic cages for urine collection 1, 2, 4, 6, 8, 12 and 24h after treatment. In order to evaluate the involvement of prostaglandins in the diuretic action of EEAS, the animals received piroxicam (5mg/kgi.p.), a nonselective inhibitor of cyclooxygenase, before treatment with EEAS at 120mg/kg. The control groups received only saline (NaCl, 0.9%), or saline and piroxicam. Urinary volume, electrolyte excretion and pH were measured. RESULTS: Oral administration of EEAS 60 and 120mg/kg significantly increased diuresis and electrolyte excretion of Na(+) and K(+) on a continuous basis throughout the study period. Both EEAS 60 and 120mg/kg caused a relative increase of around 77% and 142%, respectively, in cumulative diuresis compared with the control group. From 4th hour until the end of the experiment, the group treated with EEAS 120mg/kg provided a greater excretion of Na(+) than the furosemide group. The diuretic effects of EEAS were neutralized by piroxicam between 4 and 8h after treatment. CONCLUSION: The results suggest that EEAS could present compound(s) responsible for diuretic activities, and the mechanism could involve the prostaglandin system.

Impact of lipid dynamic behavior on physical stability, in vitro release and skin permeation of genistein-loaded lipid nanoparticles.

The aim of this study was to develop lipid nanoparticles to deliver genistein (GEN) to deeper skin layers. To do so, the impact of lipid dynamic behavior (nanoparticle flexibility) on stability, release and skin permeation studies was verified. GEN-loaded solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) were obtained and characterization was undertaken. Freshly prepared nanoparticles were produced with similar features (i.e., drug loading). However, a higher level of crystallization in GEN-SLN formulation was observed in differential scanning calorimetry experiments. Electron paramagnetic resonance measurements showed a lower mobility of the spin labels in the SLN, which would indicate that NLC could be more flexible than SLN. Despite the fact that NLC demonstrated more fluidity, GEN was released more slowly from NLC than from SLN. Skin permeation studies demonstrated that lipid nanoparticles increased GEN skin retention. More flexible particles (NLC) also favored drug penetration into deeper skin layers. GEN-NLC would seem to be a promising formulation for GEN topical delivery.