The mechanisms of calcium mobilization by procyanidins, flavonols and flavonoids from Cecropia glaziovii Sneth in pulmonary endothelial cell cultures endorse its popular use as vasodilator phytomedicine

The hypotensive and antihypertensive activities of the aqueous extract (AE) and butanolic fraction (ButF) isolated from Cecropia glaziovii Sneth have been demonstrated in previous studies in animal models. This study aimed to evaluate the molecular mechanism of action responsible for the vasodilatory effect of procyanidins, flavanols, and flavonoids found in C. glaziovii in endothelial cell culture. For this purpose, we analyzed the effect of procyanidin B2 and B3 compounds, catechin, epicatechin, orientin, isoorientin, and isovitexin in the mobilization of Ca2+ in rat endothelial cell cultures. Parallel associations with different antagonists were examined by considering the following in vivo hypotensive mechanisms: blockage of L-type calcium channels, action on β-2 adrenergic receptors, and vasodilation via the nitric oxide pathway. All measurements of calcium mobilization were carried out by using the fluorescence measurement methodology in a Flexstation M3 spectrophotometer. The results indicate that some of the compounds have mixed actions, acting through different calcium mobilization pathways. The mobilization induced by such compounds significantly decreased when they were incubated with their corresponding antagonists. Taken together, our data suggest that the beneficial effects seen with the popular use of Cecropia glaziovii Sneth in pathological conditions, such as systemic arterial hypertension, seem to be related to the plant's hypotensive effect, very probably promoted by the actions of flavonols, flavonoids, and procyanidins, by different pathways of calcium mobilization.

Soybean concentrated extract counteracts oxidative stress in the uterus of rats

OBJECTIVE

To evaluate the effects of soy isoflavone extract in the pro-oxidant/antioxidant balance in the uterus of ovariectomized rats.

METHODS

Twenty 3-month-old adult female Wistar rats were divided into four equal groups: GI: sham-operated (estrous phase); GII: control ovariectomized rats; GIII: ovariectomized rats treated with genistein (50 μg/kg/day) by gavage; GIV: ovariectomized rats subcutaneously treated with estrogen (10 μg/kg/day). After 30 consecutive days of treatment, the rats were euthanized and the uterus removed. The distal thirds of the uterine horns were processed for histomorphometric analyses of endometrial and myometrial thicknesses and glandular area. Other regions of the uteri were kept in liquid nitrogen and subsequently processed for analysis of reactive species quantification (DCF), total antioxidant capacity (TAC) and lipid oxidation status (TBARS). Data were statistically analyzed by one-way ANOVA, complemented by the Tukey-Kramer test (p < 0.05).

RESULTS

GII and GIII exhibited lower endometrial thickness, glandular area and myometrial thickness than GI and GIV, while a higher myometrial thickness was observed in GIV compared with the other groups. Moreover, the isoflavone-treated group showed lower DCF and TBARS compared to GII, and also an improvement of TAC compared to GI and GIV. Despite the significant decrease in TBARS, no significant difference in DCF nor a decrease in TAC were observed in GIV when compared to GII.

CONCLUSION

Our data show that isoflavones improve antioxidant status and counteract oxidative stress, without promoting a trophic effect in the uterus of rats.

Glutamate-induced alterations in Ca2+ signaling are modulated by mitochondrial Ca2+ handling capacity in brain slices of R6/1 transgenic mice

Huntington's disease is a neurodegenerative disorder caused by an expansion of CAGs repeats and characterized by alterations in mitochondrial functions. Although changes in Ca(2+) handling have been suggested, the mechanisms involved are not completely understood. The aim of this study was to investigate the possible alterations in Ca(2+) handling capacity and the relationship with mitochondrial dysfunction evaluated by NAD(P)H fluorescence, reactive oxygen species levels, mitochondrial membrane potential (DeltaPsi(m)) measurements and respiration in whole brain slices from R6/1 mice of different ages, evaluated in situ by real-time real-space microscopy. We show that the cortex and striatum of the 9-month-old R6/1 transgenic mice present a significant sustained increase in cytosolic Ca(2+) induced by glutamate (Glu). This difference in Glu response was partially reduced in R6/1 when in the absence of extracellular Ca(2+), indicating that N-methyl-D-aspartate receptors participation in this response is more important in transgenic mice. In addition, Glu also lead to a decrease in NAD(P)H fluorescence, a loss in DeltaPsi(m) and a further increase in respiration, which may have evoked a decrease in mitochondrial Ca(2+) Ca(2+)(m) uptake capacity. Taken together, these results show that alterations in Ca(2+) homeostasis in transgenic mice are associated with a decrease in Ca(2+)(m) uptake mechanism with a diminished Ca(2+) handling ability that ultimately causes dysfunctions and worsening of the neurodegenerative and the disease processes.