Bioenergetics: Open Access

Anthocyanins Protect the Brain against Ischemic Damage

José Roberto Meyer-Fernandes^* Institute of National Science and Technology of Structural Biology and Bioimage, Bloco H, Cidade Uni, Brazil
^*Correspondence: José Roberto Meyer-Fernandes, Institute of National Science and Technology of Structural Biology and Bioimage, Bloco H, Cidade Uni, Brazil, Email:

Published: 26-Nov-2021

Introduction

Anthocyanins are considered as bioactive components of plant-based diets that provide protection against ischemic cardiovascular pathologies by mechanisms dependent on their antioxidant and reductive capacities. However, it is not clear whether similar anthocyanin-mediated mechanisms can provide protection against ischemia-induced brain mitochondrial injury and cell death. In this study, we compared effects of three cyanidin-3-glycosides â?? glucoside, galactoside and rutinoside, with pelargonxidin-3-glucoside and found that at 10 concentrations they have no direct effect on respiratory functions of mitochondria isolated from normal or ischemia-damaged rat brain slices. However, intravenous injection of anthocyaninsbut not Cy3R in rats protected against ischemia-induced caspase activation and necrotic cell death, and reduced infarct size in cerebral cortex and cerebellum. These effects correlated with cytochrome c reducing capacity of cyanidin-3-glycosides. In contrast, intravenous injection in which has the lowest cytochrome c reducing capacity among investigated anthocyanins, had no effect on ischemia-induced caspase activation and necrosis but reduced brain infarct size whereas intravenous injection of slightly promoted necrosis in the brain. Our data suggest that reductive rather than antioxidant capacities of anthocyanins may be important components in providing protection against ischemic brain damage.

Acanthamoeba castellanii is a free-living amoeba and the etiological agent of granulomatous amoebic encephalitis and amoebic keratitis. A. castellanii can be present as trophozoites or cysts. The trophozoite is the vegetative form of the cell and has great infective capacity compared to the cysts, which are the dormant form that protect the cell from environmental changes. Phosphate transporters are a group of proteins that are able to internalize inorganic phosphate from the extracellular to intracellular medium. Plasma membrane phosphate transporters are responsible for maintaining phosphate homeostasis, and in some organisms, regulating cellular growth. The aim of this work was to biochemically characterize the plasma membrane phosphate transporter in A. castellanii and its role in cellular growth and metabolism. To measure inorganic phosphate (Pi) uptake, trophozoites were grown in liquid PYG medium at 28 °C for 2 days. The phosphate uptake was measured by the rapid filtration of intact cells incubated with 0.5 μCi of 32Pi for 1 h. The Pi transport was linear as a function of time and exhibited Michaelis-Menten kinetics. A. castellanii presented linear phosphate uptake up to 1 h with a cell density ranging from amoeba. The Pi uptake was higher in the acidic pH range than in the alkaline range. The oxygen consumption of living trophozoites increased according to Pi addition to the extracellular medium. When the cells were treated with FCCP, no effect from Pi on the oxygen flow was observed. The addition of increasing Pi concentrations not only increased oxygen consumption but also increased the intracellular ATP pool. These phenomena were abolished when the cells were treated with FCCP or exposed to hypoxia. Together, these results reinforce the hypothesis that Pi is a key nutrient for Acanthamoeba castellanii metabolism.