O extrato bruto das folhas da espécie Randia ferox (Cham & Schlecht) DC. apresenta adequado perfil de segurança e potencial antineuroinflamatório in vitro

Abstract

Neuropsychiatric diseases directly affect the quality of life of those affected and their families, becoming a public health problem. Among the hypotheses of its pathophysiology, neuroinflammation has been explored, making it a target for treatment. Natural products are widely explored due to their pharmacological activities and novelty of their substances. The Randia ferox species, popularly known as wild lemon tree, is a native species of the Atlantic Forest. Its leaves are used in popular culture to provide healing and anti-inflammatory action. Nevertheless, there are only a few studies on its effectiveness and safety. In this way, the objective of this study is to evaluate the anti-neuroinflammatory potential of the crude extract of Randia ferox species leaves, besides its in vitro safety profile. The leaves of the plant were collected in the municipality of Arroio do Tigre, dried in an oven, macerated in 70% ethanol. Hence its hydro-alcoholic extract evaporated, and its crude extract lyophilized. For the qualification and quantification of its secondary metabolites, high performance liquid chromatography coupled to a mass spectrophotometer was used. In the neuroinflammation study, microglia (BV-2) were treated with lipopolysaccharide (LPS). An extract curve at concentrations of 25, 50, 75, 100, 150, 200, and 400 μg/mL was used to assess the viability and the formation of nitric oxide (NO) and reactive oxygen species (ROS). Pro (interleukin 1β and 6, tumor necrosis factor α and interferon γ) and anti-inflammatory (interleukin 10) cytokines, caspases 8 and 3, and NLRP3 inflammasome gene expression were tested. In the study of the safety profile, peripheral blood mononuclear cells, human fibroblasts (HFF1), murine macrophages (RAW) and monkey kidney epithelial cells (VERO) were used. They were exposed to the crude extract in the curve -concentration 25- 400 μg/mL in periods of 24 and 72h. After the end of each incubation period, cell viability and proliferation tests, quantification of ON, ROS, and supernatant dsDNA were performed to assess cell death. Comet DNA, gem modifier and hemolysis tests were performed. The crude extract demonstrated an anti-neuroinflammatory potential, being able to decrease the levels of NO, ROS, pro-inflammatory cytokines, caspases 8 and 3, as well as the expression of the NLRP3 inflammasome and the increase of the anti-inflammatory cytokine, therefore demonstrating a neuroprotective mechanism of the extract under these conditions. In the safety profile, the extract was not cytotoxic in the strains and conditions studied, except on the concentration of 400 μg/mL. Only mononucleated cells showed difference in the production of ROS when exposed to the extract, without significant changes in NO modulation. None of the investigated concentration was genotoxic either hemolytic. The crude extract of the leaves of the species R. ferox showed anti-neuroinflammatory activity and was considered safe under the investigated conditions.