In vitro evaluation of cytotoxic potential of essential oil extracted from leaves of Croton heliotropiifolius Kunth in human tumor cells

Croton heliotropiifolius Kunth, popularly known as "velame," is a shrub that resides in northeastern Brazil. The essential oil of C. heliotropiifolius contains high concentrations of volatile compounds in the leaves and is widely used in folk medicine for many purposes as an antiseptic, analgesic, sedative, and anti-inflammatory agent. Due to the apparent limited amount of information, the aim of this study was to determine the cytotoxic potential of essential oil extracted from leaves of C. heliotropiifolius, utilizing different human cancer cell lines (HL-60, leukemia; HCT-116, colon; MDA-MB435, melanoma; SF295, glioblastoma) and comparison to murine fibroblast L929 cell line. The chemical characterization of the essential oil revealed the presence of large amounts of monoterpenes and sesquiterpenes, the majority of which were aristolene (22.43%), germacrene D (11.38%), ɣ-terpinene (10.85%), and limonene (10.21%). The essential oil exerted significant cytotoxicity on all cancer cells, with low activity on murine L929 fibroblasts, independent of disruption of cell membranes evidenced by absence of hemolytic activity. The cytotoxicity identified was associated with oxidative stress, which culminated in mitochondrial respiration dysfunction and direct or indirect DNA damage (strand breaks and oxidative damage), triggering cell death via apoptosis. Our findings suggest that extracts of essential oil of C. Heliotropiifolius may be considered as agents to be used therapeutically in treatment of certain cancers.

Major depression model induced by repeated and intermittent lipopolysaccharide administration: Long-lasting behavioral, neuroimmune and neuroprogressive alterations

Major depressed patients show increased bacterial translocation with elevated plasma levels of lipopolysaccharide (LPS), which may trigger immune-inflammatory and neuro-oxidative responses. Recently, an animal model based on chronic LPS administration was developed which was associated with long-lasting depressive-like and neuro-oxidative alterations in female mice. The aim of the current study was to investigate behavioral, neuroimmune and neuroprogressive alterations in female mice 6 weeks after LPS chronic exposure. Female mice received increasing doses of LPS during 5 days at one-month intervals repeated for 4 consecutive months. Six weeks after the last LPS-exposure, we assessed behavioral despair and anhedonia, microglial activation, alterations in tryptophan, 5-HT, kynurenine, quinolinic acid (QUIN) levels and spermidine/spermine N1-acetyltransferase (SAT1) expression in the hippocampus, both with and without fluoxetine administration. Our results show that six weeks post-LPS, mice present behavioral despair and anhedonia in association with increased IBA1 expression (a microglia activation marker), NF-kB p65 and IL-1β levels, indoleamine 2,3-dioxygenase (IDO1) mRNA expression, kynurenine, QUIN levels and QUIN/tryptophan ratio, and lowered tryptophan, 5-HT levels and SAT1 mRNA expression. Fluoxetine reversed the behavioral and neuroimmune alterations but had no effect in the reversal of IDO1 increased expression, QUIN levels and QUIN/tryptophan ratio. In conclusion, our results support the validity of the chronic LPS model of major depression and additionally shows its translational relevance with respect to neuroimmune and neuroprogressive pathways.