Richardia brasiliensis Gomes: phytochemical characterization, antiproliferative capacity and in vitro and in vivo toxicity.

Richardia brasiliensis, known as poaia branca, is a medicinal species widely distributed throughout Brazil and used in folk medicine. However, studies on its toxicity are practically non-existent, and little is known about its biological activity. This study aimed to investigate its phytochemical compounds, assess its in vitro and in vivo toxicities, and determine its antiproliferative activity. UHPLC-ESI-HRFTMS performed the phytochemical characterization, and the antiproliferative activity was analyzed in different tumor cell lines. In vitro toxicity was evaluated in PBMC cells, and in vivo acute and repeated dose toxicity was evaluated according to OECD guidelines. It was identified alkaloids and terpenes as significant compounds. Regarding its antiproliferative activity, the human melanoma strain decreased its viability by about 95%. In vitro toxicity showed that the extracts maintained the viability of PBMCs; however, higher concentrations were able to increase the production of dsDNA quantity. In vivo tests showed no mortality nor signs of toxicity; the alterations found in hematological and biochemical parameters are within the standards for the species. The results indicate that R. brasiliensis has a good effect against the tumor cell line; still, more studies on its toxicity at higher concentrations are needed.

Preclinical safety assessment of the crude extract from Sida rhombifolia L. aerial parts in experimental models of acute and repeated-dose 28 days toxicity in rats.

Sida rhombifolia (Malvaceae) is popularly used as a treatment for several pathological conditions; however, there is a lack of studies that identify its compounds and that evaluate comprehensively the safety of its consumption. Therefore, the aim of this study was to determinate the phytochemical constitution of the crude extract of Sida rhombifolia (CESR), and its safety in models of acute and repeated doses (28 days) toxicity. The tested dose for the model of acute toxicity was 2000 mg/kg doses for the repeated dose model were 150, 300 e 600 mg/kg. Hematological, biochemical, histopathological and oxidative markers were investigated. HPLC-DAD-MS analysis evidenced the presence of caffeic acid, coumarin, and rutin. In the acute toxicity model the only altered parameters were tissue ROS, and AST and BUN in serum. As for the repeated dose experiment both hematological and biochemical markers remained within the values of reference for the species. Obtained results demonstrate that the CESR did not present significant toxic effects when administrated orally to male and female rats in acute and repeated doses.