Ação neuroprotetora do ginseng brasileiro Pfaffia glomerata (Spreng.) Pedersen

Abstract

The plant Pfaffia glomerata, popularly called Brazilian ginseng, is widely used in Brazil for the treatment of various pathologies, including those associated with the Central Nervous System. 20-hydroxyecdysone, a phytosteroid present in this plant, can promote adaptogenic effects in the body, providing greater body resistance to exogenous and endogenous stressors. The aim of this study was to evaluate the possible neuroprotective effect of extracts and fractions from shoots and roots of P. glomerata, using in vitro methods, in addition to determining the presence and concentration of 20- hydroxyecdysone in these samples. On the other hand, the dichloromethane fraction (RD) of the methanol extract of the roots was tested in an in vivo model, since the roots are the most popularly used parts. The fractions were obtained by partitioning methanol extracts from the aerial part and roots of P. glomerata with hexane, dichloromethane, ethyl acetate and n-butanol, and the aqueous residue (water fraction) was also obtained. The samples were initially tested in antioxidant and antiglycation activities assays and, later, those most promising fractions were submitted to cytotoxicity and chromatographic analyses. Mass spectrometry and analysis by high performance liquid chromatography revealed that 20-hydroxyecdysone was the main compound in the dichloromethane fraction, both in the aerial part (PAD) with 45 μg/mg fraction, and in the roots (RD) with 33.5 μg/mg of fraction. Among the in vitro analyses, the PAD fraction showed more promising results than the RD fraction. In the in vivo model, C57BL6 mice were treated by gavage with three doses of the RD fraction (3, 10 and 30 mg/kg) and submitted to evaluation of stress, anxiety and depression parameters. Animals treated with 30 mg/kg of RD were also submitted to analysis of oxidative stress biomarkers in the cortex, striatum and hippocampus. The dose of 30 mg/kg of RD was able to reduce stress, anxiety and depression, in addition to maintaining the antioxidant defenses of the cortex and striatum of the evaluated mice. These discoveries open new perspectives for understanding the therapeutic properties of P. glomerata associating the biological activity with the presence of phytosteroids.