Pfaffia glomerata Spreng. Pedersen (ginseng brasileiro): citogenotoxidade no ensaio de Allium cepa L.

Abstract

The use of plants for therapeutic purposes is one of the oldest practices of mankind, and was recognized by the World Health Organization in 1978. However, it is known that the indiscriminate use of medicinal plants in excessive doses can be harmful to human health. The main adverse effects in response to the use of medicinal plants are the toxicity, differences in the rate of cell division and the induction of chromosomal aberrations. P. glomerata is popularly known as "Brazilian Ginseng" due it´s pharmacological properties similar to Korean ginseng (Panax ginseng C. A. Mey). The species is usually used as tonic, aphrodisiac, in the treatment of rheumatic diseases, anti-stress and antidiabetic. Several biological assays using organisms as bioindicators are available to assess these effects and Allium cepa is the most used. The A. cepa test was used in this study, with the aim to evaluate the citogenotoxic effects of P. glomerata extracts using A. cepa test model. Two different root extracts were tested: methanolic and aqueous, with concentrations ranging from 8 to 256 mg/mL. Germination and root growth assays were performed for eight days and the citogenotoxic tests were performed during 24, 48 and 72 hours of exposure. Slides were prepared by the squash technique and stained with 5% Giemsa. The results showed inhibition of germination after exposure to methanolic extract and reduction of root length in a dose-dependent manner. Significant inhibition of mitotic index was observed after exposure to the two extracts, being the index for the methanolic extract even smaller. Chromosomal aberrations were observed at all concentrations tested and the most frequent abnormalities were chromosome adherence, bridges in anaphase and telophase and micronuclei. P. glomerata roots are rich in saponins and ecdysteroids, being β- ecdysone it´s major component. The A. cepa model showed toxic and genotoxic effects for both extracts tested. These effects are probably due to the presence of saponins and ecdysteroids (β-ecdysone) in P. glomerata roots. The Allium cepa test showed that β-ecdysone also showed cytogenotoxic effects. It is suggested, therefore, the rational use of P.glomerata roots for therapeutic purposes and the necessity of further studies about its citogenotoxic potential.