Cytotoxic activity of an ethanolic extract of Gnaphalium spicatum "keto keto" on human tumor cell lines

Abstract

Objectives. To evaluate the cytotoxic activity ethanolic extracts of roots, stems, leaves and flowers of Gnaphalium spicatum in some human tumor cell lines. Material and methods. The following cell lines: HT-29, H-460, MCF-7, M-14, PC-3, DU-145, K-562, and 3T3, were exposed to four different concentrations of ethanolic extracts from roots, stems, leaves and flowers of Gnaphalium spicatum, and also to different concentrations of cisplatin, which was used as a positive control. Percentage growth was assessed after 48 hours. The minimal inhibitory concentration for 50 per cent of the cells (IC50) was determined using linear regression analysis; also, the selectivity index for each sample and the dose-response relationship between the extract concentrations and cisplatin, as well as growth percentages were determined. Results. The ethanolic extract of Gnaphalium spicatum roots showed its highest cytotoxic activity in MCF-7 and K-562 cell lines. IC50 values, expressed in µg/mL, were 98 (r=-0.98; p <0.01) and 46 (r= -0.97; p <0.01), respectively. Cytotoxicity against the 3T3 cell line was 215 (r= 0.97; p <0.01). IC50 values for cisplatin were 2 (r= -0.96 p <0.01), 7.7 (r= -0.98; p<0.01), and 3 (r= -0.97; p<0.01), for the MCF7, K562 and 3T3 cell lines, respectively. The selectivity index of the ethanolic extract from Gnaphalium spicatum roots and cisplatin were 2.2 and 0.03 for the MCF-7 cell line, and 4,7 and 1.5 for the K-562 cell line, respectively. Extracts from stems, leaves and flowers of Gnapahlium spicatum acheived IC50 levels > 0.250 mg/mL in every cell lines tested. Conclusions. The ethanolic extracts of stems, leaves and flowers of Gnaphalium spicatum did not show cytotoxic activity in this bioassay. The extract from roots showed cytotoxicity in all tumor cell lines, except in M-14. Furthermore, it was less cytotoxic than cisplatin in 3T3 cell line.