Study of the antitumor potential of Bidens pilosa (Asteraceae) used in Brazilian folk medicine

Bidens pilosa (L.) (Asteraceae) is a medicinal plant traditionally used in Brazil for treating conditions that can be related to cancer. Therefore the present study was carried out to evaluate the antitumor activity of extracts obtained from the aerial parts of this plant species. The crude hydroalcoholic extract (HAE) (water:alcohol, 6:4) and solvent fractions (chloroform = CHCl 3 ,ethyl acetate = EtOAc, methanol = MeOH) were assessed for cytotoxicity assay by the brine shrimp and hemolytic, MTT and NRU assays. The antiproliferative potential of the crude extract and fractions was investigated in vivo using the Ehrlich ascites carcinoma (EAC) in isogenic Balb/c mice that were administered intraperitoneally 150 and 300 mg/kg body weight per day for nine days beginning 24 h after tumor inoculation. In in vitro cytotoxicity using Ehrlich ascites carcinoma cell line assay CHCl 3 extract proved to be more toxic than the crude HAE with an IC 50 of 97 ± 7.2 and 83 ± 5.2 μg/mL to NRU and MTT, respectively. Histomorphological evaluations indicated that the treatment with CHCl 3 and HAE extracts significantly reduced ( P < 0.05) body weight, abdominal circumference, tumor volume, packed cell volume and viable cell count, when compared to EAC control group. Furthermore, nonviable tumor cell count increased significantly ( P < 0.01) only under treatment with CHCl 3 or HAE, and this was accompanied by a marked percentage increase in life span (54.2 and 41.7%, respectively). Biochemical assays revealed that CHCl 3 and HAE extracts were also able to decrease serum LDH activity (39.5 and 30.6%) and GSH concentration (94.6 and 50.7%) in ascitic fluid, respectively. The chloroform fraction showed the best and methanolic the worst antitumor activity.