In Vitro and In Vivo Studies Demonstrate Anticancer Property of Root Extract of Polygala senega

Polygala senega is extensively used in traditional systems of medicine against various lung diseases including cancer. In the present study we tested the anticancer potentials of ethanolic extract of roots of P. senega (generally used as a homeopathic drug) in a mammalian model, where mice, in vivo, were treated chronically with benzo[a] pyrene and in vitro where lung adenocarcinoma cell line (A549) were used. We deployed various parameters like cell viability assay, chromatin condensation studies with Hoechst 333258 staining, and maintained suitable controls. To understand the possible signal transduction pathways, expression of various signal proteins such as Aryl Hydrocarbon receptor (AhR), cytochrome P450 (CYP1A1), Bcl-2, proliferating cell nuclear antigen (PCNA), Bax and Caspase-3 was studied. Additionally, reverse transcriptase polymerase chain reaction analysis of AhR, p53, PCNA and β-actin (housekeeping) genes was made. Immunohistochemical localization of PCNA proteins was also conducted in vivo. Feeding of root extract of P. senega to mice (at the rate of 50 mg/kg and 100 mg/kg bw) chronically treated with the carcinogen (50 mg/kg bw dissolved in olive oil) showed positive modulation in expression of signal proteins. Upregulation of apoptotic signals such as p53, Caspase-3 and Bax, and downregulation of AhR, cytochrome P450 (CYP1A1), Bcl-2 and PCNA were observed. Addition of root extract of Polygala Senega (at doses of 50 μg and 100 μg) into culture medium containing A549 cells induced recovery of decreased cell viability and increased chromatin fragmentation (apoptosis). Therefore, results of both in vivo and in vitro studies scientifically validate its potential use as an anticancer agent, particularly against lung cancer, and provide important information potentially helpful in drug designing.