Naturally derived products, such as the plant extracts or their pure compounds are the major possessions that stand ahead in drug discovery, with their property of novel identity with that of the available chemical diversity (Cosa et al., 2006). Form the various cancer chemotherapy progresses of the past decades, the plant natural products had been found to be a vital source in contributing to the launch of cancer drugs in the market (Cragg et al., 1997). The importance of plant derived drugs and its implication in curing disease has made the interest in the identification of new plant sources for the management of cancer.
The in vitro viability assay of rhizome extracts of C. speciosus on MCF-7 cells proved a dose-dependent decrease in the percentage of cell’s viability in all the extracts treated cells when compared to the control [Fig 1]. The hexane extract showed a significant decrease at a very low concentration, with 50% inhibition in the cell viability at 10 µg/mL, whereas the ethyl acetate and methanol extracts had 50% inhibition of viability at 25 µg/mL and 15 µg/mL concentrations respectively. These concentrations are the IC50 values of the particular extracts and can be used for the further studies on the extract. The maximum inhibition at a minimum concentration made the choice of hexane extract (HE) for the further studies. Plant molecules are pharmacological agents that enhance the ability to induce programmed cell death. Several herbal alkaloids act as antiproliferation and anti-metastasis stimulators (Jin et al., 2012). Plant flavanoids and terpenoids inhibit cancer cell proliferation, cell cycle arrest and apoptosis via various mechanisms (Maheep et al., 2011; Huanjie et al., 2010). Thus the presence of such biologically active components in the extracts might be the reason for the induction of apoptosis in the MCF-7 cells.
Apoptosis is a mode of cell death that is found in multicellular organisms, to dispose unwanted cells in a diversity of settings (Kerr et al., 1972; Wyllie et al., 1980). Lack of this programmed cell death is directly linked with enhanced cell proliferation, leading to tumorigenicity (Scott & Lin, 2000). Tumors treated with anticancer agents reveal a high frequency of apoptosis and suppress tumor progression (Kerr et al., 1994). In the present study the induction of apoptosis in the HE treated MCF-7 cells was carried out by AO/EtBr dual staining to confirm the apoptosis inducing nature of the extract. Acridine orange stains the live cells green and ethidium bromide stains the...