Extracts of edible, medicinal Thai plants inhibit the human breast cancer cells

Purpose: To evaluate the effects of ten edible, medicinal Thai plant extracts on MCF-7 cell viability and cell migration, as well as their mechanism(s) of action. Methods: Ethanolic plant extracts of ten edible, medicinal plants were tested for their cytotoxicity against MCF-7 cells using sulforhodamine B (SRB). To investigate the cytotoxic mechanism(s) of action of these extracts, the study was examined gene expression and protein expression by reverse transcription polymerase chain reaction (RT-PCR) and Western blotting. Cell migration was studied by wound healing assay. Results: Four of the ten test extracts were potently cytotoxic, Careya sphaerica (CS), Azadirachta indica (AI), Piper nigrum (PN) and Oroxylum indicum (OI) with half maximal inhibitory concentrations (IC50) less than 100 μg/mL. All four extracts stimulated ROS overgeneration, increased caspase 3 activity and decreased growth-related gene expression including cdk2, cdk4, cdk6, cyclin D1 and cyclin E. Furthermore, the extracts significantly enhanced cyclin-dependent kinase inhibitor (CDKI) p21 levels and activated cancer cell death. The four extracts, CS, AI, PN and OI, also significantly reduced cancer cell migration, with PN being the most potent. Conclusion: Extract of the edible plants CS, AI, PN and OI have in vitro anticancer activity and are promising starting points for the development of breast cancer drugs. Keywords: Careya sphaerica (CS), Azadirachta indica (AI), Piper nigrum (PN), Oroxylum indicum (OI), Breast cancer, Cell death