Methanolic extract of Phlogacanthus thyrsiflorus Nees leaf induces apoptosis in cancer cells

Phlogacanthus thyrsiflorus Nees is a medicinal herb commonly used in traditional folk medicine, and it is known to possess anticancer activity. Here, we explored the anticancer properties of methanolic extract of P. thyrsiflorus leaves in HeLa and MCF-7 cell lines. We observed nuclear fragmentation as indication of apoptosis in the MPT treated cancer cells using haematoxylin and eosin (H&E) as well as fluorescent dye. DNA from the treated cells showed characteristic laddering of DNA fragments in agarose gel electrophoresis. Cell populations undergoing secondary necrosis following apoptosis could also be detected in FACS by annexin V/propidium iodide (PI) staining. Activated caspase-3 in the treated HeLa cells was detected by polyclonal anti-caspase-3 antibody utilizing immunocytochemistry. Using transmission electron microscopy, sub-cellular changes like rough endoplasmic reticulum, swollen mitochondria, distorted mitochondrial membrane, loss of cristae and matrix were observed in the treated HeLa cells. Extensive plasma membrane blebbing was also observed by scanning electron microscopy. Our findings support that Phlogacanthus thyrsiflorus leaves are natural source of potent anticancer agent.