Morphological and biochemical changes of andrographolide-induced cell death in human prostatic adenocarcinoma PC-3 cells

Andrographolide was extracted and purified from Andrographis panicula using hexane and water partitioning followed by ethyl acetate extraction and chromatography. It showed selective cytoxicity to prostate cancer PC-3 cells in vitro. The morphological and biochemical changes induced by the extract in carcinoma PC-3 cell death were studied. In andrographolide-treated cells, evidence of apoptosis such as cell shrinkage and surface microvilli loss after 4-hour treatment and chromatin condensation and fragmentation in H&E-stained cells between 4 to 8 hours after treatment were observed. Under electron microscopy, membrane blebbing and apoptotic bodies formation were seen after 8-hour treatment. Using immunocytochemistry staining and cellular caspase-3 activity assay, andrographolide-treated cells showed considerable caspase-3 activation and caspase-8 in PC-3 cells at 4 and 2 hours after treatment, respectively. This suggests andrographolide-induced cell death was achieved through the apoptotic pathway, via the activation of an extrinsic caspase cascade.