Page 02 1. There are two main pathways of programmed cell death (apoptosis): intrinsic (from within the cell) and extrinsic (from outside the cell). Figure 1 summarises some of the main features of the two pathways. Figure 1 Intrinsic Pathway Caspase 3 activation Caspase 8 activation Apoptosis Caspase 9 activation Cell membrane receptor binding p53 activation Extracellular death signal DNA damage Extrinsic Pathway Apoptosis is deregulated in many tumours, resulting in uncontrolled cell division despite the presence of significant DNA damage. One strategy for the discovery of new anti-cancer drugs has been to examine traditional medicinal herbs. A study was carried out to investigate the effect of an extract of the wild ginger plant, Asiasari radix, on the initiation of apoptosis in colon cancer cells. Colon cancer cells were treated with this extract and then assessed for the presence of apoptotic cells. The percentage increase in cells undergoing apoptosis was calculated by comparing the level of apoptosis in treated cells with that in untreated controls as shown in Figure 2. Figure 2 1200 1000 800 600 400 200 0 20 15 10 5 Extract concentration (μg/cm3) Increase in cells undergoing apoptosis (%)