**3.2. Artonin E treated MCF-7 breast cancer cells displayed morphology of apoptosis**

The results of the AO and PI double staining analysis showed that Artonin E treated breast cancer cells displayed morphological features typical of apoptosis. These features included chromatin condensation and membrane blebbing. The control breast cancer cells which were not exposed to Artonin E had their normal nuclear structure displayed as green fluorescence. Early apoptotic cells were observed as bright green fluorescence resulting from the interposition of acridine orange with the fragmented DNA whereas late stage apoptosis (**Figure** 2**C** and **D**) was observed as reddish-orange, resulting from the binding of propidium iodine to denatured DNA. The apoptosis inducing effect of Artonin E was observed to be time and concentration dependent.

Challenging the cancer cells with Artonin E caused a significant (p < 0.05) loss in the proportion of viable MCF-7 breast cancer cells (**Figure 3**) from 94.5% to 67, 38, and 21.5% after treatment with 3, 10, and 30 μM Artonin E respectively. There was no significant (p ≥ 0.05) increase in necrotic breast cancer cells except after exposure to 30 μM of Artonin E. This percentage decreased. There was a concentration and time dependent significant (p < 0.05) increase in the proportion of cells that entered the apoptotic phase.
