An efficient synthesis of the <i>Alpinia officinarum</i>-derived diarylheptanoids, viz., enantiomers of a β-hydroxyketone (<b>1</b>) and an α,β-unsaturated ketone (<b>2</b>) was developed starting from commercially available eugenol. Among these, compound <b>2</b> showed a superior antiproliferative effect against human breast adenocarcinoma MCF-7 cells. Besides reducing clonogenic cell survival, compound <b>2</b> dose-dependently increased the sub G1 cell population and arrested the G2-phase of the cell cycle, as revealed by flow cytometry. Mechanistically, compound <b>2</b> acts as an intracellular pro-oxidant by generating copious amounts of reactive oxygen species. Compound <b>2</b> also induced both loss of mitochondrial membrane potential (MMP) as well as lysosomal membrane permeabilization (LMP) in the MCF-7 cells. The impaired mitochondrial and lysosomal functions due to reactive oxygen species (ROS)-generation by compound <b>2</b> may contribute to its apoptotic property.