To gauge the selectivity of SSAs for ovarian cancer cells over normal human cells, the GI50 values for 1, 3, 5, 7, 9 and 1:1 enantiomeric mixture of 3 + 5 and 7 + 9 were also determined against the RPE-1 human epithelial cell line (Figure , Section S19 † ). There was no negative impact on cell growth at 350 µM for any SSA/ SSA mixtures tested apart from 1. This shows the incorporation of the benzyl and isopropyl functionalities within chiral SSAs 3, 5, 7 and 9 to increase selectivity against cancerous over non-cancerous cell lines. Of these chiral SSAs, 9 and the 1:1 enantiomeric mixture of 7 and 9, containing an additional benzyl functionality, demonstrated the greatest degree of selectivity for the cancer cells over the RPE-1 cells, while the presence of the amino acid glycine within the SSA structure removed selectivity for the cancer cells over the RPE cells.