A series of new (−)-arctigenin derivatives with variably modified O-alkyl groups were synthesized and their preferential cytotoxicity was evaluated against human pancreatic cancer cell line PANC-1 under nutrient-deprived conditions. The results showed that monoethoxy derivative 4i (PC50, 0.49 μM), diethoxy derivative 4h (PC50, 0.66 μM), and triethoxy derivative 4m (PC50, 0.78 μM) showed the preferential cytotoxicities under ...