Sample preparation
Figure 1 shows the process undertaken to prepare saponin-enriched water and ethanol extracts. Briefly,ground leaves were extracted in either water under
optimal conditions identified using RSM (85°C,25 min, water-to-leaf ratio of 100:5 mL g1) or 80%(v/v) ethanol (room temperature for 72 h). Theextracted solution was filtered and then concentratedusing a rotary evaporator (Buchi Rotavapor B-480,
Buchi Australia, Noble Park, Vic., Australia) under