Z-VAD-FMK (Z-VAD(OH)-FMK) is a well-know pan caspase inhibitor, which does not inhibit ubiquitin carboxy-terminal hydrolase L1 (UCHL1) activity even at concentrations as high as 440 μM.In Vitro: Z-VAD-FMK (40 μM) reverses the apoptotic effect exerted by total saponin of Solanum lyratum Thunb (TSSLT) in Hela cells. HeLa cells are pretreated with Z-VAD-FMK (40 μM) for 30 min and exposed to TSSLT (6 μg/mL) for 48 h[2].