Figure 6: Regulation of the intrinsic apoptotic pathway by PK. The active compounds of PK reduced their effectiveness after digesting and absorbing by patients. PK increased the expression of proapoptotic protein (Bax) and decreased antiapoptotic protein (Bcl-2, Bcl- ), with a concomitant increase in the levels of caspase-3, caspase-9 and cleaved poly-ADP-ribose polymerase (PARP) in SHG-44 cells. Caspase dependent cell death was the possible mechanism of PK’s antitumor activity.