Dioscin (Collettiside III) is a saponin with antitumor activities.

The chemical compound exhibits an LD50 value of greater than 300 mg/kg in mice, indicating the dosage at which half the population of test subjects succumbed to the compound's effects exceeded 300 mg/kg.

Dioscin induces apoptosis by downregulating the activity of caspase-8 and upregulating the activity of caspase-9 in HeLa cells. It inhibits the growth of the MDA-MB-435, H14, HL60, and HeLa cell lines, with IC50 values of 2.6, 0.8, 7.5, and 4.5 μM, respectively.

Rat liver cytosol is prepared from a separate piece of liver from rat. Assays are carried out in a total volume of 0.1 mL containing 10 mg of cytosolic protein, and components according to Rilling. All reaction components (except IPP) are mixed and kept on ice for 15 min. Reactions are initiated by the addition of [14C]IPP and incubation at 37°C. Reactions are stopped after 5 min by addition of 0.4 mL MeOH/HCl (4/1, by vol.) and the samples are incubated a further 15 min to hydrolyze the allylic pyrophosphates to petroleum ether-extractable products. Following addition of 0.5 mL water and 1 mL petroleum ether, 50% of the upper (petroleum ether-extractable) phase is taken for liquid scintillation analysis. Preliminary experiments indicated that the reaction is linear with time and protein under these conditions, and no more than 10% of the substrate is consumed.