Catharanthus roseus is a medicinal and ornamental plant with growing attention toward its economical value. Cell suspension from C. roseus were treated with 0 to 60mM of cadmium nitrate for 1, 3 and 6 days, then cell viability was determined using trypan blue and MTT assay. Cell morphology was investigated using 0, 10, 30 and 50 mM of cadmium nitrate as selected dose for 3 days. Callus of C.roseus was treated with selected doses for same period to estimate the hydrogen peroxide content, level of lipid peroxidation, proline content and the activity of superoxide dismutase, catalase and peroxidase as well as protein profile. In addition, the production of total alkaloid, flavonoid and phenolic compounds was estimated. Data was analyzed using one-way ANOVA, Duncan test and p<0.05 was taken as the level of significant. Trypan blue and MTT assay showed the significant (p<0.05) dose dependent differences in viability as compared to control. In addition a dose dependent increase of hydrogen peroxide, total alkaloid, total flavonoid, and total phenolic compounds was observed. Also the activity of superoxide dismutase, catalase and peroxidase as well as malondialdehyde level as an indicator of lipid peroxidation increased significantly. Cadmium nitrate induced protein profile changes as well as proline content elevation. As conclusion; cadmium nitrate caused cellular membrane damage and viability reduction, but an increase in the production of secondary metabolites such as total alkaloids was observed. Therefore cadmium treatment might be a useful way to increase production of alkaloids at cellular level.
