Study of viability and activity of antioxidant enzymes in Catharanthus roseus L. under the treatment of different concentration of sodium nitroprusside in culture media

Nitric oxide (NO) has signaling property in plants، therefore the effect of nitroprusside (SNP) as an NO producing agent on viability in the cell culture، lipid peroxidation and activity of superoxide dismutase، catalase and peroxidase in the callus of Catharantus roseus was investigated. Cell suspension was prepared from callus of Catharantus roseus، and the cells were treated with 0، 10، 50، 100، 150، 200 and 250 μM of sodium nitroprusside for 1، 3 and 6 days to determined the cell viability (based on trypan blue staining as well as MTT colorimetric assay). Then using 100 and 200 mM of sodium nitroprusside as selected dose، the cell suspension was used to investigate the cell morphological changes. In addition the callus tissue was treated with the same dose to estimate the level of lipid peroxidation and the activity of superoxide dismutase، catalase and guaiacol peroxidase. Comparison of the data from trypan blue and MTT methods showed that the significant (p<0. 05) differences in viability was concentration dependent with respect to control. Base on the morphology، SNP caused changes in the shape and size of the cell nuclei as well as disturbance in the chromatin. In addition changes in the cytoplasm such as shrinkage and cell border deform was observed in the treated cells compare to control. Also activity of the investigated enzymes following the oxidative stress increased significantly (p<0. 05). The level of malondialdehyde as an indicator of lipid peroxidation also increased significantly. Sodium nitroprusside as an NO producing agent caused cellular membrane damage which results in cell viability reduction in the callus of catharantus roseus. Although the activity of the antioxidant enzymes increased significantly with respect to the oxidative stress but the produced cellular response was not able to compensate the damages.