text: In a study, cyclamin was tested regarding its toxicity against several types of cancer cells: SK-BR-3, HT-29, HepG2/3A, NCI-H1299, BXPC-3, 22RV1 but also on its toxicity against human normal fibroblasts DMEM, which are not cancer cells. The results showed that cyclamin induced a significant increase of micronucleated cells after it was activated through metabolism. This means that heritable chromosome mutations could occur in these cells. This result was observed in all cell types that were analysed in this study, therefore including the fibroblasts. The toxicity was indicated by the IC50 value which gives the concentration of the compound at which it causes 50% of its inhibitory effect e.g. on enzymes in cells. The IC50 values of cyclamin were very similar across the different cell types, ranging from 0.32µM – 0.84µM, with the lowest IC50 value in the human normal fibroblasts DMEM cells, which indicates unspecific toxicity of cyclamin across different cell types (Table 1).  
  This indicates that cyclamin is more toxic to the human fibroblasts compared to its toxicity against cancer cell lines. Compared to the chemotherapeutic drug mitomycin C, which has IC50 values ranging from 0.45µM-20.20µM in the cancer cell lines, cyclamin was up to 50 times more toxic for certain cell types when comparing the IC50 values (Table 1).  
  The antioxidant activity of cyclamin was also determined. Cyclamin had an EC50 value of 0.96mM which indicates low antioxidant activity compared to reference compounds catechin (EC50 = 0.009 mM) and ascorbic acid (EC50 = 0.014 mM). The EC50 value represents the potency of a compound by stating the half-maximum concentration of the compound with regards to its concentration where it causes maximum response or effect. Furthermore, it seemed that cyclamin did not have an anticlastogenic effect in the tested cell lines.
  Another study found that cyclamin was less toxic to human colorectal cancer cells, from that type HTC 166 and HT-29, compared to the chemotherapeutical drug paclitaxel. This could be concluded from the results that cyclamin had higher IC50 values compared to paclitaxel (Table 2).  
  To conclude, cyclamin shows broad toxicity against several cancer cell types, which would make it a promising drug to be used in that respect. However, its toxicity against normal human cells should be investigated further before using it as basis for chemotherapeutic drug to reduce unwanted side effects. For instance, cyclamin has been reported to selectively inhibit the proliferation of liver cancer cells. It is suspected to be related to molecular mechanisms increasing cell membrane permeabilization via targeting cholesterol. With this, it consequently targets the ligand-independent activation of Fas signalling pathway. Only after further investigation it can be decided if cyclamin is suitable for such a medical use.