3.3. Cytotoxicity
To investigate the safety of PN as an ingredient of herbal preparations, cytotoxicity of its extracts and each of its components on ECV304 cells was evaluated. Most of the single herbs were noncytotoxic (IC50 > 2500 μg/mL) (Table 1). Both extracts of TC showed the highest cytotoxicity, while the extracts of PK and PN showed moderate toxicity (IC50