Purpose: To explore the modulatory effect of an Althaea officinalis root extract (AORE) on cisplatininduced cytotoxicity and cell proliferation in a lung cancer cell line. Methods: Aqueous AORE was obtained from peeled and powdered roots. The effect of cisplatin on cytotoxicity and cell proliferation was studied. The cisplatin concentrations tested ranged from 0 -30 mg/mL. Cell viability and proliferation were studied using trypan blue and MTT assays, respectively. The cells were also exposed

more »

... a combination of cisplatin and the AORE. Results: Cisplatin yielded a 50 % inhibitory concentration at 25 mg/mL and exhibited a dose-dependent cell proliferation loss. Combined use of the root extract and cisplatin had significant (R2 = 0.8305) modulatory effects on cytotoxicity and antiproliferative activities. The best inhibitory effects were observed in cells exposed to a combination of 8 or 10 % AORE and 25 mg/mL cisplatin. The optimal effect on cell proliferation was obtained using 25 mg/mL cisplatin and 10 % v/v AORE. Conclusion: The enhanced activity of cisplatin in combination with AORE was more pronounced for cell proliferation than cytotoxicity, indicating that AOREs may be used to control tumor progression and metastasis.