Chemical investigation on the CH 2 Cl 2 fraction of the Scutellaria litwinowii Bornm. & Sint., Lamiaceace, root extract for the fi rst time resulted in the isolation of wogonin, and neobaicalein. These compounds were evaluated for their cytotoxicity towards HeLa cell lines and lymphocytes. Meanwhile, the role of apoptosis was explored in this toxicity. The cells were cultured in RPMI medium and incubated with different concentrations of isolated fl avonoids. Cell viability was quantifi ed by

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... assay. Apoptotic cells were determined using propidium iodide staining of DNA fragmentation by fl ow cytometry (sub-G1peak). Wogonin, and neobaicalein inhibited the growth of malignant cells in a dose-dependent manner. The IC50 values of 46.62 and 79.34 µM were, respectively, found for neobaicalein and wogonin against HeLa cells after 48 h of treatment. Neobaicalein induced a sub-G1 peak in the fl ow cytometry histogram of treated cells compared to control cells indicating that apoptotic cell death is involved in neobaicalein toxicity. Neobaicalein exerts cytotoxic and pro-apoptotic effects in HeLa cell lines and could be considered as a potential chemotherapeutic agent in cancer treatment.