Introduction

Plectranthus venteri Van Jaarsv. & Hankey, an endemic species of the Lamiaceae family, is a potential source of biologically active secondary metabolites. There are no studies on the anticancer activity of extracts from transformed roots of this species. The aim of this study was to evaluate the cytotoxic and proapoptotic effects of extracts from P. venteri hairy roots in an in vitro cell model and to provide a preliminary characterization of their mechanism of action.

Methods

Transformed roots were cultured in vitro and then freeze-dried, ground, and extracted with methanol and acetone. The extracts were profiled using HPLC-ESI-QTOF-MS/MS. Cytotoxicity was assessed using the MTT assay in breast cancer cell lines (MCF-7). The mechanism of action was analyzed by determining caspase 3/7 activity, mitochondrial membrane potential (ΔΨm), and the expression of pro- and antiapoptotic genes using RT-qPCR.

Results

The MTT assay demonstrated a cytotoxic effect of the extract from transformed Plectranthus venteri roots on MCF-7 breast cancer cells, with an insignificant influence on normal human fibroblast HGF-1 cells. A dose-dependent loss of ΔΨm and activation of caspases 3/7 were observed. Molecular analysis indicated an increase in BAX/CASP3/CASP9 and a decrease in BCL2/TP53 expression, suggesting the involvement of the mitochondrial pathway in the induction of apoptosis.

Conclusions

Extracts from transformed roots of P. venteri may represent a potential source of anticancer activity. These studies constitue the first data on the biological activity of this species and provide a basis for further phytochemical and biological analyses.