6-O-(3″, 4″-di-O-trans-cinnamoyl)-α-l-rhamnopyranosylcatalpol and verbascoside: Cytotoxicity, cell cycle kinetics, apoptosis, and ROS production evaluation in tumor cells.

The aim of this study was to evaluate the impact that 6-O-(3″, 4″-di-O-trans-cinnamoyl)-α- l-rhamnopyranosylcatalpol (Dicinn) and verbascoside (Verb), two compounds simultaneously reported in Verbascum ovalifolium, have on tumor cell viability, apoptosis, cell cycle kinetics, and intracellular reactive oxygen species (ROS) level. At 100 µg/mL and 48 hours incubation time, Dicinn and Verb produced good cytotoxic effects in A549, HT-29, and MCF-7 cells. Dicinn induced cell-cycle arrest at the G₀ /G₁ phase and apoptosis, whereas Verb increased the population of subG₁ cells and cell apoptosis rates. Furthermore, the two compounds exhibited time-dependent ROS generating effects in tumor cells (1-24 hours). Importantly, no cytotoxic effects were induced in nontumor MCF-10A cells by the two compounds up to 100 µg/mL. Overall, the effects exhibited by Verb in tumor cells were more potent, which can be correlated with its structural features, such as the presence of phenolic hydroxyl groups.