Background/Objectives: Vincamine is an indole alkaloid initially isolated from plants of the Vinca genus and has previously been demonstrated to have antioxidant, hypoglycemic, and hypolipidemic activities. Vinpocetine, a synthetic derivative of vincamine with an enhanced pharmacological profile, has demonstrated promising antiproliferative properties. While previously reported vinpocetine derivatives have undergone extensive investigation for their pharmacological properties, the role of the E-ring ethyl ester in the antiproliferative properties of compounds with this scaffold has not yet been fully described. Methods: Here, the antiproliferative activity of two vinpocetine analogs with modifications at the E-ring was evaluated through cell viability and LDH assays, and their mechanism of action was investigated through cell cycle analysis, apoptosis detection, and reporter assays for Wnt-1, NF-κB, and STAT3 signaling. Results: Cell viability assays revealed that reduction of the ethyl ester to an alcohol exhibited strong dose-dependent antiproliferative activity across five mammalian cell lines, but did not induce significant markers of apoptosis or necrotic death as determined by FITC/Annexin V and cell cycle flow cytometry, respectively. Through label-free cell imaging, we found the antiproliferative activity of vinpocetine alcohol to be correlated with a decrease in membrane integrity in treated cells. We further observe that both analogs exhibit dose-dependent modulation of TCF/LEF, NF-kB, and STAT3 reporter cells, which appears to be coupled with trends in antiproliferative activity. Conclusions: Altogether, this work demonstrates the potential for E-ring modifications of vinpocetine as antiproliferative agents.
Xie et al. (Fri,) studied this question.