Identification of Ethyl Ferulate From Rubus corchorifolius L.F. Leaves and Its Inhibitory Effects on HepG2 Liver Cancer Cells

Abstract

Abstract Objectives Rubus corchorifolius L.f., also known as raspberry, March bubble, milk bubble, etc., belongs to the genus Rubus L. and the family Rosaceae. The tender leaves of Rubus corchorifolius L. f. have been made into herbal tea for drinking and relieving coughs in China since ancient times. In this study, we isolated a bioactive compound from the ethyl acetate extract of Rubus corchorifolius L.f. leaves and investigated its protective effects in HepG2 human liver cancer cell line and the underlying molecular mechanisms. Methods Structural analysis of the isolated compound was performed by spectroscopic methods and the compound was identified as ethyl ferulate. Efficacy and mechanisms of ethyl ferulate on the proliferation of HepG2 human liver cancer cells and LO2 normal human liver cells was determined by cell viability, cell morphology, apoptosis, mitochondrial membrane potential, Ca2 + release, and immunoblotting analyses. Results We found that ethyl ferulate significantly suppressed the cell proliferation of HepG2 cells (IC50 26.4 μM), while it did not cause cytotoxicity on LO2 cells. In addition, flow cytometry analysis demonstrated that ethyl ferulate inhibited HepG2 cell growth via inducing cellular apoptosis. Specifically, ethyl ferulate reduced the electrical potential of the mitochondrial membrane and increased the concentration of calcium ions inside cells. Moreover, these changes were accompanied by increases in the expression of the pro-apoptotic proteins, such as cleaved caspase-3 and Bax. In contrast, cell morphology and growth of LO2 cells remained unaffected. Conclusions In conclusion, our findings demonstrated, for the first time, that ethyl ferulate possesses great potential as an effective and safe antitumor agent for cancer chemoprevention in humans. Funding Sources This study was supported by the University of International Cooperation in Science and Technology Innovation Platform Project of Guangdong (2013gjhz0003). XC was partly supported by a scholarship from South China Agriculture University.