Fabiana imbricata Ruiz & Pav. (Solanaceae) essential oil analysis in prostate cancer cells: relevance of reactive oxygen species in proapoptotic activity.

ETHNOPHARMACOLOGICAL RELEVANCE

Fabiana imbricata Ruiz & Pav. (Solanaceae) is a Patagonian plant widely used in traditional medicine, in particular as a diuretic, digestive and for genito-urinary system diseases. Essential oils are considered promising candidates for prostate cancer treatments. Prostate cancer is the second leading cause of death among men. Therefore, new therapeutic strategies of prevention are needed for this tumor.

AIM OF THE STUDY

The present research was designed to explore the chemical composition of essential oil from fresh leaves of F. imbricata plants collected in Valparaíso region, Chile, and its activity on human prostate cancer cell lines.

MATERIALS AND METHODS

Chemical characterization was performed by chromatographic techniques and the biological activity was evaluated in androgen-sensitive (LNCaP) and androgen-insensitive (DU-145) human prostate cancer cell lines. The cells were exposed to essential oil for 72 h and cell viability and cell membrane integrity were evaluated. Genomic DNA and caspase-3 activity was tested to confirm the cell death for apoptosis. Western blot analysis was employed to evaluate the expression of Bcl-2, Bax, cleaved caspase-3, cleaved caspase-9, SOD, Hsp70 and STAT-3 proteins. Assays to evaluate reactive oxygen species (ROS) and GSH levels were also performed.

RESULTS

The results showed the capacity of essential oil, for its active components (oxygenated sesquiterpenes, 77.54 %), to reduce cell viability in prostate cancer cells. At a concentration of 200 μg/mL, the cell viability in LNCaP and DU-145 cells, was 23 % and 26 %, respectively. On the contrary, it showed no significant effect on normal cells, also at this high concentration. In addition, it induced apoptosis cell death, involving the downregulation of Hsp70 and STAT-3 proteins, correlated, at least in part, to an increase of reactive oxygen species (ROS).

CONCLUSIONS

This in vitro experimental preclinical study, suggesting a potential application of F. imbricata essential oil in prostate cancer, could be considered as a start point to design further research in animal experimental models and on its active components.