In Vitro and In Vivo Efficacy of the Essential Oil from the Leaves of R.E. Fries (Annonaceae) Against Liver Cancer.

R.E. Fries (synonyms var. R.E. Fries), popularly known in Brazil as "envireira", is a tropical tree belonging to the Annonaceae family and is traditionally used as a food source. In this work, the in vitro and in vivo anti-liver cancer effects of essential oil (EO) from leaves were investigated for the first time. The chemical composition of the EO was evaluated via GC-MS and GC-FID. The alamar blue assay was used to evaluate the cytotoxicity of EOs against different cancerous and noncancerous cell lines. Cell cycle analyses, YO-PRO-1/PI staining, and rhodamine 123 staining were performed via flow cytometry in HepG2 cells treated with EO. The in vivo antitumor activity of EO was evaluated in NSG mice that were xenografted with HepG2 cells and treated with EO at a dose of 60 mg/kg. The major constituents (>5%) of the EO were ()-caryophyllene (32.01%), 1,8-cineole (13.93%), α-copaene (7.77%), α-humulene (7.15%), and α-pinene (5.13%). EO increased apoptosis and proportionally decreased the number of viable HepG2 cells. The induction of DNA fragmentation and cell shrinkage together with a significant reduction in the ΔΨm in EO-treated HepG2 cells confirmed that EO can induce apoptosis. A significant 39.2% inhibition of tumor growth in vivo was detected in EO-treated animals. These data indicate the anti-liver cancer potential of EO from leaves.