Chemical Composition of Four Essential Oils of Eugenia from the Brazilian Amazon and Their Cytotoxic and Antioxidant Activity.

Background:Eugenia species are appreciated for their edible fruits and are known as having anticonvulsant, antimicrobial and insecticidal actions. Methods: The plant material was collected in the southeastern Pará state of Brazil and submitted to hydrodistillation. GC-MS analyzed the oils, and their antioxidant and cytotoxic activities were evaluated by the DPPH and MTT assays. Results: The main components identified in the Eugenia oils were 5-hydroxy-cis-calemene, (2E,6E)-farnesol, (2E,6Z)-farnesol, caryophylla-4(12),8(13)-dien-5α-ol-5β-ol, E-γ-bisabolene, β-bisabolene, germacrene D, and ishwarane. The oil of E. egensis showed the most significant antioxidant activity (216.5 ± 11.6 mg TE/mL), followed by the oils of E. flavescens (122.6 ± 6.8 mg TE/mL) and E. patrisii (111.2 ± 12.4 mg TE/mL). Eugenia oils were cytotoxic to HCT-116 (colon cancer) cells by the MTT assay, where the most active was the oil of E. polystachya (10.3 µg/mL), followed by the oils of E. flavescens (13.9 µg/mL) and E. patrisii (16.4 µg/mL). The oils of E. flavescens and E. patrisii showed the highest toxicity for MRC5 (human fibroblast) cells, with values of 14.0 µg/mL and 18.1 µg/mL, respectively. Conclusions: These results suggest that Eugenia oils could be tested in future studies for the treatment of colon cancer and oxidative stress management.