Chemical Characterization and in Vitro Antitumor Activity of the Essential Oils from the Leaves and Flowers of Callistemon viminalis

Abstract

The objective of this study was to characterize and verify the in vitro antitumor activity of essential oils (EOs) extracted from the leaves and flowers of Callistemon viminalis. The EOs were extracted by hydrodistillation using a modified Clevenger apparatus. The identification and quantification of constituents were performed on a gas chromatograph coupled to a mass spectrometer and a gas chromatograph with a flame ionization detector. The antitumoral activity was evaluated by a colorimetric assay (MTS) using different cell lines derived from human tumors (breast, lung, glioblastoma, and melanoma). The major constituents of the EOs of leaves and flowers were similar, only quantitative differences being observed. The compounds 1,8-cineole, α-pinene and α-terpineol were found in concentrations of 50.4%, 25.8% and 8.7% in the EOs obtained from the leaves and 48.8%, 24.5% and 3.9% in the EOs obtained from the flowers, respectively. The cytotoxic activity of the EOs was observed only in melanoma cultures (HT144). Cultures treated for 48 h with EOs from leaves and flowers (200 µg·mL−1) reduced the viability by 40% and 25%, respectively. Thus, the antiproliferative activity of the EO from leaves was more pronounced than the EO from flowers in cells derived from melanoma.