Essential oils from Schinus terebinthifolius leaves - chemical composition and in vitro cytotoxicity evaluation.

BACKGROUND

In folk medicine, Schinus terebinthifolius Raddi (Anacardiaceae), has been used as a remedy for ulcers, respiratory problems, wounds, rheumatism, gout, diarrhea, skin ailments and arthritis, as well as to treat tumors and leprosy.

OBJECTIVE

To investigate the chemical composition and cytotoxicity of essential oil from leaves of S. terebinthifolius as well as the identification of active compounds from this oil.

METHODS

Essential oil from S. terebinthifolius leaves, obtained by hydrodistillation using a Clevenger-type apparatus, was characterized in terms of its chemical composition. Also, the crude oil was subjected to chromatographic separation procedures to afford an active fraction composed of α- and β-pinenes. These compounds, including hydrogenation (pinane) and epoxydation (α-pinene oxide) derivatives from α-pinene, were tested in vitro against murine melanoma cell line (B16F10-Nex2) and human melanoma (A2058), breast adenocarcinoma (MCF7), leukemia (human leukemia (HL-60) and cervical carcinoma (HeLa) cell lines.

RESULTS

Forty-nine constituents were identified in the oil (97.9% of the total), with germacrene D (23.7%), bicyclogermacrene (15.0%), β-pinene (9.1%) and β-longipinene (8.1%) as the main compounds. The crude essential oil showed cytotoxic effects in several cell lines, mainly on leukemia and human cervical carcinoma. Fractions composed mainly of α- and β-pinenes as well as those composed of individually pinenes showed effective activities against all tested cell lines. Aiming to determinate preliminary structure/activity relationships, α-pinene was subjected to epoxydation and hydrogenation procedures whose obtained α-pinene oxide showed an expressive depression in its cytotoxicity effect, similar as observed to pinane derivative.

CONCLUSIONS

The obtained results indicated that the monoterpenes α- and β-pinenes could be responsible to the cytotoxic activity detected in the crude oil from leaves of S. terebinthifolius. In addition, it was possibly inferred that the presence of double bond in their structures, mainly at endocyclic position, is crucial to cytotoxic potential detected in these derivatives.