Chemical Composition and Bioactivity of Essential Oil from Blepharocalyx salicifolius

Abstract

Natural products represent a source of biologically active molecules that have an important role in drug discovery. The aromatic plant Blepharocalyx salicifolius has a diverse chemical constitution but the biological activities of its essential oils have not been thoroughly investigated. The aims of this paper were to evaluate in vitro cytotoxic, antifungal and antibacterial activities of an essential oil from leaves of B. salicifolius and to identify its main chemical constituents. The essential oil was extracted by steam distillation, chemical composition was determined by gas chromatography/mass spectrometry, and biological activities were performed by a microdilution broth method. The yield of essential oil was 0.86% (w/w), and the main constituents identified were bicyclogermacrene (17.50%), globulol (14.13%), viridiflorol (8.83%), γ-eudesmol (7.89%) and α-eudesmol (6.88%). The essential oil was cytotoxic against the MDA-MB-231 (46.60 μg·mL^-1) breast cancer cell line, being more selective for this cell type compared to the normal breast cell line MCF-10A (314.44 μg·mL^-1). Flow cytometry and cytotoxicity results showed that this oil does not act by inducing cell death, but rather by impairment of cellular metabolism specifically of the cancer cells. Furthermore, it presented antifungal activity against Paracoccidioides brasiliensis (156.25 μg·mL^-1) but was inactive against other fungi and bacteria. Essential oil from B. salicifolius showed promising biological activities and is therefore a source of molecules to be exploited in medicine or by the pharmaceutical industry.

Keywords: MCF-10A; MDA-MB-231; Paracoccidioides brasiliensis; bicyclogermacrene; breast cancer; eudesmol; flow cytometry; globulol; viridiflorol.

Figure 1

(a) Flow cytometry analysis of MDA-MB-231 and MCF-10A cells under action of B. salicifolius essential oil; (b) Bar diagram demonstrates that there is no difference between control cells and treated cells at the concentration of essential oil determined by cytotoxic activity assays for both cells lines. Ctrl: control; Bs: treatment with B. salicifolius essential oil. Data are expressed as mean ± standard deviation for experiments carried out in triplicate. Comparison between bars was performed by two-way ANOVA test followed by Sidak’s test using GraphPad Prism 6.01.