Chemical Composition, In Vitro Antimicrobial and Cytotoxic Activities of Buddleja polystachya Essential Oils

Abstract

The chemical composition of leaf (B-1) and flower (B-2) essential oils of Buddleja polystachya was investigated by GC-MS. Moreover, the essential oils were evaluated for their antimicrobial activity using the broth micro-dilution assay for minimum inhibitory concentrations (MIC). The crystal violet staining method (CVS) was used for evaluation of their cytotoxic activity on HepG-2 and MCF-7 human cell lines. The chemical investigation of the oils led to the identification of thirty three constituents in B-1, and thirty seven in B-2, representing 99.02 % and 99.64 % of the oils respectively. Oxygenated monoterpenes were found to be the major group in both B-1 (54.80 %) and B-2 (82.44 %). It was found that B-1 consisted mainly of camphor (48.96 %), camphene (12.89 %), α-guaiene (12.09 %), bulnesol (6.36 %), limonene (4.42 %), camphol (3.92 %), α-pinene (3.54 %), 3-carene (2.93%), β-pinene (1.10%) and α-terpineol (1.01%). B-2 was characterized by high contents of camphor (77.51 %), camphene (6.79 %), camphol (3.81 %), α-pinene (2.21 %), nopol (2.18 %), β-eudesmol (1.64 %) and limonene (1.35 %). Both oils showed moderate antimicrobial activity against the Gram-positive strains and C. albicans. However, no activity was shown against Gram-negative bacteria for B-2, while B-1 showed moderate activity on E. coli. B-1 and B-2 showed cytotoxic activity against both MCF-7 and HepG-2 carcinoma cell lines. Both B-1 and B-2 exhibited a significant cytotoxic activity against MCF-7 (IC50 = 1.2 and 2.1 μg/ml, respectively) compared to vinblastine sulphate as reference drug (IC50=4.6 µg/ml).