Chemical composition and antimicrobial activity of the essential oil from Bidens segetum Mart. Ex Colla leaves, flowers and fruits

Some Bidens species are well studied for their therapeutic purposes in various folk medicines [1]. B. segetum is a native species from the Brazilian Cerrado that, up to now, has not yet been thoroughly investigated. In this study, we analyzed the chemical composition and the antimicrobial activity of the essential oils of B. segetum flowers, fruits and leaves collected in Martinho Prado-SP. The essential oils were obtained by hydro-distillation for 3h with a yield of 0.16% for both flowers and fruits and 0.05% for the leaves. The component identification was performed by GC/MS indicating as major components α-amorphene (23.1%) for the leaves oil while in the flowers and fruits oil presented ß-phellandrene (22.9% and 40%) and α-amorphene (19.7% and 11.3%), respectively, as the main compounds. The antimicrobial activity was evaluated using the microdilution method [2] against Aspergillus niger (16404), Candida albicans (ATCC 10231), Escherichia coli (ATCC 8739) and Staphylococcus aureus (ATCC 6538). In the antifungal assay, the oils from leaves and flowers displayed a strong inhibition (93 and 99%, respectively) of the yeast C. albicans, while with the filamentous fungus A. niger only the leaf oils showed a strong inhibition (82%). In the antibacterial assay, the oils from flowers and leaves inhibited almost completely the growth of S. aureus whereas the fruits oil was almost inactive (11%). However, in the assay with E. coli the fruit oil was more active (52% inhibition) than the flowers and leaf oils (12 and 8% inhibition, respectively).

Acknowledgements: FAPESP, CNPq.

References: 1. Lorenzi H., Matos F.J.A. (2002) Plantas Medicinais no Brasil: Nativas e Exóticas. Nova Odessa: Instituto Plantarum, p.144.

2. Devienne K.F., Raddi M.S.G. (2002) Braz. J. Microbiol. 33:166–168.