Acute toxicity against Artemia franciscana of essential oils isolated from plants of the genus Lippia and Piper collected in Colombia

Thirty two essential oils, twenty from plants belonging to the genus Lippia (L. alba, L. citrodora, L. dulcis, L. micromera, and L. origanoides), and twelve from the genus Piper (P. auritum, P. bogotense, P. brachypodom, P. bredemeyeri, P. divaricatum, P. eriopodon, P. lanceifolium, P. marginatum, and P. septuplinervium), collected in different geographical sites in Colombia were isolated using microwave-assisted hydrodistillation, and their cytotoxicity measured as the medium lethal concentration (LC50), tested against Artemia franciscana. Selected oils were also characterized by gas chromatography-mass spectrometry (GC-MS)analysis. Essential oils from Lippia exhibited LC50 values ranging between 8.72-34.90 ?g/mL and 3.44-13.66 ?g/mL, after 24 and 48 h exposure, respectively. Essential oils of Piper presented acute toxicity with LC50 values between 4.43-22.38 ?g/mL and 2.54-12.64 ?g/mL after 24 and 48 h exposures, respectively. The oils with greatest bioactivities belonged to Lippia citriodora and Piper eriopodon in their respective groups. GC-MS data revealed that main constituents of essential oils from Lippia species include thymol, geranial, neral, trans-?- caryophyllene, carvone, limonene and p-cymene, whereas in Piper species those were trans-?-caryophyllene, elemecin, germacrene D, trans-sabinene hydrate, and ?-phellandrene. Most of the assayed plants are commonly used for prevention and treatment of diseases in Colombia, and the application of this screening demonstrated its usefulness to evaluate them bioactivity of these natural products at an early stage of traditional medicine development.