Poster Chemical composition and cytotoxic activity of the leaf essential oil of Ocotea tonduzii from Monteverde, Costa Rica Sayaka Takakua, Anita Bansalb, Debra M. Moriarityb, William N. Setzera a Department of Chemistry, University of Alabama in Huntsville, Huntsville, Alabama 35899, USA; bDepartment of Biological Sciences, University of Alabama in Huntsville, Huntsville, Alabama 35899, USA Introduction. The Lauraceae is composed of 52 genera and almost 3000 species, mostly from tropical and warm subtropical regions. The genus Ocotea contains about 350 species, most of which are found in the Neotropics. As with other members of the family, Ocotea spp. are generally aromatic and have found utility in both perfumery as well as flavoring. As part of our phytopharmacological investigation of the higher plants from Monteverde, Costa Rica [1], we have recently investigated essential oils for biological activity [2]. Objectives. To determine the chemical composition and cytotoxic activity of the leaf essential oil of O. tonduzii from Monteverde, Costa Rica. Methods. Leaves of Ocotea tonduzii were collected from a mature tree in the Monteverde Cloud Forest Reserve, located in the Cordillera de Tilarán in northwestern Costa Rica. The fresh leaves were chopped and hydrodistilled using a Likens-Nickerson apparatus with continuous extraction with chloroform to give the essential oil. The leaf oil of O. tonduzii was subjected to gas chromatographic-mass spectral analysis using an Agilent 6890 GC with Agilent 5973 mass selective detector. The essential oil was screened for in-vitro cytotoxic activity against four human tumor cell lines (MCF-7, MDA-MB-231, MDA-MB-468, and UACC-257) using the MTT assay for cell viability. Results. The principal constituents of O. tonduzii leaf oil were the monoterpenes alpha-pinene (41.4%) and betapinene (25.1%) and the sesquiterpenes alpha-humulene (6.9%), beta-caryophyllene (5.8%), and germacrene D (3.8%). O. tonduzii leaf oil was notably cytotoxic on MCF-7, MDA-MB-231, MDA-MB-468, and UACC-257 cells in vitro. The major essential oil components showed cytotoxic activities comparable to doxorubicin (LC-50, 20-70 ug/mL). Conclusion. The abundance of alpha- and beta-pinenes (66% of the oil) as well as the concentrations of the four sesquiterpenoids, beta-caryophyllene, alpha-humulene, germacrene D, and caryophyllene oxide (17% of the oil) account for the observed broad cytotoxicity of the essential oil. Keywords: Ocotea tonduzii, essential oil, chemical composition, cytotoxicity Selected References 1. Setzer MC, Moriarity DM, Lawton RO, Setzer WN, Gentry GA, Haber WA. (2003) Phytomedicinal potential of tropical cloudforest plants from Monteverde, Costa Rica. Revista Biologica Tropical, 51, 647-674. 2. Setzer WN, Setzer MC, Moriarity DM, Bates RB, Haber WA. (1999) Biologicalactivity of the essential oil of Myrcianthes sp. nov. “black fruit” from Monteverde,Costa Rica. Planta Medica, 65, 468-469. Presenting Author: Sayaka Takaku,
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