Phytochemical Diversity of the Essential Oils of Mexican Oregano (Lippia graveolens Kunth) Populations along an Edapho‐Climatic Gradient |
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| Authors: | Luz María Calvo‐Irabién Victor Parra‐Tabla Violeta Acosta‐Arriola Fabiola Escalante‐Erosa Luciana Díaz‐Vera Gabriel R Dzib Luis Manuel Peña‐Rodríguez |
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| Affiliation: | 1. Unidad de Recursos Naturales, Centro de Investigación Científica de Yucatán, A.?C. Calle 43 #130 Chuburná de Hidalgo, Mérida, Yucatán 97200, México, (phone: +52‐999‐9428330;2. fax: +52‐999‐9813900);3. Universidad Autónoma de Yucatán, Campus de Ciencias Biológicas y Agropecuarias, Departamento de Ecología Tropical, Km. 15.5, Carretera Mérida‐Xmatkuil, 4‐116, Mérida, Yucatán 97315, México;4. Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, A.?C. Calle 43 #130 Chuburná de Hidalgo, Mérida, Yucatán 97200, México |
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| Abstract: | Mexican oregano (Lippia graveolens) is an important aromatic plant, mainly used as flavoring and usually harvested from non‐cultivated populations. Mexican oregano essential oil showed important variation in the essential‐oil yield and composition. The composition of the essential oils extracted by hydrodistillation from 14 wild populations of L. graveolens growing along an edaphoclimatic gradient was evaluated. Characterization of the oils by GC‐FID and GC/MS analyses allowed the identification of 70 components, which accounted for 89–99% of the total oil composition. Principal component and hierarchical cluster analyses divided the essential oils into three distinct groups with contrasting oil compositions, viz., two phenolic chemotypes, with either carvacrol (C) or thymol (T) as dominant compounds (contents >75% of the total oil composition), and a non‐phenolic chemotype (S) dominated by oxygenated sesquiterpenes. While Chemotype C was associated with semi‐arid climate and shallower and rockier soils, Chemotype T was found for plants growing under less arid conditions and in deeper soils. The plants showing Chemotype S were more abundant in subhumid climate. High‐oil‐yield individuals (>3%) were identified, which additionally presented high percentages of either carvacrol or thymol; these individuals are of interest, as they could be used as parental material for scientific and commercial breeding programs. |
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| Keywords: | Lippia graveolens Essential oil Chemometrics Chemotypes Germplasm conservation Principal component analysis (PCA) Hierarchical cluster analysis (HCA) |
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