Chemical characterization of Lavandula latifolia Medik. essential oil from Spanish wild populations

A survey of Lavandula latifolia Medik. wild populations was carried out covering the distribution area of the species in Spain. Samples (194) from 6 different biogeographic provinces were gathered, dried, hydrodistilled and their essential oils analyzed by gas chromatography (GC). Forty compounds were identified, three of them (1,8-cineole, linalool and camphor) accounting for more than 70% of the total oil in all the analyzed samples. Linalool and camphor were inversely correlated. Camphor production seemed to be helped by lower altitudes. Two-step clustering analysis was conducted and samples were classified into three different clusters C1 characterized by its high content in camphor, borneol, camphene, α- and β-pinene; C2 characterized by its high content in linalool and terpinen-4-ol and C3 characterized by the presence of limonene, transcaryophyllene and/or β-phellandrene, compounds that did not appear in significant percentages in the other two groups. C1 populations are the most frequent in samples from Eastern and North-Eastern Iberian Peninsula (Balearic-Catalonian-Provençal and Cévenno-Pyrenean biogeographic provinces). Populations from Central Iberian Peninsula (Mediterranean Central and West Iberian biogeographic provinces) and upland areas from the South of Spain (Betican and Murcian-Almerian biogeographic provinces) were mainly grouped in C2. C3 samples were also found in Cévenno-Pyrenean province and, to a lesser extent, in the Central provinces (Mediterranean Central and West Iberian). This distribution showed certain relationship between the chemical composition of the essential oils and their geographical origin. © 2012 Elsevier Ltd

Perfil químico y biológico de aceites esenciales de plantas aromáticas de interés agro-industrial en Castilla-La Mancha (España)

The chemical composition and biological activities of essential oils of <i>Salvia officinalis</i> L., <i>Salvia lavandulifolia</i> Vahl., <i>Lavandula x intermedia</i> Emeric ex Loisel., <i>Lavandula latifolia</i> Medik., <i>Lavandula angustifolia</i> Mill. and <i>Thymus vulgaris</i> L. are presented. The essential oils have been analysed by Gas Chromatography Mass Spectrometry and 61 compounds were identified, 23 of which represented more than 1% of the essential oil. The 1,8 cineole (16-23%) appeared as the main compound of <i>Salvia</i> sp. essential oils. The high content of α-thujone was characteristic in <i>S. officinalis</i> oil. Remarkable concentrations of linalool (30-33%), camphor (5-17%) and linalyl acetate (9-28%) were detected in <i>Lavandula</i> sp. oils while carvacrol (21.6%) and p-cimene (23.7%) were the most abundant compounds in <i>T. vulgaris</i> oil. Biological characterization was based on their bioplaguicide activity. The essential oils studied had strong antifeedant effects against <i>Leptinotarsa decemlineata</i> Say, <i>Spodoptera littoralis</i> Boisd., <i>Myzus persicae</i> Sulzer and <i>Rhopalosiphum padi</i> L., phytotoxic activity against <i>Lactuca sativa</i> L. and <i>Lolium perenne</i> L. and also exhibited high antifungal activity against <i>Fusarium</i> sp. Oils from <i>T. vulgaris</i> and <i>L. latifolia</i> showed the highest levels of bioactivity against all target species. These results provide an added-value to the essential oils of aromatic plants of agro-industrial interest for its potential use in the development of natural agrochemicals.<br><br>En este trabajo se presenta el estudio químico y biológico de los aceites esenciales de <i>Salvia officinalis</i> L., <i>Salvia lavandulifolia</i> Vahl., <i>Lavandula</i> x intermedia Emeric ex Loisel., <i>Lavandula latifolia</i> Medik., <i>Lavandula angustifolia</i> Mill. y <i>Thymus vulgaris</i> L. El estudio químico por cromatografía de gases acoplada a espectrometría de masas de los aceites esenciales permitió la identificación de 61 compuestos, de los cuales 23 presentaron un porcentaje mayor o igual al 1 %. Los aceites esenciales de <i>Salvia</i> sp. se caracterizaron por presentar un alto contenido de 1,8 cineol (16-23%) y, en el caso específico de <i>S. officinalis</i>, una elevada proporción de α-tuyona (15.7%). En <i>Lavandula</i> sp., los compuestos mayoritarios del aceite fueron linalol (30-33%), alcanfor (5-17%) y acetato de linalilo (9-28%); mientras que en <i>T. vulgaris</i> lo fueron carvacrol (21.6%) y p-cimeno (23.7%). La caracterización biológica, desde el punto de vista de la actividad bioplaguicida, mostró que los aceites ensayados disminuyeron significativamente la alimentación de <i>Leptinotarsa decemlineata</i> Say, <i>Spodoptera littoralis</i> Boisd., <i>Myzus persicae</i> Sulzer y <i>Rhopalosiphum padi</i> L., mostraron actividad fitotóxica frente a <i>Lactuca sativa</i> L. y <i>Lolium perenne</i> L. y disminuyeron el crecimiento del micelio del hongo de Fusarium sp. Los aceites de <i>T. vulgaris</i> y <i>L. latifolia</i> fueron los más activos frente a todas las especies empleadas como dianas biológicas. Los resultados obtenidos potencian el valor añadido de los aceites de plantas aromáticas de interés agro-industrial en Castilla- La Mancha como una alternativa interesante en programas de desarrollo de agroquímicos naturales

Weed and Weeding Effects on Medicinal Herbs

Competition with weeds exerts significant depressive effects on yield and quality features of Medicinal Plants (MPs). According to the crop, the part of plant to be harvested, the environmental features (including cropping technique) and the severity of infestation, yield losses due to the presence of weeds may vary within wide intervals. Furthermore, unlike the majority of other crops, MPs are cultivated with the goal to obtain relevant quantities of specific secondary metabolites, whose final quantity determines the quality level (and, consequently, the market value) of the harvested drug. Almost all papers addressed to this topic agree on the statement that unrestricted weed growth may alter MP production also from the qualitative point of view, that is, determining an overall decrease in the yield of active substances for unit area. In part, this outcome can be attributed to the general decrease of harvestable biomass, but in some cases also modifications of crop metabolic pathways have been observed, resulting in a general unpredictability of the chemical characteristics of the product obtained in weedy fields. Competition with weeds may assume a different severity according to the time and duration of competition period. In the starting phases of cultivation, the outcome of an early weed infestation is expected to be severe, since very often weeds grow much faster than crops. The maximum tolerance period, i.e. the period when weeding operations must be started, varies according to the tolerated loss values, and in annual crops the time span when fields must be kept totally weed-free may cover more than 60% of the entire crop cycle. The tools that are used for weeds removal may affect MPs production in many ways. Chemical treatments have been studied with contrasting results, but an interference of herbicides with the metabolism of secondary products was found in some cases. Furthermore, the interest in growing MPs with organic or environmentally friendly methods is increasing. Hence, besides the traditional (and highly expensive) method of hand-weeding, other non-chemical methods are studied, including mechanical treatments, mulching, flaming, and even grazing by goats or lambs. There is scope for further research, embracing a larger number of MPs and different environments, also including the effects of weeds on MPs metabolic pathways