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[EN] Essential oil (EO) yield and composition of five accessions ofMentha longifolia(L.) L. (leaves) were determined throughout their vegetative cycle by GC-MS and GC-FID analysis. These accessions were selected based on TLC profiles of dichloromethane extracts from wild individuals. The profile rich in alpha-terpinyl acetate and 8-acetoxy carvotanacetone has not been previously reported. The maximum value of EO yield was obtained in advanced flowering stage. The major composition changes were noted at the beginning of the vegetative cycle, whereas more stability was found during the flowering stage. Thus, significant changes in the major compounds were found in some accessions: piperitone and piperitenone oxides, alpha-terpineol acetate and 8-acetoxy carvotanacetone, which showed a considerable increase (6.0% to 20.1%) during the vegetative growth, the same way that pulegone and piperitenone oxide in other accessions. As biological activities depend on EO composition, the knowledge of its seasonal changes should be emphasized.

[EN] Some essential oils (EOs) can be extracted from berries of different species, and their composition depends on their maturation level. In this work, these parameters were correlated forJuniperus oxycedrusL ssp.oxycedrus. For this purpose, a classification method based on the CIE L*a*b* colour measurement was applied. Once the samples were classified, they were subjected to simultaneous distillation extraction and gas chromatography (GC/FID and GC/MS). Hydrocarbon monoterpenes constituted the major fraction (42.8-89.8%), mainly represented by -pinene (30.1-66.4%) and myrcene (6.1-34.8%). Hydrocarbon sesquiterpenes accounted for 4.0-26.4%, with germacrene-D (0.2-16.9%) as the major component. The discriminant analysis proved that CIE L*a*b* implementation was useful to classify the ripening stage. Regarding the EO composition, significant differences were observed in myrcene, camphor and germacrene-D, as well as in the grouped oxygenated and hydrocarbon terpenoids. In general, a progressive increase in oxygenated compounds was noted over the maturation process.

[EN] The seasonal variation of essential oil composition of aerial parts and roots of Artemisia absinthium L. has been investigated. It was obtained from individuals growing wild in Teruel (Spain) by means of hydrodistillation (aerial parts) or simultaneous distillation extraction (roots), and analyzed by GC/MS and GC/FID. Results showed a predominance of oxygenated monoterpenes (81.4-89.1%) in aerial parts; mainly (Z)-epoxyocimene (49.3-71.5%), (Z)-chrysanthemyl acetate (7.6-18%) and linalool (0.7-10.4%). In spite of the high intrapopulational variability, significant variations were observed for these three compounds. Root essential oil composition showed a high amount of hydrocarbon monoterpenes (43.8-55.1%) and monoterpenic esters (36.6-41.5%) with a noticeable seasonal stability except for some allelopathic oxygenated monoterpenes. As A. absinthium is a typical invasive species, knowing the seasonal variations of these compounds may be a first step to study their release in soil as a source for natural herbicides.