ABSTRACT Essential oil (EO) yield and composition of five accessions of Mentha 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 α-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, α-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.

中文翻译：

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长叶薄荷 (L.) L. 五个种质中精油的季节性变化，具有选定的化学特征

摘要 通过 GC-MS 和 GC-FID 分析确定了整个营养周期中五份长叶薄荷 (L.) L. (叶) 的精油 (EO) 产量和组成。这些种质是根据来自野生个体的二氯甲烷提取物的 TLC 谱选择的。富含 α-松油基乙酸酯和 8-乙酰氧基香芹酮丙酮的曲线以前没有报道过。EO产量的最大值出现在开花晚期。在营养周期开始时注意到主要的组成变化，而在开花阶段发现更多的稳定性。因此，在一些种质中发现了主要化合物的显着变化：胡椒酮和胡椒烯酮氧化物、α-松油醇乙酸酯和 8-乙酰氧基香芹酮丙酮，在营养生长期间显示出相当大的增加（6.0% 至 20.1%），与其他种质中的胡薄荷酮和胡椒烯酮氧化物相同。由于生物活动取决于 EO 成分，因此应强调其季节性变化的知识。