ABSTRACT Essential oil (EO) of Citrus has some biological and pharmaceutical properties; thus, it can be used in food and drug industries. Changes in growing seasons play important roles in physiological processes of Citrus EO especially that extracted from young leaves. The aim of this study was to evaluate the EO extracted from young leaves of twelve Citrus species in different seasons (winter, spring, summer and autumn) under Egyptian conditions. The Citrus species in this investigation were Valencia Orange, Navel Orange, Sour Orange, Lemon, Volkamer Lemon, Lime, Persian Lime, Sweet Lime, Mediterranean Mandarin, Dancy Tangerine, Grapefruit and Shaddock. The EOs of young leaves were extracted by hydrodistillation method (HD), and then analyzed by GC and GC/MS. Data were statistically analyzed using ANOVA. Sabinene was identified as the major component in EO isolated from Valencia Orange, Navel Orange and Grapefruit while linalool was the main compound in EO of Sour Orange, Mediterranean Mandarin and Dancy Tangerine. The major constituent of EO produced from Lemon, Volkamer Lemon, Lime, Persian Lime and Sweet Lime was limonene, but it was E-phytol in Shaddock EO. The greatest contents (%) of EO isolated from young leaves and major constituents of all Citrus species were detected in the samples harvested during the spring season. The EO constitutes that detected in leaf EO were classified into five chemical groups “monoterpene hydrocarbons (MH), oxygenated monoterpenes (OM), sesquiterpene hydrocarbons (SH), oxygenated sesquiterpenes (OS) and oxygenated diterpenes (OD)”. It was found that the detected compounds of EO extracted from various Citrus species belonged to MH, OM, SH and OS, except the compounds of Dancy Tangerine and Shaddock were belonged to MH, OM, SH, OS and OD. Different changes were observed in the minor components and various chemical groups in different growing seasons.

中文翻译：

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生长季节对埃及栽培柑橘叶精油成分的影响

摘要柑橘精油 (EO) 具有一些生物学和药学特性；因此，它可用于食品和药品行业。生长季节的变化在柑橘 EO 的生理过程中起着重要作用，尤其是从幼叶中提取的柑橘 EO。本研究的目的是评估在埃及条件下从不同季节（冬季、春季、夏季和秋季）的 12 种柑橘属植物的幼叶中提取的 EO。本次调查中的柑橘品种为瓦伦西亚橙、脐橙、酸橙、柠檬、沃尔卡默柠檬、酸橙、波斯酸橙、甜酸橙、地中海柑橘、丹西橘、葡萄柚和柚子。采用水蒸馏法 (HD) 提取幼叶的 EO，然后通过 GC 和 GC/MS 进行分析。使用方差分析对数据进行统计分析。萨宾烯被确定为从瓦伦西亚橙、脐橙和葡萄柚中分离出来的 EO 中的主要成分，而芳樟醇是酸橙、地中海柑橘和丹西橘中 EO 中的主要化合物。Lemon、Volkamer Lemon、Lime、Persian Lime和Sweet Lime生产的EO的主要成分是柠檬烯，但Shaddock EO中的E-phytol。在春季收获的样品中检测到从幼叶和所有柑橘属物种的主要成分中分离出的 EO 含量 (%) 最高。在叶EO中检测到的EO构成分为五个化学组“单萜烃（MH）、氧化单萜（OM）、倍半萜烃（SH）、氧化倍半萜（OS）和氧化二萜（OD）”。结果表明,除丹西柑和柚子的化合物属于MH、OM、SH、OS和OD外,各柑橘属植物EO的检测化合物均属于MH、OM、SH和OS。在不同的生长季节，微量成分和各种化学基团发生了不同的变化。