Seasonal Variations in Essential Oil of Dill: A Three Months Study

Abstract This study explores the seasonal variations in the essential oil content and composition of dill (Anethum graveolens) during the spring season, emphasizing the impact of environmental factors on its bioactive properties. Essential oils from dill are highly valued for their multifaceted medicinal, therapeutic, and culinary applications, primarily due to their rich chemical composition. Understanding the influence of seasonal changes on these oils can significantly enhance their use in food, health, and pharmaceutical industries. Using Gas Chromatography-Mass Spectrometry (GC/MS), the chemical composition of dill essential oils was analyzed across three consecutive harvests during the spring. The results revealed a dynamic shift in the presence and concentration of key compounds, such as α-phellandrene, β-phellandrene, dill ether, carvacrol, germacrene D, dill apiole, and phytol, which some of them increased progressively in later harvests. A notable diversification of bioactive compounds was observed in the later stages of the season, coinciding with variations in environmental factors such as temperature, light intensity, and growth maturity. These factors collectively influenced the biosynthesis of essential oils, optimizing their chemical complexity and potency over time. This study underscores the critical role of seasonal timing in maximizing the nutritional, therapeutic, and functional value of dill essential oils. By identifying the optimal harvest periods and understanding the environmental drivers of these changes, producers can improve the quality, yield, and bioactivity of dill essential oils, supporting their broader application in developing high-value functional foods, natural remedies, and health-promoting products.