Developmental-Stage-Dependent Changes in Basil Essential Oil Composition: Implications for NO Inhibitory Activity, Estragole Exposure, and Compositional Symmetry

The chemical composition of basil essential oil is influenced by plant developmental stage, which alters the relative distribution of volatile constituents and their functional properties. In this study, we investigated developmental-stage-dependent changes in the essential oil composition of Ocimum basilicum and evaluated their relationship with nitric oxide (NO) inhibitory activity and estragole exposure. Essential oils were obtained by hydrodistillation and analyzed by gas chromatography–tandem mass spectrometry (GC–MS/MS), resulting in the identification of 54 volatile compounds representing 98.13–98.97% of the total composition. Estragole remained the dominant constituent, ranging from 70.58% to 85.55%, with the lowest proportion at the flowering stage (Day 85). In contrast, minor constituents, including eucalyptol (2.41–3.77%), β-ocimene (0.52–1.98%), and methyleugenol (~2.00%), increased during flowering. NO inhibitory activity in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages was strongest at Day 85. Estimated Daily Intake (EDI) ranged from 0.4215 to 1.1005 µg kg−1 bw day−1, and Margin of Exposure (MOE) ranged from 2999 to 7830. These findings indicate that developmental stage influences composition, activity, and exposure. From a compositional perspective, the observed redistribution among major chemical groups reflects a structured balance that can be interpreted within a symmetry-related framework in multicomponent systems.