## 3 Results and Discussion  
### Volatile Composition of Sea Fennel Leaf, Flower, and Fruit EOs and Hydrolates  
EOs from sea fennel leaves, flowers, and fruits (Figure 1) were obtained by hydrodistillation and analyzed by GC-MS (Table 1), along with their corresponding hydrolates (Table 2). While the EOs from sea fennel leaves and flowers of the Croatian chemotype have been extensively studied and well documented [10; 14; 15], there have been no reports focusing on the chemistry of the fruit EO. Likewise, while some studies have investigated hydrolates from sea fennel leaves [18; 19], this study is, to the best of the authors' knowledge, the first to report the volatile composition of hydrolates obtained from other plant parts. The classification of sea fennel chemotypes remains a topic of debate. [PERSON] et al. [32] identified two chemotypes distinguished by their allapiole content: chemotype I contains 15-17%, while chemotype II has 0-6%. In contrast, due to significant variations in essential oil composition depending on the geographical origin, [PERSON] [33] proposed a broader classification consisting of four chemotypes: the aromatic monoterpene type, the monoterpene hydrocarbon type, the phenylpropanol type, and an intermediate type. Previous studies on Croatian sea fennel [10; 14; 15] have classified its EOs as chemotype II and of the monoterpene hydrocarbon type. The most abundant compounds in all the plant parts were monoterpene hydrocarbons, reaching 97.87% in the flowers, 96.76% in the fruits, and 85.01% in the leaves (Table 1). The GC-MS analysis of sea fennel leaf, flower, and fruit EOs conducted in this study supports this classification, as allapiole was completely absent, while limonene (a monoterpene hydrocarbon) was the predominant compound,  
Figure 1: Sea fennel (**a**) leaves, (**b**) flowers, and (**c**) fruits. ranging from 68.41% in the fruits to 74.85% in the leaves. Sabinene, another abundant monoterpene hydrocarbon, was absent in the leaf essential oil, but reached 15.72% in the flowers and 12.37% in the fruits. The limonene content in the leaf (74.85%) and flower (74.30%) EOs was consistent with the literature data, according to which the EOs from summer leaves from the Split region contained limonene levels ranging from 57.5 [15] to 79.13% [10] and up to 84.53% [27]. In flower EOs, limonene ranged from 62.2 [15] to as high as 93.39% (based on our unpublished data). Previous studies have reported sabinene levels in leaves ranging from 0.15 [27] to 51.47% [21], and in flowers from 1.65 (unpublished data) to 12% [15]. Additionally, two other monoterpene hydrocarbons were found in notable amounts: \(\alpha\)-pinene was the most abundant in the fruit EO (9.07%), while \(\beta\)-ocimene was the highest in the leaves (6.54%), slightly exceeding previously published values (0.42-4.1%) [10; 21]. To evaluate the differences among EOs from different plant parts, a one-way ANOVA was performed. The level of \(\alpha\)-pinene showed significant differences across all the samples. Although there was no significant variation in the limonene content between the leaf and flower essential oils, a notable difference was observed between the fruit and leaf essential oils. In contrast, the \(\beta\)-ocimene levels differed significantly between the leaf and flower essential oils, as well as between the leaf and fruit essential oils. The most abundant compounds in sea fennel EOs are of significant value to human health. Limonene, an aromatic and volatile monoterpene, exhibits a wide range of biological activities, including anticancer, antidiabetic, gastroprotective, anti-inflammatory, antioxidant, antinociceptive, antihyperalgesic, and antiviral properties [34]. Another notable compound, \(\alpha\)-pinene, has been shown to possess cytoprotective, gastroprotective, neuroprotective, anxiolytic, and anticonvulsant effects [35]. Although sabinene has been less extensively researched, an available study suggest that it exhibits angiostatic and antiangiogenic effects, as well as antimicrobial activity [36].