Evaluation Profile of Sicilian Oenanthe aquatica (L.) Poir., O. fistulosa L. and O. pimpinelloides L. Essential Oils Under LPS-Induced Cellular Stress

The genus Oenanthe L. (Apiaceae) comprises aquatic and semi-aquatic species widely distributed across the Northern Hemisphere, some of which are traditionally used as food or in folk medicine. Despite this ethnobotanical relevance and toxicological notoriety, phytochemical and pharmacological data on the genus remain limited, especially regarding their essential oils (EOs). Essential oils, extracted by hydrodistillation from aerial parts of Sicilian Oenanthe fistulosa L. (OF), Oenanthe aquatica (L.) Poir (OA), and Oenanthe pimpinelloides L. (OP), were analyzed by GC–MS. The EO of O. fistulosa was dominated by monoterpene hydrocarbons (59.8%), with β-cis-ocimene (21.6%), sabinene (9.3%), and β-trans-ocimene (8.4%) as the main metabolites. O. pimpinelloides also exhibited a monoterpene-rich profile (60.3%), characterized by β-cis-ocimene (15.5%), sylvestrene (12.8%), and β-trans-ocimene (10.3%) but distinguished by a high apiol content (21.0%), indicating a mixed monoterpene/phenylpropanoid chemotype. In contrast, O. aquatica revealed a markedly different profile dominated by phenylpropanoids (57.2%), particularly dill apiol (53.5%), alongside α-pinene (17.2%) and sabinene (6.5%), representing an uncommon chemotype within the genus. This study aimed to evaluate whether these chemo-diverse Sicilian Oenanthe EOs (dill-apio OA 53.5%; ocimene OF 59.9%; apiol OP 21%) differentially modulated LPS-induced epithelial redox stress in Caco-2. Caco-2 cells were treated for 24 h with lipopolysaccharide (LPS) and co-treated with two concentrations (12.5 and 25 µg/mL) of EOs from three different species of Oenanthe. Assessment of proliferating cell nuclear antigen (PCNA) and the stress response of enzyme heme oxygenase-1 (HO-1) expression was performed using Western blot and reverse transcriptase-polymerase chain reaction (RT-PCR). EOs showed species- and concentration-dependent effects on LPS-induced stress in Caco-2 cells. O. aquatica and O. fistulosa EOs exerted cytoprotective and antioxidant activity at low concentrations (12.5 and 25 μg/mL), reducing 8-hydroxy-2′ -deoxyguanosine (8-OHdG) DNA damage and moderately upregulating HO-1. In contrast, O. pimpinelloides EO (apiol-rich) induced dose-dependent cytotoxicity, elevated 8-OHdG despite strong HO-1 induction, and lacked protection at higher doses. PCNA expression was reduced by LPS across all treatments, with no preservation of proliferation by any EOs. These findings reveal chemotype-specific modulation of oxidative stress and epithelial integrity.