This study was designed to examine the effect of provenance on the phytochemical and antioxidant properties of essential oil and methanolic extract from Tunisian and French fennel seeds (FFS). Analysis of the essential oil showed that although the same main compounds were found in Tunisian and FFS cultivars, some differences were present in their proportions allowing to classify them in two chemotypes. The first class was composed by trans‐anethole (63.41%–78.26%) for Tunisian cultivars and the second one by estragole (44.72%–88.92%) for French cultivars. The phenolic composition of all fennel seed extracts was characterized by its richness in quinic acid, 4‐O‐caffeoylquinic acid, p‐coumaric acid, and 4‐O‐caffeoylquinic acid. All fennel seed extracts showed a better antioxidant potential than their essential oils depending on the origin. Principal component analysis showed a dispersion of the cultivars on three groups depending on the chemotype diversity. Practical applications Recently, much attention has been focused on fennel due to the nutritional and health‐protective value of their seeds. Several studies have highlighted the importance of fennel seed extracts and essential oils as key ingredients rich in bioactive compounds serving in formulation of new functional food products. This investigation designed to examine the effect of provenance on phytochemical and antioxidant potentials of Tunisian and French fennel seed extracts and essential oils.

Knowledge on phenotypic and chemical diversity among fennel (Foeniculum vulgare Mill.) cultivars is a milestone in the improvement of this specie which is considered as one of the most important medicinal plants. For this purpose, the present study was conducted in order to compare for the first time fennel cultivars regarding their agro-morphological traits as well as their essential oil yield and composition. Ten fennel cutivars were cultivated in a randomized completely block design whereas the seeds essential oil was analysed by GC-MS analysis. All phenotypic traits showed variation among the cultivars examined. Correlations between traits showed a significant positive relation between yield and height, number of leaves, number of branches, number of umbels , number of umbellate and peduncle length. Significant genotypic variations were also observed in essential oil content and composition in which trans-anethole, estragole, fenchone and limonene were the main constituents. Clustering method classified the ten fennel cultivars into 3 major groups. Moreover, PCA analysis showed great dispersion of these cultivars. The diversity identified in this study, especially from the three varietal types, showed that some cultivars are featured with several agro-morphological and chemical characteristics and could be further exploited as promising material for the creation of new varieties.

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In the present study, the potential biocontrol ability of fennel seeds essential oil against Fusarium oxysporum f. sp. lycopersici (FOL), in vitro and in vivo conditions was evaluated. Chemical composition of the essential oil was determined by GC-MS analysis and major components identified were trans-anethole, L-Fenchone, Estragole and Limonene. The different essential oils concentrations revealed to be efficient to inhibit the FOL growth with IC50 values =300.37 µl/l. Under greenhouse conditions using susceptible tomato plants, the use fennel essential oil as a curative treatment, resulted in a good protection against Fusarium wilt. In fact, the essential oil displayed a significant decrease (42.85%) in disease severity on tomato in comparison to control. Treatment with fennel essential oil significantly exhibited a growth promotion of infected or non-infected tomato plants. Moreover, the resistance induction was associated with several physiological changes in tomato plants. After 3 weeks post infection, physiological parameters such as, relative water content, total chlorophyll and carotenoid contents were altered by FOL and interestingly increased in fennel essential oil treated plants. This study demonstrated that fennel seeds essential oil was a promising biocontrol compound and could be considered in formulation of biofungicide used against Fusarium wilt.