Gas Chromatography–Mass Spectrometry-Based Classification of 12 Fennel (Foeniculum vulgare Miller) Varieties Based on Their Aroma Profiles and Estragole Levels as Analyzed Using Chemometric Tools

Abstract

Fennel (Foeniculum vulgare Miller) is a popular aromatic plant native to the Mediterranean basin and cultivated worldwide that is valued for the nutritional and health benefits of its fruits. Headspace solid-phase microextraction of 12 fennel accessions of cultivated (F. vulgare subsp. vulgare) and wild forms ( F. vulgare subsp. piperitum) of different origins was carried out for assessing their volatile distribution. Fifty-four volatiles were identified, with ethers amounting for the major class at ca. 52− 99% attributed to the abundance of (E)-anethole and estragole. Several subsp. vulgare accessions proved to be excellent sources of the chief aroma (E)-anethole (95.9−98.4%), whereas high levels of estragole at ca. 72% were observed in subsp. piperitum from Minia and Khartoum and must be considered in the safety assessment of fennel. Other volatile classes were detected including ketones, esters, aldehydes, alcohols, and hydrocarbons (monoterpenes, sesquiterpenes, and diterpenes). Fenchone exceeded 15% of the total volatiles in some fennel specimens, linked to a conspicuous bitter aftertaste. The members of subsp. piperitum were more enriched in monoterpene hydrocarbons with sabinene found exclusively in these, while subsp. vulgare comprised a higher content of ethers. Principle component analysis determined isoterpinolene as a special component in subsp. piperitum. In all specimens from the same group, estragole was the most distinguished volatile compound according to the findings from orthogonal partial least squares-discriminant analysis. The highest estimated estragole levels were detected in subsp. piperitum from Minia at 89.8 mg/g. This comparative study provides the first comprehensive insight into volatile profiling of 12 fennel fruit varieties.

Investigating the Relationship of Genotype and Climate Conditions on the Volatile Composition and Sensory Profile of Celery (Apium graveolens)

“…Within the correlation matrix, fresh fennel exhibited many positive correlations with compounds that contribute to warm, herbal, sweet and spearmint odours such as (E)-dihydrocarvone (M20), L-carvone (M24), (E)-β-caryophyllene (S3) and α-humulene (S7) as well as sedanenolide (P4) and (cis)-ligustilide (P6). Afifi, El-Mahis, Heiss and Farag [42] classified 12 fennel varieties based on their aroma profile and similarities can be observed when comparing the monoterpene profile of celery in this study with the aroma profiles of the fresh fennel used by Afifi et al [42].…”

Anti-Inflammatory and Antimicrobial Volatile Oils: Fennel and Cumin Inhibit Neutrophilic Inflammation via Regulating Calcium and MAPKs

“…However, there is a major difference between diverse fennel samples from different geographical sources. Our results bode well with a previous report that identified a large amount of estragole in volatile oil obtained from Egyptian fennel, while the content of anethole was minor (Afifi et al, 2021). Importantly, estragole was reported as a potential genotoxic carcinogen (Afifi et al, 2021), and its high content in FEN must be taken into consideration for any future therapeutic use.…”

“…Our results bode well with a previous report that identified a large amount of estragole in volatile oil obtained from Egyptian fennel, while the content of anethole was minor (Afifi et al, 2021). Importantly, estragole was reported as a potential genotoxic carcinogen (Afifi et al, 2021), and its high content in FEN must be taken into consideration for any future therapeutic use. Cumin volatile oil (CUMIN) revealed high content of cuminaldehyde (49.9%), 2-caren-10-al (19.1%), and c-terpinene (9.6%) (Supplementary Figure S2).…”

Foeniculum vulgare Miller, a New Chemotype from Montenegro

“…[ 19 ]. ANE is responsible for the sweet, distinct, anise-like flavor characterizing FV fruits [ 24 ]. It is reported to exhibit antimicrobial, anthelmintic, insecticidal, gastroprotective, antithrombotic, spasmolytic, antioxidant, anti-inflammatory, and antinociceptive properties [ 25 , 26 , 27 ].…”