Cardiovascular Effects, Phytochemistry, Drug Interactions, and Safety Profile of Foeniculum vulgare Mill. (Fennel): A Comprehensive Review

Background/Objectives: Cardiovascular diseases remain the leading cause of mortality worldwide. According to the World Heart Federation, more than 500 million people were living with cardiovascular diseases in 2021. In this context, the use of medicinal plants has become increasingly widespread in populations as a preventive strategy against cardiovascular disorders. Foeniculum vulgare Mill., commonly known as fennel, is an aromatic and medicinal plant recognized for its beneficial properties in the treatment of various ailments, due to its richness in bioactive compounds. This review aims to summarize and analyze the cardiovascular activities of this plant, based on experimental evidence, and to provide an updated overview of its phytochemical composition and safety profile. Methods: A comprehensive literature search was conducted using databases including PubMed, Scopus, Web of Science, and Google Scholar, encompassing all publications available up to 2024. This search included research articles, reviews, mini-reviews, and clinical studies published in English. Exclusion criteria comprised publication types such as letters, conference abstracts, unpublished theses, and non-peer-reviewed reports. Studies were also excluded if they did not specifically address Foeniculum vulgare Mill. or its cardiovascular activities. All studies were screened according to predefined inclusion and exclusion criteria, and relevant data were systematically extracted and analyzed to synthesize current knowledge on the cardiovascular activities, mechanisms of action, phytochemical composition, safety, and potential drug interactions of Foeniculum vulgare Mill. Results: Numerous in vitro and in vivo studies have demonstrated that Foeniculum vulgare Mill. exhibits a wide range of activities beneficial for cardiovascular health. These include antihypertensive, cardioprotective, vasorelaxant, anti-inflammatory, antioxidant, diuretic, hypotensive, hypolipidemic, antiplatelet, and anticoagulant effects. Such pharmacological actions are largely attributed to its rich phytochemical composition, particularly its volatile oils (e.g., trans-anethole, fenchone), flavonoids (e.g., quercetin, kaempferol), and phenolic acids (e.g., p-coumaric acid, ferulic acid). Most studies report no significant signs of toxicity. Conclusions: Foeniculum vulgare Mill. emerges as a promising medicinal plant for the prevention and management of cardiovascular diseases, owing to its multifaceted beneficial effects and its favorable safety profile. However, potential interactions with cardiovascular drugs and the current limitations of existing studies highlight the need for further clinical research to fully establish its therapeutic potential.