A Year in the Life of Sea Fennel: Annual Phytochemical Variations of Major Bioactive Secondary Metabolites

Abstract

Sea fennel (Crithmum maritimum L.) is one of the most abundant and widespread Mediterranean halophytes, traditionally harvested and used in the summer months. As the plant bioactive metabolites are strongly influenced by the plant vegetation period and environmental conditions, we investigated some of the main bioactive compounds from sea fennel leaves over a one-year period to gain a deeper insight into their annual changes. A comprehensive phytochemical analysis of the essential oils using GC-MS, as well as the major phenolic and carotenoid compounds using HPLC, was performed. The results showed a high positive correlation between temperature and all major bioactive compounds, especially phenolic acids, cryptochlorogenic acid, and chlorogenic acid (r = 0.887, p = 0.0001 and r = 0.794, p = 0.002, respectively), as well as the limonene content in the essential oil (r = 0.694, p = 0.012). PCA analysis clearly distinguishes the period from February to April from the rest of the year, which contained the least bioactive metabolites overall. The overall data analyzed show great variations in sea fennel phytochemicals during the period of a year, with β-carotene content being the least effected. Therefore, it can be concluded that the plant can be used as a functional food or in other industries, such as the cosmetic and/or pharmaceutic industries, beyond its typical harvest period (early to midsummer).