A Characterization of Biological Activities and Bioactive Phenolics from the Non-Volatile Fraction of the Edible and Medicinal Halophyte Sea Fennel (Crithmum maritimum L.).

Although the biochemical composition and biological properties of the volatile fraction of the halophyte sea fennel (Crithmum maritimum L.) have been largely described, little is known about its polar constituents and bioactivities. Here, a hydromethanolic extract of Crithmum maritimum (L.) leaves was fractionated, and the fractions were evaluated in vitro for antioxidant (using DPPH, ABTS, and FRAP bioassays), anti-inflammatory (inhibition of NO production in RAW 264.7 macrophages), antidiabetic (alpha-glucosidase inhibition), neuroprotective (inhibition of acetylcholinesterase), and skin-protective (tyrosinase and melanogenesis inhibitions) activities. Polar fractions of the extract were rich in phenolics and, correlatively, displayed a strong antioxidant power. Moreover, fractions eluted with MeOH₂₀ and MeOH₈₀ exhibited a marked inhibition of alpha-glucosidase (IC₅₀ = 0.02 and 0.04 mg/mL, respectively), MeOH₆₀ fractions showed a strong capacity to reduce NO production in macrophages (IC₅₀ = 6.4 μg/mL), and MeOH₈₀ and MeOH₁₀₀ fractions had strong anti-tyrosinase activities (630 mgKAE/gDW). NMR analyses revealed the predominance of chlorogenic acid in MeOH₂₀ fractions, 3,5-dicaffeoylquinic acid in MeOH₄₀ fractions, and 3-O-rutinoside, 3-O-glucoside, 3-O-galactoside, and 3-O-robinobioside derivatives of quercetin in MeOH₆₀ fractions. These compounds likely account for the strong antidiabetic, antioxidant, and anti-inflammatory properties of sea-fennel polar extract, respectively. Overall, our results make sea fennel a valuable source of medicinal or nutraceutical agents to prevent diabetes, inflammation processes, and oxidative damage. [ABSTRACT FROM AUTHOR]