Phenolic Antioxidants in the Adriatic Halophyte Limbarda crithmoides: Variation Across Phenological Stages

Golden samphire [Limbarda crithmodes (L.) Dumort], a perennial, edible Mediterranean halophytic specie, is recognised for its richness in biologically active compounds and its associated health benefits. Despite its potential, it remains largely underexplored in Croatia. This study investigates the effect of plant's phenological stage-vegetative phase (June), pre-flowering (July), and full flowering (August)-on its phenolic profile (total phenolics, flavonoids, and tannins using spectrophotometry, and individual phenolic compounds using ultra-high performance liquid chromatography and antioxidant potential (using three complementary in vitro assays)). Total phenolics, flavonoids and related antioxidant activity progressively increased from June to August. Among the 18 identified phenolic compounds, chlorogenic acid was the most abundant (355 to 455 µg/g), reaching its highest concentration in the August sample, while among flavonoids it was quercetin (32 to 34 µg/g). These findings suggest that golden samphire collected in the late summer flowering stage exhibits the highest phenolic and antioxidant potential, and that chlorogenic acid, likely acting in synergy with other phenolics, may play the key role in the plant's biological activity, reinforcing its potential for future applications.