Comparison of growth, phytochemical content and antioxidant activities of the halophyte, Limonium tetragonum under saline and non-saline conditions

Soil salinization threatens global agriculture, increasing interest in salt-tolerant halophytes like Limonium tetragonum for their reported biological activities. However, cultivation strategies enabling their industrial utilization remain underdeveloped. This study assessed the cultivation potential of L. tetragonum under conventional agricultural conditions by comparing plants grown in saline soil (SS; high EC, Na⁺, Mg²⁺) and non-saline soil (NSS; higher organic matter, available P, Ca²⁺). Growth parameters (leaf number, leaf length, biomass) were measured, five major secondary metabolites (catechin and flavonoids) were quantified via LC-MS/MS, and antioxidant activities (DPPH, ABTS, ROS assays) were evaluated. Principal component analysis determined correlations among soil traits, plant growth, and metabolite profiles. As indicated by the diverse physicochemical differences between the two soils, cultivation in NSS was associated with significantly superior growth, higher accumulation of major bioactive compounds (including total anthocyanins and carotenoids), and stronger antioxidant capacities compared to those in SS. Correlation analysis revealed that elevated organic matter and available P in NSS were closely associated with enhanced metabolite biosynthesis and physiological activity. These results demonstrate that L. tetragonum is readily cultivable under non-saline conditions, suggesting an alternative perspective to the general assumption that salinity maximizes secondary metabolite production, and providing a scientific basis for the sustainable utilization of bioactive halophytes.