Sustainable nano-therapeutic approaches using bio-based vanillic acid nanocomposites to enhance salinity tolerance and essential oil quality in Satureja hortensis

Vanillic acid (VA), a plant-derived antioxidant, effectively neutralizes reactive oxygen species during environmental stress. To enhance its delivery to summer savory or Satureja hortensis, VA-based nanocomposites (VANCs) were synthesized via the coacervation method. This study assessed the efficacy of VA and VANCs at 0.01 mg/mL on S. hortensis under varying salt concentrations (0, 50, 100, and 150 mM NaCl), representing one of the first investigations using VANCs to counteract salinity stress in edible herbs like savory. Salinity significantly reduced plant growth parameters, photosynthetic pigments, and gas exchange traits while increasing oxidative stress markers. VANCs demonstrated superior effectiveness compared to VA alone in mitigating salinity-induced stress. Under high salinity conditions, VANCs improved growth parameters, photosynthetic performance, and antioxidant enzyme activities more effectively than VA treatment. Both forms enhanced photosynthetic system parameters, with nanocomposites showing greater effectiveness. VANCs also outperformed VA in reducing stress indicators and improving osmoregulation under salinity stress. Analysis of essential oil composition revealed that VANCs were particularly effective in preserving or enhancing bioactive compound concentrations under stress conditions. These findings indicate that bio-based VA nanocomposites can act as an eco-friendly approach to improve crop salt tolerance and the quality of essential oils. They have significant implications for sustainable agriculture, offering an innovative approach to enhance crop resilience in salt-affected soils. The demonstrated effectiveness of VANCs could help maintain the productivity and medicinal properties of herbs and other economically important crops in increasingly saline agricultural environments, potentially contributing to food security in regions affected by soil salinity.