The Effect of Salt Stress on Antimicrobial Activity and Potential Production of Anthocyanin and Total Phenolic of Salicornia in Hydroponic Culture

Plants are sources of a wide range of secondary metabolites. Secondary metabolites show a critical role in protecting plants against herbivores and microbial pathogens. In addition to understanding the resistance mechanism of Salicornia, as a halophyte plant, secondary metabolites of this plant have medicinal and nutritional importance. In this study, the antibacterial activity of S. persica was investigated under salinity stress. For this purpose, first, the seeds were sterilized, and after 4 days of germination, each pot with five seedlings was irrigated with Hoagland solution containing 50, 200 and 400 mM NaCl. After about 60–70 days, three replications of each treated plant were randomly selected and used to investigate the antimicrobial and antioxidant activity, accumulation of phenols and anthocyanin, and photosynthesis pigments of S. persica. The results showed that the antimicrobial activity of S. persica for E. coli and S. aureus was significantly different from other studied microorganisms, and the most effective and antimicrobial activity was detected for E. coli. Also, the accumulation of photosynthetic pigments, carotenoids, soluble carbohydrates, phenol and anthocyanin was observed in S. persica by increasing salt concentration in the medium. In addition, the highest lipid peroxidation was documented in plants cultured in the medium including 400 mM NaCl, which was 46% and 39% higher than the control and plants treated with 200 mM NaCl, respectively, which associated with increasing total antioxidant capacity and activity of antioxidant enzymes. Therefore, it seems that an increase in the antimicrobial activity may be related to the improved concentration of phenol, anthocyanin, carotenoids and antioxidant activity of S. persica under salt stress.