The present study aims to evaluate the antioxidant and antimicrobial activity of essential oils (EO) extracted from safflower plants grown in the absence and presence of NaCl, 50 mM. Plants treated with 50 mM of NaCl showed decreases in root, stem, and leaf dry weight. Results of the essential oils showed that roots have a higher EO yield than leaves and stems. Salinity caused a decrease in this yield in roots and leaves but not in stems. The compounds identified in the EO extracted from these organs belong to seven chemical classes of which the dominant class is the sesquiterpene hydrocarbons. The chemotype of C. tinctorius EO is variable depending on the organ and the treatment. The safflower essential oils showed low antioxidant, antiradical, and iron-reducing activities compared to those of the positive control (BHT). In an antifungal activity test, only two strains, Aspergillus niger and Candida albicans, were found to be highly sensitive to these oils as they showed almost total inhibition of their growth. For antibacterial activity, safflower EOs showed significant antimicrobial activity against Bacillus subtilis, Bacillus cereus, and Xanthomonas campestris in both control and NaCl-treated plants: for these three strains, total inhibition of growth was noted at 50,000 ppm of EO in leaves and roots; whereas for stems, total inhibition was noted only for the third strain (Xanthomonas campestris). For other strains, this inhibition was variable and weak. Salt was found to have no effect on the activities of safflower EOs.
Keywords: antimicrobial activity; antioxidant activity; essential oils; safflower; salt.