Exploratory Assessment to Evaluate Seed Sprouting under Elevated CO2 Revealed Improved Biomass, Physiology, and Nutritional Value of Trachyspermum ammi

Abstract

Elevated atmospheric CO2 (eCO2) can significantly enhance plant metabolism and improve their nutritional quality. Although several studies addressed the effect of eCO2 on plants, to our knowledge, there are no studies that have applied eCO2 to improve growth, chemical composition, and biological properties of ajwain (Trachyspermum ammi) during sprouting. Herein, eCO2 (620 µmol mol−1) was employed to enhance photosynthetic reactions. Improved photosynthesis induced primary and bioactive secondary metabolism, which led to improved biological activities of T. ammi sprouts in comparison with control sprouts and seeds. eCO2-treated sprouts showed significantly (p < 0.05) higher levels of most measured nutritional primary and secondary metabolites like soluble sugars, essential amino acids, organic acids, essential oils, phenolics, and flavonoids than control sprouts, which had significantly higher values than control seeds. eCO2 significantly improved the antimicrobial properties of T. ammi sprouts against 11 out of 13 microbial species than control sprouts, which had more potent antimicrobial activities than seeds. The significant increase in the antioxidant potential of treated sprouts was indicated by improved levels of ferric reducing antioxidant power (FRAP), DPPH, and oxygen radical absorbance capacity (ORAC). In addition, the anticancer activity against four different human tumor cell lines was significantly (p < 0.05) boosted by both sprouting and eCO2 exposure. Thus, the present study confirms the synergistic effect of sprouting with eCO2 exposure as promising approaches to produce ajwain sprouts with rich nutraceuticals, effective phytochemicals, and enhanced biological activities.