Widely targeted metabolome profiling of different colored sesame (Sesamum indicum L.) seeds provides new insight into their antioxidant activities.

Sesame seeds are considered worldwide as a functional food due to their nutritional and therapeutical values. Several physiological functions are being associated with sesame seeds and their derived products. However, the phytochemicals responsible for these various proprieties are not well understood. Thus, to acknowledge the diversity and variability of metabolites in sesame seeds of different colors and reveal key metabolites and pathways contributing to differences in antioxidant activities, black, brown, yellow, and white sesame seeds from 12 varieties were subjected to LC-MS/MS-based widely targeted metabolomics analysis. Totally, 671 metabolites were identified and chemically classified. The metabolic compounds varied significantly with the seed coat color and genotype. Many flavonoids, amino acids, and terpenoids were up-regulated in dark seeds. Sixty key differential metabolites were filtered out. Phenylpropanoid biosynthesis, amino acids biosynthesis, and tyrosine metabolism were the main differently regulated pathways. The DPPH, ABTS, and FRAP assays showed that the antioxidant activities of the seeds increased with the seed coat darkness. Therefore, the pharmacological proprieties of black seeds might be related to their high content of flavonoids and essential amino acids mostly. These findings expand phytochemicals composition information of different colored sesame seeds and provide resources for their comprehensive use and quality improvement.