Combined transcriptome and metabolome analysis and evaluation of antioxidant and antibacterial activities in white, pink, and violet flowers of Angelica gigas

Abstract

Angelica gigas is cultivated as an important medicinal and industrial crop because of its economic importance and use as traditional herbal medicine in East Asia. This study provides functional information on A. gigas flowers, revealing secondary metabolism and metabolite differences and relationships in the white, pink, and violet flowers, via transcriptome and metabolome analysis. Furthermore, the synergistic biological effects of A. gigas flower extracts via antioxidant and antimicrobial assays are revealed. Particularly, the RNA-seq analysis revealed 3073 differentially expressed genes (DEGs) between the white and violet flowers and 2161 DEGs between the pink and violet flowers with the false discovery rate (FDR) in both cases being < 0.05. The highest total phenolic content (5.69 ± 0.05 mg/g dry weight), total flavonoid content (0.57 ± 0.04 mg/g dry weight), and total coumarin content (19.66 ± 1.72 mg/g dry weight) were obtained in the pink, white, and white flower, respectively. Interestingly, the total anthocyanins content was not detected in the white flower, whereas the violet flower showed the highest accumulation (0.63 ± 0.04 mg/g dry weight). In addition, metabolite profiles showed that sucrose had a strong positive correlation with the anthocyanin content. The extract of white flowers revealed higher antioxidant and antimicrobial effects, supported by the positive correlation between the biological capacities and phenolic contents.