Analyses of the metabolism and assessment of antioxidant activity in Rhododendron chrysanthum Pall. after UV-B Irradiation

Due to their ability to act as antioxidants, many metabolites serve as plant defense chemicals. Holistic metabolomic analysis is a method to investigate UV-B radiation impacts because the metabolome directly represents the physiological state of the plant. In order to determine how the exposure to UV-B radiation affected the accumulation of primary metabolites (amino acids, organic acids), secondary metabolites (phenolic compounds, fatty acids), and their synergistic antioxidant capacity in Rhododendron chrysanthum Pall., this study used gas chromatography-time-of-flight mass spectrometry (GC-TOFMS). Metabolite analysis revealed that there were 444 metabolites in total. Most amino acids and organic acids, in particular, rose in concentration following being exposed to UV-B. Simultaneously, the levels of tricarboxylic acid cycle (TCA) intermediates and phenolic compounds grew steadily. Furthermore, after UV-B therapy, the amount of anthocyanins, which are known to be powerful antioxidants, rose. In terms of protein–protein interaction (PPI) and enzyme content, the experimental group demonstrated greater antioxidant ability. In reaction to UV-B radiation, the content of metabolites that act as antioxidants increased. This experiment proved that R. chrysanthum main and secondary metabolisms were altered by UV-B radiation. It sheds some information on the combined analysis of metabolomics and other omics in R. chrysanthum.