Metabolomics characterizes the metabolic changes of Lonicerae Japonicae Flos under different salt stresses

Salt stress affects the metabolic homeostasis of medicinal plants. However, medicinal plants are sessile organisms that cannot escape from salt stress. They acclimatize themselves to the stress by reprogramming their metabolic pathways. Lonicerae Japonicae Flos (LJF) with strong antioxidant activity is commonly used in traditional Chinese medicine, tea, and beverage. Nevertheless, the variation of integrated metabolites in LJF under different salt stresses remains unclear. In this study, High Performance Liquid Chromatography tandem triple time-of-flight mass spectrometry (HPLC- triple TOF-MS/MS) coupled with multivariate statistical analysis was applied to comparatively investigate the metabolites changes in LJF under different salt stress (0, 100, 200, 300 mM NaCl). Total 47 differential metabolites were screened from 79 metabolites identified in LJF under different salt stress. Low salt-treated group (100 mM NaCl) appeared to be the best group in terms of relative contents (peak areas) of the wide variety in bioactive components. Additionally, the phenylpropanoid pathway, monoterpenoid biosynthesis, glycolysis, TCA cycle, and alkaloid biosynthesis were disturbed in all salt-stress LJF. The results showed that LJF metabolisms were dramatically induced under salt stress and the quality of LJF was better under low salt stress. The study provides novel insights into the quality assessment of LJF under salt stress and a beneficial framework of knowledge applied to improvement the medicinal value of LJF.