LC-MS Profile, Gastrointestinal and Gut Microbiota Stability and Antioxidant Activity ofRhodiola roseaHerb Metabolites: A Comparative Study with Subterranean Organs

Golden root (Rhodiola roseaL., Crassulaceae) is a famous medical plant with a one-sided history of scientific interest in the roots and rhizomes as sources of bioactive compounds, unlike the herb, which has not been studied extensively. To address this deficiency, we used high-performance liquid chromatography with diode array and electrospray triple quadrupole mass detection for comparative qualitative and quantitative analysis of the metabolic profiles ofRhodiola roseaorgans before and after gastrointestinal digestion in simulated conditions together with various biochemical assays to determine antioxidant properties of the extracts and selected compounds.R. roseaorgans showed 146 compounds, including galloylO-glucosides, catechins, procyanidins, simple phenolics, phenethyl alcohol derivatives, (hydroxy)cinnamates, hydroxynitrile glucosides, monoterpeneO-glucosides, and flavonolO-glycosides, most of them for the first time in the species. The organ-specific distribution of compounds found for catechins, procyanidins, and cinnamyl alcohols and glucosides was typical for underground organs and flavonoids and galloylated glucoses concentrated in the herb. Extracts from rhizomes, leaves and flowers showed high phenolic content and were effective scavengers of free radicals (2,2-diphenyl-1-picrylhydrazyl (DPPH center dot), 2,2 '-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS(center dot+)), O-2(center dot-),(OH)-O-center dot) and protected beta-carotene in a bleaching assay. Digestion in the gastric and intestine phase influenced the composition ofR. roseaextracts negatively, affecting the content of catechins, procyanidins, and galloyl glucoses, and therefore, the antioxidativity level. After gut microbiota treatment, the antioxidant capacity of rhizome extract was lower than leaves and flowers due to the aglycone composition found in the colonic phase of digestion. Our study demonstrated that the herb ofR. roseais a rich source of metabolites with high antioxidant properties and could be a valuable plant for new bioactive products.