Deciphering the bioactive compounds for the expectorant effect of FF based on the gut and lung metabolomics

Abstract

Abstract Farfarae Flos (FF), derived from the flower buds of Tussilago farfarae L., is used as a traditional herbal medicine for the treatment of cough, bronchitis and asthmatic disorders. It also has been used as a dietary supplement and health tea in many countries. However, its expectorant mechanism is unknown yet. In this study, the expectorant mechanism of FF was investigated from the perspective of metabolomics. The results showed that the expectorant effect of FF was related with gut microbiota, as demonstrated by antibiotic treatment and fecal microbiota transplantation. Dihydrocaffeic acid (DCA) and quinic acid (QA), which were metabolized from caffeoylquinic acids (CQAs) by the gut microbiota, showed obvious expectorant effect and were proved as the key metabolites for the expectorant effect of FF. In addition, FF as well as DCA and QA could regulate arginine biosynthesis, which was confirmed by arginine supplementation experiment. Moreover, DCA and QA, as well as arginine could regulate the phospholipids in the lung tissue, which could be served as pulmonary surfactant. This study presented a novel approach for investigating the expectorant mechanism of FF from the perspective of gut and lung metabolomics.