Phytochemical profiling of undescribed triterpenoids from Cyclocarya paliurus leaves: structural elucidation and...

A phytochemical investigation of Cyclocarya paliurus leaves, traditionally consumed as a herbal tea, resulted in the isolation of 20 triterpenoids. Their structures were elucidated by extensive spectroscopic analysis, including 12 previously undescribed compounds (1-9, 12 and 14-15), while compounds 13, 18 and 20 were identified from this species for the first time. Among these undescribed compounds, 1-9 were characterized as A-seco dammarane-type tetracyclic triterpenoids, a class of tetracyclic triterpenoids rarely encountered in Nature. Network pharmacology combined with molecular docking was performed on all isolated compounds, demonstrating that several constituents could interact with key targets implicated in metabolic regulation, indicating promising metabolic activity. In a palmitate-induced insulin-resistant HepG2 cell model, most compounds significantly enhanced glucose consumption. Furthermore, three representative triterpenoids (4, 6 and 13) reduced intracellular lipid accumulation in a dose-dependent manner. These findings demonstrate that C. paliurus is a rich source of structurally diverse triterpenoids and provide a phytochemical basis for futher investigation of their potential roles in glucose and lipid metabolism.