Three New Minor Compounds from the Roots of Rehmannia glutinosa and Their In Silico and In Vitro AMPK Activation

Rehmannia glutinosa Libosch, which belongs to the Orobanchaceae family, is a perennial herb found in China, Japan, and Korea. In traditional medicine, it is used to cool the body, improve water metabolism in the kidney, and provide protection from metabolic diseases such as diabetes and obesity. In this study, three new compounds were isolated from the roots of R. glutinosa, along with 18 known compounds. Structure elucidation was performed with spectroscopic analyses including nuclear magnetic resonance and circular dichroism spectroscopy. As the AMP-activated protein kinase (AMPK) signaling pathway is reportedly related to metabolic diseases, AMPK activation studies were conducted using in silico simulations and in vitro assays. Among the isolated com-pounds, 1 showed a potential as an AMPK activator in both in silico simulations and in vitro ex-periments. Our findings expand the chemical profiles of the plant R. glutinosa and suggest one newly found compound (1) activates AMPK.