Ent-labdane-type diterpene glycosides obtained from Rubus chingii Hu and their inhibitory effects on PDE5A activity

Abstract

In this study, 16 new ent-labdane-type diterpene glycosides, designated as goshonosides J1–J16 (1–16), along with nine previously known diterpene glycosides (17–25) were extracted from the fruits of Rubus chingii Hu. The structures of goshonosides J1–J16 were elucidated using various analytical techniques, such as nuclear magnetic resonance, electron capture detector ECD, high-resolution electrospray ionization mass spectrometry HREIMS, single-crystal X-ray diffraction, and hydrolysis. Furthermore, the isolates' efficacy in inhibiting the activity of phosphodiesterase type 5 A was evaluated. Goshonosides J1, J2, and G effectively inhibited the activity of the aforementioned enzyme (IC50 values: 6.15 ± 1.76, 3.27 ± 0.65, and 9.61 ± 2.36 μM, respectively). Our findings highlight the remarkable structural diversity of bioactive compounds in R. chingii Hu and offer insights into the use of this shrub.