Cassaine diterpenoid glycosides from the seeds of Erythrophleum fordii Oliv. and their antiviral and anti-inflammatory activities

Abstract

Seven new cassaine diterpenoids (1–7) along with four known ones (8–11) were isolated from the seeds of Erythrophleum fordii Oliv. (Leguminosae). Their chemical structures were elucidated by extensive spectroscopic data interpretation and chemical methods. Compound 1 is a rare unsymmetrical dimer, which is formed by the linking of another cassaine diterpenoid acid glycoside to the 6-hydroxyl group of the sugar unit in a cassaine amide glycoside through an ester bond. Compound 2 is a cassaine diterpenoid acid derivative featuring an unusual Z double bond at C-13 and C-15. The in vitro antiviral and anti-inflammatory activities of 1–11 were evaluated. The results showed that compounds 1, 2 and 3 showed significant antiviral activities against human respiratory syncytial virus (RSV) with IC50s of 6.3, 7.8, and 9.4 μM, respectively. Compound 9 significantly suppressed the expression of nuclear factor-kappa B (NF-κB) with an IC50 value of 2.6 μM.