NO inhibitory phytochemicals as potential anti-inflammatory agents from the twigs of Trigonostemon heterophyllus

Abstract

Studies on the relationship of nitric oxide (NO) and inflammation have revealed that compounds with NO inhibitory effects are potentially useful for inflammation and related inflammatory disorders. A phytochemical investigation to obtain new NO inhibitors resulted in the isolation of two new cleistanthane diterpenoids (1 and 2) and 11 known terpenoids (3-13) from Trigonostemon heterophyllus. The structures of these terpenoids were established by analysis of their NMR, MS, and electronic circular dichroism (ECD) data. Compounds 1 and 2 possess rare 3,4-seco-cleistanthane diterpenoid skeletons. All of the isolates were evaluated biologically for their NO inhibitory effects in lipopolysaccharide (LPS)-induced murine microglial BV-2 cells and compounds 1, 6, and 8-10 showed strong NO inhibitory effects with IC50 values less than 40 mu M. Using Western blotting experiments and molecular docking, the possible mechanism of NO inhibition was investigated.