Anti-Inflammatory ent -Kaurane Diterpenoids from Isodon serra .

Ten new ent -kaurane diterpenoids, including two pairs of epimers 1 / 2 and 4 / 5 and a 6,7- seco - ent -kauranoid 10 , were obtained from the aerial parts of Isodon serra . The structures of the new compounds were confirmed by extensive spectroscopic methods and electronic circular dichroism (ECD) data analysis. An anti-inflammatory assay was applied to evaluate their nitric oxide (NO) inhibitory activities by using LPS-stimulated BV-2 cells. Compounds 1 and 9 exhibited notable NO production inhibition with IC ₅₀ values of 15.6 and 7.3 μM, respectively. Moreover, the interactions of some bioactive diterpenoids with inducible nitric oxide synthase (iNOS) were explored by employing molecular docking studies.