Two new diterpenoids, neoorthosiphonones B and C (1 and 2), and one known diterpenoid, were isolated from the aerial parts of Clerodendranthus spicatus. Their structures including absolute configurations were determined by comprehensive spectroscopic analyses and X-ray crystallographic methods. No compound was found to inhibit fibronectin production at the concentration of 20 μM.
Keywords: Clerodendranthus spicatus; Diterpenoid; Neoorthosiphonones B and C.