Andropanolide and isoandrographolide, minor diterpenoids from Andrographis paniculata:: Structure and X-ray crystallographic analysis

Phytochemical investigation of the leaves of Andrographis paniculata has led to the isolation of a new labdane type diterpenoid, andropanolide (1), along with seven known diterpenoids including isoandrographolide (2), previously reported as a rearrangement product of andrographolide. The structures and stereochemistry of compounds 1 and 2 were established by X-ray crystallographic analysis.