Four new derivatives of andrographolide were chromatographically isolated from its complicated sulfonation product mixture, and then characterized by spectroscopic methods. Together with 1D and 2D NMR technology, including 1H NMR, 13C NMR, DEPT, 1H-1H COSY, HSQC, HMBC and NOSEY, and comparison of the NMR data with those of the parent compound, the structures of all the four derivatives were elucidated as 3,19-dihydroxy-labdanum-8,11,13-trien-15,16-olide (1), 3-hydroxy-labdanum-8,11,13- trien-15,16-olide-19-sulfuric ester (2), labdanum-8,11,13-trien-15,16-olide-3,19-disulfuric ester (3), and 3-hydroxy-8(R)-12(S)-8(12)-epoxy-labdanum-13-en-15,16-olide-19-sulfuric ester (4), respectively.

Key words: andrographolide, sulfonating reaction, nuclear magnetic resonance, characterization