Antioxidant and anticholinesterase potential of diterpenoid alkaloids from Aconitum heterophyllum.

Extensive chromatographic separations performed on the basic (pH=8-10) chloroform soluble fraction of Aconitum heterophyllum resulted in the isolation of three new diterpenoid alkaloids, 6β-Methoxy, 9β-dihydroxylheteratisine (1), 1α,11,13β-trihydroxylhetisine (2), 6,15β-dihydroxylhetisine (3), and the known compounds iso-atisine (4), heteratisine (5), hetisinone (6), 19-epi-isoatisine (7), and atidine (8). Structures of the isolated compounds were established by means of mass and NMR spectroscopy as well as single crystal X-ray crystallography. Compounds 1-8 were screened for their antioxidant and enzyme inhibition activities followed by in silico studies to find out the possible inhibitory mechanism of the tested compounds. This work is the first report demonstrating significant antioxidant and anticholinesterase potentials of diterpenoid alkaloids isolated from a natural source.