Three New Cholinesterase Inhibitory Cassioates from Cassia Fistula

Three new compounds – cassioates D (4-((9E,11E)-dodeca-9,11-dien-1-yl)-3-methylcyclohexyl tetrahydro-2H-pyran-2-carboxylate), E (2-ethyl-3-methoxy-4,4,15,15-tetramethyl-4,5,6,7,8,9,10, 11,12,15,16,17-dodecahydro-1H-cyclopanta[α]phenanthren-16-yl propionate), and F ((E)-17-(2,6-dimethylhept-3-en-3-yl)-7-ethoxy-3-hydroxy-4-isopropyl-10-methyl-2-propoxy-2,3,4,7,10,11,12,13,14,15,16,17-dodecahydro-1H-cycl openta[α]phenanthren-12-ylpropionate) – were isolated from Cassia fistula Linn. The structures of these compounds were elucidated with the help of chemical and spectroscopic techniques. All the three cassioates (D – F) were checked for their acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory action in dose dependent manner. The IC50 (50% inhibitory effect) values of compounds E and F against AChE were 10.26 ± 0.44 and 4.20 ± 0.01 μM while the values obtained against BChE were 14.03 ± 0.21 and 7.59 ± 0.04 μM, respectively. Molecular docking based in silico inhibitory potential of compounds D – F against cholinesterase enzyme target is matching to bioassay screening results. At the same time, compound D showed feeble inhibition profile.