Isolation and Structure Elucidation of Acetyl Cholinesterase Inhibitor from Gyrostoma helianthus of the Red Sea, Egypt

4 Abstract: The present study was carried out to isolate, purify and elucidate the structure of low molecular weight bioactive compounds from sea anemone, Gyrostoma helianthus of the Red Sea environment. The obtained results indicated that the ethanolic crude extract of the sea anemone, Gyrostoma helianthus showed inhibition activity against acetylcholinesterase (AchE). The 0.5kD fraction inhibited the activity of AchE that indicated the presence of low molecular weight active compound(s) of less than 0.5kD. Two active fractions were obtained after BioGel P2 fractionation of the 0.5kD of the Gyrostoma helianthus. The first active fraction inhibited the activity of the acetylcholinesterase, while the other fraction was not. HPLC technique aided by semipreparative columns was used to isolate the target compounds in a pure form for the structure elucidation, one dimensional NMR analysis ( H and C-NMR) and DEPT were carried out to elucidate the structure of the 1 13