Nostotrebin 6, a bis(cyclopentenedione) with cholinesterase inhibitory activity isolated from Nostoc sp. str. Lukešová 27/97

Abstract

Nostotrebin 6, a new polyphenolic compound with a fully substituted 2,2′-bis(cyclopent-4-en-1,3-dione) skeleton, was isolated from a methanolic extract of the cyanobacterial strain Nostoc sp. str. Lukešová 27/97. The structure of this compound was determined using X-ray crystallography and further supported by NMR, IR spectroscopy, and MS. Nostotrebin 6 is an S-parabolic I-parabolic noncompetitive inhibitor of acetylcholinesterase (IC50 = 5.5 μM) and an S-parabolic I-parabolic mixed inhibitor of butyrylcholinesterase (IC50 = 6.1–7.5 μM). The inhibitory potency of nostotrebin 6 was compared with that of tacrine and galanthamine.