Megastigmane and guaiane-type glycosides with cholinesterase inhibitory effects from Ceriscoides campanulata leaves

Two megastigmane glycosides (1–2), a guaiane-type sesquiterpenoid glycoside (3), three flavones (4–6), a hydroxycoumarin (7), and a caffeoylquinic acid (8) were isolated from the butanolic fraction of Ceriscoides campanulata leaves. Eight previously described compounds were isolated using chromatographic techniques and their structures were elucidated employing spectrometric, spectroscopic analysis and data of the literature. The antidiabetic and anticholinesterase properties of compounds 1–3 were evaluated. Compound 2 showed weak α -glucosidase inhibition (IC50 = 595 ± 16 μM). Compound 1 inhibited both acetylcholinesterase (AChE, IC50 = 46.4 ± 8.1 μM) and butyrylcholinesterase (BChE, IC50 = 81.1 ± 1.6 μM), whereas compound 2 showed comparatively stronger inhibition of AChE, with an IC50 of 39.3 ± 6.8 μM. Both compounds were less potent than the reference drug galantamine. Notably, for the first time, the acetylcholinesterase inhibitory activities of compounds 1 and 2 were also confirmed in cellular model using SH-SY5Y human neuroblastoma cells, further supporting their potential neuroprotective effects.