Bioactive Isoquinoline Alkaloids with Diverse Skeletons from Fissistigma polyanthum

Six new isoquinoline alkaloids, including aporphine alkaloids (2, 3, 9, and 10), a benzylisoquinoline alkaloid (13), and a protoberberine alkaloid (17), were isolated from the roots of Fissistigma polyanthum, along with a new furanone (20) and 13 known isoquinoline alkaloids (1, 4-8, 11, 12, 14-16, 18, and 19). The structures of the new compounds were elucidated by the analysis of spectroscopic data. Compounds 1 and 2 are rare oxalylfused dehydroaporphine alkaloids. Compound 12 presented the most potent dual-target activities on AChE inhibition and A beta aggregation inhibition, while compounds 13 and 19 simultaneously exhibited discernible AChE and BChE inhibitions with antioxidant activities. The activity results indicate that F. polyanthum alkaloids have a potential of inhibition and prevention of Alzheimer's disease mainly through both ChEs and beta-amyloid pathways in addition to antioxidant activity. [GRAPHICS] .

Automated summary

Six new isoquinoline alkaloids were isolated from the roots of Fissistigma polyanthum, along with a new furanone and 13 known isoquinoline alkaloids. The structures of the new compounds were identified through spectroscopic analysis. Compounds 1 and 2 are rare oxalylfused dehydroaporphine alkaloids. Compound 12 exhibited the strongest dual-target activities on AChE inhibition and A beta aggregation inhibition among the compounds tested, while compounds 13 and 19 showed noticeable inhibitions of AChE and BChE along with antioxidant activities. The alkaloids from F. polyanthum have the potential to inhibit and prevent Alzheimer's disease through ChEs, beta-amyloid pathways, and antioxidant activity.