Isoquinoline Alkaloids from the Roots of Dactylicapnos scandens and Their Antibacterial Activities

Abstract:

To study the isoquinoline alkaloids of Dactylicapnos scandens and their antibacterial activities, ten isoquinoline alkaloids were isolated from its roots. Based on physical and chemical properties and spectral data, their structures were identified as protopine (1), 1-methoxyberberine (2), allocryptopine (3), pseudoprotopine (4), palmatine (5), sinomenine (6), jatrorrhizine (7), sanguinarine (8), tetrahydropalmatine (9), isocorydine (10). Compounds 2-4 and 8 were isolated from this plant for the first time. Moreover, compound 4 exhibited significant antimicrobial activity against Escherichia coli with an MIC value of 6.25 μg/mL, which is better than the clinical antibacterial drug berberine (25.0 μg/mL).

Key words:Isoquinoline alkaloid;Dactylicapnos scandens;Chemical constituent;Antibacterial activity