Mucroniferanines A–G, Isoquinoline Alkaloids from Corydalis mucronifera

Abstract

Five pairs of isoquinoline alkaloid enantiomers, mucroniferanines A-E (1-5), two inseparable epimeric pairs, mucroniferanines F and G (6, 7), and 10 known isoquinoline alkaloids (8-17) were obtained from Corydalis mucronifera. The structures were characterized using spectroscopic data analysis, and the absolute configurations were established by ECD and X-ray data analysis. The new compounds except for 3 possess a rare 9-methyl group in the isoquinoline alkaloids, and compounds 2 and 3 possess rare benzo[1,2-d:3,4-d]bis[1,3]dioxole moieties. It is the first report of stereoisomerism involving the 9-methyl phthalideisoquinoline alkaloids. Compounds (-)-4, 6, and 7 exhibited acetylcholinesterase inhibitory activities with IC values of 28.3, 12.2, and 11.3 μM, respectively.

Biologically active isoquinoline alkaloids covering 2014–2018

“…Only two compounds of this type were identified during the past 5 years. Protopine ( 210 ) and cryptopine ( 211 ) were isolated from F. officinalis , 24 and the former compound also was found in Corydalis mucronifera 82 (Figure 9).…”

Application of HPLC-DAD for In Vitro Investigation of Acetylcholinesterase Inhibition Activity of Selected Isoquinoline Alkaloids from Sanguinaria canadensis Extracts

“…Many plant extracts demonstrate acetylcholinesterase activity, for example, extract from Crinum jagus containing Amaryllidaceae and isoquinolinone alkaloids [6], Cryptocarya species containing isoquinoline alkaloids [10], Narcissus pseudonarcissus L. containing Amarylidaceae alkaloids [7], Catharanthus roseus containing indole alkaloids [9], secophenanthroindolizidine and proaporphine alkaloids from Cryptocarya densiflora Blume [10], Ocotea percoriacea containing benzylisoquinoline, bisbenzylisoquinoline, aporphine, proaporphine, phenanthrene, and morphinane alkaloids [9], Rauvolfia vomitoria containing monoterpene indole alkaloids [11], Crinum jagus containing Amarylidaceae and isoquinoline alkaloids [6], Lycoris longituba containing Amaryllidaceae alkaloid [12], Psychotria leiocarpa containing alkaloid vincosamide [13], Huperzia serrata containing macrocyclic Lycopodium alkaloids [14], Psychotria nemorosa containing azepine-indole alkaloids [15], Uncaria rhynchophylla containing indole alkaloids [16], Berberis vulgaris containing isoquinoline alkaloids [17], Lycopodium platyrhizoma containing Lycopodium alkaloids [18], Huperzia cunninghamioides containing Lycopodium alkaloids [19], Corydalis mucronifera containing isoquinoline alkaloids [20], Palicourea sessilis containing indole alkaloids [21], and Zephyranthes candida containing galanthamine, plicamine, and secoplicamine [22]. There have also been published articles summarizing the application of plant materials containing alkaloids for inhibition of acetylcholinesterase activity [23,24].…”

“…Acetylcholinesterase in vitro inhibition was investigated by spectrophotometry [6,7,9,12,14,[16][17][18]20,22,[26][27][28][29][30]. Usually acetylcholinesterase activity was determined according to Ellman et al [31].…”

Synthesis of 4-(1H-isochromen-1-yl)isoquinolines through the silver-catalysed homodimerization of ortho-alkynylarylaldehydes and subsequent condensation of the 1,5-dicarbonyl motif with NH3

“…The 1H-isochromene skeleton is the core structure of many biologically active molecules possessing important pharmaceutical activities, such as the those involved in the inammatory activation of microglia, 1 antimicrobial activity against the Gram-positive bacteria Staphylococcus aureus and Streptococcus pneumoniae, 2 selective receptor antagonists of neurokinin-1 (NK1), 3 and antagonists of Mycobacterium bovis BCG. 4 Isoquinoline derivatives are also a class of important heterocycles having acetylcholinesterase inhibitory activities, 5 murine tumor cell cytotoxicity, 6 antiplasmodial activities, 7 and so on. Thus, compounds with a combination of these two structural motifs could possess important potential bioactivity properties.…”