Indole glucoalkaloids from Chimarrhis turbinata and their evaluation as antioxidant agents and acetylcholinesterase inhibitors.
As part of our study on bioactive agents from Brazilian rainforest plants, two new glucoalkaloids, 3,4-dehydro-strictosidine (1) and 3,4-dehydro-strictosidinic acid (2), were isolated from Chimarrhis turbinata, along with seven known glucoalkaloids, cordifoline (3), strictosidinic acid (4), strictosidine (5), 5 alpha-carboxystrictosidine (6), turbinatine (7), desoxycordifoline (8), and harman-3-carboxylic acid (9). The structures of the new alkaloids were established on the basis of comprehensive spectral analysis, mainly 1D and 2D NMR experiments, as well as high-resolution HRESIMS. Alkaloid 3 showed strong free-radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) as well as pronounced antioxidant activity evidenced by redox properties measured by ElCD-HPLC. Additionally, alkaloids 1-9 were submitted to TLC screening for acetylcholinesterase inhibitors. Both 7 and 8 were shown to be moderate acetylcholinesterase inhibitors at a concentration of 0.1 and 1.0 microM, respectively. In an in vitro rat brain assay, 7 showed moderate activity (IC(50) 1.86 microM), compared to the standard compound, galanthamine (IC(50) 0.92 microM).
Cardoso
Carmem Lucia
CL
Núcleo de Biossíntese, Bioensaios e Ecofisologia de Produtos Naturais, Instituto de Química da Universidade Estadual Paulista, C.P. 355-14800-900, Araraquara, Brazil.
Castro-Gamboa
Ian
I
Silva
Dulce Helena Siqueira
DH
Furlan
Maysa
M
Epifanio
Rosângela de A
Rde A
Pinto
Angelo da Cunha
Ada C
Moraes de Rezende
Cláudia
C
Lima
Josélia Alencar
JA
Bolzani
Vanderlan da Silva
Vda S
D000818:Animals; D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D001921:Brain / Q000378:metabolism; D001938:Brazil; D002800:Cholinesterase Inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D026121:Indole Alkaloids / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D020128:Inhibitory Concentration 50; D015394:Molecular Structure; D010084:Oxidation-Reduction; D051381:Rats; D019666:Rubiaceae / Q000737:chemistry*
C495166:3,4-dehydro-strictosidine; C495167:3,4-dehydro-strictosidinic acid; D000975:Antioxidants; D002800:Cholinesterase Inhibitors; D026121:Indole Alkaloids