Viviane Brandt

Quaternary indole alkaloids from the stem bark of Strychnos guianensis.

Two new quaternary alkaloids, 9-methoxy-Nb-methylgeissoschizol and guiachrysine together with the known compounds C-alkaloid O, fluorocurine, mavacurine, macusine B and C-profluorocurine, were isolated from Strychnos guianensis stembark. The structures of the compounds were elucidated on the basis of spectroscopic studies.

β-Carboline glucoalkaloids from Strychnos mellodora

Abstract Two new N b -methylated β -carbolinium glucoalkaloids, 3,4,5,6-tetradehydropalicoside and 3,4,5,6-tetradehydrodolichantoside, together with the known β -carboline compounds desoxycordifoline (β-carboline 3-carboxylate glucoalkaloid) and melinonine F ( N b -methylated harmanium cation), were isolated from Strychnos mellodora stembark. The structures of the compounds were elucidated on the basis of spectroscopic studies.

3 ',4 ',5 ',6 ' tetradehydrolongicaudatine Y, an anhydronium base from Strychnos usambarensis

Abstract A new bis indole alkaloid, tetradehydrolongicaudatine Y, has been isolated from the stem bark of Strychnos usambarensis collected from the Ivory Coart. Elucidation of its structure is based mainly on spectroscopic studies and places it among the relatively small collection of zwitterionic indoloquinolizine alkaloids.

Main glucosidase conversion products of the gluco-alkaloids dolichantoside and palicoside

The enzymatic glucose cleavage of palicoside revealed the biosynthetic pathway to akagerine, whereas the conversion of dolichantoside led to a new quaternary heteroyohimbine alkaloid named N(b)-methyl-21-beta-hydroxy-mayumbine. The hypothetical models of reactions occurring after the conversion of both substrates are proposed. Dolichantoside and palicoside, as well as Strychnos mellodora stem bark crude ethanol extract, exhibit significant antimycotic activity against human pathogens in presence of specific glucosidase.