Seven new indole alkaloids (1-7) comprising four vobasine, two tacaman, and one corynanthe-tryptamine bisindole alkaloid were isolated from the stem-bark extract of a Malayan Tabernaemontana. Two of the new vobasine alkaloids (1, 3), as well as 16-epivobasine (15) and 16-epivobasenal (17), showed appreciable cytotoxicity toward KB cells (IC50 ca. 5 μg/mL). The structure of the known Tabernaemon...

A general, efficient, and conceptually new approach to the total syntheses of marine-derived indole alkaloids, including (+/-)-flustramines A (1) and B (2), (+/-)-flustramides A (3) and B (4), and (+/-)-debromoflustramine B (5), is outlined. The key step in the syntheses involves the conjugated addition of an organomagnesium species derived from prenyl bromide to 2-hydroxyindolenines. Compounds...

A new polyketide compound 1 and a new naturally occurring chromone derivative 2, along with two known indole alkaloids 3-4 were characterized from the ethyl acetate extract of a soil-derived fungal strain, Exophiala pisciphila PHF-9. The structures of compounds 1-4 were established by detailed spectroscopic analysis and comparison with literature data. The absolute configuration of 1 was determ...

The methanolic extract of Tabernaemontana catharinensis (Apocynaceae) roots, which contains alkaloids with several biological activities, was separated on a preparative scale using high-speed counter-current chromatography. The optimum solvent system was found to be a mixture of CHCl(3)-MeOH-H(2)O [5:10:6 (v/v/v)] and led to a successful separation of two monoterpenic indole alkaloids, voachalo...

The terpene indole alkaloid biosynthetic pathway can utilize a secologanin substrate analog containing a handle for functionalization, and the resulting non-natural alkaloids can be chemoselectively derivatized in crude extracts of plant tissue.

Five indole alkaloids, corynantheidine, corynantheine, dihydrocorynantheine, alpha-yohimbine and corynanthine were isolated from bark of Corynanthe pachyceras K. Schum. (Rubiaceae). The structures were established by spectroscopic methods, including previously unreported assignment of all 1H-NMR resonances by COSY and NOESY experiments. These and related alkaloids showed pronounced activity aga...

The grass parasitic fungus Claviceps purpurea sensu lato produces sclerotia with toxic indole alkaloids. It constitutes several genetic groups with divergent habitat preferences that recently were delimited into separate proposed species. We aimed to 1) analyze genetic variation of C. purpurea sensu lato in Norway, 2) characterize the associated indole alkaloid profiles, and 3) explore relation...

Eight naturally occurring monoindole alkaloids were evaluated in vitro for their ability to inhibit Plasmodium falciparum growth and, in drug combination, to reverse the resistance of a chloroquine-resistant strain of Plasmodium falciparum. None of these indole alkaloids has significant intrinsic antiplasmodial activity (IC(50) > 10 microM or 5 microg/ml). Nevertheless, three alkaloids (icajine...

The title compound, C20H22N2O2, an alkaloid isolated from the Madagascar periwinkle, crystallizes in P1 with two independent but closely similar mol-ecules in the unit cell. The mol-ecules are linked into pairs by two N-H⋯O=C hydrogen bonds. The absolute configuration was confirmed by anomalous dispersion effects as S at the 3 and 15 positions, and R at the 7 position.