Two New Indole Alkaloids from Emmenopterys henryi

Two new indole alkaloids, 5‐oxodolichantoside ( 1 ) and deglycocadambine ( 2 ), were isolated from the twigs and leaves of Emmenopterys henryi, together with four known indole alkaloids and five known iridoids. The structures of the new compounds were elucidated on the basis of extensive spectroscopic analyses, including 1D‐ and 2D‐NMR experiments, and confirmed by single‐crystal X‐ray diffraction studies. This is the first report on the isolation of indole alkaloids from this species. The indole alkaloids were evaluated for their cytotoxic activities against five human cancer lines.     

Sorellin und Hobartin,zwei neue Indolalkaloide aus Aristotelia peduncularis (LABILL.) HOOK. F. 173. Mitteilung über organische Naturstoffe

Sorelline and Hobartine, Two New Indole Alkaloids from Aristotelia peduncularis (LABILL .) HOOK . F. From Aristotelia peduncularis (LABILL .) HOOK . F. two new indole alkaloids, sorelline ( 1 ) and hobartine ( 2 ), have been isolated. Their structures were elucidated on the basis of spectroscopic data (the formulae represent their relative configurations). The alkaloids 1 and 2 have closely related structures with a monosubstituted indole moiety and an unrearranged monoterpene unit in the aliphatic part.     

Two new monoterpenoid indole alkaloids from Tabernaemontana divaricata

Two new monoterpenoid indole alkaloids, tabervarines A (1) and B (2), along with seven known monoterpenoid indole alkaloids, were isolated from the methanol extract of the twigs and leaves of Tabernaemontana divaricata. The structures including the absolute configurations of the new alkaloids were elucidated based on MS, NMR, and ECD calculation. The in vitro cytotoxic activities of the isolated alkaloids against several human cancer cell lines were also evaluated.     

Seven New Monoterpenoid Indole Alkaloids from Gelsemium elegans

Seven new indole alkaloids were isolated from the roots of Gelsemium elegans Benth. and their structures were determined by spectroscopic analysis and chemical transformation from known alkaloids. Kounaminal ( 1 ) is a new koumine‐type alkaloid that contains an unusual aminal moiety. Humantenoxenine ( 2 ) and 15‐hydroxyhumantenoxenine ( 3 ) are humantenine‐type alkaloids that contain a novel β‐amino‐α,β‐unsaturated ketone residue. The other four novel alkaloids are two gelsedilam‐related and two gelsenicine‐related alkaloids.     

Indole Alkaloids from the Whole Plants of Ervatamia officinalis

Three new ervatamine‐type indole alkaloids, 6‐oxo‐16,20‐episilicine ( 1 ), 16,20‐episilicine ( 2 ), and 6,16‐didehydro‐20‐episilicine ( 6 ), along with seven known alkaloids, were isolated from the whole plants of Ervatamia officinalis. Their structures were elucidated by spectroscopic methods.     

Two New Indole Alkaloids from the Marine‐Derived Bacterium Aeromonas sp. CB101

Two new indole alkaloids, arsindolines A and B ( 1 and 2 , resp.), together with six known indole alkaloids, were isolated from a marine‐derived bacterium strain CB101, identified as Aeromonas sp. Their structures were established by spectroscopic methods, and their antitumor activities were evaluated by SRB and MTT methods.     

Cytotoxic 5‐Hydroxyindole Alkaloids from the Marine Sponge Scalarispongia sp.

Three new 5‐hydroxyindole alkaloids ( 1 , 2 , 3 ) along with seven known analogs ( 4 , 5 , 6 , 7 , 8 , 9 , 10 ) were isolated from a Dokdo marine sponge Scalarispongia sp. The elucidation of the structures of the new compounds by spectroscopic analyses indicated that these compounds were an indole glyoxylate ( 1 ), a mono‐indole analog of hyrtinadine A ( 2 ), and a symmetrical bis‐indole with pyridine linker ( 3 ). The comparison of IC₅₀ values for obtained compounds against a human leukemia cell line revealed that the bis‐indole structure is a requirement for cytotoxicity.     

Die Isolierung weiterer Alkaloide aus Pleiocarba talbotii WERNHAM. 150. Mitteilung über Alkaloide

From the leaves of the Apocynaceae Pleiocarpa talbotii WERNHAM three new indole alkaloids were isolated and identified as 3,4,5,6-tetradehydrotalbotine ( 2 ), 5,6-dehydrotalbotine ( 3 ) and deformyl talbotinic acid methylester ( 4 ). From the stem bark of the same plant normacusine B (tombozine) was isolated.     

Die Alkaloide aus Hedranthera barteri (Hook. f.) Pichon. 139. Mitteilung über Alkaloide

From the root bark of the apocynacea Hedranthera barteri (Hook. f.) Pichon were isolated the known indole alkaloids vobtusine ( 1 ), voacamine ( 2 ), callichiline ( 3 ), voacangine ( 4 ) and conoflorine ( 5 ), as well as the unknown plant bases amataine, goziline and owerreine, and also beninine and 1, 2-dehydrobeninine. The structures of the two last mentioned alkaloids were shown in an earlier publication to be 6 and 7 , respectively. Amataine, goziline and owerreine are bis-indole alkaloids, which on the basis of their chemical and spectroscopic (especially mass spectroscopic) properties have been assigned the structures 8 , 9 and 10 , respectively.     

New Tryptophan Metabolites from Cultures of the Lipophilic Yeast Malassezia furfur

Eleven new indole alkaloids were isolated from cultures of the human pathogenic yeast Malassezia furfur after addition of L ‐tryptophan as the sole N‐source: pityriacitrin B ( 2 ), the malassezindoles A ( 3 ) and B ( 4 ), malassezialactic acid ( 6 ), the malasseziazoles A ( 7 ), B ( 8 ), and C ( 9 ), pityriazole ( 10 ), malasseziacitrin ( 11 ), and malassezione ( 12 ), along with the known d‐ indole‐3‐lactic acid (=(αR)‐α‐hydroxy‐1H‐indole‐3‐propanoic acid 5 ), and 2‐hydroxy‐1‐(1H‐indol‐3‐yl)ethanone ( 13 ). The structural elucidation of these compounds was performed by spectroscopic methods (MS as well as 1D‐ and 2D‐NMR). The biogenetic relationships (Scheme) and biological activities of the new metabolites are discussed.     

喜树中的吲哚生物碱

从喜树(Camptetheca acuminata Decne)果中分到五个微量吲哚类生物碱, 其中两个为新生物碱, 分别为camptacumotint(1)和camptacumanine(2), 另外三个为已知生物碱naucleficine(3), angustoline(4)和新天然产物二氢异喹胺(dihydroisoquinamine, 5).     

New Indole Alkaloids from Rauvolfia yunnanensis

Three new indole alkaloids, 10‐methoxy‐16‐de(methoxycarbonyl)pagicerine ( 1 ), (5β)‐17‐O‐deacetyl‐5,11‐dimethoxyakuammiline ( 2 ), and ((16S,19E)‐N¹‐(hydroxymethyl)isositsirikine ( 3 ) were isolated from the roots of Rauvolfia yunnanensis, together with seven known alkaloids. The structures of the new compounds were elucidated by in‐depth spectroscopic and mass‐spectrometric analyses.     

Two New Indole Alkaloids from the Bark of Anthocephalus chinensis

Two new indole alkaloids, cadambinic acid ( 1 ) and isonauclefidine ( 2 ), were isolated from the bark of Anthocephalus chinensis. The structures were identified by spectroscopic methods, and the compounds were tested for their biological activities. Both compounds showed weak cytotoxicities against A549, BGC‐823, and HeLa cells in biological assays.     

Voafrine A and Voafrine B,New Dimeric Indole Alkaloids from Cell Suspension Cultures of Voacanga africana Stapf

The structures of voafrine A and voafrine B, two novel dimeric indole alkaloids isolated from Voacanga africana Stapf cell suspension cultures, were established and the medium-dependent formation of both alkaloids was investigated.     

Alkaloids from stems of Ervatamia yunnanensis

Six indole alkaloids were isolated from the stems of Ervatamia yunnanensis. Among them, yunnanensine (I) is new. The other five are known alkaloids, namely: 19,20-E-vallesamine (II), 19s-heyneanine (HI), ibogaine (IV), ibogamine (V), coronaridine (VI). The structural elucidation of the alkaloids was based on spectral means.     

Monoterpenoid Indole Alkaloids Bearing an N4‐Iridoid from Gelsemium elegans

Five new alkaloids, gelseganines A–D ( 1 – 4 ) and humantenine N₄‐oxide ( 5 ), were isolated from the stems and leaves of Gelsemium elegans. Compounds 1 – 4 represent a rare class of monoterpenoid indole alkaloids that bear an N₄‐iridoid unit. The structures of 1 – 5 were determined by spectroscopic analysis, single‐crystal X‐ray diffraction, and chemical correlation, and their absolute configurations were elucidated by CD analysis. A plausible biogenetic pathway for alkaloids 1 – 5 was also postulated.     

Taichunamides: Prenylated Indole Alkaloids from Aspergillus taichungensis (IBT 19404)

Seven new prenylated indole alkaloids, taichunamides A–G, were isolated from the fungus Aspergillus taichungensis (IBT 19404). Taichunamides A and B contained an azetidine and 4‐pyridone units, respectively, and are likely biosynthesized from notoamide S via (+)‐6‐epi‐stephacidin A. Taichunamides C and D contain endoperoxide and methylsulfonyl units, respectively. This fungus produced indole alkaloids containing an anti‐bicyclo[2.2.2]diazaoctane core, whereas A. protuberus and A. amoenus produced congeners with a syn‐bicyclo[2.2.2]diazaoctane core. Plausible biosynthetic pathways to access these cores within the three species likely arise from an intramolecular hetero Diels–Alder reaction.     

Kopsifolines A–F: a New Structural Class of Monoterpenoid Indole Alkaloids from Kopsia

Six new indole alkaloids, named kopsifolines A–F ( 1 – 6 ), with an unprecedented hexacyclic carbon skeleton, constituting a new structural group of monoterpenoid indole alkaloids, were obtained from the leaf extract of a Malayan Kopsia species, and their structures were established by spectroscopic analysis.     

Rigorous biogenetic network for a group of indole alkaloids derived from strictosidine

Strictosidine, the precursor of more than 2,500 indole alkaloids, was isolated from four species of three plant families. By searching the Dictionary of Natural Products on DVD it was found that about 150 indole alkaloids were obtained from the same species (coalkaloids), which is a direct proof of their common origin. On the base of their three-dimensional structure, taxonomic properties and standard reaction mechanisms an extended network was established which involved the four fundamental skeletons, the three types of carbon framework in the secologanin subunit and all major groups of indole alkaloids derived from secologanin and tryptamine (except a few minor groups, in which only less then 10 alkaloids were known). The system was extended to the heterodimer indole alkaloids and the quinoindole alkaloids as well.     

Monoterpenoid Indole Alkaloids from Alstonia mairei

Three new monoterpenoid indole alkaloids, (14α,15α)‐14,15‐epoxyaspidofractinine ( 1 ) and maireines A and B ( 2 and 3 , resp.), together with 19 known alkaloids, were isolated from the leaves and twigs of Alstonia mairei. The structures of the new compounds were elucidated by 1D‐ and 2D‐NMR spectroscopic methods in combination with MS experiments.