Prenylated Indole Alkaloid Derivatives from Marine Sediment‐Derived Fungus Penicillium paneum SD‐44

Three new prenylated indole alkaloids, including two β‐carbolines, penipalines A and B ( 1 and 2 , resp.), and one indole carbaldehyde derivative, penipaline C ( 3 ), as well as two known indole derived analogs, 4 and 5 , were isolated from the deep‐sea‐sediment derived fungus Penicillium paneum SD‐44 cultured in a 500‐l bioreactor. The structures of the new compounds were determined on the basis of 1D‐ and 2D‐NMR spectroscopy, as well as by high‐resolution mass spectrometry. The new compounds 2 and 3 showed potent cytotoxic activities against A‐549 and HCT‐116 cell lines.     

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.     

Alkaloids from Ochrosia borbonica

Ten new monoterpenoid indole alkaloids, ochroborines A and B ( 1 and 2 , resp.), 10‐hydroxyisovallesiachotamine ( 3 ), 10‐hydroxyisositsirikine ( 4 ), 10,11‐dimethoxysitsirikine ( 5 ), 10‐methoxyapoyohimbine ( 6 ), 10‐hydroxyakuammidine ( 7 ), akuammidine 17‐O‐β‐D ‐glucoside ( 8 ), 15α‐hydroxyapparicine ( 9 ), and 15α‐hydroxy‐10‐methoxyapparicine ( 10 ), and 24 known alkaloids were isolated from leaves and twigs of Ochrosia borbonica J. F.Gmel . These structures were elucidated based on 1D‐ and 2D‐NMR, FT‐IR, UV, and MS data. 10‐Hydroxyisovallesiachotamine ( 3 ), ellipticine, and 10‐methoxyellipticine showed cytotoxic activities against five human cancer cell lines.     

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.     

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.     

Two New 11‐Hydroxy‐Substituted Gelsedine‐Type Indole Alkaloids from the Stems of Gelsemium elegans

Two new 11‐hydroxy‐substituted gelsedine‐type indole alkaloids, named 11,14‐dihydroxygelsenicine ( 1 ) and 11‐hydroxygelsenicine ( 2 ), together with six known alkaloids, i.e., koumine, gelsemine, 14‐hydroxygelsenicine, 11‐hydroxyhumantenine, gelsenicine, and (19Z)‐akuammidine, were isolated from the EtOH extract of the stems of Gelsemium elegans Benth. Their structures were determined mainly by means of spectroscopic analyses including HR‐ESI‐MS and 2D‐NMR (HSQC, HMBC, ¹H,¹H‐COSY). The configuration of 1 was confirmed by X‐ray‐diffraction analysis.     

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.     

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.     

Further Alkaloids from the Leaves of Trigonostemon lii

Four new indole alkaloids, trigonoliimines D–G ( 1 – 4 , resp.), were isolated from Trigonostemon lii. Their structures were elucidated by spectroscopic methods, including extensive 1D‐ and 2D‐NMR experiments.     

Three New Alkaloids from the Leaves of Uncaria rhynchophylla

Three new alkaloids, 2′‐O‐β‐D ‐glucopyranosyl‐11‐hydroxyvincoside lactam ( 1 ), 22‐O‐demethyl‐22‐O‐β‐D ‐glucopyranosylisocorynoxeine ( 2 ), and (4S)‐corynoxeine N‐oxide ( 3 ) were isolated from the leaves of Uncaria rhynchophylla, together with four known tetracyclic oxindole or indole alkaloids, isocorynoxeine N‐oxide ( 4 ), rhynchophylline N‐oxide ( 5 ), isorhynchophylline N‐oxide ( 6 ), and dihydrocorynantheine ( 7 ), and an indole alkaloid glycoside, strictosidine ( 8 ). The structures of 1 – 3 were elucidated by spectroscopic methods including UV, IR, ESI‐TOF‐MS, 1D‐ and 2D‐NMR, as well as CD experiments. The activity assay showed that 8 (IC₅₀=8.3 μM ) exhibited potent inhibitory activity on lipopolysaccharide(LPS)‐induced nitrogen monoxide (NO) release in N9 microglia cells. However, only weak inhibitory activities were observed for 1 – 7 (IC₅₀>100 μM for 1 – 6 or >30 μM for 7 ).     

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.     

Henrycinols A and B,Two Novel Indole Alkaloids Isolated from Melodinus henryi Craib

Henrycinols A ( 1 ) and B ( 2 ), two novel indole alkaloids, together with three known compounds, (+)‐Δ¹⁴‐vincamine ( 3 ), (+)‐16‐epi‐Δ¹⁴‐vincamine ( 4 ), and (+)‐isoeburnamine ( 5 ), were isolated from the roots of Melodinus henryi Craib . Their structures were established on the basis of 1D‐ and 2D‐NMR spectroscopic analysis. The relative configuration of henrycinols A and B was determined by NOESY analysis.     

Two New Lycopodium Alkaloids from Lycopodium obscurum

Two new Lycopodium alkaloids, (+)‐cermizine D N‐oxide ( 1 ) and (8β)‐8‐(acetyloxy)obscurumine A ( 2 ), along with five known compounds, were isolated from the crude alkaloid portion of Lycopodium obscurum. Their structures were elucidated on the basis of spectroscopic data and chemical correlation. All of these alkaloids were tested in an assay for acetylcholine esterase (AChE) inhibitory activity.     

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 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.     

Ophiobolin Sesterterpenoids and Pyrrolidine Alkaloids from the Sponge‐Derived Fungus Aspergillus ustus

Chemical examination of the fungus Aspergillus ustus isolated from the Mediterranean sponge Suberites domuncula yielded the five new ophiobolin‐type sesterterpenoids 1 – 5 and the two new pyrrolidine alkaloids 6 and 7 , together with the known compound aurantiamine and cerebroside D. The structures of the new compounds were unambiguously elucidated on the basis of extensive spectroscopic‐data analysis (1D‐ and 2D‐NMR, MS, and UV) and comparison with literature data. All compounds were evaluated for their cytotoxicity against murine lymphoma cell line L5178Y.     

Anti‐inflammatory Activity of Two New Indole Alkaloids from the Stems of Nauclea officinalis

Two new indole alkaloid derivatives ( 1 , 2 ), together with six known indole alkaloids ( 3  –  8 ) were isolated from the 70% EtOH/H₂O extract of the stem of Nauclea officinalis. Their structures were determined on the basis of extensive analyses of spectroscopic data (IR, MS, 1D‐ and 2D‐NMR). All the isolates were evaluated for their anti‐inflammatory activities on lipopolysaccharide (LPS)‐induced nitric oxide (NO) production in RAW 264.7, and all the compounds showed significant inhibitory activities with the IC₅₀ values of 0.82, 6.45, 9.75, 1.34, 3.40, 2.69, 1.58, and 1.96 μm , compared to the positive drug control group aminoguanidine with an IC₅₀ value of 1.80 μm , especially compound 1 had the most significant activity.     

Indole alkaloids from camptotheca acuminata

Five minor alkaloids were isolated from the seeds of Camptotheca acuminata Decne. Two of them are new indole alkaloids named camptacumotine (1) and camptacumanine (2) respectively. The others are known indole alkaloids naucleficine (3), angustoline (4) and dihydroisoquinamine (5), which was isolated for the first time from the plant.     

Two New Indole Alkaloids from Tabernaemontana hystrix Steud. (Apocynaceae)

Two new monoterpene indole alkaloids named ibogamine‐7,8‐dione ( 1 ) and 12‐methoxyvoachalotine ( 2 ), and eight known ones, coronaridine ( 3 ), coronaridine hydroxyindolenine ( 4 ), 5‐oxocoronaridine ( 5 ), 3‐oxocoronaridine hydroxyindolenine ( 6 ), 3‐oxocoronaridine ( 7 ), vobasine ( 8 ), ibogamine ( 9 ), and olivacine ( 10 ), were isolated from a CH₂Cl₂ extract of the root bark from Tabernaemontana hystrix. The structures of the compounds were elucidated on the basis of spectroscopic data analyses, mainly ¹H‐ and ¹³C‐NMR, including 2D experiments (¹H,¹H‐COSY, HMBC, and HMQC).     

Two New Cytotoxic Alkaloids from Mappianthus iodoides Hand.‐Mazz.

Two new alkaloids, mappine A ( 1 ) and mapposidic acid ( 2 ), together with eleven known compounds, were isolated from the stems of Mappianthus iodoides Hand.‐Mazz. Their structures were elucidated by means of spectroscopic and mass‐spectrometric analyses, particularly 1D‐ and 2D‐NMR spectroscopy. The cytotoxic activities of the two new alkaloids were also evaluated.