Showing papers on "Indole alkaloid published in 2010"
TL;DR: Notoamide O possesses a novel hemiacetal/hemiaminal ether functionality hitherto unknown among this family of prenylated indole alkaloids in the biogenetic pathway.
Abstract: Notoamides O−R were isolated from a marine-derived Aspergillus sp. Notoamide O possesses a novel hemiacetal/hemiaminal ether functionality hitherto unknown among this family of prenylated indole alkaloids. The structure represents an unusual branch point for the oxidative modification of other members in the family of prenylated indole alkaloids in the biogenetic pathway.
92 citations
TL;DR: An efficient and flexible 2-step procedure to complex multicyclic indole alkaloid-type compounds involving Ugi MCR and Pictet-Spengler reaction is communicated.
64 citations
TL;DR: A pair of new isomeric indole alkaloids, naucleaorals A and B were isolated from the roots of Nauclea orientalis and proved to be inactive in antimalarial assays.
60 citations
TL;DR: While the Old Yellow Enzyme homologue EasA from the ergot biosynthetic gene cluster of Aspergillus fumigatus acts on chanoclavine-I aldehyde 1 to yield festuclavine 2, EasAFrom Neotyphodium lolii, in contrast, produces agroclavine 3.
Abstract: The ergot alkaloids are a diverse class of fungal-derived indole alkaloid natural products with potent pharmacological activities. The biosynthetic intermediate chanoclavine-I aldehyde 1 represents a branch point in ergot biosynthesis. Ergot alkaloids festuclavine 2 and agroclavine 3 derive from alternate enzymatic pathways originating from the common biosynthetic precursor chanoclavine-I aldehyde 1. Here we show that while the Old Yellow Enzyme homologue EasA from the ergot biosynthetic gene cluster of Aspergillus fumigatus acts on chanoclavine-I aldehyde 1 to yield festuclavine 2, EasA from Neotyphodium lolii, in contrast, produces agroclavine 3. Mutational analysis suggests a mechanistic rationale for the switch in activity that controls this critical branch point of ergot alkaloid biosynthesis.
57 citations
TL;DR: Through bioassay-guided fractionation and chromatography technique, eight indole alkaloids were furnished from the stems of Ervatamia hainanensis, in which compounds 1 and 3 exhibited the same level of activities as galantamine, a marketed cholinesterase inhibitor for the treatment of Alzheimer's disease.
53 citations
TL;DR: Two new Erythrinan alkaloids, cristanines A and B (1, 2), were isolated from the bark of EryTHrina crista-galli L. together with nine known EryThrinan aloids and an indole alkaloid and showed significant inhibitory activity on lipopolysaccharide induced nitric oxide production.
Abstract: Two new Erythrinan alkaloids, cristanines A and B (1, 2), were isolated from the bark of Erythrina crista-galli L. together with nine known Erythrinan alkaloids (3-5, 7-12) and an indole alkaloid (13). The structures of the compounds, cristanines A (1) and B (2), were elucidated by spectroscopic methods. Three of the twelve compounds isolated showed significant inhibitory activity on lipopolysaccharide induced nitric oxide (NO) production.
40 citations
TL;DR: In this paper, three unusual natural products, viz., alstopirocine, a macroline alkaloid incorporating a substituted pyrrole moiety, pleiomaltinine, an alkaloidepyrone adduct, and pleiomalicine (pyrrole substituted with pleiocarpamine), were isolated from the Malayan Alstonia angustifolia.
38 citations
Journal Article•
TL;DR: A tetrakis monoterpene indole alkaloid, alasmontamine A (1) consisting of bis-vobtusine-type skeletons, was isolated from the leaves of Tabernaemontana elegans.
Abstract: A novel tetrakis monoterpene indole alkaloid, alasmontamine A (1) consisting of bis-vobtusine-type skeletons, was isolated from the leaves of Tabernaemontana elegans. The structure including the relative stereochemistry was elucidated on the basis of spectroscopic data. Alasmontamine A (1) exhibited moderate cell growth inhibitory activity against HL-60 cells.
35 citations
TL;DR: A new indole alkaloid, together with four known indole alkaloids, was isolated from the 95% EtOH extract of the traditional Chinese medicinal plant Isatis indigotica as mentioned in this paper.
Abstract: A new indole alkaloid 1, together with four known indole alkaloids 2–5, was isolated from the 95% EtOH extract of the traditional Chinese medicinal plant Isatis indigotica. Alkaloids 2–5 were found in the plant for the first time. Their structures were elucidated as 3-hydroxy-3-acetonitrile-4-hydroxy-2-indolone (1), 1-methoxy-3-indoleacetonitrile (2), 3-indoleacetic acid (3), 3-indolealdehyde (4), and 1-methoxy-3indolecarbaldehyde (5) on the basis of spectroscopic data. Their anti-HSV effects in vitro were evaluated by plaque reduction assay.
30 citations
TL;DR: An efficient total synthesis of notoamide J, a new prenylated indole alkaloid and potential biosynthetic precursor, is described herein.
Abstract: An efficient total synthesis of notoamide J, a new prenylated indole alkaloid and potential biosynthetic precursor, is described herein. Starting from l-proline and a substituted tryptophan derivative, this synthesis also employs an oxidation and pinacol rearrangement for the formation of the oxindole in the final step.
28 citations
TL;DR: Two new indole alkaloids, kopsiyunnanines G and H, possessing the Aspidosperma skeleton were isolated from the aerial part of Yunnan Kopsia arborea BLUME (Apocynaceae) by means of MS and 2D NMR analyses.
Abstract: Two new indole alkaloids, kopsiyunnanines G (1) and H (2), possessing the Aspidosperma skeleton were isolated from the aerial part of Yunnan Kopsia arborea BLUME (Apocynaceae). Their structures and stereochemistry were elucidated by means of MS and 2D NMR analyses.
TL;DR: The structures of the new humantenine-type and gelsemine-type oxindole alkaloids were determined by spectroscopic analyses as mentioned in this paper, and 6-hydroxyhumantenines (5) is the first example of a Gelsemium alkaloid with an oxygen function at C-6 position.
TL;DR: In this paper, 1.1-Phenylsulfonylindole is converted in eight steps into 2-(2-iodo-(Z)-but-2-en-1-yl)-6-methyl-1,2,3,4-tetrahydroazocino[4,3-b]indole, previously converted in one step into the indole alkaloid apparicine.
Abstract: 1-Phenylsulfonylindole is converted in eight steps into 2-(2-iodo-(Z)-but-2-en-1-yl)-6-methyl-1,2,3,4-tetrahydroazocino[4,3-b]indole, previously converted in one step into the indole alkaloid apparicine. The syntheses of other hexahydroazocino[4,3-b]indole potential precursors to the alkaloid are also described.
TL;DR: The stems of Ervatamia yunnanensis have afforded a new indole alkaloid, ervataine, whose structure was determined by spectroscopic analysis.
TL;DR: This result indicates that the aromatic moiety of exophialin originates from 2-hydroxyjuglone, a shunt product of the 1,8-dihydroxynaphthalene melanin biosynthesis, which is only produced by the wild-type strain, but not by the mutant.
TL;DR: The chemical investigation of the liana Strychnos moandaensis De Wild led to the isolation of moandaensine, a novel dimeric indole alkaloid, which was elucidated by a thorough analysis of the spectroscopic data and by molecular modeling.
TL;DR: Cathenamine reduction by sodium borohydride leading to tetrahydroalstonine revealed the chemo-enzymatic indole alkaloid synthesis, demonstrating functional co-expression of both STR1- and SG-cDNAs.
Journal Article•
TL;DR: A test with the microalga Chlorella vulgaris was used to evaluate the allelopathic potential activity of indole alkaloids present in cereals and the toxicity of barley aqueous extracts is in agreement with the phytotoxicity of pure gramine.
Abstract: A test with the microalga Chlorella vulgaris was used to evaluate the allelopathic potential activity of indole alkaloids present in cereals. Gramine, the main indole alkaloid present in barley shows the highest toxicity. A model mechanism of action for auxin was used to analyze the structural effect on the observed toxicity. Germination inhibition on seeds and shoot length inhibition activities of gramine on barley, rye, oat, wheat, lettuce cultivars and the weed Lollium rigidum were measured. Results are discussed in relation to the phytotoxic selectivity of gramine on the seeds germination. In addition, the toxicity of barley aqueous extracts on the germination of oat seed was also determined. Phytotoxicity of the extracts is in agreement with the phytotoxicity of pure gramine.
Journal Article•
TL;DR: To study chemical constituents of the leaves of Nauclea officinalis, eight alkaloids were isolated from 95% ethanol extract by various chromatographic methods and identified as naucleactonin C, which is a new indole alkaloid.
Abstract: To study chemical constituents of the leaves of Nauclea officinalis, eight alkaloids were isolated from 95% ethanol extract by various chromatographic methods. The structures were elucidated on the basis of spectroscopic data (IR, UV, ESI-MS, 1D and 2D NMR) and identified as naucleactonin C (1), strictosamide (2), vincosamide (3), pumiloside (4), angustoline (5), angustine (6), 18, 19-dihydroangustine (7) and naucleofficine D (8). Compound 1 is a new indole alkaloid. Compounds 6 and 7 were isolated from this plant for the first time.
TL;DR: Martefragin A (1), a novel indole alkaloid, was isolated from a red alga, Martensia fragilis, by repeated column chromatography as mentioned in this paper.
Abstract: Martefragin A (1), a novel indole alkaloid, was isolated from a red alga, Martensia fragilis, by repeated column chromatography. The structure of 1 was elucidated on the basis of spectral analysis of its methyl ester (2), including 1H- and 13C-NMR, 1H-1H correlation spectroscopy (COSY), and 13-1H COSY. A single crystal X-ray analysis of the hydrochloride of 1 confirmed the assignment. Martefragin A (1) showed inhibitory activity on NADPH-dependent lipid peroxidation in rat liver microsomes. The IC50 values of 1, α-tocopherol and ascorbic acid were 2.8, 87 and 200 μM, respectively.
TL;DR: A pentacyclic indole alkaloid, tronocarpine, incorporating a seven-membered lactam unit, was obtained from the stem-bark extract of Tabernaemontana corymbosa and its structure elucidated by spectral analysis.
Abstract: A novel pentacyclic indole alkaloid, tronocarpine, incorporating a seven-membered lactam unit, was obtained from the stem-bark extract of Tabernaemontana corymbosa and its structure elucidated by spectral analysis.
10 Oct 2010
TL;DR: In this article, the chemical constituents of Rauvolfia yunnanensis Tsiang have been investigated for extending the utilizable efficiency of resources in the arid hot valley region of China.
Abstract: Rauvolfia yunnanensis Tsiang are commonly used as a folklore herb to treat hypertension, snake bites, and insanity in the southwest of China, and an important industrial raw material of reserpine. The phytochemical constituents of the rhizome of it have been investigated intensively. Reserpine and yohimbine are two effective biological activities compounds isolated from the rhizome of Rauvolfia yunnanensis. But the wild resources of it reduced gradually in recent years, thus we have introduced and cultivated it to the arid hot valley region of Yunnan. China, and investigated the chemical constituents variety of it for the sustainable utilization. In the present work, the chemical-constituents of the flowers of R. yunnanensis have been investigated for extending the utilizable efficiency of resources. The dried flowers powder(1.0 kg) of R. yunnanensis was extracted with 95% EtOH(10 L x 6, 48 h each) at room temperature, and then extracted successively with EtOAc(1 L x 6). The EtOAc portion(50 g) led to the isolation of nine compounds by column chromatography (silica, alumina and Sephadex LH-20 gel) methods. Their structures were identified as(18Z)-11-methoxypicrinine(1), caberoline(2), 11-methoxystrictamine(3), strictamine(4), russulamide(5), ursolic acid (6), urs-12 (13)-en-3 alpha-yl acetate(7), beta-amyryl nonanoate(8) and beta-sitosterol (9) by spectral analysis(UV, IR, MS and ID, 2D NMR), respectively. Among them, compound 1 is a new indole alkaloids, compounds 5, 7 and 8 are firstly isolated from it. But reserpine and yohimbine haven't been isolated.
TL;DR: In this paper, two indole alkaloids with diastomeric structure, named Mataranine A and B, were isolated from the base fraction of Alstonia scholaris R. Br., and elucidated on the basis of UV, NMR and mass spectral data.
Abstract: Alstonia scholaris R. Br., (Apocynaceae) is widely distributed in Indonesia and in Lombok Island, the plant locally known as “lolon nita” has been used to treat malaria. To locate potential bioactive compounds, acid-base extraction was carried out. From the base fraction, two new indole alkaloids with diastomeric structure, named Mataranine A and B, were isolated. The structures of the two alkaloids were elucidated on the basis of UV, NMR and mass spectral data.
TL;DR: In this paper, an efficient total synthesis of notoamide J, a new prenylated indole alkaloid and potential biosynthetic precursor, is described, starting from l-proline and a substituted tryptophan derivative, also employing an oxidation and pinacol rearrangement for the formation of the oxindole in the final step.
Abstract: An efficient total synthesis of notoamide J, a new prenylated indole alkaloid and potential biosynthetic precursor, is described herein. Starting from l-proline and a substituted tryptophan derivative, this synthesis also employs an oxidation and pinacol rearrangement for the formation of the oxindole in the final step.
Journal Article•
TL;DR: Wang et al. as mentioned in this paper used column chromatography (silica, alumina and Sephadex LH-20 gel) methods to identify caberine (1), 19-ethoxyl-demethyl-Delta'-17-acetylajmaline(2), vellosimine(3), beta-yohimbine(4), yohimbines(5), vinorine(6), picrinine(7), nareline (8), akuammicine(9), strictamine(10), reserpine(
Abstract: Rauvolfia yuananensis Tsiang are commonly used as a folklore herb to treat hypertension, snake bites, and insanity in the southwest of China, and an important industrial raw material of reserpine and vertical. But the wild resources of it reduced gradually in recent years, thus we have introduced and cultivated it to the arid-hot valley region of Yunnan Province, China, and investigated the chemical constituents variety of it for the sustainable utilization. The dried leaves powder (8.0 kg) of R. yunnanensis was extracted with 95% (volume fraction) EtOH(40 L x5, 8 h each), and led to the isolation of eleven indole alkaloids by column chromatography (silica, alumina and Sephadex LH-20 gel) methods. Their structures were identified as caberine (1), 19-ethoxyl-demethyl-Delta'-17-acetylajmaline(2), vellosimine(3), beta-yohimbine(4), yohimbine(5), vinorine(6), picrinine(7), nareline (8), akuammicine(9), strictamine(10), reserpine(11) by spectral analysis (UV, IR, MS and 1 D, 2D NMR), respectively. Among them, compound 2 was a new indole alkaloids, compounds 1, 8 and 9 were firstly isolated from this plant.
TL;DR: A tetrakis monoterpene indole alkaloid, alasmontamine A (1) consisting of bis-vobtusine-type skeletons, was isolated from the leaves of Tabernaemontana elegans.
Abstract: A novel tetrakis monoterpene indole alkaloid, alasmontamine A (1) consisting of bis-vobtusine-type skeletons, was isolated from the leaves of Tabernaemontana elegans. The structure including the relative stereochemistry was elucidated on the basis of spectroscopic data. Alasmontamine A (1) exhibited moderate cell growth inhibitory activity against HL-60 cells.
Journal Article•
TL;DR: Wang et al. as mentioned in this paper used column chromatography (silica, alumina and Sephadex LH-20 gel) methods to identify caberine, 19-ethoxyl-1-demethyl-Δ1-17-acetylajmaline(2),vellosimine(3),β-yohimbine(4),yohIMine(5),vinorine(6),picrinine(7),nareline(8),akuammicine(9),st
Abstract: Rauvolfia yunnanensis Tsiang are commonly used as a folklore herb to treat hypertension,snake bites,and insanity in the southwest of China,and an important industrial raw material of reserpine and verticalBut the wild resources of it reduced gradually in recent years,thus we have introduced and cultivated it to the arid-hot valley region of Yunnan Province,China,and investigated the chemical constituents variety of it for the sustainable utilizationThe dried leaves powder(80 kg) of Ryunnanensis was extracted with 95%(volume fraction) EtOH(40 L×5,8 h each) ,and led to the isolation of eleven indole alkaloids by column chromatography(silica,alumina and Sephadex LH-20 gel) methodsTheir structures were identified as caberine(1) ,19-ethoxyl-1-demethyl-Δ1-17-acetylajmaline(2) ,vellosimine(3) ,β-yohimbine(4) ,yohimbine(5) ,vinorine(6) ,picrinine(7) ,nareline(8) ,akuammicine(9) ,strictamine(10) ,reserpine(11) by spectral analysis(UV,IR,MS and 1D,2D NMR) ,respectivelyAmong them,compound 2 was a new indole alkaloids,compounds 1,8 and 9 were firstly isolated from this plant