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Results for “Indole Alkaloids”

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At least 19 recordsLinked to original sources
PubMed1979

Cytotoxicity of modified indole alkaloids.

Indole alkaloids of the iboga series were structurally modified by incorporation of a 3,4-dimethoxybenzyl or -benzoyl unit so that they contained the N-O-O triangle required for antileukemic activity according to the triangulation hypothesis. The cytotoxicities of the modified alkaloids in the in vitro P-388 system were not significantly increased over the unmodified alkaloids, suggesting that the triangulation hypothesis does not apply in this series at least.

Alkaloids↗
PubMed2001

General approach for the synthesis of sarpagine/macroline indole alkaloids. Enantiospecific total synthesis of the indole alkaloid trinervine.

[structure: see text] The total synthesis of the indole alkaloid trinervine 1 was accomplished in enantiospecific fashion in an overall yield of 20% (from the tetracyclic ketone 8) in 10 reaction vessels (12.5% from tryptophan methyl ester). The synthesis of the N(a)-H substituted macroline equivalent 2 was also completed in high yield via the same intermediate 13. The unique protection/hydroboration process developed here should provide a method to functionalize the C(19)-C(20) double bond in similar systems.

Animals↗
PubMed1995

Screening for in vitro antifungal activities of some indole alkaloids.

Several indole alkaloids were tested by the agar dilution technique on a panel of human pathogenic fungi, yeasts, and dermatophytes. Our results indicate that the most active compounds possess a beta-carboline skeleton and that the presence of a 3-4 double bond enhances the activity. Our results also show that antifungal activities are not linked to the cytotoxic, antimicrobial or antiparasitic properties.

Alkaloids↗
PubMed1997

Perhydrogenation of tabersonine, ans Aspidiosperma indole alkaloid.

The natural indole alkaloid (-)-tabersonine (1) easily provided (-)-decahydrotabersonine (4a), isolated as dihydrochloride (4b), by catalytic hydrogenation. Saponification of 4a led to the beta-amino acid 5. A binding study of 1, 4b, and 5 on various receptors and ionic channels showed that none of the compounds had a strong affinity for the receptors tested.

Alkaloids↗
PubMed2004

The indole alkaloids brucine, yohimbine, and hypaphorine are indole-3-acetic acid-specific competitors which do not alter auxin transport.

The indole alkaloids brucine and yohimbine, just like hypaphorine, counteract indole-3-acetic acid (IAA) activity in seedling roots, root hairs and shoots, but do not appear to alter auxin transport in roots or in cultured cells. In roots, the interactions between IAA and these three alkaloids appear competitive and specific since these molecules interact with IAA but with neither 1-naphthaleneacetic acid (NAA) or 2,4-dichlorophenoxyacetic acid (2,4-D), two synthetic auxins. The data reported further support the hypothesis that hypaphorine brucine and yohimbine compete with IAA on some auxin-binding proteins likely to be auxin receptors and that 2,4-D and NAA are not always perceived by the same receptor as IAA or the same component of that receptor. At certain steps of plant development and in certain cells, endogenous indole alkaloids could be involved in IAA activity regulation together with other well-described mechanisms such as conjugation or degradation. Hypaphorine with other active indole alkaloids remaining to be identified, might be regarded as a new class of IAA antagonists.

Journal Article↗
PubMed1996

Enzymology of indole alkaloid biosynthesis in Catharanthus roseus.

Indole alkaloids in Catharanthus roseus have been in focus because of their medicinal value. These alkaloids consist of an indole moiety provided by tryptamine and a terpenoid portion provided by the secologanin. The most important catharanthus alkaloids are vinblastine (VLB), vincristine (VCR) and ajmalicine. VLB and VCR are clinically useful anticancer agents whereas ajmalicine is used for the treatment of circulatory diseases. VCR and VLB are the most expensive because of their low abundance in the plant, and are formed by the coupling of monomeric indole alkaloids vindoline and catharanthine, catalysed by peroxidases. The pathway that lead to monomeric indole alkaloids involves more than 20 enzymes of which 16 enzymes have been isolated and characterized biochemically, and only three at the molecular level. The present state of knowledge on enzymes and genes involved in indole alkaloid biosynthesis and various aspects of their regulation has been discussed.

Alkaloids↗
PubMed1995

[Chemical studies of indole alkaloids].

Up to now, more than two thousands indole alkaloids having structural variety have been found from the three families of Gentianales: Loganiaceae, Apocynaceae, and Rubiaceae plants. These compounds generally possess characteristic biological activities and many of them are utilized for the medicinal purpose and for the lead-compounds to develop new synthetic drugs. The author of this review has been investigated the alkaloidal constituents of the above mentioned plants native to Japan and overseas countries. Especially, a cooperative work with Thai researchers concerning the plants in Thailand was developed. On the basis of biogenetic consideration of the structures of monoterpenoid indole alkaloids, chemical bond cleavage between the C3-N4 linkage in the C/D ring of indole alkaloids was discovered. It was speculated that, either in biogenesis, the flexibility of the ring-opening compounds having ten membered ring enabled the construction of indole alkaloids having highly strained polycyclic structures. Along with this conception, the syntheses of structurally complex indole alkaloids utilizing a biomimetic procedure have been investigated. In this review, recent results on the chemical synthesis of many skeletally varied Gelsemium alkaloids (Loganiaceae plant) are mainly described.

Alkaloids↗
PubMed2005

Gastroprotective mechanisms of indole alkaloids from Himatanthus lancifolius.

The indole alkaloids mixture (AlkF) obtained from the barks of Himatanthus lancifolius (Muell. Arg.) Woodson was evaluated for gastroprotective properties in rodents. The AlkF potently protected rats from experimentally induced gastric lesions by ethanol (ED (50) = 30 mg/kg, p. o.) and reduced gastric acid hypersecretion induced by pylorus ligature (ED (50) = 82 mg/kg, i. d.). Protective effects of the AlkF in the ethanol and hypersecretion models included increase of GSH levels of gastric mucosa indicating activation of GSH-dependent cytoprotective mechanisms. Also, an increase of the antioxidant capacity as measured through glutathione S-transferase activity was observed in the hypersecretory but not in the ulcerative model. Furthermore, the amount of nitric oxide derivatives (NO (3) + NO (2)) in the forestomach was increased while the amount released into the gastric juice during pylorus ligature was decreased by the AlkF suggesting an alteration of NO-related mechanisms. Reduction of gastric acid hypersecretion induced by pylorus ligature seems to correlate with the blockade of H (+),K (+)-ATPase activity as determined in vitro by the capacity of the AlkF mix to decrease the hydrolysis of ATP by the ATPase isolated from dog gastric mucosa (EC (50) = 212 microg/mL). Cholinergic mechanisms can be excluded since intestinal transit was not modified with doses up to 100 mg/kg ( p. o.). GC-MS investigation of components of the AlkF resulted in the identification of 3 main indole alkaloids, uleine (53 %), its isomer (13 %), demethoxyaspidormine (23.8 %) and traces of at least other five alkaloids. Collectively, the results show the novel gastroprotective properties of the indole AlkF of H. lancifolius through a variety of mechanisms.

Administration, Oral↗
PubMed2002

Subincanadines A-C, novel quaternary indole alkaloids from Aspidosperma subincanum.

Three novel quaternary indole alkaloids with an unprecedented 1-azoniatricyclo[4.3.3.0(1,5)]undecane moiety, subincanadines A-C (1-3), as well as two new indole alkaloids with a 1-azabicyclo[5.2.2]undecane moiety, subincanadines D (4) and E (5), and a new indole alkaloid with a 1-azabicyclo[4.3.1]decane moiety, subincanadine F (6), have been isolated from the barks of Aspidosperma subincanum Mart, and the structures of 1-6 and the stereochemistry of 1-3 were elucidated by spectroscopic data and chemical means.

Aspidosperma↗
PubMed2004

Cytotoxic effects and reversal of multidrug resistance by ibogan and related indole alkaloids.

A series of indole alkaloids of the ibogan-type was assessed for their cytotoxic effects as well as their potential in reversing MDR in vincristine-resistant KB cells. Of a total of 25 compounds tested, 3(S)-cyanocoronaridine, 3(S)-cyanoisovoacangine, 3(S)-cyanovoacangine, and 10,11-demethoxychippiine were found to show appreciable cytotoxicity toward KB cells, while coronaridine, heyneanine, 19-epi-heyneanine, dippinine B, and dippinine C, were found to reverse MDR in vincristine-resistant KB cells.

Cell Line, Tumor↗
PubMed1998

Reversal of multidrug resistance (MDR) by aspidofractinine-type indole alkaloids.

A series of indole alkaloids of the aspidofractinine-type was assessed for their potential in reversing MDR in vincristine-resistant KB cells. Of the compounds tested, kopsiflorine, kopsamine, pleiocarpine, 11-methoxykopsilongine, lahadinine A and N-methoxycarbonyl-11,12-methylenedioxy-delta 16,17-kopsinine were found to show appreciable activity.

Alkaloids↗
PubMed1998

Bis-indole alkaloids from Tabernaemontana bovina.

Besides the known indole alkaloid, isovoacristine, the new bis-indole alkaloids, tabernaebovine and methylenebismehranine, have been isolated from the leaves and stems of Tabernaemontana bovina. Their structures have been assigned by NMR investigations.

Journal Article↗
PubMed2003

Naucleamides A-E, new monoterpene indole alkaloids from Nauclea latifolia.

Five new monoterpene indole alkaloids, naucleamides A-E (1-5), were isolated from the bark and wood of Nauclea latifolia, and the structures and relative stereochemistry were elucidated from the spectroscopic data. Naucleamide E (5) is a unique monoterpene indole alkaloid possessing a pentacyclic ring system with an amino acetal bridge.

Amides↗