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At least 91 records · Page 5Linked to original sources
PubMed1995

Analysis of pyrrolizidine alkaloids: a competitive enzyme-linked immunoassay (ELISA) for the quantitative determination of some toxic pyrrolizidine alkaloids.

A highly sensitive and specific competitive enzyme-linked immunoassay (ELISA) for the determination of retrorsine, senecionine, and integerrimine in the nanogram range has been developed. Pyrrolizidine alkaloids were detected in Senecio rupestris. No cross-reactivity was seen with either retrosine N-oxide, otonecine alkaloids, or other macrocyclic pyrrolizidine alkaloids.

Animals↗
PubMed2005

(+)-12alpha-Hydroxysophocarpine, a new quinolizidine alkaloid and related anti-HBV alkaloids from Sophora flavescens.

(+)-12alpha-Hydroxysophocarpine (8), a new quinolizidine alkaloid was isolated from the roots of Sophora flavescens, together with 10 known quinolizidine alkaloids, (+)-oxymatrine (1), (+)-matrine (2), (+)-9alpha-hydroxymatrine (3), (+)-allomatrine (4), (+)-oxysophocarpine (5), (-)-sophocarpine (6), (-)-9alpha-hydroxysophocarpine (7), (+)-lehmannine (9), (-)-13,14-dehydrosophoridine (10), and (-)-anagyrine (11). Their structures were elucidated by spectroscopic methods, and the stereochemistry of 8 was confirmed by X-ray analysis. These alkaloids were tested for anti-hepatitis B virus (HBV) activity in vitro, compounds 5, 6, 9, and 10 showed significant anti-HBV activity with inhibitory potency against HBsAg secretion at 48.3-79.3% and that against HBeAg secretion at 24.6-34.6%.

Alkaloids↗
PubMed1988

Separation of eight alkaloids and meconic acid and quantitation of five principal alkaloids in gum opium by gradient reversed-phase high-performance liquid chromatography.

The separation of the five principal alkaloids (morphine, codeine, thebaine, noscapine and papaverine), three minor alkaloids (laudanosine, cryptopine and narceine), meconic acid and some unidentified constituents in gum opium samples has been achieved on a reversed-phase phenyl column by gradient high-performance liquid chromatography using a simple and inexpensive mobile phase system. The linear gradient programme was started at 5% and ended at 70% methanol in triethylammonium phosphate buffer in 20 min. The five principal alkaloids were also determined with good precision. The method requires minimum sample preparation and is suitable for routine analysis.

Alkaloids↗
PubMed1996

Study on the anti-inflammatory action of Berberis vulgaris root extract, alkaloid fractions and pure alkaloids.

Extracts obtained from the roots of Berberidaceae species have been used in Eastern and Bulgarian folk medicine in rheumatic and other chronic inflammatory disorders. The investigations of the chemical composition and immunological properties show that their activity is mainly due to the alkaloid constituents. In the present study the anti-inflammatory properties of total ethanol extract (TEE), three alkaloid fractions, a major alkaloid berberine and oxyacanthine isolated from Berberis vulgaris roots were compared. All these were applied in acute inflammation (carrageenan- and zymosan-induced paw oedema), as the TEE showed the highest reducing effect. Their ability to alter in vivo and in vitro complement activity was determined. Also, the TEE was most effective in a chronic inflammatory model of adjuvant arthritis. The protoberberine fractions Bv2, Bv3 and berberine suppressed a delayed type hypersensitivity (DTH) reaction. Fraction Bv1 and berberine diminished antibody response against SRBC in vivo. The in vitro treatment of splenocytes with berberine showed that the anti-SRBC antibody synthesis was influenced in a different manner depending on the time course of its application. Oxyacanthine was less effective than berberine in the tests used.

Alkaloids↗
PubMed2006

Tripfordines A-C, sesquiterpene pyridine alkaloids from Tripterygium wilfordii, and structure anti-HIV activity relationships of Tripterygium alkaloids.

Three new sesquiterpene pyridine alkaloids, tripfordines A-C (1-3), were isolated from an ethanolic extract of the roots of Tripterygium wilfordii, along with eight known pyridine alkaloids, and tested for in vitro cytotoxic and anti-HIV activity. The structures of the new compounds were established on the basis of spectroscopic data interpretation. Anti-HIV structure-activity relationships (SAR) for this compound type are proposed on the basis of the screening results from the newly isolated compounds and prior data of known sesquiterpene pyridine alkaloids. The position of a carboxyalkyl chain on the pyridine moiety was not critical since both 2'- and 4'-substituted compounds exhibited high anti-HIV activity (EC(50) 0.1 microg/mL). In contrast, a hydroxy group at C-8' (carboxypropyl side chain) or C-9' (carboxybutyl side chain) was found to affect anti-HIV activity.

Alkaloids↗
PubMedDate not supplied

Macrocyclic pyrrolizidine alkaloids from Senecio anonymus. Separation of a complex alkaloid extract using droplet counter-current chromatography.

Ten 12-membered macrocyclic pyrrolizidine alkaloids, all of them esters of the necines, retronecine or otonecine, have been isolated from Senecio anonymus. The separation, carried out by droplet counter-current chromatography, afforded senecionine [1], integerrimine [2], retrorsine [3], senkirkine [5], neosenkirkine [6], otosenine [10], hydroxysenkirkine [7], and a new alkaloid given the trivial name anonamine [9]. Traces of usaramine [4] and another new alkaloid, hydroxyneosenkirkine [8], were detected by 1H nmr. In addition, the previously unreported 3a beta-hydroxy-4-ethoxy-2,6-perhydroindoledione [11] was isolated. X-ray structures were obtained for neosenkirkine [6], hydroxysenkirkine [7], anonamine [9], and [11]. 1H-13C heteronuclear shift correlated nmr (HETCOR) provided unambiguous chemical shift assignments for 13C-nmr data. Antitumor activity was assayed using the A204-rhabdomyosarcoma cell line in soft agarose.

Antineoplastic Agents, Phytogenic↗
PubMedDate not supplied

Alkaloids from a panamanian poison frog, Dendrobates speciosus: identification of pumiliotoxin-A and allopumiliotoxin class alkaloids, 3,5-disubstituted indolizidines, 5-substituted 8-methylindolizidines, and a 2-methyl-6-nonyl-4-hydroxypiperidine.

Dendrobates speciosus is a small red or orange frog that occupies a small geographic range in the highlands of western Panama, where it occurs abundantly in some cloud forest habitats. Gc-ms analysis indicated the presence of at least 30 alkaloids in MeOH skin extracts from population samples at the extreme eastern end of the known geographic range. Eleven alkaloids were isolated by cc in quantities sufficient for 2D-nmr spectral analysis, which in some cases confirmed their identity with alkaloids known from other species and in other cases led to assignment of structures. Pumiliotoxin 251D, pumiliotoxin A [307A], pumiliotoxin B [323A], and allopumiliotoxin 267A were identified as major constituents. N-Oxides of 323A and 267A were also isolated. Indolizidines 195B and 223AB with 3-butyl-5-methyl and 3-butyl-5-propyl substituents, respectively, were identified. The 5-substituents of the 8-methyl-indolizidines 207A and 235B' were assigned as -(CH2)3CH = CH2 and -(CH2)5CH = CH2, respectively; indolizidine 235B' from D. speciosus is, thus, a positional double-bond isomer of indolizidine 235B previously isolated from a closely related poison frog, Dendrobates pumilio. A piperidine 241D was isolated and assigned the structure cis-cis-2-methyl-6-nonyl-4-hydroxypiperidine.

Alkaloids↗
PubMedDate not supplied

Two new natural azafluorene alkaloids and a cytotoxic aporphine alkaloid from Polyalthia longifolia.

The stem and stem bark of Polyalthia longifolia afforded the cytotoxic aporphine alkaloid liriodenine [1], as well as two aporphine alkaloids, noroliveroline [2] and oliveroline-beta-N-oxide [3] and three azafluorene alkaloids, darienine [4], polyfothine [6], and isooncodine [7], which are not bioactive. Polyfothine [6] and isooncodine [7] are new natural compounds.

Alkaloids↗
PubMed1995

Heteronuclear NMR studies of the chromone alkaloids and revision of the structure of some piperidino-chromone alkaloids.

The 13C-NMR spectra of seven chromone alkaloids isolated from Schumanniophyton magnificum have been obtained. Assignment of signals was carried out with the help of heteronuclear coupling experiments and other correlation techniques on the alkaloids and their acyl derivatives. On the basis of the signals observed the structures of the piperidino-alkaloid schumannificine and its N-methyl and anhydro analogues have been revised to that of a piperidone ring linked to the noreugenin via a carbon-carbon bond and a lactol bridge.

Alkaloids↗
PubMed2002

Evolutionary recruitment of a flavin-dependent monooxygenase for the detoxification of host plant-acquired pyrrolizidine alkaloids in the alkaloid-defended arctiid moth Tyria jacobaeae.

Larvae of Tyria jacobaeae feed solely upon the pyrrolizidine alkaloid-containing plant Senecio jacobaea. Ingested pyrrolizidine alkaloids (PAs), which are toxic to unspecialized insects and vertebrates, are efficiently N-oxidized in the hemolymph of T. jacobaeae by senecionine N-oxygenase (SNO), a flavin-dependent monooxygenase (FMO) with a high substrate specificity for PAs. Peptide microsequences obtained from purified T. jacobaeae SNO were used to clone the corresponding cDNA, which was expressed in active form in Escherichia coli. T. jacobaeae SNO possesses a signal peptide characteristic of extracellular proteins, and it belongs to a large family of mainly FMO-like sequences of mostly unknown function, including two predicted Drosophila melanogaster gene products. The data indicate that the gene for T. jacobaeae SNO, highly specific for toxic pyrrolizidine alkaloids, was recruited from a preexisting insect-specific FMO gene family of hitherto unknown function. The enzyme allows the larvae to feed on PA-containing plants and to accumulate predation-deterrent PAs in the hemolymph.

Amino Acid Sequence↗
PubMed1977

New curare alkaloids. II. New bisbenzylisoquinoline alkaloids from Abuta grisebachii (Menispermaceae).

From Abuta grisebachii Triana & Planchon, Menispermacea used by Sanama tribe for the preparation of curare, five bisbenzylisoquinoline alkaloids have been isolated; four of them are tertiary (peinamine and three new alkaloids, 7-O-demethylpeinamine, N-methyl,7-O-demethylpeinamine and macolidine) and one is a new quaternary alkaloid called macoline. Their structures have been elucidated on the basis of chemical reactions and spectroscopic data.

Alkaloids↗
PubMedDate not supplied

Alkaloids of Carnegiea gigantea. Arizonine, a new tetrahydroisoquinoline alkaloid.

The alkaloid composition of the giant cactus, Carnegiea gigantea Br. & R., was studied. Chromatographic separation led to the isolation of four tetrahydroisoquinoline alkaloids: carnegine, salsolidine, gigantine and arizonine. The structure of the new natural product, arizonine, was establihsed by spectroscopic data and total synthesis via two independent routes. Salsolidine is reported for the first time in the cacti. Also new to this species are 3-methoxytyramine and 3,4-dimethoxypenethylamine, which were identified in the alkaloid extract by gas chromatography-mass spectrometry. Dopamine was isolated from fresh plant material.

Alkaloids↗
PubMed2003

Gluco-indole alkaloids from Nauclea cadamba in Thailand and transformation of 3 alpha-dihydrocadambine into the indolopyridine alkaloid, 16-carbomethoxynaufoline.

Three monoterpenoid gluco-indole alkaloids, 3beta-isodihydrocadambine, cadambine, and 3alpha-dihydrocadambine, were isolated from Nauclea cadamba ROXB. growing in Thailand. The stereochemistry at C19 in 3beta-isodihydrocadambine was elucidated to be R by spectroscopic analysis. Treatment of 3alpha-dihydrocadambine with beta-glucosidase in aqueous ammonium acetate solution gave an indolopyridine alkaloid, 16-carbomethoxynaufoline, and an unusually rearranged compound.

Alkaloids↗
PubMedDate not supplied

[Fungus Penicillium citrinum, isolated from permafrost sediments, as a producer of ergot alkaloids and new quinoline alkaloids quinocitrinines].

Quinocitrinines and ergot alkaloids are synthesized by the strain Penicillium citrinum VKM FW-800 as the culture grows. The major part of these secondary metabolites are secreted into the medium. In the phase of growth deceleration, these metabolites were partly absorbed by the producer cells. Zinc ions stimulated both the primary and secondary metabolic processes. Addition of this microelement into the culture medium stimulated biomass accumulation and the synthesis of clavine alkaloids and quinocitrinines.

Alkaloids↗
PubMedDate not supplied

Alkaloids of Thalictrum. XXI. Isolation and characterization of alkaloids from the roots of Thalictrum podocarpum.

Thirteen alkaloids, hernandezine, thalidezine, N-desmethylthalidezine, isothalidezine, thalistyline, thalistyline methodiiodide, N-desemethylthalistyline, berberine, columbamine, jatrorrhizine, palmatine, thalifendine, magnoflorine and the artifact, 8-trichloromethyldihydroberberine were isolated from the roots of Thalictrum podocarpum Humb. In addition, oxyberberine and thaliglucinone were obtained in very minor amounts and identified by tlc. Of these compounds, N-desmethylthalidezine and isothalidezine are new bisbenzylisoquinoline alkaloids. Sucrose was isolated from the alcoholic extract. Hernandezine, thalistyline, thalidezine, thalistyline methodiiodide and N-desmethylthalistyline were found to possess antimicrobial activity against Mycobacterium smegmatis at concentrations of 100 microgram/ml or less.

Alkaloids↗
PubMed1994

[Polycyclic aromatic alkaloids. 10. Annonaceous alkaloids with antimycotic activity].

Two strategies towards the synthesis of isomerically pure azafluorenones are described. Cyclization of the aryl nicotinic acid 7 with polyphosphoric acid and subsequent reductive debromination gives 8-methoxyonychine (3) ("method A"). 6-Methoxyonychine (2), an alkaloid from annonaceae, can be prepared by Parham-cyclization of the carboxylic acid 7 or of the ester 6 ("method B"). In an agar-well diffusion assay 2, 3, and onychine (9a) show moderate activity against Candida albicans. 9e has stronger activity, while other azafluorenones are almost inactive. The structurally related azaoxoaporphine alkaloid sampangine (12) has very strong antifungal activity.

Alkaloids↗
PubMed1975

Alkaloids of Vinca rosea L. (Catharanthus roseus G. Don) XXXVI: Isolation and characterization of new dimeric alkaloids.

In a continuing effort to study thoroughly the alkaloids of Catharanthus roseus, new dimeric alkaloids were isolated and characterized. Structures are proposed for leurocolombine and vinamidine based on UV, IR, PMR, high-resolution mass spectrometry, and CMR. Pseudovincaleukoblastine diol was identified by PMR and mass spectrometry. Leurocolombine exhibited antimitotic activity and marginal antitumor activity against the Ridgeway osteogenic sarcoma.

Acetylation↗
PubMed1986

Comparative pharmacokinetics of antitumor Vinca alkaloids: intravenous bolus injections of navelbine and related alkaloids to cancer patients and rats.

The kinetics of distribution and elimination in rats of the antitumor drug navelbine and of two of its analogues, Na-formyl navelbine and deacetyl navelbine amide, have been studied by radioimmunoassay and compared with the kinetics obtained with vinblastine and vincristine. Fitting to two-exponential curves was used to derive pharmacokinetic parameters. Clearance was found to parallel toxicity for all drugs: it increases from 0.19 1 h-1 kg-1 for vincristine to 0.41 for Na-formyl navelbine, 1.4 for vinblastine, 2.3 for navelbine, and 2.6 for deacetyl navelbine amide. Terminal half-lives were longer for the Na-formyl-substituted alkaloids (around 13 h) than for the others (8-10 h). We have also studied navelbine kinetics in cancer patients entered in recent navelbine clinical trials and found that navelbine pharmacokinetics are characterized by fast and extensive distribution, high clearance (0.92 +/- 0.27 1 h-1 kg-1), and a relatively long terminal half-life (31.2 +/- 4.4 h). Relationships between chemical structure, pharmacokinetic properties, and toxicity or therapeutic efficiency within the Vinca alkaloid series are discussed, together with the relevance of animal models such as the rat in the screening of new antitumor drugs.

Animals↗