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At least 19 recordsLinked to original sources
PubMed1996

[Highlights from 43 years of chemistry of naturally occurring nitrogen-containing heterocycles. (1). Syntheses and structure determinations of benzo[a]quinolizidine-type and indolo[2,3-a]quinolizidine-type alkaloids isolated from several plants].

Nineteen benzo[a]quinolizidine alkaloids (1-19) isolated so far from Alangium plants can be classified into four types (I-IV) according to their chemical structures. Studies on racemic and chiral syntheses of these I-IV-type alkaloids are reviewed with particular emphasis on the strategies and tactics for the syntheses employed by the author. It has been found that racemic syntheses of all of these types of alkaloids are possible through the "lactim ether route" or the "3-acetylpyridine route"; and chiral syntheses, through the "cincholoipon-incorporating route" or the "chiral lactim ether route". As a result of such total syntheses, the structures and absolute configurations of four II-type, two III-type, and two IV-type Alangium alkaloids have been established. Extensions of the "chiral lactim ether route" to the syntheses of the Ochrosia alkaloid (-)-ochropposinine [(-)-93g], the Neisosperma alkaloid (-)-ochromianine [(-)-97], and the Ophiorrhiza alkaloid (-)-ophiorrhizine [(-)-98] have unequivocally established the absolute stereochemistries of these three indolo[2,3-a]-quinolizidine alkaloids.

Alkaloids↗
PubMed1993

Alkaloids in Madagascan frogs (Mantella): pumiliotoxins, indolizidines, quinolizidines, and pyrrolizidines.

Brightly colored ranid frogs of the genus Mantella are found only in rain forests of Madagascar. Gc-ms and gc-Ft-ir analyses of skin alkaloids of seven different species, including four populations of Mantella madagascariensis, are reported. All contain one or more representatives of the pumiliotoxin A (PTX-A) class with the 13,14-dihydro derivatives 309A and 325A found in major amounts in the four populations of M. madagascariensis, while 307A (PTX-A) is found in two populations of M. madagascariensis and in three additional species, Mantella aurantiaca, Mantella viridis, and Mantella crocea. The latter three species also contain appreciable quantities of 323A (PTX-B). The four populations of M. madagascariensis show major amounts of two 1,4-disubstituted quinolizidines, 217A and 231A, and a 5,8-disubstituted indolizidine, 217B, in addition to many minor or trace quinolizidines and indolizidines. Such disubstituted quinolizidines and indolizidines are present as trace alkaloids in the six other species of Mantella, along with 3,5-disubstituted indolizidines, 3,5-disubstituted pyrrolizidines, the decahydroquinoline cis-195A, tricyclic alkaloids, and homopumiliotoxins. A new alkaloid class, which appears to contain a quinolizidine moiety, is seen in M. aurantiaca and M. crocea and is represented by 235C and several congeners.

Alkaloids↗
PubMed1987

Indolizidine and quinolizidine derivatives of the dopamine autoreceptor agonist 3-(3-hydroxyphenyl)-N-n-propylpiperidine (3-PPP).

Eight indolizidine and quinolizidine derivatives of 3-PPP were synthesized and tested for possible dopamine (DA) autoreceptor activity. The equatorial indolizidine derivative 19e had the profile of a selective autoreceptor agonist and was half as active as 3-PPP. However, resolution of the compound revealed that the 8R enantiomer was an unselective DA agonist with a profile similar to (+)-3-PPP, while the 8S enantiomer was a weak DA antagonist without any DA agonist activity. The unsaturated quinolizidine derivative 21 also had the profile of a DA antagonist while the axial quinolizidine derivative 18a had an amphetamine-like profile in 6-OHDA-lesioned rats. All other derivatives were inactive. The observed structure-activity relationships were in agreement with existing DA receptor models, although these models are not apparently detailed enough to explain why the 8S enantiomer of 19e is inactive as a DA agonist.

Animals↗
PubMed2005

Cascade iminium ion reactions for the facile synthesis of quinolizidines. Concise syntheses of (+/-)-epilupinine and (-)-epimyrtine.

Several novel cascade processes have been designed and developed that involve sequential reactions of imines and iminium ions to form substituted quinolizidine ring systems in a single step from simple and readily available starting materials. The utility and promise of these cascade reactions is evident from their application to extraordinarily concise syntheses of the representative quinolizidine alkaloids (+/-)-epilupinine and (-)-epimyrtine.

Alkaloids↗
PubMedDate not supplied

Determination of quinolizidine alkaloids in Sophora tonkinensis by HPCE.

A simple, rapid and reliable high-performance capillary electrophoresis method has been developed to determine quantitatively the alkaloid content of Sophora tonkinensis, a Chinese herb commonly known as shan-dou-gen. A total of seven quinolizidine alkaloids (cytisine, sophocarpine, matrine, lehmannine, sophoranol, oxymatrine and oxysophocarpine) could be readily separated within 15 min. The running buffer was 50 mM phosphate buffer (pH 2.5) containing 1% hydroxypropyl-beta-cyclodextrin and 3.3% isopropanol in water. The applied voltage was 25 kV, the capillary temperature was 25 degrees C, the detection wavelength was 200 nm and scopolamine butylbromide was used as internal standard. The method was used to analyse the chemical constituents of two commercial alternatives to shan-dou-gen. The alkaloid constituents of authentic shan-dou-gen gave a specific HPCE electropherogram that could be used to distinguish the drug from potential substitutes. Furthermore, the content of oxymatrine and the total content of the seven quinolizidine alkaloids could be used as quantitative markers in order to assess the quality of S. tonkinensis.

Alkaloids↗
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↗
PubMed2004

Quinolizidine alkaloids isolated from Lupinus species enhance insulin secretion.

We have analyzed the effect of quinolizidine alkaloids from Lupinus species upon insulin secretion. Isolated normal rat islets were incubated with 3.3, 8.3, and 16.7 mM glucose, in the presence or absence of different concentrations of lupanine (0.05, 0.5, and 1.0 mM), 13-alpha-OH lupanine, 17-oxo-lupanine, and 2-thionosparteine. Insulin release was measured by radioimmunoassay. While 2-thionosparteine enhanced insulin secretion at all glucose concentrations, lupanine did at 8.3 and 16.7 mM, and 13-alpha-OH lupanine or 17-oxo-lupanine only at 16.7 mM glucose. Diazoxide (0.1 mM) decreased the effect of all alkaloids, without suppressing it completely. Consequently, blockage of beta-cell K(ATP)-sensitive channels is at least one of the mechanisms involved in the enhancing secretagogue effects of quinolizidine alkaloids. The fact that 13-alpha-OH lupanine and 17-oxo-lupanine only exert their secretagogue effect at high glucose concentrations could be of additional value when considering their potential use in the treatment of type 2 diabetes.

Alkaloids↗
PubMed2002

Quinolizidine alkaloids from the curare adjuvant Clathrotropis glaucophylla.

The bark of Clathrotropis glaucophylla (Fabaceae) is used as admixture of curare arrow poison by the Yanomami; Amerindians in Venezuela. A new quinolizidine alkaloid (QA), (-)-13alpha-hydroxy-15alpha-(1-hydroxyethyl)-anagyrine [(-)-clathrotropine], was isolated from the alkaloid extract of C. glaucophylla bark, together with eleven known QAs: (-)-anagyrine, (-)-thermopsine, (-)-baptifoline, (-)-epibaptifoline, (-)-rhombifoline, (-)-tinctorine, (-)-cytisine, (-)-N-methylcytisine, (-)-lupanine, (-)-6alpha-hydroxylupanine and (+)-5,6-dehydrolupanine. The isolation and structure elucidation were performed with the aid of chromatographic (TLC, HPLC and CC) and spectroscopic (UV and 1D/2D NMR) methods, and mass spectrometry. To our knowledge, this is the first time quinolizidine alkaloids have been isolated from an arrow poison ingredient. It is also the first report on Clathrotropis species being used for preparation of arrow poison.

Alkaloids↗
PubMed1993

Quinolizidine and piperidine alkaloid teratogens from poisonous plants and their mechanism of action in animals.

Quinolizidine and piperidine alkaloid teratogens from Lupinus, Conium, and Nicotiana genera have been identified as causes of birth defects in livestock induced by poisonous plants. Many defects now known to be related to poisonous plant ingestion were once thought to have a genetic origin. This supposition delayed diagnosis, reporting, and understanding of such birth defects, because breeders and producers feared the news would make it difficult to sell breeding stock. Defects caused by quinolizidine and piperidine teratogens include cleft palate and contracture-type skeletal defects such as arthrogryposis, scoliosis, torticollis, and kyphosis. Teratogens have been identified, differences in susceptibility to teratogenic compounds among livestock species have been elucidated, periods of gestation when specific types of birth defects occur have been determined, and information about mechanism of action has been developed.

Alkaloids↗
PubMed2002

Bacterial removal of quinolizidine alkaloids and other carbon sources from a Lupinus albus aqueous extract.

Two Gram-negative bacterial strains capable of using lupanine, the predominant quinolizidine alkaloid in Lupinus albus, as a sole carbon source were isolated from soil in which L. albus and L. luteus had been grown [Santana, F. M. et al. J. Ind. Microbiol. 1996, 17, 110-115]. In the present study, we present results suggesting that these isolates are of potential interest for removing lupanine and other quinolizidine alkaloids (QA) from the effluent resulting from the wet processing of Lupinus seeds, at temperatures within the range 20-34 degrees C. Growth in L. albus aqueous extract was diauxic, with a first period of rapid growth leading to the simultaneous consumption of a significant part of the initial concentration of QA (3 g L(-1), being 2 g L(-1) lupanine) and amino acids (1.5 g L(-1)). This period was followed by a second period of slower growth corresponding to the subsequent partial utilization (25%) of the carbohydrates (initial concentration of 20 g L(-1)) together with further removal of QA and amino acids. Despite the differences detected in the susceptibility of the two strains to lupanine toxicity, in particular at supraoptimal temperatures, and in the efficiency of lupanine catabolism, their performance on L. albus extract did not vary significantly.

Alkaloids↗
PubMed1985

Substituted benzamides with conformationally restricted side chains. 1. Quinolizidine derivatives as selective gastric prokinetic agents.

The gastric prokinetic action of metoclopramide may not be primarily due to its dopamine antagonist activity. The present aim was to obtain a selective gastric prokinetic agent lacking dopamine antagonist activity by conformationally restricting the side chain of metoclopramide. In a series of quinolizidinylbenzamides, only compounds with the benzamide moiety at position 2 of the quinolizidine ring retain gastric activity. Of these 2-substituted compounds, the 2 alpha, 9a alpha isomer has potent selective gastric prokinetic activity with only weak dopamine antagonist properties. Spectroscopic data show that the quinolizidine ring preferentially adopts a trans chair-chair conformation with an axial benzamide moiety. However, energy calculations indicate that, at nondopaminergic receptors controlling gastric motility, an alternative cis chair-chair conformation with an equatorial benzamide moiety cannot be ruled out.

Animals↗
PubMed1976

Synthesis and biological actions of 2-substituted quinolizidines.

A series of 2-substituted quinolizidines was synthesized and tested for their effects on motor activity in mice. In the 2-aryl-2-hydroxyquinolizidines (5 and 6) a difference was noted in potency between the axial and equatorial aryl analogs. A significant difference in activity was also found between the epimeric 2-(4-fluorobenzoyl) quinolizidines (10c and 11c).

Animals↗
PubMed2003

Determining the scope of the organolanthanide-catalyzed, sequential intramolecular amination/cyclization reaction: formation of substituted quinolizidines, indolizidines, and pyrrolizidines.

The scope of the lanthanide-mediated, intramolecular amination/cyclization reaction was determined for the formation of substituted quinolizidines, indolizidines, and pyrrolizidines. A methyl group was installed at diverse positions in the substrates to determine the sense and magnitude of diastereoselection. High diastereoselectivity (>20:1) was achieved for the formation of some quinolizidines and indolizidines. The sense of relative asymmetric induction was contrary to previously studied systems, and although some questions remain, a rationalization for these results is put forward.

Alkylation↗
PubMed1994

Binding of quinolizidine alkaloids to nicotinic and muscarinic acetylcholine receptors.

Fourteen quinolizidine alkaloids, isolated from Lupinus albus, L. mutabilis, and Anagyris foetida, were analyzed for their affinity for nicotinic and/or muscarinic acetylcholine receptors. Of the compounds tested, the alpha-pyridones, N-methylcytisine and cytisine, showed the highest affinities at the nicotinic receptor, while several quinolizidine alkaloid types were especially active at the muscarinic receptor.

Alkaloids↗
PubMed1996

A 1,4-disubstituted quinolizidine from a Madagascan mantelline frog (Mantella).

A major alkaloid, 217A, in skin extracts of a mantelline frog (Mantella baroni) was isolated by HPLC and the structure defined by 1H-NMR spectral analysis as (1R,4S,10S)- or (1R,4R,10R)- 1-methyl-4-(Z)-(1-pent-2-en-4-ynyl) quinolizidine (1). Four other alkaloids-207I (2), 231A (3), 233A (4), and 235E' (5)-detected in frog skin extracts are proposed to be 1,4-disubstituted quinolizidines based on diagnostic mass and FTIR spectra.

Animals↗
PubMed2003

High performance liquid chromatographic fingerprint evaluation of the quinolizidine alkaloids from commercial Radix Sophorae Flavescentis.

Fifteen commercial samples of Radix Sophorae Flavescentis were collected from different parts of China. HPLC analysis showed that the commercial samples all contained quinolizidine alkaloids and a total of nine chromatographic peaks were identified by referring to standard compounds, HPLC/MS analysis and comparison of the physicochemical data of the isolated peak with the literature. The contents of the major alkaloids were determined and the ratio of the major alkaloids contents was shown to be correlated with their source of origin. The commercial samples from China gave a distinct HPLC pattern showing the main alkaloids contents. The sample preparations were researched and the extraction conditions of the alkaloids were optimized. Reproducible HPLC fingerprints can be obtained for the quinolizidine alkaloids under the well-controlled extraction conditions. The HPLC fingerprint analysis method is suitable for the quality control of the Radix Sophorae Flavescentis and the standardization of phytomedicines.

Alkaloids↗