Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “ALKALOIDS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 883 records · Page 49Linked to original sources
PubMed2002

Predicting toxicity of tall larkspur (Delphinium barbeyi): measurement of the variation in alkaloid concentration among plants and among years.

Tall larkspur (Delphinium barbeyi) is the principal mountain larkspur responsible for the majority of cattle deaths on mountain rangelands in western Colorado and central and southern Utah in the United States. Ten plants in each of two tall larkspur populations in the mountains near Ferron and Salina, Utah, were marked, and single stalks were harvested periodically through the growing season for 4 yr. Toxic alkaloid concentration [alkaloids containing the N-(methylsuccimimido)-anthranilik ester group] was determined by Fourier transform infrared (FTIR) spectroscopy. Individual larkspur plants varied in alkaloid concentrations, especially in early growth (14-38 mg/g). As the concentration declined over the growing season, variation among plants also declined. There were yearly differences in alkaloid concentration among individual plants (P < 0.01) and populations (P < 0.001), even after accounting for differences in phenological growth between years. Variables such as precipitation, temperature, days since snow melt, growing degree days (sum of mean temperature each day from snow melt), and plant height and weight were all considered in a Mallows Cp multiple regression selection procedure to predict alkaloid concentration. The mixed model procedure in SAS adjusted the regression equation for locations and years. Growing degree days was the best single predictor of alkaloid levels: In y = (3.581 - 0.00423 GDD), R2 = 0.85. Internal validation of this equation within individual years and locations from which the equation was developed, produced correlations between observed versus predicted values ranging from r = 0.73 to 0.93. External validations on nine other larkspur populations produced correlations ranging from r = 0.76 to 0.99. This predictive equation can provide a tool for ranchers and land managers to make management decisions of when to graze cattle in larkspur areas.

Alkaloids↗
PubMed2003

Sequestration and metabolism of protoxic pyrrolizidine alkaloids by larvae of the leaf beetle Platyphora boucardi and their transfer via pupae into defensive secretions of adults.

Several neotropical leaf-beetles of the genus Platyphora ingest and specifically metabolize plant acquired pyrrolizidine alkaloids (PAs) of the lycopsamine type (e.g., rinderine or intermedine) and enrich the processed alkaloids in their exocrine defensive secretions. In contrast to the related palaearctic leaf beetles of the genus Oreina, which absorb and store only the non-toxic alkaloid N-oxides, Platyphora sequesters PAs exclusively as protoxic tertiary amines. In this study, the ability of P. boucardi larvae to accumulate PAs was investigated. Tracer studies with [14C]rinderine and its N-oxide revealed that P. boucardi larvae, like adult beetles, utilize the two alkaloidal forms with the same efficiency, but accumulate the alkaloid as a tertiary amine exclusively. Ingested rinderine is rapidly epimerized to intermedine, which is localized in the hemolymph and all other tissues; it is also detected on the larval surface. Like adults, larvae are able to synthesize their own alkaloid esters (beetle PAs) from orally administered [14C]retronecine and endogenous aliphatic 2-hydroxy acids. These retronecine esters show the same tissue distribution as intermedine. A long-term feeding experiment lasting for almost four months revealed that retronecine esters synthesized from [14C]retronecine in the larvae are transferred from larvae via pupae into the exocrine glands of adult beetles. Pupae contain ca. 45% of the labeled retronecine originally ingested, metabolized, and stored by larvae; ca. 12% of larval radioactivity could be recovered from the defensive secretions of adults sampled successively over two and a half months. Almost all of this radioactivity is found in the insect-made retronecine esters that are highly enriched in the defensive secretions, i.e., more than 200-fold higher concentration compared to pupae.

Animals↗
PubMed2004

Indolizidine and quinolizidine alkaloids.

This review covers the isolation, structure determination, synthesis, chemical transformations and biological activity of indolizidine and quinolizidine alkaloids from microbial, plant and animal sources. Included in the review are the hydroxylated indolizidines lentiginosine, swainsonine, castanospermine and their analogues; alkaloids from animal sources, including ants, amphibians and beetles; ipalbidine, phenanthroindolizidines and related alkaloids; Lycopodium alkaloids; lupine alkaloids; and alkaloids from bacterial and marine sources. The literature from July 2002 to June 2003 is reviewed, and 174 references are cited.

Alkaloids↗
PubMed1999

Activity against Mycobacterium tuberculosis of alkaloid constituents of Angostura bark, Galipea officinalis.

The activity of an ethanolic extract of Galipea officinalis bark against Mycobacterium tuberculosis was shown to reside mainly in the basic alkaloidal fraction although the major part of the alkaloids present were in the neutral fraction. Six alkaloids were isolated from the bark including two other alkaloids not previously reported from G. officinalis and a new quinoline named allocuspareine, whose structure was determined by spectroscopic methods. 1H- and 13C-NMR spectral data for three of these compounds are reported for the first time. Isolation and testing of fractions and individual alkaloids against ten strains of M. tuberculosis showed that all the alkaloids possessed some activity but that the unidentified most polar basic fraction exhibited the greatest effect.

Alkaloids↗
PubMed1995

Inhibitory effects of bisbenzylisoquinoline alkaloids on induction of proinflammatory cytokines, interleukin-1 and tumor necrosis factor-alpha.

Bisbenzylisoquinoline alkaloids are known to affect immune responses as well as inflammatory responses, and have been used for the treatment of inflammatory symptoms in China. This study is aimed at elucidating the inhibitory effects of two alkaloids, fangchinoline and isotetrandrine, on the induction of the proinflammatory cytokines, interleukin-1 (IL-1), and tumor necrosis factor-alpha (TNF-alpha), by Staphylococcus aureus Cowan 1 (SAC)-stimulated human peripheral blood mononuclear cells. These two alkaloids inhibited cytokine production in a dose-dependent manner, and they inhibited it by more than 90% at 10 micrograms/ml at every time point examined. Of note was that these two alkaloids appeared to inhibit IL-1 beta production more effectively than IL-1 alpha production. When the levels of cytokine mRNA were measured by semiquantitative RT-PCR, these alkaloids reduced the levels of the mRNAs of IL-1 beta and TNF-alpha, but not that of beta 2-microglobulin, suggesting that these alkaloids may suppress cytokine transcription selectively.

Alkaloids↗
PubMed1981

Variability in the content and composition of alkaloids found in Canadian ergot. I. Rye.

The total alkaloid content and individual alkaloid composition were determined by colorimetry and high performance liquid chromatography, respectively, for Canadian rye ergot sclerotia. The total alkaloid content was highly variable between sclerotia from the same head, field, or region and ranged from 0.011 to 0.452% (av. 0.249%). Levels were lowest in ergot from Prince Edward Island. The individual alkaloid composition was uniform throughout a single sclerotium or in different sclerotia from the same head, somewhat uniform for averages in different fields throughout a region, but highly variable from head to head in a given field. On a regional basis, ergotamine followed by ergocristine were the major alkaloids observed in the east whereas the order was reversed in the west. Ergometrine, ergosine, ergocornine, and ergocryptine were also observed to a lesser degree; ergostine was not observed. Isomerization of ergometrine increased from near 0% in the east to about 40% in the west, but was relatively constant (about 30%) for the peptide alkaloids in all regions.

Canada↗
PubMed1982

Variability in the content and composition of alkaloid found in Canadian ergot. III. Triticale and barley.

The total alkaloid content and individual alkaloid composition were determined by colorimetry and high performance liquid chromatography, respectively, for Canadian triticale and barley ergot (Claviceps purpurea). The total alkaloid content was highly variable between individual sclerotia from the same or different sources and ranged from 0.042 to 0.752% for triticale and from 0.082 to 1.04% for barley; average values were 0.239% for Ottawa triticale, 0.289% for Prairie triticale, and 0.264% for barley. Ergocristine and its isomer ergocristinine were the major constituents in both grains. On average, Canadian ergot pooled from rye, wheat, triticale, and barley consists of ergocristine (31%), ergocristinine (13%), ergocristinine (13%), ergotamine (17%), ergotaminine (8%), ergocryptine (5%), ergocryptinine (3%), ergometrine (5%), ergometrinine (2%), ergosine (4%), ergostinine (2%), ergocornine (4%), ergocorninine (2%), and unidentified alkaloids (3%), and an average total alkaloid content of 0.236%. With the exception of rye and barley ergot from the maritime regions, Canadian rye, wheat, triticale, and barley ergot is fairly uniform in individual alkaloid composition.

Canada↗
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↗
PubMed1997

The effects of a selection of alkaloids on the invertase activity of some higher plants.

The effects of several alkaloids on the invertase activities of Ricinus communis, Solanum tuberosum, Oryza sativa and Carica papaya were studied. The following alkaloids: caffeine, berberine, strychnine, morphine, ethyl-narceine and nornicotine, have different inhibitory effects on invertase activity. Kinetic studies of the alkaloid inhibition revealed that different alkaloids exhibited diverse types of inhibition of invertase. It was found that alkaloids form reversible complexes with invertases. However cocaine and potato glycoalkaloids were activators of some invertase. The sugar moiety of potato glycoalkaloids were also activators. It is concluded that alkaloids may be effectors of higher plant invertase activity.

Alkaloids↗
PubMed2000

Contribution of fungal loline alkaloids to protection from aphids in a grass-endophyte mutualism.

Fungal endophytes provide grasses with enhanced protection from herbivory, drought, and pathogens. The loline alkaloids (saturated 1-aminopyrrolizidines with an oxygen bridge) are fungal metabolites often present in grasses with fungal endophytes of the genera Epichloë or Neotyphodium. We conducted a Mendelian genetic analysis to test for activity of lolines produced in plants against aphids feeding on those plants. Though most loline-producing endophytes are asexual, we found that a recently described sexual endophyte, Epichloë festucae, had heritable variation for loline alkaloid expression (Lol+) or nonexpression (Lol-). By analyzing segregation of these phenotypes and of linked DNA polymorphisms in crosses, we identified a single genetic locus controlling loline alkaloid expression in those E. festucae parents. We then tested segregating Lol+ and Lol- full-sibling fungal progeny for their ability to protect host plants from two aphid species, and observed that alkaloid expression cosegregated with activity against these insects. The in planta loline alkaloid levels correlated with levels of anti-aphid activity. These results suggested a key role of the loline alkaloids in protection of host plants from certain aphids, and represent, to our knowledge, the first Mendelian analysis demonstrating how a fungal factor contributes protection to plant-fungus mutualism.

Alkaloids↗
PubMed2006

Leaf herbivory and nutrients increase nectar alkaloids.

Correlations between traits may constrain ecological and evolutionary responses to multispecies interactions. Many plants produce defensive compounds in nectar and leaves that could influence interactions with pollinators and herbivores, but the relationship between nectar and leaf defences is entirely unexplored. Correlations between leaf and nectar traits may be mediated by resources and prior damage. We determined the effect of nutrients and leaf herbivory by Manduca sexta on Nicotiana tabacum nectar and leaf alkaloids, floral traits and moth oviposition. We found a positive phenotypic correlation between nectar and leaf alkaloids. Herbivory induced alkaloids in nectar but not in leaves, while nutrients increased alkaloids in both tissues. Moths laid the most eggs on damaged, fertilized plants, suggesting a preference for high alkaloids. Induced nectar alkaloids via leaf herbivory indicate that species interactions involving leaf and floral tissues are linked and should not be treated as independent phenomena in plant ecology or evolution.

Adaptation, Physiological↗
PubMed1990

In situ response to vinka alkaloids by microtubules in cultured post-implanted mouse embryos.

The response of microtubules to treatment with vinca alkaloids was investigated in vivo and in situ in the embryonic nervous system of mice. For this purpose we used rotatory cultures of post-implanted embryos in a serum medium containing the alkaloid combined with immunofluorescence using a tubulin-specific polyclonal antibody on high molecular weight polyethylene glycol embedded semithin sections. In mitotic cells, kinetochore microtubules were seen to be more resistant to the action of vinca alkaloids than interpolar microtubules. Increasing drug concentrations induced an increasing rate of mitosis together with an increasing rate of disassembly of the cytoplasmic microtubule complex, suggesting a probable relation between these events. In bipolar neuroepithelial cells at interphase, a small pool of microtubules was resistant to the vinca alkaloids. These microtubules were located near the centriolar apparatus associated with the primary cilium; they were short, curly and bent. Disruption of the cytoplasmic microtubule complex did not alter the shape of the bipolar neuroepithelial cells. In the axonal profiles, a drug-stable pool of microtubules were not disrupted by the alkaloids and were also short. They seem to act as microtubule organizing centres. These observations suggest vinca alkaloids seem to act in vivo much more by inducing, at a given concentration, the disruption of a particular group of microtubules without altering the others. The fact that these drugs affect the number, but not the length, of the microtubules raises the hypothesis that these drugs act on microtubules by a mechanism similar to that described as "dynamic instability".

Animals↗
PubMed1988

Procedure for isolating the endophyte from tall fescue and screening isolates for ergot alkaloids.

A procedure was developed to isolate and determine ergot alkaloid production by Acremonium coenophialum, the endophytic fungus of tall fescue. The procedure established that macerated leaf sheath or pith from inflorescence stem placed either in a liquid medium or on a corn meal-malt extract agar medium produced isolated mycelium and characteristic conidia within a 3- to 3.5-week period. Once isolated, each fungus was placed in another liquid medium, M104T, where competent strains produced total ergot alkaloids ranging from 38 to 797 mg/liter. Several isolates were negative for ergot alkaloid synthesis. The production of ergot alkaloids by individual isolates was unstable; isolates rapidly degenerated in their ability to produce ergot alkaloids during subculture. However, the procedure as presented allows the assessment of an isolate for ergot alkaloid synthesis during its initial isolation.

Acremonium↗
PubMed1971

Correlation of certain alterations in metabolic activity with alkaloid production by submerged Claviceps.

Alkaloid biosynthesis in Claviceps paspali MG-6 was favored by unbalanced growth. A positive correlation between the rate of protein turnover and alkaloid formation was noted. The pattern of the orthophosphate content in the mycelium resembled that in the ripening sclerotia of the parasitic strains. Alkaloids were revealed as potentially effective in energy metabolism. Reduced adenosine triphosphate (ATP) utilization and an increase in the ATP pool were found to be favorable for alkaloid production. Acetyl-coenzyme A carboxylase activity and the level of cell lipids were directly related to the intensity of alkaloid biosynthesis. An inverse relationship was observed between the activities of the tricarboxylic acid and glycoxylate cycles and the rate of alkaloid formation.

Adenine Nucleotides↗
PubMed1978

Binding interactions of ergot alkaloids with monoaminergic receptors in the brain.

The interactions of ergot alkaloids and of other drugs with dopamine (DA) and alpha-adrenergic receptors were investigated. The tested ergot alkaloids inhibit synaptosomal tyrosine hydroxylase activity and reverse the apomorphine-elicited inhibition of synaptosomal tyrosine hydroxylase activity. Thus, ergot alkaloids interact as both agonists and antagonists with the presynaptic DA receptors. Ergot alkaloids also compete effectively for the binding of 3H-DA and 3H-haloperidol to bovine striatal membranes. These results show that these drugs are mixed agonist-antagonists with respect to the postsynaptic DA receptors. To determine the effects of ergot alkaloids and of neuroleptics on the alpha-adrenergic receptors in the CNS, we have measured their effects on the binding of 3H-dihydroergocryptine and 3H-WB-4101 to cerebral cortical membranes. The displacing potencies of the tested ergot alkaloids and of the neuroleptics indicated that they have a high affinity for the alpha-adrenoreceptors in the CNS. The mechanisms underlying the therapeutic efficacy of mixed agonist-antigonists of DA and alpha-adrenergic receptors in Parkinson's disease and in geriatric disorders were considered.

Animals↗
PubMed2004

Water potentiates the pressor effect of ephedra alkaloids.

BACKGROUND: The use of ephedra alkaloids in over-the-counter preparations has been associated with potentially serious cerebrovascular events. Because of its potential association with hemorrhagic strokes, phenylpropanolamine has been largely substituted for by pseudoephedrine, but it is not clear whether this is indeed a safer alternative. It would be important to understand the cardiovascular effects of ephedra alkaloids, but these are normally masked by baroreflex buffering mechanisms. We therefore investigated the effects of ephedra alkaloids in patients with autonomic impairment and explored their potential interaction with water ingestion. METHODS AND RESULTS: The cardiovascular effects of phenylpropanolamine or pseudoephedrine, alone and in combination with water, were determined in 13 subjects with impairment of baroreflex function due to autonomic failure. Phenylpropanolamine, 12.5 to 25 mg PO, increased systolic blood pressure (SBP) by 21+/-14 mm Hg after 90 minutes. However, when ingested with 16 oz of room temperature tap water, phenylpropanolamine increased SBP by 82+/-2 mm Hg. Pseudoephedrine, 30 mg PO, increased SBP on average 52+/-9 mm Hg when taken with 16 oz of water and by as much as 88 mm Hg. CONCLUSIONS: Ephedra alkaloids increase blood pressure significantly in individuals with impaired baroreflex function. Concomitant ingestion of ephedra alkaloids and water produced a greater increase in blood pressure. If used cautiously, this interaction can be beneficial in the treatment of orthostatic hypotension. On the other hand, it could contribute to the cardiovascular complications associated with the use of ephedra alkaloids, given that baroreflex function varies widely in normal individuals and is impaired in several medical conditions.

Aged↗
PubMed2006

The incidence of extravasation of vinca alkaloids supplied in syringes or mini-bags.

STUDY OBJECTIVE: The aim of this retrospective study was to determine the incidence of vinca alkaloid extravasation following administration via syringes or mini-bags. METHODS: An electronic survey was sent to pharmacy departments at hospitals throughout Australia. The survey was designed to collect data on the administration methods of vinca alkaloids (vincristine, vinblastine, vinorelbine) and the corresponding documented incidence of extravasation. The questionnaire requested the following information: how the drugs were prepared for administration (syringe or mini-bag); volume of each product; number of items supplied; and the number of cases of extravasation reported for each product. RESULTS: Questionnaires were sent to 228 hospital pharmacy departments in Australia. Sixty-eight questionnaires were received (29.8%), including responses from most major cancer centres. Data represented a range of 3 to 120 months (mean: 38 months) of clinical experience. The reported incidence of vincristine extravasation from syringes was 0.03% (11/37 084) and 0.041% (3/7255) with mini-bags. One case of vinblastine extravasation was reported with syringes 0.013% (1/7913), none from mini-bags (0/1421). Vinorelbine data were difficult to interpret as cases may represent phlebitis rather than extravasation. The reported incidence from vinorelbine syringes was 0.029% (2/6914) and 0.146% (8/5475) with mini-bags. Excluding vinorelbine data, the reported vinca alkaloid extravasation episodes from syringes (0.027%) and mini-bags (0.035%) were found to be similar and infrequent. CONCLUSION: The data suggest that vinca alkaloids can be given safely as low volume, short infusions via mini-bags. Policies and practices that ensure the same careful monitoring of infusional therapy as is recommended with administration by syringe may further reduce the incidence of untoward effects. Mini-bags should be used for the administration of vinca alkaloids and this practice will prevent the inadvertent intrathecal administration of vinca alkaloids via syringes.

Antineoplastic Agents↗
PubMed1991

A comparative study of the cerebrovascular complications of cocaine: alkaloidal versus hydrochloride--a review.

Cocaine, especially in its alkaloidal or "crack" form, has been increasingly associated with cerebrovascular disease. Before the crack epidemic, cocaine hydrochloride (HCl) was also implicated as a cause of stroke. However, less is known about the differences in stroke subtypes, age at stroke onset, or presence of underlying structural cerebrovascular disease with different forms of cocaine use. We compared 26 patients (previously reported) from our four institutions plus 16 cases reported in the literature of stroke associated with alkaloidal cocaine to 63 (57 reported in the literature and six not previously reported from our four institutions) cases of stroke associated with cocaine HCl. Ischemic and hemorrhagic strokes are equally likely after alkaloidal cocaine use, whereas cocaine HCl is more likely (approximately 80% of the time) to cause hemorrhagic stroke, with approximately half the intracranial hemorrhages occurring from ruptured cerebral saccular aneurysms or vascular malformations. The presence of an underlying cerebral aneurysm was more common among patients with cocaine HCl-associated strokes than alkaloidal cocaine-associated strokes. Cerebral infarction was significantly more common among the alkaloidal cocaine users than in all the cocaine HCl users, and this was also true when alkaloidal cocaine users were compared with parenteral cocaine HCl (intravenous and intramuscular) users. Only hemorrhagic stroke has been reported with intravenous cocaine HCl use. We conclude that the pathogenesis of cocaine-related stroke is heterogeneous, and depends, in part, on the form of cocaine used.

Administration, Intranasal↗