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Biomedical subjects

P Moyna

Publications and source records attributed to P Moyna.

At least 19 recordsLinked to original sources
PubMed2001

Design, synthesis, and biological evaluation of a series of simple and novel potential antimalarial compounds.

A series of compounds bearing an endocyclic -N-O- moiety with potential antimalarial activity based on simple derivatives of the tropolone purpurogallin was prepared by means of a hetero Diels-Alder reaction using nitrosobenzene as a dienophile. The rationale behind the design of these compounds is presented, together with the synthetic route to derivatives bearing aromatic and aliphatic esters of the C4'-position hydroxyl group of the purpurogallin framework, as well as biological data obtained from in vitro assays against Plasmodium falciparum and Trypanosoma cruzi. Several of the new compounds have activities in the 3-9 microM range, and provide leads for the development of a novel class of antiparasitic drugs with improved biological and pharmacological properties.

Animals↗
PubMed2000

Determination of the phospholipid/lipophilic compounds ratio in liposomes by thin-layer chromatography scanning densitometry.

The determination of the ratio of phospholipid/lipophilic compounds in liposomes was achieved after thin-layer chromatography (TLC) by measuring the spot intensities of dipalmitoyl phosphatidylcholine and the lipophilic compound. The liposome components under study were separated on one TLC plate, developed in two steps, and detected after charring the plate with specific visualization reagents. The method shows good reproducibility and provides a simple way to quantify the level of lipophilic compound incorporated in the liposome bilayer.

Chromatography, Gas↗
PubMed2000

A new antibacterial compound from Ibicella lutea.

Ibicella lutea is a 'quasi-carnivorous' plant that grows wild in Uruguay where it is used in popular medicine as an antiseptic for eye and skin infections. In an earlier screening, it showed a broad antibacterial spectrum. From the chloroform extract of the plant the main antibacterial compound has now been isolated and identified by several MS and NMR methods as a new compound, 11-O-(6'-O-acetyl-beta-D-glucopyranosyl)-stearic acid.

Anti-Infective Agents↗
PubMed2000

Achyrocline satureioides essential oils from southern Brazil and Uruguay.

The essential oils of the aerial parts of Achyrocline satureioides (D.C.) Lam., a regional medicinal plant, from different collection locations in the South of Brazil and Uruguay were examined by GC and GC-MS. Monoterpene and sesquiterpene hydrocarbons were the main fractions of both the oils from Brazil and Uruguay. The oxygenated monoterpenes and sequiterpenes were at much lower percentage in both samples. The Uruguayan samples have 1,8-cineole which is not present in the Brazilian samples and has not been reported in other samples from Brazil. The results indicated a high biodiversity of the native populations of A. satureioides.

Asteraceae↗
PubMed2000

An aphid repellent glycoside from Solanum laxum.

A spirostanic saponin was isolated from the ethanolic extract of the aerial parts of Solanum laxum Steud. The compound, named luciamin, was characterised by NMR spectroscopy, mass spectrometry and chemical methods, as (22R, 25S)-spirost-5-en-3 beta, 15 alpha-diol 3-O-|beta-D-glucopyranosyl (1 --> 2)-beta-D-glucopyranosyl-( 1 --> 4)-[alpha-L-rhamnopyranosyl-( 1 --> 2)]-beta-D-galactopyranoside|. The compound was tested against the aphid Schizaphis graminum by incorporation in artificial diets. It showed a deterrent (toxic) activity against the insect and is the first spirostane glycoside reported to have this activity.

Journal Article↗
PubMed2000

An aphid repellent glycoside from Solanum laxum.

A spirostanic saponin was isolated from the ethanolic extract of the aerial parts of Solanum laxum Steud. The compound, named luciamin, was characterised by NMR spectroscopy, mass spectrometry and chemical methods, as (22R, 25S)-spirost-5-en-3 beta, 15 alpha-diol 3-O-[beta-D-glucopyranosyl (1 --> 2)-beta-D-glucopyranosyl-( 1 --> 4)-[alpha-L-rhamnopyranosyl-( 1 --> 2)]-beta-D-galactopyranoside]. The compound was tested against the aphid Schizaphis graminum by incorporation in artificial diets. It showed a deterrent (toxic) activity against the insect and is the first spirostane glycoside reported to have this activity.

Animals↗
PubMed1997

Chemical basis of the resistance of barley seeds to pathogenic fungi.

The 5-(n)-alkylresorcinol fraction of the epicuticular waxes of Hordeum vulgare seeds appeared to be responsible for their in-born resistance to pathogenic fungi such as Aspergillus niger and Penicillium crysogenum. The antifungal properties of this fraction were evaluated qualitatively and quantitatively with a novel bioassay where the extreme lipophilicity of these compounds was taken into account. The minimum inhibitory concentration in the fungi tested ranged from 5.6 to 10 micrograms cm-2 for the alkyresorcinols. The behaviour of the different cultivars against these fungi could be predicted by measuring the natural amount of resorcinols of each variety by TLC-scanning densitometry. The ranking of cultivars thus established correlated well with the field behaviour of each cultivar, providing a useful and rapid method for predicting the behaviour against fungi of new varieties being developed.

Chromatography, Thin Layer↗
PubMed1996

Steroid saponins from Solanum laxum.

Two new steroid saponins, named laxumins A and B, were isolated from the ethanolic extract of the aerial parts of Solanum laxum. These compounds were characterized, using mainly NMR spectroscopy, mass spectrometry and chemical methods, as (23S,25S)-spirost-5-en-3 beta, 15 alpha, 23-triol 3-O-{beta-D-glucopyranosyl-(1-->2)- beta-D-glucopyranosyl-(1-->4)-[alpha-L-rhamnopyranosyl-(1-->2)]-beta-D- galactopyranoside} and 3-O-{beta-D-glucopyranosyl-(1--> 4)-alpha-L-rhamnopyranosyl-(1-->2)]-beta-D-galactopyranoside}, respectively.

Carbohydrate Conformation↗
PubMed1995

Inhibition of in-vitro lymphocyte transformation by the isoquinoline alkaloid berberine.

Berberine is an isoquinoline alkaloid with multiple pharmacological actions, including an anti-inflammatory activity. The effects of berberine on in-vitro cellular proliferation of human peripheral lymphocytes stimulated with phytohaemagglutinin, concanavalin A and pokeweed mitogen were studied. Mononuclear cells were cultured in flat-bottomed 96-well microplates at 37 degrees C for 96-144 h in the presence of one mitogen at different concentrations and the alkaloid at doses of 2.5 to 20 microg mL-1. The mitogen-induced response of lymphocytes was evaluated from the extent of the incorporation of [3H]thymidine into cells in-vitro. A consistent and progressive inhibitory influence of berberine with increasing concentrations in culture was identified with all mitogens and was more pronounced with pokeweed mitogen. The effect of berberine was observed in phytohaemagglutinin (PHA)-and concanavalin A-activated lymphocytes when the drug was added during the first 24 h of culture, whereas the same effect occurred throughout the incubation period in pokeweed mitogen-stimulated cells. The viability of lymphocytes following treatment with the drug, as assessed by the trypan blue exclusion test, revealed no change when compared with the same untreated lymphocytes, indicating no lymphocytotoxic activity. We conclude that some effects of berberine, especially its anti-inflammatory action, may arise in part from the inhibition of DNA-synthesis in activated lymphocytes.

Adult↗
PubMed1993

Genotoxicity of the isoquinoline alkaloid berberine in prokaryotic and eukaryotic organisms.

Berberine, a medically important isoquinoline alkaloid, was tested for the presence of genotoxic, mutagenic and recombinogenic activities in microorganisms. This alkaloid did not show genotoxic activity with or without metabolic activation in the SOS chromotest. It was also unable to induce significant cytotoxic, mutagenic or recombinogenic effects during treatments performed under nongrowth conditions. However, in dividing cells, this alkaloid induced important cytotoxic and cytostatic effects in proficient and repair-deficient Saccharomyces cerevisiae strains. Among the different repair-deficient mutants examined, a mutant blocked in the DNA strand-break repair pathway (rad52-1) was found to be the most sensitive to the cytotoxic effect of berberine. A triple mutant blocked in the excision (rad2-6), in the mutagenic (rad6-1) and in the recombinogenic (rad52-1) repair pathways demonstrated the same sensitivity as the single rad52-1 mutant. In dividing cells, the induction of frameshift and mitochondrial mutations, as well as crossing over, showed that this alkaloid is not a potent mutagenic agent. The possible implication of DNA topoisomerases in berberine toxicity mechanisms is discussed.

Berberine↗
PubMed1986

Studies on mate drinking.

The habit of drinking mate is very strongly established in the Rio de la Plata region of South America. A chemical study of the commercial herbal material and of the infusion itself is described.

Argentina↗