P. Gayral

Isolation of leishmanicidal triterpenes and lignans from the Amazonian liana Doliocarpus dentatus (dilleniaceae)

The in vitro antileishmanial activity of triterpenes and lignans of an Amazonian medicinal plant, Doliocarpus dentatus (Aublet) Standley, is reported for the first time against amastigotes of Leishmania amazonensis. Terpenes, for example, betulinic acid, betulin and betulinaldehyde were isolated by bioassay‐linked extraction. The lignans were characterized as (+) pinoresinol, (+) medioresinol and (−) lirioresinol B.

Presence of norepinephrine and other biogenic amines in stonefish venom

Although fish venoms exert a cardiovascular effect, the presence of adrenergic substances was not previously demonstrated. Chromatographic analysis with electrochemical detection showed the presence of substances co-migrating with norepinephrine, dopamine and tryptophan. Serotonin, which was thought to be implicated in the intense pain following fish envenomation, was not detected. Norepinephrine was identified as a component of the stonefish Synanceia verrucosa venom by gas chromatography-mass spectrometry.

In-vitro evaluation of filaricidal activity of GABA and 1,3-dipalmitoyl-2-(4-aminobutyryl)glycerol HCl: a diglyceride prodrug

Abstract— A diglyceride ester of γ‐aminobutyric acid (GABA) has been synthesized and its filaricidal activity compared with GABA, and progabide in‐vitro, on infective larvae and microfilariae of Molinema dessetae, a rodent filaria. GABA induced paralysis in infective larvae but was inactive on microfilariae. There were interactions between the culture medium and GABA. The ester drug at 0·1 mmol L−1 (1,3‐dipalmitoyl‐2‐(4‐aminobutyryl)glycerol HCl) was as active as progabide on infective larvae and hundredfold more potent than GABA. Its microfilaricidal activity at 1 mmol L−1 was lower than that progabide at 0·1 mmol L−1 but a delayed effect was observed. The data confirm filariae sensitivity to GABA derivatives.

Aminothiazines et aminothiazoles analogues ouverts du lévamisole: synthèse et approche du mode d'action nématicide

New compounds with thiazoline or dihydrothiazine rings substituted by alkylamino or arylamino groups were synthesized and screened in vitro against three Nematodes. Inhibition of fumarate-reductase activity was also evaluated. For all in vitro anti-parasitic tests, dihydrothiazines were more potent than corresponding thiazolines derivatives, however, thiazolines showed a greater inhibition of fumarate-reductase.

Unloaded polyisobutylcyanoacrylate nanoparticles: efficiency against bloodstream trypanosomes

The potential use of polyisobutylcyanoacrylate nanoparticles in antiparasitic chemotherapy is described. The nanoparticles on their own proved to have trypanocidal activity against Trypanosoma brucei brucei in‐vitro but not against Trichomonas vaginalis or Entamoeba histolytica. The trypanocidal activity was partly confirmed in‐vivo with T. brucei‐infected mice.

Synthèse, activités anti-parasitaire et anti-fongique d'arylalkyl- et d'arylvinylthiazolines

Abstract Twenty-seven arylalkyl- or arylvinylthiazolines were synthesized and tested in vitro against three genera of nematodes, various yeasts and opportunistic fungi. Vinyl compounds seem to have an interesting filaricidal activity against Molinema dessetae and anti-fungal activity against yeasts.

Biogenic amines in newly-ecdysed cockroaches

1. Simultaneous quantification (HPLC and electrochemical detection) of biological extracts have shown dopamine, N-acetyl dopamine, tryptophan, 5-hydroxytryptamine, a 5-hydroxyindolacetic acid-like substance in nervous tissue and hemolymph of Blaberus craniifer and Periplaneta americana. 2. 5-Hydroxytryptophan was only detected in head and thoraco-abdominal nerve cord. 3. Octopamine, but not N-acetyl-5-HT was quantified in the hemolymph.

Biogenic amines and gaba in the larval and adult forms of the nematode Nippostrongylus brasiliensis

1. Simultaneous detection (HPLC and electrochemical detection) of biological extracts of larval and adult stages of Nippostrongylus brasiliensis was performed in order to assay biogenic amines. 2. Gamma-amino-butyric acid was assayed in the same samples. 3. Tryptophan, 5-hydroxyindoleacetic acid were at the same level in adults and larvae. 4. 5-Hydroxytryptophan, serotonin, dihydroxyphenylalanine and dopamine were significantly higher in larvae in which gamma-amino-butyric acid was not detected.

Effects of ecdysteroids on reproductive physiology of Nippostrongylus brasiliensis (nematoda) in vivo

1. The influence of ecdysteroids (ecdysone and ecdysterone) was investigated on the control of reproduction in the parasitic nematode Nippostrongylus brasiliensis in vivo. 2. Infestive larvae (L3) were immersed in solutions of ecdysteroids (2.2 microM) at 37 degrees C for 4 hr before injection into the host. The effect on egg-laying was observed two stages later. 3. The treatment increased egg-laying, but had no influence on the timing of the reproductive period. The greatest effect was observed with ecdysone, ecdysterone only inducing a small and non-significant stimulation under our experimental conditions. 4. The physiological role of ecdysteroids in meiosis and gonadal development in nematodes is discussed.

Synthesis and nematocidal activities of new analogs of pyrantel

Summary A set of new analogs of pyrantel was synthesized in good yields by lithiation of 1,2-dimethyltetrahydropyrimidine with n -butyllithium in tetrahydrofuran and condensation with aromatic esters. Spectrometric studies showed the large influence of intramolecular bonding in the tautomeric equilibria between the possible structures. Anthelmintic screening showed in vitro efficiency against Molinema dessetae , but a weak activity against Rhabditis pseudoelongata and Nippostrongylus brasiliensis .