Esther del Olmo

Anti-Trypanosoma activity of some natural stilbenoids and synthetic related heterocyclic compounds

We report the anti-Chagasic activity of the natural dihydrostilbenoid isonotholaenic acid and several simple derivatives, as well as that of some representative compounds of related synthetic series, with basic structures of benzalphthalides, dihydrostilbamides, isoindoles, phthalazin-1-ones, imidazo[2,1-a]isoindoles and pyrimido[2,1-a]isoindoles. The evaluation was performed in vitro on cultures of epimastigote and trypomastigote forms of Trypanosoma cruzi. Some of the tested compounds resulted to be as potent as benznidazole (epimastigotes), and others were shown to be more active than gentian violet (trypomastigotes), used as reference drugs.

The imidazo[2,1-a]isoindole system. A new skeletal basis for antiplasmodial compounds

The in vitro antiplasmodial activity of some dihydrostilbenamides, phtalazinones, imidazo[2,1-a]isoindole and pyrimido[2,1-a]isoindole derivatives related to the natural dihydrostilbenoid isonotholaenic acid is reported. The evaluation was performed on cultures of F32 strain of Plasmodium falciparum and potent representative compounds were also evaluated in the ferriprotoporphyrin IX biomineralization inhibition test (FBIT). Compounds having the imidazo[2,1-a]isoindole skeleton were the most active and one compound of this group resulted to be as potent as chloroquine, but acting through a mechanism different that of the inhibition of heme biomineralization.

Leishmanicidal activity of some stilbenoids and related heterocyclic compounds.

We have evaluated the leishmanicidal activity of some natural and semisynthetic dihydrostilbenoids and several compounds of other series of dihydrostilbamides, isoindoles, phthalazinones, imidazoisoindoles and pyrimidoisoindoles. The evaluation was performed in vitro, on cultures of cutaneous, mucocutaneous and visceral strains of Leishmania spp. The most potent and selective compounds of these series were the dihydrostilbene piperidides.

Synthesis and enzyme inhibitory activities of a series of lipidic diamine and aminoalcohol derivatives on cytosolic and secretory phospholipases A2.

We have synthesised some lipidic diamines and aminoalcohols and examined their behaviour as inhibitors of secretory and cytosolic PLA2. Some structure-activity relationships considerations have been deduced. Compound 14 was a potent and selective inhibitor of cPLA2 and compound 4 showed a dual inhibitory profile against both types of PLA2 while no cytotoxicity at 10 microM on human neutrophils or on murine macrophage line was observed for both.

LAAE-14, a new in vitro inhibitor of intracellular calcium mobilization, modulates acute and chronic inflammation

A new lipidic acid-amido ether derivative (LAAE-14) able to reduce dose-dependently the calcium increases mediated either by calcium ionophore ionomycin, by the endoplasmic reticular Ca(2+)-ATPase inhibitor thapsigargin, or by the chemotactic tripeptide N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP), in human neutrophils as well as in murine peritoneal macrophages, but not ATP, has been evaluated as a potential anti-inflammatory drug. This compound attenuated leukocyte activation by means of its inhibitory effect on the respiratory burst elicited in both types of cells by 12-O-tetradecanoyl phorbol 13-acetate, by inhibition of the degranulation process induced by cytochalasin B+fMLP or cytochalasin B+platelet activating factor, as well as by reduction of leukotriene B(4) synthesis induced by the calcium ionophore A23187. In addition, in zymosan-stimulated mouse peritoneal macrophages LAAE-14 caused a potent inhibition of nitrite and prostaglandin E(2) production. This compound exerted acute and chronic anti-inflammatory effects by oral route, that may be related with several mechanisms such as attenuation of leukocyte activation, inhibition of inducible nitric oxide synthase, cyclo-oxygenase-2 and cytosolic phospholipase A(2) expression as well as reduction in tumour necrosis factor-alpha production. Its anti-inflammatory profile is clearly correlated with its behavior as inhibitor of intracellular calcium mobilization. The profile and potency of this compound may have relevance for the inhibition of the inflammatory response at different levels and may represent a new approach to the development of new anti-inflammatory drugs.

Synthesis, Bioevaluation and Structural Study of Substituted Phthalazin-1(2H)-ones Acting as Antifungal Agents

Twenty-five polysubstituted phthalazinone derivatives were synthesized and tested for their antifungal activity against a panel of pathogenic and clinically important yeasts and filamentous fungi. Among them, the compound 4-(4-chlorobenzyl)-2-methylphthalazin-1(2H)-one (5) exhibited a remarkable antifungal activity against standardised strains of dermatophytes and Cryptococcus neoformans, as well as against some clinical isolates. A physicochemical study performed on compound 5 revealed its conformational and electronic characteristics, providing us with useful data for the future design of novel related antifungal analogues.

LAAE-14, a new anti-inflammatory drug, increases the survival of Candida albicans-inoculated mice.

LAAE-14, a lipidic acid-amido ether derivative, has been recently described as a new anti-inflammatory drug. We have studied the effect of treatment with this compound on the susceptibility of mice to in vivo experimental Candida albicans infection. ICR mice orally treated with LAAE-14 (25 mg kg(-1)) and experimentally intravenously infected showed a significantly increased survival as compared to control mice. In vitro, the compound did not inhibit the growth of C. albicans yeast cells or the yeast-to-hyphal transition. The in vitro production of prostaglandin E2 by peritoneal macrophages in response to the yeasts and hyphae of C. albicans was significantly decreased upon treatment with LAAE-14, in a dose-dependent manner. Thus, reduced prostaglandin production during fungal infection could be an important factor in controlling fungal colonisation and infection.

Trypanocidal Activity of Long Chain Diamines and Aminoalcohols

Thirteen aminoalcohols and eight diamines were obtained and tested against Trypanosoma cruzi epimastigotes strains MG, JEM and CL-B5 clone. Some of them were equal or more potent (1.0–6.6 times) than the reference compound nifurtimox. From them, three aminoalcohols and two diamines were selected for amastigotes assays. Compound 5 was as potent as the reference drug nifurtimox against amastigotes of the CL-B5 strain (IC50 = 0.6 µM), with a selectivity index of 54.

Neoflavonoids as Inhibitors of HIV-1 Replication by Targeting the Tat and NF-κB Pathways

Twenty-eight neoflavonoids have been prepared and evaluated in vitro against HIV-1. Antiviral activity was assessed on MT-2 cells infected with viral clones carrying the luciferase reporter gene. Inhibition of HIV transcription and Tat function were tested on cells stably transfected with the HIV-LTR and Tat protein. Seven 4-phenylchromen-2-one derivatives showed HIV transcriptional inhibitory activity but only the phenylchrome-2-one 10 inhibited NF-κB and displayed anti-Tat activity simultaneously. Compounds 10, 14, and 25, inhibited HIV replication in both targets at concentrations <25 μM. The assays of these synthetic 4-phenylchromen-2-ones may aid in the investigation of some aspects of the anti-HIV activity of such compounds and could serve as a scaffold for designing better anti-HIV compounds, which may lead to a potential anti-HIV therapeutic drug.

Lipid methyl transferase inhibitory activity of novel α-amino alkylic acid derivatives

Abstract S -Adenosylhomocysteine (SAH) is a natural inhibitor of S -adenosylmethionine (SAM) methylation in biological processes. Analogues were synthesised, where the nucleoside moiety was replaced with a long alkyl chain substituent. Lipid methylation inhibitory activities of SAM/SAH analogues 1–8 were determined on microsomes. Compound 4 , with the highest inhibitory activity, showed 40% inhibition at a concentration of 10 −7 M, while SAH required 3 orders of magnitude higher concentration for the same effect.