A convenient approach for evaluating the toxicity profiles of in vitro neuroprotective alkylaminophenol derivatives

Inhibitory activity of marine sponge-derived natural products against parasitic protozoa

In this study, thirteen sponge-derived terpenoids, including five linear furanoterpenes: furospinulosin-1 (1), furospinulosin-2 (2), furospongin-1 (3), furospongin-4 (4), and demethylfurospongin-4 (5); four linear meroterpenes: 2-(hexaprenylmethyl)-2-methylchromenol (6), 4-hydroxy-3-octaprenylbenzoic acid (7), 4-hydroxy-3-tetraprenyl-phenylacetic acid (8), and heptaprenyl-p-quinol (9); a linear triterpene, squalene (10); two spongian-type diterpenes dorisenone D (11) and 11 beta-acetoxyspongi-12-en-16-one (12); a scalarane-type sesterterpene; 12-epi-deoxoscalarin (13), as well as an indole alkaloid, tryptophol (14) were screened for their in vitro activity against four parasitic protozoa; Trypanosoma brucei rhodesiense, Trypanosoma cruzi, Leishmania donovani and Plasmodium falciparum. Cytotoxic potential of the compounds on mammalian cells was also assessed. All compounds were active against T. brucei rhodesiense, with compound 8 being the most potent (IC(50) 0.60 microg/mL), whereas 9 and 12 were the most active compounds against T. cruzi, with IC(50) values around 4 microg/mL. Compound 12 showed the strongest leishmanicidal activity (IC(50) 0.75 microg/mL), which was comparable to that of miltefosine (IC(50) 0.20 microg/mL). The best antiplasmodial effect was exerted by compound 11 (IC(50) 0.43 microg/mL), followed by compounds 7, 10, and 12 with IC(50) values around 1 microg/mL. Compounds 9, 11 and 12 exhibited, besides their antiprotozoal activity, also some cytotoxicity, whereas all other compounds had low or no cytotoxicity towards the mammalian cell line. This is the first report of antiprotozoal activity of marine metabolites 1-14, and points out the potential of marine sponges in discovery of new antiprotozoal lead compounds.

[Metabolites of ecstasy and cytotoxicity effects]

Intracerebroventricular injection of methylenedioxymethamphetamine (MDMA, ecstasy) in rats fails to reproduce long-term toxic effects observed after peripheral administration. Therefore, systemic metabolites would play an essential role in the development of cytotoxicity. In humans, the major metabolite is the 3,4-dihydroxymethamphetamine derivative (HHMA), which is easily oxidizable to the orthoquinone species. This can either participate to redox cycling generating semiquinone radicals and reactive oxygen species (ROS), or react with endogenous thiol derivatives yielding catechol-thioether conjugates whose the toxicity is not well established. A one pot electrochemical procedure has been developed allowing the synthesis of several catechol-thioether metabolites. Two in vitro assays have been used for evaluating their specific cytotoxicity. The first one is a bacterial assay, which shows that HHMA and some catechol-thioether conjugates can induce toxic phenomena leading to the formation of ROS, through redox cycling processes involving o-quinonoid species. The second one is an assay of cellular viability, performed on rat hippocampal pyramidal neurons. It confirms that some of these metabolites exhibit a noticeable cytotoxicity by markedly eliciting both necrosis and apoptosis markers.