RESUMEN
Organochalcogens are important intermediates and useful reagents in organic synthesis, which can increase human exposure risk to these chemicals in the workplace. As well, there are a number of reported cases of acute toxicity following organochalcogen ingestion of vitamins and dietary supplements. Since, the erythrocytic delta-ALA-D activity could be an important indicator of toxicity this report investigated the organochalcogens effects on blood delta-ALA-D in vitro. To investigate a possible involvement of cysteinyl groups in the inhibitory actions of diphenyl diselenide, diphenyl ditelluride and Ebselen (4-100 micro M), the effects of thiol reducing agents (0-3 mM) or zinc chloride (0-2 mM) were examined. Diphenyl ditelluride, diphenyl diselenide and Ebselen inhibited in a concentration-dependent manner delta-ALA-D activity from human erythrocytes. Ebselen was lesser delta-ALA-D inhibitor than (PhSe)(2) and (PhTe)(2), whereas the diorganoyldichalcogenides displayed similar inhibitory potency towards delta-ALA-D. Dithiothreitol, a hydrophobic SH-reducing agent, was able to reactivate and to protect inhibited delta-ALA-D. The pre-incubation of blood with the inhibitors changed considerably the reversing potency of thiols. From these findings we suggest that organochalcogens inactivate in vitro human erythrocyte delta-ALA-D by an interaction with the sulfhydryl group essential of the enzyme activity.
Asunto(s)
Antioxidantes/toxicidad , Azoles/toxicidad , Derivados del Benceno/toxicidad , Disulfuros/toxicidad , Eritrocitos/efectos de los fármacos , Compuestos Organometálicos/toxicidad , Compuestos de Organoselenio/toxicidad , Porfobilinógeno Sintasa/metabolismo , Azoles/antagonistas & inhibidores , Azoles/sangre , Derivados del Benceno/antagonistas & inhibidores , Derivados del Benceno/sangre , Cisteína/farmacología , Disulfuros/antagonistas & inhibidores , Disulfuros/sangre , Ditiotreitol/farmacología , Interacciones Farmacológicas , Eritrocitos/enzimología , Glutatión Transferasa/farmacología , Humanos , Isoindoles , Compuestos Organometálicos/antagonistas & inhibidores , Compuestos Organometálicos/sangre , Compuestos de Organoselenio/antagonistas & inhibidores , Compuestos de Organoselenio/sangre , Porfobilinógeno Sintasa/antagonistas & inhibidores , Zinc/farmacologíaRESUMEN
Ajoene (4,5,9-trithiadodeca-1,6,11-triene 9-oxide), a product initially isolated from extracts of garlic (Allium sativum), was tested for its antimalarial activity in vivo in a well-characterized murine model. A single ajoene dose of 50 mg/kg, on the day of infection, suppressed the development of parasitemia; there were no obvious acute toxic effects from the tested dose. The combination of ajoene (50 mg/kg) and chloroquine (4.5 mg/kg), given as a single dose on the day of the infection, completely prevented the subsequent development of parasitemia in treated mice.