RESUMEN
In the present study we have analyzed the production of reactive oxygen species by toxin T-514 of the genus Karwinskia in vitro (primary liver cell cultures and microsomes), as well as their possible role in its cytotoxicity. The role of catalase and superoxide dismutase (SOD) as defense mechanisms against oxidative stress was also studied. Freshly isolated hepatocytes or microsomes were exposed to T-514 in the presence or absence of catalase and SOD. Cytotoxicity was determined by methylthiazoltetrazolium (MTT) reduction. Oxidative stress was evaluated by the dichlorofluorescein diacetate (DCFDA) fluorescent probe and the reduction of ferricytochrome c. Exposure of hepatocytes to toxin T-514 for 2-, 4-, 6- and 24-h periods resulted in a time- and concentration-dependent increase in the suppression of mitochondrial metabolic activity. T-514 induced the production of reactive oxygen species in both hepatocytes and microsomes. Catalase and superoxide dismutase had a protective effect against the cytotoxicity of T-514 in hepatocytes and also inhibited the production of oxygen reactive species in microsomes. The results indicate that oxidative stress mediated by reactive intermediates may be a mechanism by which T-514 induces its cytotoxic effect.
Asunto(s)
Antracenos/efectos adversos , Karwinskia/química , Estrés Oxidativo , Especies Reactivas de Oxígeno , Animales , Catalasa/farmacología , Citotoxinas , Hepatocitos , Hígado/citología , Masculino , Microsomas Hepáticos , Ratas , Ratas Sprague-Dawley , Ratas Wistar , Superóxido Dismutasa/farmacologíaRESUMEN
Peroxisomicine A1 is a potential antineoplastic substance extracted from plants of the genus Karwinskia. An RP-HPLC-DAD method was developed and validated for the separation and quantification of four isomers of this compound. These isomers coelute in the preparative procedure and are present at a proportion ranging between 3 and 5% in the peroxisomicine A1 purified in the laboratory. The desirability coefficient of the method described here was enhanced 140% with respect to the previously reported method.
Asunto(s)
Antracenos/análisis , Cromatografía Líquida de Alta Presión/métodos , Reproducibilidad de los ResultadosRESUMEN
Peroxisomicine A1 (PA1) is a dimeric hydroxyanthracenone isolated from fruits of plants belonging to the genus Karwinskia. Showing selective toxicity between malignant and benign cell lines, it is currently under screening as an antineoplastic agent. Very little is known about its mechanism of action. In the present work the extent of binding of this substance with Bovine Serum Albumin (BSA) and Human Serum Albumin (HSA) at pH 7.2 and 7.4 has been evaluated using the spectrophotometric method. Absorbance of PA1 was altered by the presence of albumin and this property was used to generate binding isotherms. The investigation was carried out at four different temperatures. The data were analyzed by assuming two types of binding sites. Results indicated that PA1 binds to both albumins at physiological pH, which is reflected by the affinity constants of the order of 10(5). There are two types of binding sites in the albumin for PA1; with the electrostatic forces being discarded, the hydrophobic and hydrogen bond are more probable. Binding with HSA is stronger than with BSA.
Asunto(s)
Antracenos/metabolismo , Antineoplásicos Fitogénicos/metabolismo , Animales , Bovinos , Humanos , Concentración de Iones de Hidrógeno , Cinética , Unión Proteica , Albúmina Sérica , Albúmina Sérica Bovina , Espectrofotometría Ultravioleta , TermodinámicaRESUMEN
Peroxisomes are single-membrane-bound organelles present in almost all eukaryotic cells. Hypolipidemic agents such as clofibrate, herbicides and plasticizers induce an increase in the number and size of peroxisomes from mammalian cells. However, there is no evidence of drugs causing a decrease in the number of these organelles. In this paper, we report the effect in vivo of toxin T-514 extracted from the plant Karwinskia humboldtiana, now re-named peroxisomicine-A1, on hepatic peroxisomes from rats intoxicated with this compound. Rats were treated with a single dose of 25 mg/kg of peroxisomicine-A1 and at different times were killed by decapitation. For the peroxisomal counting, liver tissue sections from control and treated rats were processed for the localization of catalase in peroxisomes. The results of the quantitative analysis demonstrated a significant decrease in the number of liver peroxisomes from rats intoxicated with peroxisomicine-A1. This finding suggests that peroxisomicine-A1 as in yeast, causes a damage to mammalian peroxisomes. The diminution in the number of peroxisomes could be a consequence of damage to the organelle, which is further removed by an autophagic process.
Asunto(s)
Antracenos/toxicidad , Citotoxinas/toxicidad , Hígado/ultraestructura , Microcuerpos/ultraestructura , Animales , Catalasa/antagonistas & inhibidores , Inhibidores Enzimáticos/farmacología , Femenino , Hígado/efectos de los fármacos , Hígado/enzimología , Masculino , Microcuerpos/efectos de los fármacos , Microcuerpos/metabolismo , Ratas , Ratas Wistar , Factores de TiempoRESUMEN
Dimeric anthracenones have been isolated from toxic plants of the genus Karwinskia (Rhamnaceae). T 514 or peroxisomicine A1 is one of the anthracenonic compounds which produce irreversible and selective damage on the peroxisomes of yeast cells in vivo. In this paper we describe the effect of two structurally related anthracenones on cell viability and on the peroxisomes of the methylotrophic yeast Candida boidinii. As has been described for peroxisomicine A1, peroxisomicine A2 and T 544 caused a decrease in the viability of C. boidinii at all concentrations tested, and disruption of the peroxisomal membrane, T 544 showing the strongest effect. In C. boidinii cell death and peroxisomal damage seem to be independent events.
Asunto(s)
Antracenos/farmacología , Antineoplásicos Fitogénicos/farmacología , Microcuerpos/efectos de los fármacos , Neurotoxinas/farmacología , Piranos/farmacología , Candida/efectos de los fármacos , Candida/crecimiento & desarrollo , Candida/metabolismo , Microcuerpos/ultraestructura , Microscopía Electrónica , Proteínas de Plantas/farmacologíaRESUMEN
Peroxisomicine is a toxic compound isolated from plants of the genus Karwinskia (Rhamnaceae). This toxin produces irreversible and selective damage to the peroxisomes of yeast cells in vivo. Peroxisomicine also inhibits catalase activity in vitro, when using purified enzyme. This paper reports on the effect of peroxisomicine on liver catalase in tissue fragments, in situ, as well as in mice intoxicated with peroxisomicine, in vivo. The catalase activity was determined by biochemical and histochemical methods. In contrast with the reported findings in vitro, the results demonstrate that there is no inhibition of the activity of tissue catalase, and suggest that catalase in situ and in vivo is protected against the inhibitory effect of peroxisomicine by an unknown factor.
Asunto(s)
Antracenos/toxicidad , Catalasa/metabolismo , Hígado/enzimología , Neurotoxinas/toxicidad , Piranos/toxicidad , Amitrol (Herbicida)/toxicidad , Animales , Fraccionamiento Químico , Citosol/efectos de los fármacos , Citosol/enzimología , Hígado/efectos de los fármacos , Hígado/patología , Ratones , Microcuerpos/efectos de los fármacos , Microcuerpos/enzimología , Microcuerpos/patología , Orgánulos/efectos de los fármacos , Orgánulos/enzimologíaRESUMEN
Dimeric anthracenones obtained from the genus Karwinskia (Rhamnaceae) are characteristic compounds isolated from the plants of this species. Previous toxicity studies demonstrated Diast T-514 to be toxic to animals in experimental settings. Diast T-514 extracted and characterized from Karwinskia parvifolia, was studied in CD1 mice. The LD50 for this compound was determined. Animals were tested with Diast T-514 following enteral and parenteral administration. An LD50 dose by both oral and intraperitoneal administration showed selective damage to target organs.
Asunto(s)
Antracenos/toxicidad , Antineoplásicos Fitogénicos/toxicidad , Administración Oral , Animales , Antracenos/administración & dosificación , Enfermedad Hepática Inducida por Sustancias y Drogas , Dimerización , Femenino , Inyecciones Intraperitoneales , Hepatopatías/patología , Ratones , Ratones Endogámicos , Especificidad de Órganos , Polímeros/administración & dosificación , Polímeros/toxicidad , Edema Pulmonar/inducido químicamente , Edema Pulmonar/patologíaRESUMEN
The ingestion of ripe fruit of the Karwinskia humboldtiana, a shrub commonly known as tullidora or coyotillo, produces an intoxication described in the literature as a symmetric flaccid paralysis of the hind limbs, progressive and ascendent, that in severe cases may cause bulbar paralysis and death. The cause of an acute accidental intoxication of an entire family is presented here, wherein ten out of thirteen members ingested the ripe fruit of the tullidora. Three died, the father and two daughters. For the first time the toxins determination in blood by thin layer chromatography method is described. This method supports the diagnosis with other polyradiculoneuritis such as poliomyelitis and the Guillain Barre's syndrome.
Asunto(s)
Frutas/envenenamiento , Parálisis/etiología , Niño , Preescolar , Salud de la Familia , Femenino , Humanos , Masculino , Persona de Mediana Edad , Hipotonía Muscular , Parálisis/sangre , Toxinas Biológicas/sangreRESUMEN
Intoxication produced by Karwinskia humboldtiana presents a neurological picture similar to that of poliomyelitis, Guillain-Barré syndrome or other polyradiculoneuritis with which it is frequently confused. The purpose of this paper is to report the frequency of this intoxication, by means of the antecedent of ingestion of the fruit and the detection of toxins in blood using a thin layer chromatography method. One hundred fifty four samples of cases with acute flaccid paralysis from 18 states of the country were received. The antecedent of ingestion in 56 of them was corroborated and the detection was positive in 50 of these. In 98 patients there was not antecedent of ingestion and detection was negative in 95 of them. We estimated that the sensibility and specificity of detection method are 89% and 96.9% respectively.
Asunto(s)
Intoxicación por Plantas/epidemiología , Plantas Medicinales , Plantas Tóxicas , Rhamnus , Adolescente , Anciano , Niño , Preescolar , Diagnóstico Diferencial , Femenino , Humanos , Incidencia , Lactante , Masculino , México/epidemiología , Hipotonía Muscular/diagnóstico , Hipotonía Muscular/epidemiología , Hipotonía Muscular/etiología , Parálisis/diagnóstico , Parálisis/epidemiología , Parálisis/etiología , Intoxicación por Plantas/complicaciones , Intoxicación por Plantas/diagnóstico , Polirradiculoneuropatía/diagnósticoRESUMEN
The teratogenic effect of toxins 544 and 514 from K. humboldtiana upon the mouse embryo was evaluated. One half of the LD50 dose for the mouse was administered at day 8 of gestation. At the end of pregnancy, reproduction and fetal data were recorded. Dams treated with toxin 544, but not with toxin 514, showed a higher incidence of reabsorptions, malformations, as well as lower fetal length compared to the control group.