In vitro evaluation of the effect of botanical formulations used in the control of Aedes aegypti L. (Diptera: Culicidae) on liver enzymes.

Abstract: INTRODUCTION: Dengue fever is a viral disease transmitted by the Aedes aegypti Linn. (1792) (Diptera: Culicidae) mosquito, which is endemic in several regions of Brazil. Alternative methods for the control of the vector include botanical insecticides, which offer advantages such as lower environmental contamination levels and less likelihood of resistant populations. Thus, in this study, the ability of botanical insecticide formulations to inhibit the activity of the liver enzymes serum cholinesterase and malate dehydrogenase was evaluated. METHODS: Inhibition profiles were assessed using in vitro assays for cholinesterase and malate dehydrogenase activity and quantitated by ultraviolet-visible spectroscopy at 410nm to 340nm. RESULTS Insecticide products formulated from cashew nutshell liquid [A] and ricinoleic acid [B] showed cholinesterase activity levels of 6.26IU/mL and 6.61IU/mL, respectively, while the control level for cholinesterase was 5-12IU/mL. The products did not affect the level of 0.44IU/mL established for malate dehydrogenase, as the levels produced by [A] and [B] were 0.43IU/mL and 0.45IU/mL, respectively. CONCLUSIONS Our findings show that in vitro testing of the formulated products at concentrations lethal to A. aegypti did not affect the activity of cholinesterase and malate dehydrogenase, indicating the safety of these products.

Acute toxicity and cholinesterase inhibition of the nematicide ethoprophos in larvae of gar Atractosteus tropicus (Semionotiformes: Lepisosteidae)

Biomarkers are a widely applied approach in environmental studies. Analyses of cholinesterase (ChE), glutathione S-transferase (GST) and lipid peroxidation (LPO) are biomarkers that can provide information regarding early effects of pollutants at different biochemical levels on an organism. The aim of this study was to evaluate the biomarker approach on a Costa Rican native and relevant species. For this, larvae of gar (Atractosteus tropicus) were exposed to the organophosphorus nematicide, ethoprophos. Acute (96hr) exposure was conducted with pesticide concentrations ranging from 0.1μg/L to 1 500μg/L. The 96hr LC50 calculated was 859.7μg/L. After exposure, three biomarkers (ChE, GST and LPO) were analyzed in fish that survived the acute test. The lowest observed effect concentration (LOEC) regarding ChE activity inhibition was 50μg/L. This concentration produced a significant inhibition (p<0.05) of the enzyme by 20%. The highest concentration tested without showing any effect on ChE activity and therefore considered as no observed effect concentration (NOEC) was 10μg/L. Ethoprophos concentration of 400μg/L caused a ChE inhibition by 79%. In this study, no significant variations (p>0.05) in GST activity and LPO were observed in A. tropicus larvae after exposure to ethoprophos.

El proceso de reproducción inducida de Atractosteus tropicus es útil para la acuicultura y la reintroducción en zonas donde las poblaciones silvestres se han reducido considerablemente. En larvas de esta especie se evaluó la toxicidad aguda, así como la respuesta de tres biomarcadores: actividad colinesterasa (ChE), actividad de Glutation S-transferasa (GST) y peroxidación de lípidos (LPO). Asimismo, se realizaron exposiciones agudas (96hr) a etoprofos (nematicida organofosforado), en donde se utilizaron concentraciones entre 0.1μg/L y 1 500μg/L del nematicida. La concentración letal 50 (LC50) calculada fue de 859.7μg/L; la máxima concentración sin efecto en los organismos (NOEC) 10μg/L y la concentración más baja en la cual se observó algún efecto (LOEC) 50μg/L. A esa concentración, el efecto observado fue una reducción significativa (p<0.05) en la actividad de la ChE. Una concetración de etoprofos de 400μg/L causó una inhibición del 79% en la actividad ChE. La actividad GST y la LPO no mostraron una respuesta significativa (p>0.05) luego de la exposición de los organismos a etoprofos.

Effect of panax ginseng on the activity of cholinesterase in different tissues of experimentally-induced diabetes in rats

In the present study cholinesterase [ChE] activity in seven brain regions [cerebral cortex, thalamus, hypothalamus, midbrain, cerebellum, pons and medulla oblongata], heart, liver and serum of adult male albino rats were determined following diabetes induction by a single subcutaneous injection of alloxan monohydrate [120 mg/kg body weight], oral administration of Panax ginseng extract [100 mg/kg body weight] for 12 consecutive days and the coadministration of both treatments. The enzyme activity was estimated after 2, 4, 8 and 12 days of alloxan and or Panax ginseng administration. Concomitant variation in blood glucose level and body weight of treated rats were also recorded. The results showed that injection of alloxan provoked a highly significant rise in blood glucose level coupled with failure of the treated animals to gain weight. Moreover, diabetes induction resulted in a general increase in ChE activity in most of the brain region studied. The increase was most prominent in the cerebral cortex while the cerebellum and pons were the less affected regions. This effect may be attributed to differences in the regulation of acetylcholine metabolism in these regions. In heart of diabetic rats, ChE activity exhibited a significant decrease after 12 days, however in the liver a significant increase was noticed after 4 days. Serum ChE was highly significantly elevated after 4 and 12 days. Administration of ginseng alone or following alloxan injection was associated with an elevation in ChE activity in the cerebral cortex and thalamus. Meanwhile, a reduction in the enzyme activity appeared in the midbrain, cerebellum, and pons of ginseng treated rats and to a lesser extent in the cerebellum and pons of rats treated with both alloxan and ginseng. In the heart tissue, administration of ginseng was characterized by an elevation in ChE activity, while combined treatment with alloxan and ginseng extract induced nonsignificant changes. Serum and liver ChE was markedly reduced in the ginseng treated rats and tended to be normalized in rats coadministered alloxan and ginseng thus showing an ameliorative effect of ginseng. It can be suggested that ginseng may possess a significant anti-hyperglycemic effect and may prove to be beneficial in improving the management of diabetes. Besides, it may have selective positive effect on the cholinergic system

Sintomatología persistente en trabajadores industrialmente expuestos a plaguicidas organofosforados / Persistent symptomatology in workers industrially exposed to organophosphate pesticides

Objetivo. Describir los patrones de ocurrencia de sintomatología persistente en trabajadores industrialmente expuestos a plaguicidas organofosforados. Material y métodos. Se realizó un estudio descriptivo, transversal y observacional. Se aplicó un cuestionario a las autoridades de la empresa y otro a 89 trabajadores a quienes se les detrminó el nivel de colinesterasa sanguínea con los métodos Magnotti y Lovibond. Para la descripción de la información se elaboraron tasas, medidas de tendencia central y de disperción. Para evaluar la diferencia entre grupos se utilizó la prueba X² y se calculó razón de momios. Resultados. La prevalencia de sintomatología persistente fue de 6.3 por cada 10 trabajadores; 50 por ciento tuvo seis síntomas o más. No se encontraron diferencia estadísticamante significativas en el riesgo de padecer sintomatología persistente de acuerdo con la edad, antigüedad, área de trabaja y puesto. No obstante, las proporciones más altas de síntomas se encontraron en los trabajadores de 31 a 40 años de edad, con 6 a 13 años de antigüedad en la fábrica, en el área de mantenimiento y en los puestos de obrero general y supervisor. En los 13 trabajadores que tuvieron antecedentes de intoxicación previa, la prevalencia de sintomatología persistente fue de 6.9 contra 6.1 de los que nunca se habían intoxicado. El riesgo de intoxicación agua previa entre quienes tenían más de 14 años de antigüedad en la empresa fue cuatro veces mayor que el de aquellos con menos de 14 años (p<0.05). El promedio del nivel de colinesterasa sanguínea fue normal (4.4 u/ml). Conclusiones. Los resultados muestran una relación entre la exposición a plaguicidas organofosforados y la presencia de síntomas persistentes. Luego entonces es necesario llevar a cabo investigaciones para determinar la prevalencia de esta sintomatología en distintas poblaciones expuestas y no expuestas

comparative study of inhibition of brain and plasma cholinesterase and hepatic and plasma aliesterases in young and adult rats following exposures to three organophosphorothionate insecticides

Young rats are more sensitive than adults to a variety of Organophosphorothionate insecticides [OPS], compounds which act in vivo by inhibition of Cholinesterase and aliesterases. Little is known, however, regarding age-related differences in biochemical responses to these toxicants. The time course of Cholinesterase and aliesterases inhibit and recovery in different tissues were compared in young [14 days of age] and adult [90-100 days of -age] rats after treatment with high sublethal intraperitoneal dosages of parathion, methyl parathion or chlorpyrifos. Young rats were more sensitive than adult in all cases [high sublethal doses for parathion, methyl parathion and chlorpyrifos; young = 0.5, 5 and 10 mg/kg, i.p.; adult = 4, 12 and 60 mg/kg, i.p... respectively]. In general, the maximal inhibition of brain regions and plasma Cholinesterase activity was not immediate with parathion and chlorpyrifos, in young and adult rats, reflecting the time required for bioactivation of the phosphorothionates as well as the effectiveness of the aliesterases to inactive much of the hepatically generated oxons. In contrast, brain regions and plasma Cholinesterase activities were rapidly inhibited following administration of methyl parathion in both age groups reflecting the low sensitivity of the aliesterases to methyl paraoxon. In general, maximal plasma and brain regions Cholinesterase inhibition was similar [greater than 80 percent] in both age groups but Cholinesterase activity recovered faster in young rats. Aliesterases were inhibited to a greater extent than acetyl cholinesterase at each sampling time with parathion and chlorpyrifos in young and adult rats where the reverse was true with methyl parathion .The very prolonged inhibition of esterase activities following chlorpyrifos treatment probably results from its substantially greater lipophilicity compared to the other compouritls, which would allow it to be stored and released for gradual bioactivation The data reported indicate that young rats are more sensitive to sublethal dosages from these compounds and that high sublethal doses exposure produce extensive plasma and different brain regions cholinesterase and plasma and liver aliesterases inhibition in both age groups. Significant inhibitor- related and age-related differences in the duration of cholinesterase and aliesterases inhibition can ensue, however, following such Organophosphorothionate insecticides exposures. Additionally, under defined experimental conditions plasma cholinesterase inhibition may be a useful quantitative index for the degree of brain cholinesterase inhibition following organophosphorous exposures

Studies on tissue cholinesterase in experimental trichinosis in albino rat2-Effect of treatment with mintezol and 5-fluorouracil-endoxan

The changes in cholinesterase [ChE] activity were studied in different tissues of normal and 60 days T. spiralis infected albino rats following treatment with mintezol [5 mg/rat/day for 5 days] and 5- fluorouracil-endoxan [500 mg/rat/day-100 mg/rat/day for 5 days]. In normal rats, administration of either mintezol or 5-fluorouracil- endoxan provoked a general decrease in the ChE activity of the various rat tissues. Treatment of 60 days T. spiralis infected rats with mintezol increased markedly the ChE activity of the brain, liver, gastrocnemius muscle and serum. Meanwhile, treatment with 5- fluorouracil-endoxan decreased the enzyme activity in the selected rat tissues. It can be concluded that treatment with mintezol and 5- fluorouracil-endoxan in trichinellosis represents a certain danger. This danger results from general inhibition of ChE activity which may cause accumulation of acetylcholine