Up and down-regulation of mRNA in the cytotoxicity and genotoxicity of Plumbagin in HepG2/C3A.

Studies that evaluated the mechanisms of action of Plumbagin (PLB) and its toxicity may contribute to future therapeutic applications of this compound. We investigate biomarker important in the mechanisms of action correlate the expression of mRNA with the cytotoxic and genotoxic effects of PLB on HepG2/C3A. In the analysis of cytotoxicity, PLB decreased cell viability and membrane integrity at concentrations ≥ 15µM. Xenobiotic-metabolizing system showed strong mRNA induction of CYP1A1, CYP1A2, and CYP3A4, suggesting extensive metabolization. PLB induced apoptosis and an increase in the mRNA expression of genes BBC3, CASP3, and CASP8. At a concentration of 15µM, there was a reduction in the expression of PARP1 mRNA and an increase in the expression of BECN1 mRNA, suggesting that PLB may also induce cell death by autophagy. PLB induced an arrest at the G2/M phase due to DNA damage, as observed in the comet assay. This damage is associated with the increased mRNA expression of genes p21, GADD45A, and H2AFX and with changes in the expression of proteins H2AX, p21, p53, Chk1, and Chk2. These results allow a better understanding of the cellular action of PLB and of its toxicity, thereby contributing to the development of PLB-based drugs, with markers of mRNA expression possibly playing a role as indicators for monitoring toxicity in human cells.

Toxicities of 4,5-Dihydroisoxazoles Against Root-Knot Nematodes and in Silico Studies of Their Modes of Action.

The present work sought to contribute to the development of new nematicides. Benzaldehydes were initially converted to nitrile oxides that underwent 1,3-dipolar cycloaddition reactions with methyl acrylate to generate 4,5-dihydroisoxazoles. In in vitro tests, methyl 3-phenyl-4,5-dihydroisoxazole-5-carboxylate (1) and methyl 3-(4-chlorophenyl)-4,5-dihydroisoxazole-5-carboxylate (4) increased the mortality of Meloidogyne exigua and Meloidogyne incognita second-stage juveniles (J2). Compounds 1 and 4 presented necessary concentrations of 398 and 501 µg mL-1, respectively, to kill 50% of M. incognita J2 (LC50 values), while the value for carbofuran (positive control) was 168 µg mL-1. In in vivo tests, compounds 1 and 4 reduced the number of M. incognita galls in tomato roots by 70 and 40%, respectively, and the number of eggs by 89 and 44%. Using an in silico approach, we showed that compounds 1 and 4 were toxic to the nematodes by binding to the allosteric binding sites of the agonist-binding domains of the nematode nicotinic acetylcholine receptors. These results opened up possibilities for further investigations aimed at developing novel commercial nematicides.

In vitro nematicidal activity of natural and semisynthetic cadinenes from Heterotheca inuloides against the plant-parasitic nematode Nacobbus aberrans (Tylenchida: Pratylenchidae).

BACKGROUND: Nacobbus aberrans (Tylenchida: Pratylenchidae) is one of the main plant-parasitic nematodes species that affects crops in Mexico, generating substantial economic losses. Traditionally, the control of the nematodes is carried out using chemical products; however, research efforts are presently focused on the search for new methods for the control of this pest. Natural products derived from plants are an alternative for the control of populations of plant-parasitic nematodes. The genus Heterotheca (Asteraceae) is characterized by containing sesquiterpenes with cadinane skeleton, and some species of this genus exert nematicidal activity. RESULTS: We determined the effects of selected Heterotheca inuloides plant metabolites and some semisynthetic derivatives on the hatching of eggs isolated from the gelatinous matrix and infective second-stage juveniles (J2) of the false root-knot nematode N. aberrans using an in vitro experimental model. Among the evaluated compounds, nematodes were more susceptible to hydroxylated and quinone compounds, whereas the remaining compounds showed moderate or no activity. The presence of the hydroxyl group is essential for nematicidal potential, with changes at the hydroxyl group modifying the nematicidal activity. CONCLUSION: Flowers of Heterotheca inuloides contain bioactive compounds that showed nematicidal activity against N. aberrans. Here we report the nematicidal activities of cadinenes isolated from the flowers of H. inuloides and their semisynthetic derivatives against the false root-knot nematode N. aberrans. © 2018 Society of Chemical Industry.

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 0.1 microg/L to 1 500 microg/L. The 96hr LC50 calculated was 859.7 microg/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 50 microg/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 10 microg/L. Ethoprophos concentration of 400 microg/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.

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.

Identification of nematicidal fatty acids and triglycerides from seeds of Jubaea chilensis by GC-EI-MS and chemical transformation methods.

Nematicidal bioassay-guided fractionation of the n-hexane extract of the seeds of Jubaea chilensis led to the identification of eight known fatty acids and a mixture of triglycerides, reported for the first time for this species. In addition, their corresponding methyl esters were identified to be artifacts generated during the extraction and isolation procedures by using GC-EI-MS and chemical transformation methods. The fatty acid composition of the triglycerides was analyzed by GC-EI-MS and chemical transformation techniques. Among the 17 compounds, only lauric acid and myristic acid exhibited significant inhibitory effects on the movement of Caenorhabditis elegans with minimum inhibitory concentrations (MIC) of 75 microg/ml.

[The efficacy of entomopathogenic bacilli against ancylostomide larvae--Nippostrongylus braziliensis Travassons, 1914]. / Effektivnost' éntomopatogennykh batsill protiv lichinok ankilostomid--Nippostronylus braziliensis Travassons, 1914.

Effects of seven bioinsecticides, containing Bacillus thuringiensis and B. sphaericus toxins, against N. braziliensis larvae were studied in vitro. Bitoxibacillin, astur-3, astur-4, gomelin, lepidocide, dendrobacillin, thuringin and sphaerix were found highly effective larvicides. Protein endotoxin was the principal component responsible for the larvicidal effect, the spores were of no importance.