Antimutagenic effect of neem leaves extract in freshwater fish, Channa punctatus evaluated by cytogenetic tests

Azadirachtin in the aquatic environment: Fate and effects on non-target fauna

The present-day inclination towards increased application of pesticides derived from natural sources is not without its own hazards. Such pesticides are indubitably less harmful compared to the newer classes of low persistence organophosphates; however, these pesticides may be hydrolyzed to yield secondary products which often exhibit significantly different toxicity. Additionally, studies show that the inert materials used in formulation can exhibit significant toxicity on their own. The toxicity of secondary products and inert materials are largely unknown since these molecules are largely uncharacterized. Azadirachtin is such a candidate pesticide. It is derived from the neem tree Azadirachta indica, and it ticks all the above boxes. In its pure form, formulation and crude extracts, it can generate ecotoxicological effects ranging from behavioural anomalies and physiological imbalances to growth suppression. Authors at various times have pointed out the ability of azadirachtin (or that of its metabolites’/break-down products’) to cause specific, documentable effects on growth and reproduction of non-target fauna. Since extensive reports are available on the toxicology of azadirachtin to terrestrial beneficial fauna like bees and earthworms, this review aims to present a coherent picture of the effects of azadirachtin on non-target aquatic organisms through a documentation of relevant reports published during the last three decades. It is hoped that this compilation will help sensitize public opinion about the erroneous supposition that pesticides derived from natural sources are not innately harmful to non-target biota.

Auxinic herbicides induce oxidative stress on Cnesterodon decemmaculatus (Pisces: Poeciliidae)

Pesticides might increase the production of reactive oxygen species (ROS). Dicamba (DIC) and 2,4-dichlorophenoxyacetic acid (2,4-D) are auxinic herbicides commonly applied in agroecosystems to control unwanted weeds. We analysed the oxidative damage exerted on the fish Cnesterodon decemmaculatus by an acute exposure to DIC- and 2,4-D-based herbicides formulations Banvel® and DMA®, respectively. The Endo III- and Fpg-modified alkaline comet assay was employed for detecting DNA damage caused by oxidative stress, whereas enzymatic and non-enzymatic biomarkers such as the activities of catalase (CAT), glutathione-S-transferase (GST), acetylcholinesterase (AChE), and glutathione content (GSH) were used to assess antioxidant response to these two herbicides. At the DNA level, results demonstrate that both auxinic herbicides induce oxidative damage at purines level. An increase on CAT and GST activities were detected in 48 h- and 96 h-treated specimens with both auxinics. GSH content decreased in fish exposed to DIC during 48 h and to 2,4-D after 96 h of exposure. Additionally, a diminished AChE activity in specimens treated with DIC and 2,4-D was observed only after 96 h. Total protein content decreased in fish exposed to both auxinics during 96 h. These results represent the first evaluation of oxidative damage related to DIC and 2,4-D exposure on a fish species as the Neotropical freshwater teleost C. decemmaculatus.

Genotoxicity by long-term exposure to the auxinic herbicides 2,4-dichlorophenoxyacetic acid and dicamba on Cnesterodon decemmaculatus (Pisces: Poeciliidae)

Long-term genotoxic effects of two auxinic herbicide formulations, namely, the 58.4% 2,4-dichlorophenoxyacetic acid (2,4-D)-based DMA^® and the 57.7% dicamba (DIC)-based Banvel^® were evaluated on Cnesterodon decemmaculatus. Primary DNA lesions were analyzed by the single-cell gel electrophoresis methodology. Two sublethal concentrations were tested for each herbicide corresponding to 2.5% and 5% of the LC50_96h values. Accordingly, fish were exposed to 25.2 and 50.4 mg/L or 41 and 82 mg/L for 2,4-D and DIC, respectively. Fish were continuously exposed for 28 days with replacement of test solutions every 3 days. Genotoxicity was evaluated in ten individuals from each experimental point at the beginning of the exposure period (0 day) and at 7, 14, 21 and 28 days thereafter. Results demonstrated for first time that 2,4-D-based formulation DMA^® induced primary DNA strand breaks after 7-28 days exposure on C. decemmaculatus regardless its concentration. On the other hand, DIC-based formulation Banvel^® exerted its genotoxic effect after exposure during 7-14 days and 7 days of 2.5 and 5% LC50_96h, respectively. The present study represents the first evidence of primary DNA lesions induced by two widely employed auxinic herbicides on C. decemmaculatus, namely 2,4-D and DIC, following long-term exposure.

Simultaneous determination of five azadirachtins in the seed and leaf extracts of Azadirachta indica by automated online solid-phase extraction coupled with LC-Q-TOF-MS

Neem (Azadirachta indica) extract is well-known as a natural pesticide for the control of agricultural pests. Azadirachtin A and its structural analogues are considered as active compounds. However, the amounts of azadirachtins varies in neem extracts, providing a variety of insecticidal activities. In this study, a novel method of automated online solid-phase extraction coupled with liquid chromatography/quadrupole-time-of-flight mass spectrometry (SPE-LC–Q-TOF–MS) was developed and validated for simultaneous quantification of five azadirachtins (azadirachtins A, B, D, H and I) in seed and leaf extracts of A. indica. Different experimental parameters (such as SPE cartridge, injection volume and washing step) were optimized. The optimized SPE-LC–Q-TOF–MS method showed good recovery (82.0–102.8%), linearity (r² ≥ 0.9991) and precision (0.83–4.83%). The limit of detections (LODs) for the five analytes ranged from 0.34 to 0.76 ng mL⁻¹. The validated method was successfully applied for determination of the analytes in the neem leaves and seeds from different locations and a neem formulation. The online SPE-LC–Q-TOF–MS method was found to be a simple, precise and accurate and can be used as a powerful tool for quality control of neem extracts or its formulations.

Podophyllum hexandrum ameliorates endosulfan-induced genotoxicity and mutagenicity in freshwater cyprinid fish crucian carp

CONTEXT

Medicinal plants continue to act as a repository for novel drug leads with novel mechanisms of action. Podophyllum hexandrum Royale (Berberideceae) treats diverse conditions in folk medicine.

OBJECTIVE

The antimutagenic potential of P. hexandrum was evaluated against endosulfan-induced clastogenicity in a piscine model by cytogenetic endpoints.

MATERIALS AND METHODS

Podophyllum hexandrum rhizomes were subjected to successive solvent extraction. Fish were exposed to hexane, chloroform, ethyl acetate, methanol and aqueous extracts (15 mg/L each) of plant and endosulfan (0.05 mg/L) alone followed by their combination for antimutagenicity estimates. Chromosomal aberrations (CA) were made from kidney cells and micronuclei (MN) slides from peripheral blood erythrocytes at 48, 72 and 96 h. Antioxidant activity was analyzed by the DPPH assay. Phytochemical analyses were carried out using chromatographic and spectroscopic techniques.

RESULTS

Endosulfan induced significant (p < .05) MN, authenticated by scanning electron microscopy, and CA in a time-dependent manner. However, methanol and ethyl acetate extracts revealed ameliorating effects. The column eluted methanolic fraction-2 (ME-F2) showed highest reduction profile of 83 and 84% in CA and MN, followed in its extent (73 and 72%) by ethyl acetate fraction-4 (EE-F4). ME-F2 and EE-F4 showed three and six major peaks when analyzed by GC-MS. To explore possible mechanism of action, ME-F2 showed potent antioxidant potential and strong correlation (R²=.900) with antimutagenic activity, whereas EE-F4 seemed to act through a different mechanism.

DISCUSSION AND CONCLUSION

This study confirms the antimutagenic potential of the subject plant with the identification of some novel compounds, justifying their use in folk medicine, and their corresponding benefit to mankind.

Screening of Pesticides with the Potential of Inducing DSB and Successive Recombinational Repair

A study was realized to ascertain whether eight selected pesticides would induce double strand breaks (DSB) in lymphocyte cultures and whether this damage would induce greater levels of proteins Rad51 participating in homologous recombination or of p-Ku80 participating in nonhomologous end joining. Only five pesticides were found to induce DSB of which only glyphosate and paraoxon induced a significant increase of p-Ku80 protein, indicating that nonhomologous end joining recombinational DNA repair system would be activated. The type of gamma-H2AX foci observed was comparable to that induced by etoposide at similar concentrations. These results are of importance since these effects occurred at low concentrations in the micromolar range, in acute treatments to the cells. Effects over longer exposures in actual environmental settings are expected to produce cumulative damage if repeated events of recombination take place over time.

Amelioration of the cyclophosphamide induced genotoxic damage in mice by the ethanolic extract of Equisetum arvense

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Plants like E. arvense posess not only nutritional value but therapeutic value as well.

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CPA is an important chemotherapeutic agent but is associated with various mutagenic and other toxic side effects.

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Ethanolic extract of the plant has immense protective effect against the genotoxic damage induced by the cyclophosphamide.

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GC–MS analysis of the extract shows various important phyto components which may be associated with its antimutagenic property.

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Plant can be used in cancer as a chemopreventive agent or even as a coadjuvant to chemotherapy to reduce the side effects associated with it.

In the present study, we evaluated the potential of the plant E. arvense against the cytotoxic and mutagenic effects induced by cyclophosphamide (chemotherapeutic agent) in the bone marrow cells of mice using the Chromosome assay (CA) and Mitotic index (MI) in vivo as the biomarkers. The study was performed following 3 protocols: pre-treatment, simultaneous treatment and post-treatment with the ethanolic extract of the plant. The results demonstrated that the plant extract was not cytotoxic and mutagenic and has a protective effect against the mutagenicity induced by cyclophosphamide in pre, simultaneous and post treatments and against its cytotoxicity as well. Because of its ability to prevent chromosomal damage, E. arvense is likely to open an interesting field concerning its possible use in clinical applications, most importantly in cancer as a chemopreventive agent or even as a coadjuvant to chemotherapy to reduce the side effects associated with it.

Toxic and genotoxic effects of the 2,4-dichlorophenoxyacetic acid (2,4-D)-based herbicide on the Neotropical fish Cnesterodon decemmaculatus

Acute toxicity and genotoxicity of the 54.8% 2,4-D-based commercial herbicide DMA® were assayed on Cnesterodon decemmaculatus (Pisces, Poeciliidae). Whereas lethal effect was used as the end point for mortality, frequency of micronuclei (MNs), other nuclear abnormalities and primary DNA damage evaluated by the single cell gel electrophoresis (SCGE) assay were employed as end points for genotoxicity. Mortality studies demonstrated an LC50 96 h value of 1008 mg/L (range, 929-1070) of 2,4-D. Behavioral changes, e.g., gathering at the bottom of the aquarium, slowness in motion, slow reaction and abnormal swimming were observed. Exposure to 2,4-D within the 252-756 mg/L range increased the frequency of MNs in fish exposed for both 48 and 96 h. Whereas blebbed nuclei were induced in treatments lasting for 48 and 96 h, notched nuclei were only induced in fish exposed for 96 h. Regardless of both concentration and exposure time, 2,4-D did not induce lobed nuclei and binucleated erythrocytes. In addition, we found that exposure to 2,4-D within the 252-756 mg/L range increased the genetic damage index in treatments lasting for either 48 and 96 h. The results represent the first experimental evidence of the lethal and several sublethal effects, including behavioral alterations and two genotoxic properties namely the induction of MNs and primary DNA strand breaks, exerted by 2,4-D on an endemic organism as C. decemmaculatus.

Assessment of endosulfan induced genotoxicity and mutagenicity manifested by oxidative stress pathways in freshwater cyprinid fish crucian carp (Carassius carassius L.)

Over the past few decades, endosulfan, one of the polychlorinated pesticides still in use, has received considerable attention of a number of international regulations and restriction action plans worldwide. This study aimed to evaluate the cytogenetic effects of endosulfan using robust genotoxicity assays, along with the oxidative stress pathways in order to understand biochemical mechanism, in Carassius carassius L. The LC50-96 h (95% confidence limits) value of endosulfan was 0.070 (0.046-0.093) ppm; and on its basis three test concentrations (sub-lethal I: 0.052, II: 0.035 and III: 0.017 ppm) were selected for 35 d in vivo exposure. The mean concentration of endosulfan in aquaria was always constant, when analyzed by dispersive liquid-liquid micro extraction (DLLME) followed by GC-MS. Autopsy was done on days 1, 2, 3, 4, 7, 14, 21, 28 and 35 of endosulfan exposure; the micronucleus formation (MN), authenticated by scanning electron microscopy, and chromosomal aberrations (CA), were induced significantly (p<0.05) in all the treated groups, including positive control cyclophosphamide (4 ppm), when compared to negative control. Similarly lipid peroxidation (LPO) was induced significantly with the maximal at higher concentration (SL-I) on 4th day (722.45%; p<0.01). Antioxidant biomarkers like glutathione reduced, superoxide dismutase and catalase also fluctuated significantly (p<0.01) in all treatment groups. Collective findings demonstrated that genotoxic effects were invariably accompanied and correlated with increased oxidative stress and disturbance of antioxidant enzymes; and the MN and CA assays are useful tools in determining potential genotoxicity of aquatic xenobiotics and might be appropriate as a part of monitoring program.

Genotoxic effects of glyphosate or paraquat on earthworm coelomocytes

The potential genotoxicity (nuclear anomalies, damage to single-strand DNA) and pinocytic adherence activity of two (glyphosate-based and paraquat-based) commercial herbicides to earthworm coelomocytes (immune cells in the coelomic cavity) were assessed. Coelomocytes were extracted from earthworms (Pheretima peguana) exposed to concentrations Collapse

Key Words

• coelomocytes
• comet assay
• earthworm
• glyphosate
• micronucleus assay
• paraquat
• pinocytic adherence activity

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MESH Headings

• Animals
• Cell Adhesion
• Comet Assay
• DNA Damage
• Glycine/analogs & derivatives
• Glycine/toxicity
• Herbicides/toxicity
• Micronucleus Tests
• Mutagens/toxicity
• Oligochaeta/cytology
• Oligochaeta/drug effects
• Oligochaeta/genetics
• Paraquat/pharmacology
• Paraquat/toxicity
• Pinocytosis
• Toxicity Tests, Acute
• Toxicity Tests, Subacute
• Glyphosate

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Affiliation(s)

Ptumporn Muangphra Biology Department, Faculty of Science, Silpakorn University, Nakhon Pathom 73000, Thailand
Wimon Kwankua
Ravi Gooneratne

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Genotoxic potential of two herbicides and their active ingredients assessed with comet assay on a fish cell line, epithelioma papillosum cyprini (EPC)

The aim of this study was to optimize the epithelioma papillosum cyprini (EPC) cell line handling procedure for the comet assay to investigate the genotoxic potential of widely used pesticides. The effects of various media and handling of the EPC cell line were examined. Results indicated that avoiding trypsin to detach cells led to lower level of DNA damage in the negative control. Further, two commonly used herbicides (Dezormon and Optica trio) and their four active ingredients (4-chloro-o-tolyloxyacetic acid, 2,4-dichlorophenoxyacetic acid, 2-(4-chloro-2-methylphenoxy)propionic acid, 2-(2,4-dichlorophenoxy)propionic acid) individually and in a ternary mixture were examined with the comet assay. Data showed that among the active ingredients only 2,4-D and MCPA induced DNA damage, while both herbicides were genotoxic at high concentrations.

Homeostatic imbalance and colon cancer: the dynamic epigenetic interplay of inflammation, environmental toxins, and chemopreventive plant compounds

The advent of modern medicine has allowed for significant advances within the fields of emergency care, surgery, and infectious disease control. Health threats that were historically responsible for immeasurable tolls on human life are now all but eradicated within certain populations, specifically those that enjoy higher degrees of socio-economic status and access to healthcare. However, modernization and its resulting lifestyle trends have ushered in a new era of chronic illness; one in which an unprecedented number of people are estimated to contract cancer and other inflammatory diseases. Here, we explore the idea that homeostasis has been redefined within just a few generations, and that diseases such as colorectal cancer are the result of fluctuating physiological and molecular imbalances. Phytochemical-deprived, pro-inflammatory diets combined with low-dose exposures to environmental toxins, including bisphenol-A (BPA) and other endocrine disruptors, are now linked to increasing incidences of cancer in westernized societies and developing countries. There is recent evidence that disease determinants are likely set in utero and further perpetuated into adulthood dependent upon the innate and environmentally-acquired phenotype unique to each individual. In order to address a disease as multi-factorial, case-specific, and remarkably adaptive as cancer, research must focus on its root causes in order to elucidate the molecular mechanisms by which they can be prevented or counteracted via plant-derived compounds such as epigallocatechin-3-gallate (EGCG) and resveratrol. The significant role of epigenetics in the regulation of these complex processes is emphasized here to form a comprehensive view of the dynamic interactions that influence modern-day carcinogenesis, and how sensibly restoring homeostatic balance may be the key to the cancer riddle.