Magnetite interaction with arsenic during sorptive removal from groundwater: a mechanistic study.

A magnetic mixed iron oxide, magnetite (Fe3O4), was synthesized in the laboratory and characterized before its use as sorbent for arsenic removal. The characterization techniques used were X-ray diffraction (XRD), specific surface area, zeta potential and particle size measurements. The sorbent was applied for arsenic removal, without any pre or post treatment, from groundwater. The efficiency of sorption can only be improved by understanding the sorbent-sorbate interaction. For onsite monitoring of the sorbent-sorbate interaction, an electrochemical investigation using cyclic voltammetry (CV) measurement was developed. The study confirmed that the sorption of As(III) on Fe3O4 is dynamic (reversible) whereas that of As(V) is static (irreversible) in nature. Detailed investigation after the sorption was carried out utilizing X-ray photoelectron spectroscopy (XPS) measurement. The complexation of As(III)-Fe3O4 and As(V)-Fe3O4 without any redox transformation was evident from the XPS data. By careful examination of the results, a mechanism of arsenic removal by Fe3O4 was proposed.

An insight into the sequestration of tetra and hexavalent actinides by tri ethoxysilyl-amino-propyl-3-oxa-glutaramic acid (SAPOGA) functionalized titania.

Silyl-amino-propyl-3-oxa-glutaramic acid (SAPOGA) functionalized titania has been synthesized for highly efficient solid phase sequestration of thorium and uranyl ions from an aqueous acidic waste stream. The XRD pattern suggested that the grafting was performed on the anatase phase, leading to a rougher surface resulting in better interaction with actinides. The successful grafting of SAPOGA bridging was confirmed using spectroscopic methods. The Langmuir isotherm and the intraparticle diffusion-based kinetics model were found to be operative with sorption capacities of 231 mg g-1 and 458 mg g-1 and rate constants of 51 mg g-1 min-1 and 48 mg g-1 min-1 for U and Th, respectively. The entropy driven sequestration process was thermodynamically favourable (ΔGU = -6.0 kJ mol-1 and ΔGTh = -9.1 kJ mol-1) and endothermic in nature. The experimentally corroborated complexation pattern was assisted by density functional theory (DFT) calculations, which gave further insight into the metal-ligand interaction.

Mechanistic and recent updates in nano-bioremediation for developing green technology to alleviate agricultural contaminants.

The rise in environmental pollutant levels in recent years is mostly attributable to anthropogenic activities such as industrial, agricultural and other activities. Additionally, these activities may produce excessive levels of dangerous toxicants such as heavy metals, organic pollutants including pesticide and herbicide chemicals, and sewage discharges from residential and commercial sources. With a focus on environmentally friendly, sustainable technology, new technologies such as combined process of nanotechnology and bioremediation are urgently needed to accelerate the cost-effective remediation process to alleviate toxic contaminants than the conventional remediation methods. Numerous studies have shown that nanoparticles possess special qualities including improved catalysis and adsorption as well as increased reactivity. Currently, microorganisms and their extracts are being used as promising, environmentally friendly catalysts for engineered nanomaterial. In the long term, this combination of both technologies called nano-bioremediation may significantly alter the field of environmental remediation since it is more intelligent, safe, environmentally friendly, economical and green. This review provides an overview of soil and water remediation techniques as well as the use of nano-bioremediation, which is made from various living organisms. Additionally, current developments related to the mechanism, model and kinetic studies for remediation of agricultural contaminants have been discussed.

Evidences on As(III) and As(V) interaction with iron(III) oxides: Hematite and goethite.

Arsenic, which is ubiquitous in nature, was found associated with iron oxides in soils and sediments. Our interest was to utilize the same mechanism for the sorptive removal of arsenic from groundwater. The iron(III) oxides: hematite, goethite, were synthesized, characterized and sorption studies of arsenic [As(III) and As(V)] were carried out in batch mode. For studying the evidence of the interaction between arsenic and iron oxide during the process of sorption, a new electrochemical method was developed. Differential pulse voltammetry (DPV) study indicated that the sorbed arsenic species is redox active on the surface of the sorbent. X-ray photoelectron spectroscopy (XPS) measurement was performed for confirmation of the changes occurring to the oxidation states of iron as well as arsenic after the sorption. XPS studies confirmed that the behavior of arsenic species on hematite/goethite was similar and occurs via a partial redox reaction. During sorption of As(III), a partial oxidation occurs resulting in As(V) species, simultaneously the Fe(III) present in the iron oxide gets reduced to Fe(II). However, during the sorption of As(V), there occurs a Fe(II) oxidation followed by As(V) reduction. Based on the results, a mechanistic scheme for sorption of arsenic on iron(III) oxides as sorbents was proposed.

Identification of common virulence factors present in enterotoxigenic Escherichia coli isolated from diarrhoeal patients in Kolkata, India.

AIMS: Development of an effective vaccine against enterotoxigenic Escherichia coli (ETEC) is largely dependent on the conscientious understanding of different virulence associated factors from diverse geographical areas. So, the objective of this study is to elucidate the distribution of enterotoxins, CF and NCVF in clinical ETEC strains isolated between 2008 and 2014 from two hospitals in Kolkata, India. METHODS AND RESULTS: Multiplex PCR method was used for detection of two enterotoxin genes, 11 common CFs and five common NCVFs. Among the 350 tested ETEC strains, 61% strains possessed est+elt genes, 25% est and 14% elt. Among 56% CF positive ETEC strains, CS21 was the prevalent one (37%) followed by CS6 (36%). NCVF genes were present in 59% of the ETEC strains; eatA was the most prevalent (65%) followed by etpA (51%). There were 29% strains negative for any CFs or NCVFs. CONCLUSIONS: We conclude that a pattern exists between CS6, eatA and toxins. We observed est with or without elt, CS6 with or without CS5 and with or without eatA were present in 24% of clinical ETEC strains (59/250) analysed. CS21 has emerged as another predominant CF but it had diverse CFs and NCVFs. SIGNIFICANCE AND IMPACT OF THE STUDY: Prevalence of ETEC virulence factors would help in tracking ETEC globally and suggests the need of a multivalent ETEC vaccine.

Solvated electron-induced synthesis of cyclodextrin-coated Pd nanoparticles: mechanistic, catalytic, and anticancer studies.

Herein, using in situ generated solvated electrons in the reaction media, a highly time-efficient, one-pot green approach has been employed to synthesize palladium (Pd) nanoparticles (NPs) coated with a molecular assembly of α-cyclodextrin (α-CD). The appearance of a shoulder peak at 280 nm in the UV-Vis absorption spectra indicated the formation of Pd NPs, which was further confirmed from their cubic phase XRD pattern. The nanomorphology varied considerably as a function of the dose rate, wherein sphere-shaped NPs (average size ∼ 7.6 nm) were formed in the case of high dose rate electron-beam assisted synthesis, while nanoflakes self-assembled to form nanoflower-shaped morphologies in a γ-ray mediated approach involving a low dose rate. The formation kinetics of NPs was investigated by pulse radiolysis which revealed the formation of Pd-based transients by the solvated electron-induced reaction. Importantly, no interference of α-CD was observed in the kinetics of the transient species, rather it played the role of a morphology directing agent in addition to a biocompatible stabilizing agent. The catalytic studies revealed that the morphology of the NPs has a significant effect on the reduction efficiency of 4-nitrophenol to 4-aminophenol. Another important highlight of this work is the demonstration of the morphology-dependent anticancer efficacy of Pd NPs against lung and brain cancer cells. Notably, flower-shaped Pd NPs exhibited significantly higher cancer cell killing as compared to spherical NPs, while being less toxic towards normal lung fibroblasts. Nonetheless, these findings show the promising potential of Pd NPs in anticancer treatment.

3,3'-Diselenodipropionic acid (DSePA) forms 1:1 complex with Hg (II) and prevents oxidative stress in cultured cells and mice model.

Mercury is one of the most toxic heavy metal for mammals particularly in inorganic form. In present study, 3,3'-diselenodipropionic acid (DSePA), a well-known pharmacological diselenide was evaluated for its interaction with HgCl2 and ability to prevent HgCl2-induced toxicity in experimental cellular and mice models. UV-visible, stopped flow, Fourier-transform infrared spectroscopy and 1H nuclear magnetic resonance spectroscopy studies confirmed that DSePA sequestered Hg (II) ions with stoichiometry of 1:1 and binding constant of ~104 M-1. X-ray photoelectron spectroscopy and X-ray powder diffraction analysis suggested that diselenide group of DSePA was involved in the complexation with Hg (II) ions. Further, Hg-DSePA complex degraded within 10 days to form excretable HgSe. The binding constant of DSePA and Hg (II) was comparable with that of dihydrolipoic acid, a standard disulfide compound used in heavy metal detoxification. Corroborating these observations, pre-treatment of DSePA (10 µM) significantly prevented the HgCl2 (50 µM)-induced glutathione oxidation (GSH/GSSG), decrease of thioredoxin reductase (TrxR) and glutathione peroxidase (GPx) activities and cell death in Chinese Hamster Ovary (CHO) cells. Similarly, intraperitoneal administration of DSePA at a dosage of 2 mg/kg for 5 consecutive days prior to exposure of HgCl2 (1 mg/kg) significantly suppressed oxidative stress in renal and hepatic tissues of C57BL/6 mice. In conclusion, the protective effect of DSePA against Hg induced oxidative stress is attributed to its ability to rescue the activities of GPx, TrxR and GSH by sequestering Hg (II) ions. DSePA being a relatively safer selenium-compound for in vivo administration can be explored for mercury detoxification.

Antiviral Activity of Zinc Oxide Nanoparticles and Tetrapods Against the Hepatitis E and Hepatitis C Viruses.

Hepatitis E virus (HEV) causes an acute, self-limiting hepatitis. The disease takes a severe form in pregnant women, leading to around 30% mortality. Zinc is an essential micronutrient that plays a crucial role in multiple cellular processes. Our earlier findings demonstrated the antiviral activity of zinc salts against HEV infection. Zinc oxide (ZnO) and its nanostructures have attracted marked interest due to their unique characteristics. Here we synthesized ZnO nanoparticles [ZnO(NP)] and tetrapod-shaped ZnO nanoparticles [ZnO(TP)] and evaluated their antiviral activity. Both ZnO(NP) and ZnO(TP) displayed potent antiviral activity against hepatitis E and hepatitis C viruses, with the latter being more effective. Measurement of cell viability and intracellular reactive oxygen species levels revealed that both ZnO(NP) and ZnO(TP) are noncytotoxic to the cells even at significantly higher doses, compared to a conventional zinc salt (ZnSO4). Our study paves the way for evaluation of the potential therapeutic benefit of ZnO(TP) against HEV and HCV.

Bovine beta-lactoglobulin modified by 3-hydroxyphthalic anhydride blocks the CD4 cell receptor for HIV.

Sexual transmission is the most frequent (86%) route of adult HIV-1 transmission worldwide. In the absence of a prophylactic anti-HIV vaccine, other methods of preventing infection should be implemented. Virucidal spermicides have been considered for this purpose, but their application is contraindicated by adverse effects. Anti-HIV drugs or virus-neutralizing monoclonal antibodies are expensive, suggesting that their wide use in topical chemoprophylaxis is unlikely. This emphasizes the importance of developing other methods for preventing HIV transmission. The target cells for sexual and mucosal HIV transmission include T lymphocytes, monocytes/macrophages and dendritic cells. Therefore, compounds blocking HIV-CD4 binding are expected to inhibit virus transmission. In exploring the possibility that chemical modification of food proteins might lead to compounds with anti-HIV-1 activity, we found that bovine beta-lactoglobulin (beta-LG) modified by 3-hydroxyphthalic anhydride (3HP-beta-LG) (1) blocked at nanomolar concentrations the binding to CD4 of human (HIV) and simian (SIV) immunodeficiency virus surface glycoproteins and monoclonal antibodies specific for the HIV binding site on CD4 and (2) inhibited infection by HIV-1, including primary virus isolates, by HIV-2 and by SIV. The inexpensive and widely available source (whey) for production of 3HP-beta-LG suggests its potential application (nonparenteral) for diminishing the frequency of HIV transmission.

Temperature dependent current-voltage characteristics of iron-phthalocyanine thin films.

The current-voltage (I-V) characteristics of the crystalline alpha-phase iron phthalocyanine (FePc) thin films grown by molecular beam epitaxy have been investigated by using a planar geometry in which the metal electrodes are separated by 15 microm. By carrying out the room temperature I-V measurements on vacuum annealed (200 degrees C for 30 min under 10(-6) torr) FePc thin films under vacuum and after exposing them to the air, we demonstrate that the hysteresis in FePc films is intimately related to the filling and de-filling of surface traps created by chemisorbed oxygen. The presence of chemisorbed oxygen has been confirmed by the X-ray photoelectron spectroscopy. Room temperature I-V characteristics of air exposed films showed ohmic conduction in the lower voltage range and space-charge-limited-conductivity (SCLC) in the relatively high voltage. Temperature dependent measurements show that the hysteresis disappears at 250 K and the surface traps are distributed in energy about 0.22 eV deep.

Oxygen Reduction Reaction Activity of Microwave Mediated Solvothermal Synthesized CeO2/g-C3N4 Nanocomposite.

Electrocatalytic active species like transition metal oxides have been widely combined with carbon-based nanomaterials for enhanced Oxygen Reduction Reaction (ORR) studies because of the synergistic effect arising between different components. The aim of the present study is to synthesize CeO2/g-C3N4 system and compare the ORR activity with bare CeO2. Ceria (CeO2) embedded on g-C3N4 nanocomposite was synthesized by a single-step microwave-mediated solvothermal method. This cerium oxide-based nanocomposite displays enhanced ORR activity and electrochemical stability as compared to bare ceria.

Fabrication of plasmonic dye-sensitized solar cells using ion-implanted photoanodes.

Plasmonic dye-sensitized solar cells containing metal nanoparticles suffer from stability issues due to their miscibility with liquid iodine-based electrolytes. To resolve the stability issue, herein, an ion implantation technique was explored to implant metal nanoparticles inside TiO2, which protected these nanoparticles with a thin coverage of TiO2 melt and maintained the localized surface plasmon resonance oscillations of the metal nanoparticles to efficiently enhance their light absorption and make them corrosion resistant. Herein, Au nanoparticles were implanted into the TiO2 matrix up to the penetration depth of 22 nm, and their influence on the structural and optical properties of TiO2 was studied. Moreover, plasmonic dye-sensitized solar cells were fabricated using N719 dye-loaded Au-implanted TiO2 photoanodes, and their power conversion efficiency was found to be 44.7% higher than that of the unimplanted TiO2-based dye-sensitized solar cells due to the enhanced light absorption of the dye molecules in the vicinity of the localized surface plasmon resonance of Au as well as the efficient electron charge transport at the TiO2@Au@N719/electrolyte interface.

Dietary supplies of iodine & thiocyanate in the aetiology of endemic goitre in Imphal East district of Manipur, north east India.

BACKGROUND & OBJECTIVE: The present investigation was undertaken to study the iodine nutritional status of school children of Imphal east district in Manipur where endemic goitre persists during post-salt iodization phase along with the investigation of the factors responsible for the occurrence of goitre endemicity. METHODS: A total of 1,286 children (6-12 yr) were clinically examined for goitre from study areas of Imphal east district. A total of 160 urine samples were collected and analyzed to measure urinary iodine and thiocyanate levels. Iodine content was measured in 140 salt samples and 16 drinking water samples. RESULTS: Overall goitre prevalence was about 30 per cent (grade 1-24.7%; grade 2-5.3%) and median urinary iodine level was 17.25 microg/dl. The mean urinary thiocyanate level was 1.073 +/- 0.39 mg/dl. Iodine/thiocyanate ratio (microg/mg) was in the ranges from 15.65 to 22.34. The mean iodine content in drinking water samples was 2.92 +/- 1.75 microg/l and 97.8 per cent of edible salts had iodine level above 15 ppm at the consumption point. INTERPRETATION & CONCLUSION: Our findings showed that in spite of no biochemical iodine deficiency, iodine deficiency disorders (IDD) is a serious public health problem in Imphal east district of Manipur. The consumption pattern of certain plant foods containing thiocyanate (or its precursors) was relatively high that interfere with thyroid hormone synthesis resulting in the excretion of more iodine. Thus, the existing dietary supplies of thiocyanate in relation to iodine may be a possible aetiological factor for the persistence of endemic goitre in the study region during post salt iodization period.

An efficient protocol for in vitro direct shoot organogenesis of Sesamum indicum L. using cotyledon as explant.

Establishment of a suitable regeneration protocol is a pre-requisite to carry out transformation study in Sesamum indicum L. (sesame). In this paper, different parameters of regeneration were standardised to develop an efficient protocol for in vitro plant regeneration via direct adventitious shoot organogenesis using de-embryonated cotyledons of sesame as explants. Among the various treatments of MS medium supplemented with 6-benzylaminopurine, thidiazuron and indole-3-acetic acid, maximum regeneration frequency (25.93  ±  2.21%) was obtained in BTI 4 medium (MS supplemented with 33.33 µM BAP with 2.85 µM IAA) within 6 weeks of culture. Regeneration frequency increased further (50.37 ± 2.49%) by fortifying BTI 4 with 29.43 µM silver nitrate (AG 3 medium). Pre-culture of cotyledon explants in AB 3 medium (AG 3 supplemented with 3.78 µM abscisic acid) for 14 days followed by sub-culture in AG 3 medium further improved the regeneration frequency (68.15 ± 2.68%). The highest rate of shoot regeneration (94.82 ± 1.34%) was obtained by pre-culturing 4-day-old cotyledon in a vertical position in AB 3 medium for 14 days and sub-culturing in AG 3 medium for 4 weeks. Regenerated shoots proliferated in MS medium supplemented with 4.44 µM BAP and 1.44 µM gibberelic acid (GA3). The highest frequency (65.33 ± 3.78%) of root induction was achieved by culturing the elongated shoots in MS medium supplemented with 2.69 µM α-naphthalene acetic acid (NAA) for 6 weeks. Rooted plants were acclimatised in soilrite and transferred to soil after 6-8 weeks. The rate of acclimatisation of plants was 76%.

Tailoring of the chlorine sensing properties of substituted metal phthalocyanines non-covalently anchored on single-walled carbon nanotubes.

To investigate how central metal tunes the synergetic interactions between substituted metallo-phthalocyanine and single-walled carbon nanotubes in enhancing the gas sensing properties, a comparative study has been performed by varying the central metal ion in fluorinated metal phthalocyanines and single-walled carbon nanotube hybrid. Hybrids of metal(ii)-1,2,3,4,8,9,10,11,15,16,17,18-24,25-hexa-decafluoro-29H,31H-phthalocyanine/single-walled carbon nanotube (F16MPc/SWCNTs-COOH, where M = Co, Zn) have been synthesized through π-π stacking interactions using the solution route. Spectroscopic (FT-IR, UV-vis, XPS and Raman), electron microscopic (TEM and FE-SEM) and TGA investigations have confirmed the successful functionalization and interaction of SWCNTs-COOH with F16MPc. Parts per billion (ppb) level Cl2-selective chemiresistive gas sensors have been fabricated on glass substrates with precoated gold electrodes by using these hybrids. The responses of various F16MPc/SWCNTs-COOH sensors have demonstrated the central metal ion-dependence in the sensitivity of Cl2.

Carbon nano tubes functionalized with novel functional group- amido-amine for sorption of actinides.

The manuscript presents the results on the sorption of U(VI), Am(III) & Eu(III) from pH medium by a novel amido-amine functionalized multiwalled carbon nanotube (MWCNT). The novel functional group was introduced in the MWCNT by two step processes and characterized by various instrumental techniques like Scanning Electron Microscopy (SEM), Raman and X-ray Photoelectron Spectroscopy (XPS). The sorption process was found to be highly dependent on the pH of the solution with maximum sorption for both 233U, 241Am & 152+154Eu at pH 7.0. Kinetics of sorption was found to be fast with equilibrium reached in ∼15min and the sorption was found to be following pseudo 2nd order kinetics for the radionuclides. The sorption for both 233U and 152+154Eu followed Langmuir sorption model with maximum sorption capacity of 20.66mg/g and 16.1mg/g respectively. This has been explained by DFT calculations which shows that more negative solvation energy of U(VI) compared to Am(III) and Eu(III) and stronger U-MWCNT-AA complex is responsible for higher sorption capacity of U(VI) compared to Am(III) and Eu(III).The synthesized amido-amine functionalized MWCNT is a very promising candidate for removal of actinides and lanthanides from waste water solution with high efficiency.

Bioactive molecules from amphibian skin: their biological activities with reference to therapeutic potentials for possible drug development.

The amphibian skin contains various bioactive molecules (peptides, proteins, steroids, alkaloids, opiods) that possess potent therapeutic activities like antibacterial, antifungal, antiprotozoal, antidiabetic, antineoplastic, analgesic and sleep inducing properties. Research on amphibian skin derived biomolecules can provide potential clue towards newer drug development to combat various pathophysiological conditions. An overview on the bioactive molecules of various amphibian skins has been discussed.

Breed, Coat Color, and Hair Length as Risk Factors for Hyperthyroidism in Cats.

BACKGROUND: Hyperthyroidism is very common in older cats, but the etiopathogenesis is poorly understood. Decreased risk of hyperthyroidism has been reported in certain colorpoint breeds, and this observation previously has been hypothesized to result from relatively greater tyrosine availability for thyroid hormone production because of limited ability to convert tyrosine to melanin pigment. However, studies investigating a potential link between coat pigmentation and risk of hyperthyroidism are limited. OBJECTIVE: To identify associations between coat phenotype and hyperthyroidism by investigation of breed, coat color, and hair length as risk factors for the disease. ANIMALS: Data were used from 4,705 cats aged ≥10 years, referred to a single veterinary teaching hospital (2006-2014) in the United Kingdom. METHODS: Retrospective, epidemiological, cross-sectional study using Bayesian multivariable logistic regression to assess risk factors for hyperthyroidism. RESULTS: Burmese (odds ratio [OR], 0.01; 0.00-0.23; P = .004), Tonkinese (OR, 0.05; 0.00-0.95; P = .046), Persian (OR, 0.21; 0.10-0.44; P < .001), Siamese (OR, 0.27; 0.12-0.61; P = .002), Abyssinian (OR, 0.04; 0.00-0.74; P = .031), and British shorthair (OR, 0.47; 0.28-0.79; P = .004) breeds had decreased risk of hyperthyroidism compared to domestic shorthairs. Longhaired, nonpurebred cats (OR, 1.30; 1.03-1.64; P = .028) were at increased risk of hyperthyroidism. Coat color/pattern was not associated with hyperthyroidism in nonpurebred cats. CONCLUSIONS AND CLINICAL IMPORTANCE: We identified decreased risk of hyperthyroidism in the Tonkinese, Abyssinian, and British shorthair breeds, identified an association between risk of hyperthyroidism and hair length, and confirmed decreased risk in Burmese, Siamese, and Persian breeds. Additional studies are warranted to further investigate these findings.

Mixed-matrix membranes with enhanced antifouling activity: probing the surface-tailoring potential of Tiron and chromotropic acid for nano-TiO2.

Mixed-matrix membranes (MMMs) were developed by impregnating organofunctionalized nanoadditives within fouling-susceptible polysulfone matrix following the non-solvent induced phase separation (NIPS) method. The facile functionalization of nanoparticles of anatase TiO2 (nano-TiO2) by using two different organoligands, viz. Tiron and chromotropic acid, was carried out to obtain organofunctionalized nanoadditives, FT-nano-TiO2 and FC-nano-TiO2, respectively. The structural features of nanoadditives were evaluated by X-ray diffraction, X-ray photoelectron spectroscopy, Raman and Fourier transform infrared spectroscopy, which established that Tiron leads to the blending of chelating and bridging bidentate geometries for FT-nano-TiO2, whereas chromotropic acid produces bridging bidentate as well as monodentate geometries for FC-nano-TiO2. The surface chemistry of the studied membranes, polysulfone (Psf): FT-nano-TiO2 UF and Psf: FC-nano-TiO2 UF, was profoundly influenced by the benign distributions of the nanoadditives enriched with distinctly charged sites ([Formula: see text]), as evidenced by superior morphology, improved topography, enhanced surface hydrophilicity and altered electrokinetic features. The membranes exhibited enhanced solvent throughputs, viz. 3500-4000 and 3400-4300 LMD at 1 bar of transmembrane pressure, without significant compromise in their rejection attributes. The flux recovery ratios and fouling resistive behaviours of MMMs towards bovine serum albumin indicated that the nanoadditives could impart stable and appreciable antifouling activity, potentially aiding in a sustainable ultrafiltration performance.

Antiproliferative, cytotoxic and apoptogenic activity of Indian toad (Bufo melanostictus, Schneider) skin extract on U937 and K562 cells.

The antiproliferative, cytotoxic and apoptogenic activities of Bufo melanostictus (Indian common toad) skin extract (TSE) on U937 and K562 leukemic cell line has been investigated. TSE significantly (P<0.001) reduced the time-dependent cell proliferation and decreased MTT values in U937 and K562 cells. TSE (IC50 doses) suppressed the proliferating cell nuclear antigen expression in both the cells. It was demonstrated that, TSE (IC50 doses) primarily arrested the U937 and K562 cells at G1 phase of the cell cycle. Confocal microscopy showed the altered fragmented nuclei and apoptotic bodies formation in TSE (IC50 doses) treated U937 and K562 cells. Membrane blebbing, cell surface shrinkage and perforation were observed through scanning electron microscope. TSE-induced DNA fragmentation in U937 and K562 cells was reflected in single-cell gel electrophoresis. TSE significantly (P<0.001) increase the length-width ratio of DNA mass as compared to control in comet assay. The flow cytometric analysis of annexin-V binding to the cancer cells further supported the apoptotogenic activity of TSE. The effect of TSE on normal human peripheral blood mononuclear cells viability and cytotoxicity was studied in culture and found to be less cytotoxic than on the U937 and K562 cells. The findings from the present study suggested that TSE might possess potent antineoplastic agent having antiproliferative, cytotoxic and apoptogenic activity against U937 and K562 myeloid leukemic cells.