Differential toxicity and teratogenic effects of the hot water and cold water extracts of Lignosusrhinocerus (Cooke) Ryvarden sclerotium on zebrafish (Danio rerio) embryos.

ETHNOPHARMACOLOGICAL RELEVANCE: The sclerotium of Lignosusrhinocerus (Cooke) Ryvarden is highly valued for its purported medicinal properties. The decoction and macerated materials prepared from the sclerotium are used for treating cancer and other ailments based on extensive traditional knowledge. Scientific evidence from in vitro cytototoxicity, anti-inflammatory and immunomodulatory analyses showed the effectiveness of sclerotial water extracts but toxicity assessment of such preparations has not been reported. AIM OF THE STUDY: This study aimed to compare the differential toxicity and teratogenicity (if any) of the hot water (HW) and cold water (CW) extracts of both wild and cultivated sclerotium on zebrafish (Danio rerio) embryos. MATERIALS AND METHODS: Zebrafish embryos were treated with varying concentrations of the sclerotial HW and CW extracts (0.3-500 µg/mL) for 72 h until hatching. The hatching, mortality and heartbeat rate of the embryos as well as the potential teratogenic effect of the extracts were assessed in embryos post-treatment with the extracts. RESULTS: While the sclerotial HW extracts were nontoxic (LC50 > 500 µg/mL), the sclerotial CW extracts delayed the hatching of the embryos up to 48 h and showed slight toxicity with LC50 values of 398.4 µg/mL and 428.3 µg/mL for the cultivated and wild sclerotium, respectively. The sclerotial CW extracts also induced minor tachycardia in zebrafish larvae. Phenotypic assessment revealed that, while yolk sac edema was observed at high concentrations (300 and 500 µg/mL) of all extracts, curved trunk and bent tail were only observed in the embryos treated with CW extracts of wild sclerotium (300 and 500 µg/mL) but not for CW extracts of cultivated sclerotium at similar concentrations. CONCLUSION: The sclerotial water extracts of L.rhinocerus prepared using different methods have varying degree of toxicity and teratogenicity in zebrafish embryos with the sclerotial CW extracts showed higher toxicity than the HW extracts.

Hypoxia: A teratogen underlying a range of congenital disruptions, dysplasias, and malformations.

In this review, we explore evidence that hypoxia in the developing human fetus can lead not only to the more commonly accepted disruptive-type defects, but also patterns of anomalies that suggest that hypoxia can exert a more classic teratogenic effect, using the brain as one example. We review neuropathology in the context of intrauterine hypoxia, particularly as it relates to carbon monoxide poisoning, in utero strokes, and homozygous alpha-thalassemia. In general, the associated brain injuries resemble those seen with other causes of hypoxic-ischemic injury. Fetal strokes during development usually lead to loss of brain tissue in areas that do not follow a typical embryologic pattern, and therefore are considered disruptions. However, there is also evidence that fetal brain ischemia can cause more classically recognized patterns of abnormal embryonic neuronal migration and organization such as polymicrogyria, cortical dysplasia, or dysgenesis, including select types of focal cortical dysplasia. This study summarizes available literature and evidence to raise clinicians' awareness regarding the association between hypoxia and congenital anomalies, including brain malformations.

Insights into Structural Modifications of Valproic Acid and Their Pharmacological Profile.

Valproic acid (VPA) is a well-established anticonvulsant drug discovered serendipitously and marketed for the treatment of epilepsy, migraine, bipolar disorder and neuropathic pain. Apart from this, VPA has potential therapeutic applications in other central nervous system (CNS) disorders and in various cancer types. Since the discovery of its anticonvulsant activity, substantial efforts have been made to develop structural analogues and derivatives in an attempt to increase potency and decrease adverse side effects, the most significant being teratogenicity and hepatotoxicity. Most of these compounds have shown reduced toxicity with improved potency. The simple structure of VPA offers a great advantage to its modification. This review briefly discusses the pharmacology and molecular targets of VPA. The article then elaborates on the structural modifications in VPA including amide-derivatives, acid and cyclic analogues, urea derivatives and pro-drugs, and compares their pharmacological profile with that of the parent molecule. The current challenges for the clinical use of these derivatives are also discussed. The review is expected to provide necessary knowledgebase for the further development of VPA-derived compounds.

The multi-dimensional embryonic zebrafish platform predicts flame retardant bioactivity.

Flame retardant chemicals (FRCs) commonly added to many consumer products present a human exposure burden associated with adverse health effects. Under pressure from consumers, FRC manufacturers have adopted some purportedly safer replacements for first-generation brominated diphenyl ethers (BDEs). In contrast, second and third-generation organophosphates and other alternative chemistries have limited bioactivity data available to estimate their hazard potential. In order to evaluate the toxicity of existing and potential replacement FRCs, we need efficient screening methods. We built a 61-FRC library in which we systemically assessed developmental toxicity and potential neurotoxicity effects in the embryonic zebrafish model. Data were compared to publicly available data generated in a battery of cell-based in vitro assays from ToxCast, Tox21, and other alternative models. Of the 61 FRCs, 19 of 45 that were tested in the ToxCast assays were bioactive in our zebrafish model. The zebrafish assays detected bioactivity for 10 of the 12 previously classified developmental neurotoxic FRCs. Developmental zebrafish were sufficiently sensitive at detecting FRC structure-bioactivity impacts that we were able to build a classification model using 13 physicochemical properties and 3 embryonic zebrafish assays that achieved a balanced accuracy of 91.7%. This work illustrates the power of a multi-dimensional in vivo platform to expand our ability to predict the hazard potential of new compounds based on structural relatedness, ultimately leading to reliable toxicity predictions based on chemical structure.

Therapeutic Drug Monitoring of Antiepileptic Drugs in Women with Epilepsy Before, During, and After Pregnancy.

During pregnancy, the pharmacokinetics of an antiepileptic drug is altered because of changes in the clearance capacity and volume of distribution. These changes may have consequences for the frequency of seizures during pregnancy and fetal exposure to antiepileptic drugs. In 2009, a review was published providing guidance for the dosing and therapeutic drug monitoring of antiepileptic drugs during pregnancy. Since that review, new drugs have been licensed and new information about existing drugs has been published. With this review, we aim to provide an updated narrative overview of changes in the pharmacokinetics of antiepileptic drugs in women during pregnancy. In addition, we aim to formulate advice for dose modification and therapeutic drug monitoring of antiepileptic drugs. We searched PubMed and the available literature on the pharmacokinetic changes of antiepileptic drugs and seizure frequency during pregnancy published between January 2007 and September 2018. During pregnancy, an increase in clearance and a decrease in the concentrations of lamotrigine, levetiracetam, oxcarbazepine's active metabolite licarbazepine, topiramate, and zonisamide were observed. Carbamazepine clearance remains unchanged during pregnancy. There is inadequate or no evidence for changes in the clearance or concentrations of clobazam and its active metabolite N-desmethylclobazam, gabapentin, lacosamide, perampanel, and valproate. Postpartum elimination rates of lamotrigine, levetiracetam, and licarbazepine resumed to pre-pregnancy values within the first few weeks after pregnancy. We advise monitoring of antiepileptic drug trough concentrations twice before pregnancy. This is the reference concentration. We also advise to consider dose adjustments guided by therapeutic drug monitoring during pregnancy if the antiepileptic drug concentration decreases 15-25% from the pre-pregnancy reference concentration, in the presence of risk factors for convulsions. If the antiepileptic drug concentration changes more than 25% compared with the reference concentration, dose adjustment is advised. Monitoring of levetiracetam, licarbazepine, lamotrigine, and topiramate is recommended during and after pregnancy. Monitoring of clobazam, N-desmethylclobazam, gabapentin, lacosamide, perampanel, and zonisamide during and after pregnancy should be considered. Because of the risk of teratogenic effects, valproate should be avoided during pregnancy. If that is impossible, monitoring of both total and unbound valproate is recommended. More research is needed on the large number of unclear pregnancy-related effects on the pharmacokinetics of antiepileptic drugs.

Endopleura uchi (Huber) Cuatrec.: A medicinal plant for gynecological treatments - A reproductive toxicity assessment in zebrafish (Danio rerio).

ETHNOPHARMACOLOGICAL RELEVANCE: Endopleura uchi (Huber) Cuatrec is a plant species from the Brazilian Amazon. The barks of this tree are used in folk medicine - mainly as a decoction - for dyslipidemia, uterine infection, fibroids, polycystic ovary, menstrual disorders, as a contraceptive and abortive agent, among others. However, the data available about its developmental toxicity are still insufficient. AIM OF THE STUDY: This study aimed to evaluate the reproductive toxicity and teratogenic effects in embryos from zebrafish treated with the hydroethanolic extract from the barks of Endopleura uchi (EEu). MATERIALS AND METHODS: Both sexes of zebrafish (Danio rerio) were treated with EEu either through immersion (1.2, 2.5, and 5 mg/L) or orally (75, 200, and 500 mg/kg) over 21 consecutive days. Next, we assessed their fertility and gonads' histopathology; in their embryos were assessed teratogenesis, lethalities, and heart rate during daily observations (24, 48, 72, and 96 hpf). RESULTS: The phytochemical analysis of EEu through HPLC/MS shows bergenin as the major compounds. After 21 days of treatment were detected minor histopathological changes in parental fishes, such as atretic oocytes, interstitial fibrosis, and decreased the percentage of early vitellogenic oocytes, but without impairing the reproduction of treated animals. However, in the embryos was observed significantly increased frequency of malformation in all the groups treated through immersion, and in the group treated orally with the highest concentration (500 mg/kg). CONCLUSION: Based on the results, EEu caused no adverse effects in the progenitors on both treatments (immersion and oral). However, it was observed that the concentrations 1.2, 2.5, and 5 mg/L (immersion), and the dose 500 mg/kg (oral) caused malformations in the offspring (F1 generation). These results emphasize the need for attention when using preparations from E. uchi, mainly for pregnant women. Further studies are needed to compare its effects with the extract's primary compound (bergenin).

Teratogenic jervine increases the activity of doxorubicin in MCF-7/ADR cells by inhibiting ABCB1.

Jervine is a natural teratogenic compound isolated from Veratrum californicum. In this study, for the first time, we revealed a novel activity of jervine in sensitizing the anti-proliferation effect of doxorubicin (DOX). We demonstrated that the synergistic mechanism was related to the intracellular accumulation of DOX via modulating ABCB1 transportation. Jervine did not affect the expression of ABCB1 in mRNA nor protein levels. However, jervine increased the ATPase activity of ABCB1 and possibly served as a substrate of ABCB1. The molecular docking results indicated that jervine was bound to a closed ABCB1 conformation and blocked drug entrance to the central binding site at the transmembrane domain. The present study identifies jervine acts as a substrate of ABCB1, and has potential to be developed as a novel and potent chemotherapy sensitizer used for patients developing multidrug resistance.

Toxicity, bioactivity, release of H2S in vivo and pharmaco-kinetics of H2S-donors with thiophosphamide structure.

H2S donors are substitutes of H2S with various biological activities like inhibiting the inflammatory response and protecting myocardial cells from injury. In order to confirm whether the H2S donors have drug-like properties, two series thiophosphamide H2S donors were evaluated including toxicity, bioactivity and pharmacokinetic properties in vivo and in vitro. The following results were obtained. Firstly, all the compounds released H2S under measuring condition; with the increase of pH value, the H2S release rate of all the compounds decreased and the amount reduced, but pH value had little effect on the maximum release of H2S. Secondly, in the organs and tissues of rats, the compounds released H2S in the same way as in PBS. In plasma, compound 1 reached the Cmax after administration 55 min, and no compound 1 was detected after 12 h; for compound 18, the Cmax reached only after administration 100 min, and after 6 h, compound 18 was not detected; in organs and tissues, the H2S-release rates were different from those in PBS, but the mechanism of H2S release was the same. Thirdly, in the test of toxicity, all the compounds displayed low toxicities to 5 cancer cells and W138 cell lines; compounds 1 and 18 had slight effect on the physiological tissue and function of rat liver at low concentration; the compounds had almost no effect on the hatching rate, survival rate of zebrafish embryos, and the spontaneous movement of zebrafish embryos at below 0.5 µM, but when they were over 1 µM, the compounds displayed inhibitory effect in the manner of concentration dependence. Fourthly, in the course of anti-inflammatory test, all the tested compounds significantly reduced the level of TNF-α and increased the level of IL-10; when they were 100 µM, the levels of IL-10 were three times as high as those in the control group. Among them, compounds 10 and 18 displayed stronger activities than the others. In addition, the compounds protected H9c2 cells from injure and improved myocardial injury through anti-oxidation pathway. In summary, the compounds have druglike properties due to low toxicity, better activity and good pharmacokinetic property. Therefore, they have potential to be as candidates to investigate further.

Dose-dependent effects of a glyphosate commercial formulation - Roundup® UltraMax - on the early zebrafish embryogenesis.

The use of herbicides with glyphosate as an active ingredient, the so-called glyphosate-based herbicides (GBH), has increased dramatically in recent years currently being the most widely used in the world. Therefore, glyphosate residues have been detected in water and soils near the application sites. Recent studies indicate that GBH may cause adverse effects on vertebrates although these have been attributed to the presence of adjuvants in the commercial formulations rather than to the sole compound. Accordingly, the objective of this work was to investigate the lethal and sub-lethal developmental effects, neurotoxic potential and oxidative stress responses of zebrafish embryos to Roundup® Ultramax (RU) exposure. Embryos were exposed during 72 h to 0, 2, 5, 8.5 µg a.i. mL-1 of RU. Increased mortality was observed in embryos exposed to concentrations above 8.5 µg a.i. mL-1 as well as increased number of malformations. Decreased heart rate and hatchability were also observed. By contrast, exposure to concentrations that do not evoke teratogenic outcomes induced a dose-dependent decrease of heart rate although not inducing significant developmental changes. However, histological changes were not observed in the larvae exposed to these concentrations. Moreover, the generation of reactive oxygen species, the antioxidant enzymes activities (SOD and CAT), the GST biotransformation activity, the glutathione levels (GSH and GSSG), the oxidative damage (MDA) and the acetylcholinesterase and lactate dehydrogenase were similar among groups following exposure. Overall, available evidence suggests a dose-dependent toxicological effect of this formulation at concentrations that are not routinely detected in the environment. However, additional studies should be performed to better understand the underlying molecular mechanisms in favor of this formulation.

Genotoxic and mutagenic studies of teratogens in developing rat and mouse.

In this review, genotoxic and mutagenic effects of teratogenic chemical agents in both rat and mouse have been reviewed. Of these chemicals, 97 are drugs and 33 are pesticides or belong to other groups. Large literature searches were conducted to determine the effects of chemicals on chromosome abnormalities, sister chromatid exchanges, and micronucleus formation in experimental animals such as rats and mice. In addition, studies that include unscheduled DNA synthesis, DNA adduct formations, and gene mutations, which help to determine the genotoxicity or mutagenicity of chemicals, have been reviewed. It has been estimated that 46.87% of teratogenic drugs and 48.48% of teratogenic pesticides are positive in all tests. So, all of the teratogens involved in this group have genotoxic and mutagenic effects. On the other hand, 36.45% of the drugs and 21.21% of the pesticides have been found to give negative results in at least one test, with the majority of the tests giving positive results. However, only 4.16% of the drugs and 18.18% of the pesticides were determined to give negative results in the majority of the tests. Among tests with major negative results, 12.50% of the teratogenic drugs and 12.12% of the teratogenic pesticides were negative in all conducted tests.

Evaluation of toxicological and teratogenic effects of carbosilane glucose glycodendrimers in zebrafish embryos and model rodent cell lines.

Glycodendrimers (Glyco-DDMs) represent a rapidly growing class of nanoparticles with promising properties for biomedical applications but concerns regarding the impact on human health and environment are still justified. Here we report, for the first time, the comparative study of in vivo developmental toxicity of carbosilane Glyco-DDMs and their cytotoxicity in vitro. Carbosilane Glyco-DDMs (generation 1-3) containing 4, 8, and 16 ß-d-glucopyranosyl units at the periphery (DDM1Glu, DDM2Glu, and DDM3Glu) were synthesized and characterized by 1H, 13C and 29Si NMR, mass spectrometry, dynamic light scattering, atomic force microscopy (AFM), and computer modeling. In vitro cytotoxicity assay (MTT) of DDM1-3Glu was performed on three different rodent cell lines (Cricetulus griseus) - B14 (ATCC, CCL-14.1), BRL 3A (ATCC, CRL-1442), and NRK 52E (ATCC, CRL-1571). Overall, very low cytotoxicity was observed with calculated IC50 in mM range with slight difference between each cell line and DDM generation investigated. Modified fish embryo test (FET) was further used for DDM3Glu developmental toxicity testing on zebrafish (Danio rerio) embryos. While seemingly harmless to intact embryos, adverse effects of DDMs on the embryonic development become evident after chorion removal (LD50=2.78 µM at 96 hpe). We summarized that the modified FET test showed a two to three orders of magnitude difference between the in vitro cytotoxicity and in vivo developmental toxicity of DDM3Glu. While, in general, the Glyco-DDMs show great promises as efficient vectors in targeted drug delivery or as therapeutic molecules itself, we suggest that their developmental toxicity should be thoroughly investigated to exclude safety risks associated with their potential biomedical use.

SALL4 mediates teratogenicity as a thalidomide-dependent cereblon substrate.

Targeted protein degradation via small-molecule modulation of cereblon offers vast potential for the development of new therapeutics. Cereblon-binding therapeutics carry the safety risks of thalidomide, which caused an epidemic of severe birth defects characterized by forelimb shortening or phocomelia. Here we show that thalidomide is not teratogenic in transgenic mice expressing human cereblon, indicating that binding to cereblon is not sufficient to cause birth defects. Instead, we identify SALL4 as a thalidomide-dependent cereblon neosubstrate. Human mutations in SALL4 cause Duane-radial ray, IVIC, and acro-renal-ocular syndromes with overlapping clinical presentations to thalidomide embryopathy, including phocomelia. SALL4 is degraded in rabbits but not in resistant organisms such as mice because of SALL4 sequence variations. This work expands the scope of cereblon neosubstrate activity within the formerly 'undruggable' C2H2 zinc finger family and offers a path toward safer therapeutics through an improved understanding of the molecular basis of thalidomide-induced teratogenicity.

InP/ZnS QDs exposure induces developmental toxicity in rare minnow (Gobiocypris rarus) embryos.

We investigated the in vivo toxicity of InP/ZnS quantum dots (QDs) in Chinese rare minnow (Gobiocypris rarus) embryos. The 72 h post-fertilization (hpf) LC50 (median lethal concentration) was 1678.007 nmol/L. Rare minnows exposed to InP/ZnS QDs exhibited decreased spontaneous movement, decreased survival and hatchability rates, and an increased malformation rate. Pericardial edema, spinal curvature, bent tails and vitelline cysts were observed. Embryonic Wnt8a and Mstn mRNA levels were significantly up-regulated after InP/ZnS QDs treatment at 48 hpf (200 nmol/L) (p < 0.05). The superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels at 96 hpf (800 nmol/L) had an increasing trend. Hsp70 mRNA expression was significantly changed at 48 hpf (200 nmol/L), but compared with the blank control, the different InP/ZnS QDs treatments did not significantly change the Olive tail moments (p > 0.05). Thus, InP/ZnS QDs caused teratogenic effects and death during the development of Chinese rare minnow embryos, but InP/ZnS QDs did not cause significant genetic toxicity during Chinese rare minnow development.

Teratogenic and anticonvulsant effects of zinc and copper valproate complexes in zebrafish.

Valproic acid (VPA) is an antiepileptic drug (AED) that has the broadest spectrum across all types of seizures and epileptic syndromes. Unfortunately, approximately 30% of epileptic patients are refractory to the classical AED. Metal ions have been frequently incorporated into pharmaceuticals for therapeutic or diagnostic purposes and research. In this preliminary study, we assess the embryo toxicity and the anticonvulsant activity of 4 novel metallodrugs, with Zn+2 and Cu+2, a derivative of valproic acid and the N-donor ligand in an adult zebrafish epileptic seizure model induced by pentylenetetrazole. The most toxic complex was [Cu(Valp)2Bipy], in which the LC50 was 0.22 µM at 48 h post fertilization (HPF) and 0.12 µM at 96 HPF, followed by [Zn(Valp)2Bipy] (LC50 = 10 µM). These same metallodrugs ([Cu(Valp)2Bipy] 10 mM/kg and [Zn(Valp)2Bipy] 30 mM and 100 mM/kg) displayed superior activity, thus reducing the seizure intensity by approximately 20 times compared to sodium valproate (175 mM/kg). Overall, [Cu(Valp)2Bipy] showed the best anticonvulsant effects. However, because of the toxicity of copper, [Zn(Valp)2Bipy] is considered the most promising anticonvulsant for future studies.

Teratogenic effects induced by chitosan oligosaccharide in Wistar female rat Rattus norvegicus.

The aim of this research is to investigate the teratogenic effects of chitosan oligosaccharide in Wistar female rats (Rattus norvegicus). Chitosan LD50 value was calculated by probit analysis. High dose, 1/10 LD50 which equal to 150 mg/kg body weight, and low dose, 1/30 LD50 which equal to 50 mg/kg body weight, were administrated orally to Wistar female rats to examine the teratogenic effect during organogenesis period from 6th day to 15th day of gestation. Treated and control rats were sacrificed and their foetuses were examined for external, skeletal and visceral anomalies, number and length of foetuses and their weights. Obtained results showed toxicity and teratogenic effects of chitosan on treated rats and their progenies, i.e. high fetal mortality, offspring's weight and length reduction, and high incidence of fetal external, skeletal and visceral abnormalities. This suggested that chitosan is a teratogenic compound, restricted to current results from orally treated Wistar rats.

Structural basis of thalidomide enantiomer binding to cereblon.

Thalidomide possesses two optical isomers which have been reported to exhibit different pharmacological and toxicological activities. However, the precise mechanism by which the two isomers exert their different activities remains poorly understood. Here, we present structural and biochemical studies of (S)- and (R)-enantiomers bound to the primary target of thalidomide, cereblon (CRBN). Our biochemical studies employed deuterium-substituted thalidomides to suppress optical isomer conversion, and established that the (S)-enantiomer exhibited ~10-fold stronger binding to CRBN and inhibition of self-ubiquitylation compared to the (R)-enantiomer. The crystal structures of the thalidomide-binding domain of CRBN bound to each enantiomer show that both enantiomers bind the tri-Trp pocket, although the bound form of the (S)-enantiomer exhibited a more relaxed glutarimide ring conformation. The (S)-enantiomer induced greater teratogenic effects on fins of zebrafish compared to the (R)-enantiomer. This study has established a mechanism by which thalidomide exerts its effects in a stereospecific manner at the atomic level.

Glycol chitosan functionalized asenapine nanostructured lipid carriers for targeted brain delivery: Pharmacokinetic and teratogenic assessment.

Blood brain barrier (BBB) is a complex, tight barrier between endothelial cells of cerebral blood vessels. It acts as a physical barrier and provides access to only those moieties which are necessary for proper brain functioning. However, this selective prudence also acts as a hindrance in therapeutic targeting of brain necessitating pharmaceutical intervention. Intranasal drug delivery is one such approach which we have exploited here for targeted brain delivery of asenapine by glycol chitosan coated nanostructured lipid carrier (GC-ANLC). The best formulation was characterized for particle size (184.2±5.59nm), zeta potential (18.83±1.18mV), entrapment efficiency (83.52±2.59%) and surface morphology (spherical and smooth). In-vitro drug-release study showed that Higuchi model (r2=0.9938, AIC=52.94) dictated asenapine release from GC-ANLC. Cell compatibility study suggested biocompatibility of GC-ANLC with A549 cell line as well as nasal epithelial cell membrane. After intranasal delivery, Charles-Foster rats demonstrated approximately 2.3 and 4 fold higher systemic and brain bioavailability of GC-ANLC compared to asenapine solution (ASM). Embryo fetal toxicity study was further conducted to investigate the teratogenic effect of GC-ANLC. In conclusion, prepared GC-ANLC could be used as a promising drug carrier for delivery of asenapine via intranasal route with better pharmacokinetic and safety profile.

Constraining the Teratogenicity of Pesticide Pollution by a Synthetic Nanoreceptor.

The teratogenicity of the pesticide nereistoxin (NTX) and its derivative thiocyclam (THI) towards aquatic life was dramatically constrained by a synthetic nanoreceptor, cucurbit[7]uril, through selective encapsulation of the pesticides (KCB[7]-NTX of 3.24(±0.31)×106 m-1 and KCB[7]-THI of 7.46(±0.10)×105 m-1 ), as evidenced by the rate of hatchability, morphology development, and tyrosinase activity of zebrafish larvae incubated with the pesticides (3-300 µm) in the absence and in the presence of 300 µm cucurbit[7]uril, demonstrating the significant potential of the nanoreceptor in managing ecological pollution of these pesticides.

Toxicity, teratogenicity and antibacterial activity of posterior salivary gland (PSG) toxin from the cuttlefish Sepia pharaonis (Ehrenberg, 1831).

Toxins from the posterior salivary gland (PSG) of cuttlefishes are known toxins with pronounced toxicity. In the present study, ionic peptide rich PSG toxin from the cuttlefish S. pharaonis was isolated by ion exchange chromatography and purified by Reversed Phase High Performance Liquid Chromatography (RP-HPLC), with active fraction at a retention time of 26min. The net protein content of the PSG toxin was estimated to be 46.6mg at a proximate molecular weight of∼50kDa. Fourier Transform Infrared Spectroscopy (FT-IR) of PSG toxin revealed the presence of alcoholic OH, primary NH, alkyl CH and conjugated CONH functional groups. Circular Dichroism (CD) spectroscopy and K2D analysis of the PSG toxin confirmed the presence of secondary structure with 36.77% α-helix,12.31% ß sheet and 50.92% random coil. Scanning Electron Microscopy (SEM) of the PSG toxin eluted amberlite IRA 900 Cl- resin showed surface abrasion and corrosive blebbing. Energy Dispersive X-ray Spectrometry (EDX) analysis of PSG toxin treated resin revealed increase in nitrogen and sulphur content corresponding to amino acid composition. Teratogenicity of PSG toxin against Zebrafish embryo demonstrated developmental malformations and premature hatching at a maximum tolerated dose of 1.25µM. The PSG toxin (50µM) exhibited commendable inhibitory activity with pronounced zone of inhibition against gram E. coli (10mm) and K. pneumonia (10mm). The results strongly demonstrate the toxicity of the ionic peptide rich PSG toxin from S. pharaonis and its exploitation for its promise as a potential antibacterial agent of the future.

The Dihydroxy Metabolite of the Teratogen Thalidomide Causes Oxidative DNA Damage.

Thalidomide [α-(N-phthalimido)glutarimide] (1) is a sedative and antiemetic drug originally introduced into the clinic in the 1950s for the treatment of morning sickness. Although marketed as entirely safe, more than 10 000 babies were born with severe birth defects. Thalidomide was banned and subsequently approved for the treatment of multiple myeloma and complications associated with leprosy. Although known for more than 5 decades, the mechanism of teratogenicity remains to be conclusively understood. Various theories have been proposed in the literature including DNA damage and ROS and inhibition of angiogenesis and cereblon. All of the theories have their merits and limitations. Although the recently proposed cereblon theory has gained wide acceptance, it fails to explain the metabolism and low-dose requirement reported by a number of groups. Recently, we have provided convincing structural evidence in support of the presence of arene oxide and the quinone-reactive intermediates. However, the ability of these reactive intermediates to impart toxicity/teratogenicity needs investigation. Herein we report that the oxidative metabolite of thalidomide, dihydroxythalidomide, is responsible for generating ROS and causing DNA damage. We show, using cell lines, the formation of comet (DNA damage) and ROS. Using DNA-cleavage assays, we also show that catalase, radical scavengers, and desferal are capable of inhibiting DNA damage. A mechanism of teratogenicity is proposed that not only explains the DNA-damaging property but also the metabolism, low concentration, and species-specificity requirements of thalidomide.