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1.
Physiol Mol Biol Plants ; 27(3): 605-617, 2021 Mar.
Article in English | MEDLINE | ID: mdl-33854287

ABSTRACT

Medicinal plants are a valuable resource for traditional as well as modern medicine. Consequently huge demand has exerted a heavy strain on the existing natural resources. Due to over exploitation and unscientific collection most of the commercially traded ayurvedic plants are in the phase of depletion. Adulteration of expensive raw drugs with inferior taxa has become a common practice to meet the annual demand of the ayurvedic industry. Although there are several recommended methods for proper identification varying from the traditional taxonomic to organoleptic and physiochemical, it is difficult to authenticate ayurvedic raw drugs available in extremely dried, powdered or shredded forms. In this regard, the study addresses proper authentication and illicit trade in Coscinium fenestratum (Gaertn.) Colebr. using CBOL recommended standard barcode regions viz. nuclear ribosomal-Internally Transcribed Spacer (nrDNA- ITS), maturase K (matK), ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit (rbcL), and psbA-trnH spacer regions. Further, an integrated analytical approach employing Maximum Likelihood phylogenetic tree and Machine Learning Approach, Waikato Environment for Knowledge Analysis was employed to prove efficacy of the method. The automated species identification technique, Artificial Intelligence uses the ability of computers to build models that can receive the input data and then conduct statistical analyses which significantly reduces the human labour. Concurrently, scientific management, restoration, cultivation and conservation measures should be given utmost priority to reduce the depletion of wild resources as well as to meet the rapidly increasing demand of the herbal industries.

2.
Br J Dermatol ; 174(3): 594-601, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26473312

ABSTRACT

BACKGROUND: Oral propranolol is widely prescribed as first-line treatment for infantile haemangiomas (IHs). Anecdotally, prescribing practice differs widely between centres. OBJECTIVES: The Propranolol In the Treatment of Complicated Haemangiomas (PITCH) Taskforce was founded to establish patterns of use of propranolol in IHs. METHODS: Participating centres entered data on all of their patients who had completed treatment with oral propranolol for IHs, using an online data capture tool. RESULTS: The study cohort comprised 1097 children from 39 centres in eight European countries. 76·1% were female and 92·8% had a focal IH, with the remainder showing a segmental, multifocal or indeterminate pattern. The main indications for treatment were periocular location (29·3%), risk of cosmetic disfigurement (21·1%) and ulceration and bleeding (20·6%). In total 69·2% of patients were titrated up to a maintenance regimen, which consisted of 2 mg kg(-1) per day (85·8%) in the majority of cases. 91·4% of patients had an excellent or good response to treatment. Rebound growth occurred in 14·1% upon stopping, of whom 53·9% were restarted and treatment response was recaptured in 91·6% of cases. While there was no significant difference in the treatment response, comparing a daily maintenance dose of < 2 mg kg(-1) vs. 2 mg kg(-1) vs. > 2 mg kg(-1) , the risk of adverse events was significantly higher: odds ratio (OR) 1 vs. adjusted OR 0·70, 95% confidence interval (CI) 0·33-1·50, P = 0·36 vs. OR 2·38, 95% CI 1·04-5·46, P = 0·04, Ptrend < 0·001. CONCLUSIONS: The PITCH survey summarizes the use of oral propranolol across 39 European centres, in a variety of IH phases, and could be used to inform treatment guidelines and the design of an interventional study.


Subject(s)
Antineoplastic Agents/administration & dosage , Hemangioma/drug therapy , Propranolol/administration & dosage , Skin Neoplasms/drug therapy , Administration, Oral , Antineoplastic Agents/adverse effects , Dose-Response Relationship, Drug , Female , Humans , Infant , Male , Propranolol/adverse effects , Treatment Outcome
6.
3 Biotech ; 11(11): 463, 2021 Nov.
Article in English | MEDLINE | ID: mdl-34745814

ABSTRACT

Adulteration of expensive raw drugs with inferior taxa has become a routine practice, conceding the quality and safety of derived herbal products. In this regard, the study addresses the development of an integrated approach encompassing DNA barcode and HPTLC fingerprinting to authenticate chiefly traded ayurvedic raw drugs in south India [viz. Saraca asoca (Roxb.) Willd., Terminalia arjuna (Roxb. ex DC.) Wight and Arn., Sida alnifolia L. and Desmodium gangeticum (L.) DC.] from its adulterants. Consortium of Barcode of Life (CBOL) recommended DNA barcode gene regions viz. nuclear ribosomal-Internal Transcribed Spacer (nrDNA-ITS), maturase K (matK), ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit (rbcL) and psbA-trnH spacer regions along with HPTLC profiling were experimented and a reference database was created. Further, an integrated analytical approach employing genetic distance-based Maximum Likelihood phylogenetic tree and Artificial Intelligence (AI)based Machine Learning Algorithms (MLA)-Waikato Environment for Knowledge Analysis (WEKA) and Barcoding with Logic (BLOG) were employed to prove efficacy of DNA barcode tool. Even though, among the four barcodes, psbA-trnH (S. alnifolia and its adulterants, T. arjuna and its adulterants) or ITS region (S. asoca and its adulterants, D. gangeticum and its adulterants) showed highest inter specific divergences in the selected Biological Reference Materials (BRMs), rbcL or matK barcode regions alone were successful for authentication of traded samples. The automated species identification techniques, WEKA and BLOG, experimented for the first time in India for raw drug validation, could achieve rapid and precise identification. A national certification agency for raw drug authentication employing an integrated approach involving a DNA barcoding tool along with standard organoleptic and analytical methods can strengthen and ensure safety and quality of herbal medicines in India. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-021-03001-5.

7.
3 Biotech ; 10(11): 497, 2020 Nov.
Article in English | MEDLINE | ID: mdl-33150123

ABSTRACT

India, with a rich heritage of floral diversity, is well-known for its medicinal plant wealth and is the largest producer of medicinal herbs in the world. Ethnobiological Survey of Ministry of Environment and Forests (MOEF) could identify 8000 plant species utilized in various systems of medicine with approximately 25,000 effective herbal formulations. The extensive consumption to meet demand-supply ratio exerts a heavy strain on the existing resources. This subsequently led to the adulteration and substitution of medicinal plants with look-alike species. The consumer's faith on herbal medicine is in the phase of decline due to the extremities in adulteration/substitution and ensuing consequences. It is imperative to bring forth universally acceptable standard tools to authenticate raw drugs before being processed further into formulations. A vast array of techniques such as physical, chemical (analytical), biochemical, anatomical, organoleptic, and recently emerged DNA based molecular methods are widely used for plant species authentication. In recent years, DNA barcoding has made remarkable progress in the field of medicinal plants research. DNA metabarcoding is the latest development for qualitative evaluation of the herbal formulations, whereas for quantitative analysis, combination of pharmacognostic, pharmacovigilance and analytical methods are inevitable for authentication. This review addresses the overall strengths and shortcomings of the existing as well as recently emerged techniques in authenticating ayurvedic raw drugs.

8.
Toxicology ; 256(1-2): 118-27, 2009 Feb 04.
Article in English | MEDLINE | ID: mdl-19084044

ABSTRACT

Okadaic acid (OA) is the major component of diarrhetic shell fish poisoning toxins and a potent inhibitor of protein phosphatase 1 and 2A. We investigated the signal transduction pathways involved in OA induced cell death in HeLa cells. OA induced cytotoxicity and apoptosis at IC50 of 100nM. OA treatment resulted in time dependent increase in reactive oxygen species and depleted intracellular glutathione levels. Loss of mitochondrial membrane permeability led to translocation of bax, cytochrome-c and AIF from mitochondria to cytosol. The cells under fluorescence microscope showed typical apoptotic morphology with condensed chromatin, and nuclear fragmentation. We investigated the mitochondrial-mediated caspase cascade. The time dependent activation and cleavage of of bax, caspases-8, 10, 9, 3 and 7 was observed in Western blot analysis. In addition to caspase-dependent pathway AIF mediated caspase-independent pathway was involved in OA mediated cell death. OA also caused time dependent inhibition of protein phosphatase 2A activity and phosphorylation of p38 and p42/44 MAP kinases. Inhibitor studies with Ac-DEVO-CHO and Z-VAD-FMK could not prevent the phosphorylation of p38 and p42/44 MAP kinases. Our experiments with caspase inhibitors Ac-DEVD-CHO, Z-IETD-FMK and Z-VAD-FMK inhibited capsase-3, 8 cleavages but did not prevent OA-induced apoptosis and DNA fragmentation. Similarly, pretreatment with cyclosporin-A and N-acetylcysteine could not prevent the DNA fragmentation. In summary, the results of our study show that OA induces multiple signal transduction pathways acting either independently or simultaneously leading to apoptosis.


Subject(s)
Apoptosis/drug effects , Carcinogens/toxicity , Okadaic Acid/toxicity , Signal Transduction/drug effects , Blotting, Western , Caspase Inhibitors , Caspases/metabolism , Cytochromes c/metabolism , DNA Fragmentation/drug effects , Enzyme Inhibitors/pharmacology , Glutathione/metabolism , HeLa Cells , Humans , L-Lactate Dehydrogenase/metabolism , Membrane Potentials/drug effects , Mitochondria/drug effects , Mitogen-Activated Protein Kinases/metabolism , Phosphoprotein Phosphatases/metabolism , Phosphorylation , Reactive Oxygen Species/metabolism
9.
J Biochem Mol Toxicol ; 23(3): 212-21, 2009.
Article in English | MEDLINE | ID: mdl-19526462

ABSTRACT

T-2 toxin is one of the most potent trichothecenes, and on exposure causes severe human and animal diseases. We investigated the dose- and time-dependent effect of T-2 toxin on certain biochemical variables, oxidative damage in terms of antioxidant enzyme activity, and gene expression profile in mice. Mice treated intraperitoneally with either 1 LD50 or 2 LD50 dose (5.61 and 11.22 mg/kg body weight, respectively) of T-2 toxin showed significant alterations in hepatic alanine amino transferase, aspartate amino transferase, and lactate dehydrogenase. Significant changes in hepatic lipid peroxidation, depletion of glutathione (GSH), and expression of heat shock protein-70 indicated oxidative damage. We also evaluated the activity of antioxidant enzymes and compared the gene expression profile by quantitative real-time reverse transcriptase-polymerase chain reaction. Except for glutathione reductase (GR), there was a significant increase in activity of glutathione-S-transferase (GST), glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase at 1 LD50 dose. At 2 LD50 dose, SOD showed decrease in activity, whereas GST, GPx, and catalase showed significant increase. In contrast, gene expression profile showed downregulation in GR, GPx, GST, and catalase at 1 LD50 dose. At 2 LD50 dose except GSH synthetase, all other genes were downregulated. The results clearly show oxidative stress as one of the mechanisms of T-2 toxin-mediated toxicity.


Subject(s)
Antioxidants/metabolism , Gene Expression Regulation, Enzymologic/drug effects , Liver/enzymology , Oxidative Stress/drug effects , Oxidoreductases/biosynthesis , T-2 Toxin/toxicity , Animals , Dose-Response Relationship, Drug , Gene Expression Profiling , Humans , Male , Mice , Oxidation-Reduction/drug effects
10.
Cell Mol Biol (Noisy-le-grand) ; 53(5): 92-102, 2007 May 30.
Article in English | MEDLINE | ID: mdl-17543238

ABSTRACT

Ricin a glycoprotein from the Ricinus communis seeds, is known to have diverse toxic effects on cells of different visceral organs. We have studied the effect of ricin (0.5, 1.0 and 2.0 LD50) on various oxidative stress markers at 1, 3 and 7 day post exposure following i.p. administration in Swiss albino male mice. Results of this study revealed that ricin induces generation of reactive species, lipidperoxidation, DNA fragmentation and depletion of GSH. Activity of antioxidant cascade related enzyme like superoxide dismutase (SOD), glutathione peroxidase (GPx) decreased, while glutathione reductase (GR) and catalase activity increased. Superoxide dismutase and glutathione peroxidase activity was decreased significantly in liver, spleen and kidney. The decrease was more prominent on 7 day of post exposure in all the exposed doses. A significant increase in the activities of catalase was observed in plasma, liver, spleen and kidney on 7 day following ricin exposure. Glutathione reductase increased significantly as early as 24 h following 1.0 LD50 dose. Lipid peroxidation increased and non protein sulfhydryl content decreased in all the tissues at different time intervals. Total antioxidant status was reduced as early as 1 day post exposure. Nearly two fold increase was observed in DNA fragmentation following 0.5 LD50 dose of ricin on 1 day post exposure. DNA diffusion assay also indicated an early damage to DNA due to ROS. An early change in DNA fragmentation, DNA diffusion, and total antioxidant status and in the activity of various enzymes indicates that ricin produce oxidative stress by generation of reactive oxygen species as early as 24 h at a minimum dose of 0.5 LD50. Probably this is the first study which indicate that ricin induced oxidative stress at a minimum dose of 0.5 LD50.


Subject(s)
Antioxidants/metabolism , DNA Damage/drug effects , Oxidative Stress/drug effects , Ricin/pharmacology , Animals , Catalase/metabolism , DNA Fragmentation/drug effects , Dose-Response Relationship, Drug , Enzyme Activation/drug effects , Glutathione Peroxidase/metabolism , Glutathione Reductase/metabolism , Kidney/drug effects , Kidney/metabolism , Lipid Peroxidation/drug effects , Liver/drug effects , Liver/metabolism , Male , Mice , Reactive Oxygen Species/metabolism , Spleen/drug effects , Spleen/metabolism , Superoxide Dismutase/metabolism
11.
Toxicon ; 48(3): 272-7, 2006 Sep 01.
Article in English | MEDLINE | ID: mdl-16860833

ABSTRACT

Microcystins are cyclic peptide toxins implicated in several livestock and human deaths. The toxicity of microcystins has been attributed to the highly specific inhibition of serine/theronine protein phosphatases-1 and 2A. Reversible protein phosphorylation is an essential regulatory mechanism in many cellular processes. We aimed to investigate the protein phosphatase inhibition, profile of phosphorylated proteins of serine and threonine residues and microcystin-protein phosphatase adduct in vivo after microcystin-LR exposure by intraperitoneal route in mice. At 1 LD(50), there was significant inhibition of protein phosphatases 1 and 2A activity in liver after 30-120 min exposure but there was no effect in kidney. At 0.5 LD(50) there was no inhibition of protein phosphatase activity in both liver and kidney. Similarly, time-dependent phosphorylation of serine and threonine residues was observed at 1 LD(50). Microcystin-LR-protein phosphatase adduct was time and dose dependent in liver. At 0.5 LD(50) the adduct could be detected at 1 and 3 days post-exposure. No adduct could be detected in kidney.


Subject(s)
Kidney/drug effects , Liver/drug effects , Peptides, Cyclic/toxicity , Animals , Kidney/metabolism , Liver/metabolism , Marine Toxins , Mice , Microcystins , Phosphorylation
12.
Toxicology ; 220(2-3): 136-46, 2006 Mar 15.
Article in English | MEDLINE | ID: mdl-16427180

ABSTRACT

Microcystins are cyclic heptapeptide toxins produced by certain strains of Microcystis aeruginosa and microcystin-LR (MC-LR) is the most toxic among the 70 variants isolated so far. These toxins have been implicated in both human and livestock mortality. In the present study we investigated the microcystin-LR induced oxidative stress in mice in terms of its effect on activity and gene expression profile of certain antioxidant enzymes and expression of heat shock protein-70 (HSP-70). Mice were treated with 0.5 LD50 (38.31 microg/kg) and 1 LD50 (76.62 microg/kg) and the biochemical variables were determined at 1, 3, 7 days and 15, 30, 60 and 120 min post-exposure for 0.5 and 1 LD50 dose, respectively. A significant time-dependent increase in HSP-70 expression over control was observed at 1 LD50 dose. The toxin induced significant increase in liver body weight index, hepatic lipid peroxidation and depletion of GSH levels at 1 LD50 compared to control group. There was significant decrease in the activity of antioxidant enzymes glutathione peroxidase (GPX), superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) and glutathione-S-transferase (GST) at 1 LD50. Except catalase, there was no effect on other antioxidant enzymes at 0.5 LD50 dose. In contrast to activity of antioxidant enzymes the gene expression profile did not show any significant difference compared to control at 1 LD50. GR showed significant decrease in expression at 1, 3 and 7 days in animals dosed with 0.5 LD50 MC-LR. The results of our in vivo study clearly show the oxidative stress induced by MC-LR, and a correlation with activity and regulation at gene expression level of antioxidant enzymes.


Subject(s)
Gene Expression Regulation/drug effects , Liver/enzymology , Peptides, Cyclic/toxicity , Animals , Female , Gene Expression Profiling , Glutathione/metabolism , Glutathione Synthase/genetics , Glutathione Synthase/metabolism , Glutathione Transferase/genetics , Glutathione Transferase/metabolism , HSP70 Heat-Shock Proteins/metabolism , Lethal Dose 50 , Lipid Peroxidation/drug effects , Liver/drug effects , Liver/metabolism , Marine Toxins , Mice , Microcystins , Oxidative Stress , Oxidoreductases/genetics , Oxidoreductases/metabolism
13.
Biochem Pharmacol ; 69(5): 855-65, 2005 Mar 01.
Article in English | MEDLINE | ID: mdl-15710362

ABSTRACT

The mechanism of ricin-induced apoptosis in human cervical cancer cell line HeLa was studied. The present study demonstrated that ricin induces apoptosis of human cervical cancer cells (HeLa) in a time dependent manner with an IC(50) for cell viability of 1 microg/ml. Ricin treatment resulted in a time dependent increase in LDH leakage, DNA fragmentation, percent apoptotic cells, generation of reactive oxygen species and depletion of intracellular glutathione levels. DNA agarose gel electrophoresis showed typical oligonucleosomal length DNA fragmentation. Additionally, DNA diffusion assay was performed to confirm DNA damage and apoptosis. Ricin activated caspase-3 as evidenced by both proteolytic cleavage of procaspase-3 into 20 and 18 kDa subunits, and increased protease activity. Caspase activity was maximum at 4h and led to the cleavage of 116 kDa poly(ADP-ribose) polymerase (PARP), resulting in the 85 kDa cleavage product. Ricin-induced caspase-3 activation also resulted in cleavage of DNA fragmentation factor-45 (DFF45/ICAD) and DFF40 or caspase-activated DNase in HeLa cells. Activation of caspase-3, cleavage of PARP and DNA fragmentation was blocked by pre-treatment with caspase-3 specific inhibitor Ac-DEVD-CHO (100 microM) and broad-spectrum caspase inhibitor Z-VAD-FMK (40 microM). Ricin-induced DNA fragmentation was inhibited by pre-treatment with PARP inhibitors 3-aminobenzamide (100 microM) and DPQ (10 microM). Our results indicate that ricin-induced cell death was mediated by generation of reactive oxygen species and subsequent activation of caspase-3 cascade followed by down stream events leading to apoptotic mode of cell death.


Subject(s)
Apoptosis/drug effects , Ricin/pharmacology , Caspase 3 , Caspases/metabolism , DNA Fragmentation/drug effects , Dose-Response Relationship, Drug , Enzyme Activation/drug effects , Glutathione/metabolism , HeLa Cells , Humans , Oxidative Stress , Poly(ADP-ribose) Polymerases/physiology
14.
J Environ Biol ; 26(3): 511-5, 2005 Jul.
Article in English | MEDLINE | ID: mdl-16334290

ABSTRACT

Most frequently encountered freshwater cyanobacterial toxin is Microcystin-LR (MC-LR). Microcystins released from cells into water have been responsible for the death of humans, domestic and wild animals. Removal of microcystin by active carbon has been one of the best methods available so far. This study evaluates three grades of active carbon namely 40, 60 and 80 CTC for their removal efficiency of MC-LR from contaminated water. Kinetics of toxin removal was studied in time course experiments. Protection in mouse model was studied for the samples after the adsorption. Toxin quantitation was done by HPLC method. The MC-LR concentration after 24 hr treatment with 40, 60 and 80 CTC carbons were 4.8, 3.3 and 1.3 microg/ml respectively from an initial concentration of 5.2 microg/ml. Protection in mouse bioassay was seen after 48, 24 and 2 hr of adsorption time respectively for 40, 60 and 80 CTC carbons. 80 CTC carbon was found to be most efficient in removing MC-LR from contaminated water.


Subject(s)
Bacterial Toxins/chemistry , Carbon/chemistry , Peptides, Cyclic/chemistry , Water Purification/methods , Adsorption , Animals , Biological Assay , Chromatography, High Pressure Liquid , Cyanobacteria/chemistry , Evaluation Studies as Topic , Female , Filtration/methods , Kinetics , Marine Toxins , Mice , Microcystins , Survival Analysis , Time Factors
15.
Br Dent J ; 228(10): 734-735, 2020 05.
Article in English | MEDLINE | ID: mdl-32444707
16.
PhytoKeys ; (52): 95-103, 2015.
Article in English | MEDLINE | ID: mdl-26312036

ABSTRACT

Rhizophoramucronatavar.alokii (Rhizophoraceae), a new variety of Rhizophora from the Andaman and Nicobar Islands, India, is described and illustrated. The new variety is remarkable in having four stamens, laterally folded leaves, a short peduncle, thick leathery petals, and a four-sided ovary with a sessile style. A key for the species of Rhizophora of the Andaman and Nicobar Islands is also provided.

17.
Toxicon ; 44(7): 723-30, 2004 Dec 01.
Article in English | MEDLINE | ID: mdl-15500848

ABSTRACT

The cyclic peptide toxins microcystins and nodularins are the most common and abundant cyanotoxins present in diverse water systems. They have been the cause of human and animal health hazards and even death. Development of suitable chemoprotectants against microcystin is essential considering the human health importance. In the present study, three agents cyclosporin-A (10mg/kg), rifampin (25mg/kg) and silymarin (400mg/kg) pre-treatment gave 100% protection against lethal dose of microcystin-LR (100 microg/kg). Various biochemical parameters were evaluated to study the recovery profile of protected animals at 1, 3, 7 and 14 days post-toxin treatment. There was significant depletion of hepatic glutathione in protected animals compared to control group till 7 days post-treatment but normalised by 14 days. Similarly enhanced hepatic lipid peroxidation, inhibition of protein phosphatase activity was observed till 3-7 days post-treatment in protected animals. Elevated levels of enzymes alanine amino transferase, lactate dehydrogenase and sorbitol dehydrogenase were observed in serum at 1 day post-treatment. All the biochemical variables reached control levels by 14 day post-treatment. Immunoblotting analyses of liver homogenates showed microcystin-protein phosphatase adduct in liver samples of toxin treated as well as antidote-protected animals. The adduct could be seen even after 14 days post-toxin treatment. The study shows that though cyclosporin-A, rifampin and silymarin could offer 100% protection against microcystin-LR induced lethality many of the toxic manifestations are persistent and could not be reversed till 7 days.


Subject(s)
Bacterial Toxins/poisoning , Cyanobacteria/chemistry , Liver/drug effects , Peptides, Cyclic/poisoning , Protective Agents/pharmacology , Alanine Transaminase/blood , Animals , Blotting, Western , Cyclosporine/pharmacology , Female , Glutathione/metabolism , L-Iditol 2-Dehydrogenase/blood , L-Lactate Dehydrogenase/blood , Marine Toxins , Mice , Microcystins , Phosphoprotein Phosphatases/metabolism , Rifampin/pharmacology , Silymarin/pharmacology , Spectrometry, Fluorescence
18.
J Environ Biol ; 23(3): 215-24, 2002 Jul.
Article in English | MEDLINE | ID: mdl-12597562

ABSTRACT

Many species of cyanobacteria (blue-green algae) produce secondary metabolites with potent biotoxic or cytotoxic properties. These metabolites differ from the intermediates and cofactor compounds that are essential for cell structural synthesis and energy transduction. The mass growth of cyanobacteria which develop in fresh, brackish and, marine waters commonly contain potent toxins. Cyanobacterial toxins or cyanotoxins are responsible for or implicated in animal poisoning, human gastroenteritis, dermal contact irritations and primary liver cancer in humans. These toxins (microcystins, nodularins, saxitoxins, anatoxin-a, anatoxin-a(s), cylindrospermopsin) are structurally diverse and their effects range from liver damage, including liver cancer to neurotoxicity. Several incidents of human illness and more recently, the death of 60 haemodialysis patients in Caruaru, Brazil, have been linked to the presence of microcystins in water. In response to the growing concern about the non-lethal acute and chronic effects of microcystins, World Health Organization has recently set a new provisional guideline value for microcystin-LR of 1.0 microg/L in drinking water. Cyanobacteria including microcystin-producing strains produce a large number of peptide compounds, e.g. micropeptins, cyanopeptolins, microviridin, circinamide, aeruginosin, with varying bioactivities and potential pharmacological application. This article discusses briefly cyanobacterial toxins and their implications on human health.


Subject(s)
Bacterial Toxins/adverse effects , Cyanobacteria/chemistry , Eutrophication , Gastroenteritis/etiology , Liver Neoplasms/etiology , Marine Toxins/adverse effects , Peptides, Cyclic/adverse effects , Public Health , Humans , Microcystins , Renal Dialysis , Water Supply
20.
Toxicology ; 262(2): 153-61, 2009 Aug 03.
Article in English | MEDLINE | ID: mdl-19524637

ABSTRACT

T-2 toxin is the most toxic trichothecene and both humans and animals suffer from several pathological conditions after consumption of foodstuffs contaminated with trichothecenes. We investigated the molecular mechanism of T-2 toxin induced cytotoxicity and cell death in HeLa cells. T-2 toxin at LC50 of 10 ng/ml caused time dependent increase in cytotoxicity as assessed by dye uptake, lactatedehydrogenase leakage and MTT assay. The toxin caused generation of reactive oxygen species as early as 30 min followed by significant depletion of glutathione levels and increased lipid peroxidation. The results indicate oxidative stress as underlying mechanism of cytotoxicity. Single stranded DNA damage after T-2 treatment was observed as early as 2 and 4h by DNA diffusion assay. The cells exhibited apoptotic morphology like condensed chromatin and nuclear fragmentation after 4h of treatment. Downstream of T-2 induced oxidative stress and DNA damage a time dependent increase in expression level of p53 protein was observed. The increase in Bax/Bcl2 ratio indicated shift in response, in favour of apoptotic process in T-2 toxin treated cells. Western blot analysis showed increase in levels of mitochondrial apoptogenic factors Bax, Bcl-2, cytochrome-c followed by activation of caspases-9, -3 and -7 leading to DNA fragmentation and apoptosis. In addition to caspase-dependent pathway, our results showed involvement of caspase-independent AIF pathway in T-2 induced apoptosis. Broad spectrum caspase inhibitor z-VAD-fmk could partially protect the cells from DNA damage but could not inhibit AIF induced oligonucleosomal DNA fragmentation beyond 4 h. Results of the study clearly show that oxidative stress is the underlying mechanism by which T-2 toxin causes DNA damage and apoptosis.


Subject(s)
Apoptosis/drug effects , Oxidative Stress/drug effects , T-2 Toxin/toxicity , Uterine Cervical Neoplasms/drug therapy , Amino Acid Chloromethyl Ketones/pharmacology , Cell Survival/drug effects , DNA Damage , DNA, Neoplasm/drug effects , Female , Glutathione/metabolism , HeLa Cells , Humans , Lipid Peroxidation/drug effects , Malondialdehyde/metabolism , Mitochondria/drug effects , Mitochondria/metabolism , Neuroprotective Agents/pharmacology , Oxidative Stress/physiology , Signal Transduction , Tumor Suppressor Protein p53/metabolism , Uterine Cervical Neoplasms/metabolism , Uterine Cervical Neoplasms/pathology
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