Introduction We report, herein, in vitro, and in vivo toxicity evaluation of silver nanoparticles stabilized with gum arabic protein (AgNP-GP) in Daphnia similis, Danio rerio embryos and in Sprague Dawley rats. Purpose The objective of this investigation was to evaluate in vitro and in vivo toxicity of silver nanoparticles stabilized with gum arabic protein (AgNP-GP), in multispecies due to the recognition that toxicity evaluations beyond a single species reflect the environmental realism. In the present study, AgNP-GP was synthesized through the reduction of silver salt using the tri-alanine-phosphine peptide (commonly referred to as “Katti Peptide”) and stabilized using gum arabic protein. Methods In vitro cytotoxicity tests were performed according to ISO 10993–5 protocols to assess cytotoxicity index (IC 50 ) values. Acute ecotoxicity (EC 50 ) studies were performed using Daphnia similis , according to the ABNT NBR 15088 protocols. In vivo toxicity also included evaluation of acute embryotoxicity using Danio rerio (zebrafish) embryos following the OECD No. 236 guidelines. We also used Sprague Dawley rats to assess the toxicity of AgNP-GP in doses from 2.5 to 10.0 mg kg −1 body weight. Results AgNP-GP nanoparticles were characterized through UV (405 nm), core size (20±5 nm through TEM), hydrodynamic size (70–80 nm), Zeta (ζ) potential (- 26 mV) using DLS and Powder X ray diffraction (PXRD) and EDS. PXRD showed pattern consistent with the Ag (1 1 1) peak. EC 50 in Daphnia similis was 4.40 (3.59–5.40) μg L −1 . In the zebrafish species, LC 50 was 177 μg L −1 . Oral administration of AgNP-GP in Sprague Dawley rats for a period of 28 days revealed no adverse effects in doses of up to 10.0 mg kg −1 b.w. in both male and female animals. Conclusion The non-toxicity of AgNP-GP in rats offers a myriad of applications of AgNP-GP in health and hygiene for use as antibiotics, antimicrobial and antifungal agents.

No abstract

Agradeço a Deus pela minha existência e pela oportunidade de aprender sempre nessa escola que é a vida. Aos meus pais que sempre estiveram ao meu lado, me incentivado, torcendo por mim em todos os momentos, e que se não fosse por eles não teria chegado até aqui. Ao Dr. José Roberto Rogero pela oportunidade, pelo acolhimento, pela orientação, pelos conselhos, pelo apoio, pela confiança, paciência e amizade. Muito obrigada por tudo. À Ms. Sizue Ota Rogero por sempre estar ao meu lado em todos os momentos, principalmente os difíceis, me dando apoio sempre. Obrigada pela sua amizade que quero levar para a vida. À Dra. Mônica Lopes Ferreira, do Laboratório Especial de Toxinologia Aplicada (LETA), do Instituto Butantan, pela amizade, pelo fornecimento dos embriões para o estudo, pelos ensinamentos e pelo incentivo. Ao Dra. Ademar Benévolo Lugão pelo acolhimento, atenção, apoio, conselhos e por proporcionar condições laboratoriais para a conclusão deste trabalho.

Human beings concern about healthy life has driven researchers to study new compounds capable of reaching that desire. Resveratrol (3, 4 ', 5-trihydroxystilbene) a phenolic compound, is one of these substances which presents a variety of pharmacological actions, as antioxidant potential, anti-inflammatory capacity, protection against heart and cancer diseases. Despite the resveratrol health benefits studies, there is a little evidence of its toxicity in the literature in aquatic organisms, and especially the data on the concentration of resveratrol in the environment, making the present study fundamental for information about resveratrol ecotoxicity in the aquatic system. The aim of this study was to evaluate the toxicity of resveratrol in embryos and larvae of Danio rerio (zebrafish). The in vitro cytotoxicity and ecotoxicity assays were performed. The IC 50 obtained in the NCTC-L929 cell line cytotoxicity assay was 38.5 mg L-1. The LC 50 (96h) obtained in fish embryo toxicity test was 75.3 mg L-1 and the mean value of resveratrol LC 50 (168h) obtained in the short-term chronic ecotoxicity assays performed with zebrafish larvae was 51.4 mg L-1. This work provided data on the toxicity of resveratrol in the embryonic stage of fish of the species Danio rerio and the toxic effects are dependent on its concentration.

Coal Fly ash is a major solid waste from coal-fired power stations. In Brazil, more than 4 million tons per year of fly ash are generated and only 30% is applied as raw material for cement and concrete production. The remaining is disposed in on-site ponds, nearby abandoned or active mine sites and landfills. The inadequate disposal of fly ash may pose a significant risk to the environment due to the possible leaching of hazardous pollutants into the surrounding soil and groundwater. A combination of leaching tests, cytotoxicity and ecotoxicological assays were used in this studyin order toevaluate the possible adverse effects of coal fly ash in non-target organisms. The sample was collected from coal-fired power plant located in Southern Brazil and the coal fly ash was submitted to a leaching procedure using USEPA SW 864 Method 1311. The leachate was prepared in six dilutions: 1.56%, 3.12%, 6.25%, 12.5%, 25% and 50%. Acute toxicity tests were performed on NCTC clone 929 (CCIAL-020) culture cells by neutral red uptake cytotoxicity method; acute ecotoxicity usingDaphnia similisand Danio rerio embryos according to ABNT NBR 12713 and OECD 236, respectively were employed. The cytotoxicity index (CI 50 ) obtained was 33%; the EC 50 of D. similis after 48 h of exposure to the leachate was 7.25% and the LC 50 of D. rerio after 96 h of exposure was 4.39%. The results of these bioassays indicated toxicity of the coal fly ash leachate toward exposed organisms.

pela oportunidade, orientação, incentivo e confiança no desenvolvimento do doutoramento. Agradeço pela parceria e ensinamentos. Ao Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP) e ao Centro de Química e Meio Ambiente (CEQMA) pela disponibilidade da infraestrutura para a realização deste estudo. Ao Prof. Dr. José Roberto Rogero por me orientar no Programa de Pós-graduação -Mestrado do IPEN e me auxiliar na minha formação como Mestre. Agradeço pelo acolhimento, pelos conselhos, pelo apoio, pela confiança e amizade. À Profª. MSc. Sizue Ota Rogero por sempre estar ao meu lado em todos os momentos, principalmente os difíceis, me dando apoio sempre. Obrigada pela sua amizade que quero levar para a vida.