Green Fabrication of Silver Nanoparticles using Euphorbia serpens Kunth Aqueous Extract, Their Characterization, and Investigation of Its in Vitro Antioxidative, Antimicrobial, Insecticidal, and Cytotoxic Activities

The silver nanoparticles (AgNPs) were synthesized via green synthesis approach using Euporbia serpens Kunth aqueous extract. The synthesized AgNPs were characterized by UV-visible spectroscopy and Furrier Transformer Infra-Red spectroscopy to justify the reduction and stabilization of AgNPs from its precursors. AgNPs characteristic absorption peak was observed at 420 nm in the UV-visible spectrum. The SEM and TEM analysis demonstrated the spherical shape of the synthesized nanoparticles with particle sizes ranging from 30 nm to 80 nm. FTIR transmission bands at 2920 cm-1, 1639 cm-1, 1410 cm-1, 3290 cm-1, and 1085 cm-1 were attributed to C-H, C=O, C-C, N-H, and C-N functional groups, respectively. XRD peaks could be attributed to (111), (200), (220), and (311) crystalline plane of the faced-centered cube (FCC) crystalline structure of the metallic silver nanoparticles. The AgNPs showed good antibacterial activity against all the tested bacteria at each concentration. The particles were found to be more active against Escherichia coli (E. coli) with 20±06 mm and Salmonella typhi (S.Typhi) with 18±0.5 mm zone of inhibition in reference to standard antibiotic amoxicillin with 23±0.3 mm and 20±0.4 mm zone of inhibition, respectively. Moderate antifungal activities were observed against Candida albicans (C. albicans) and Alternaria alternata (A. alternata) with zone of inhibitions 16.5 mm and 15 mm, respectively, compared to the standard with 23 mm of inhibition. Insignificant antifungal inhibition of 7.5 mm was observed against Fusarium gramium (F. gramium). All the tested concentrations of AgNPs showed comparable % RSA with the standard reference ascorbic acid in the range sixty percent to seventy five percent. The percent motility at 3 hours postincubation showed quick response and most Tetramorium caespitum were found deceased or paralyzed. Similarly, the percent mortality showed a linear response at concentration and time. It was observed that 1 μg/mL to 2 μg/mL concentration of AgNPs displayed a significant cytotoxic activity against Artemia salina with LD50 of 5.37 and 5.82, respectively

Extraction, partial characterization and susceptibility to Hg2+ of acid phosphatase from the microalgae Pseudokirchneriella subcapitata Extração, caracterização parcial e susceptibilidade ao Hg2+ da fosfatase ácida da microalga Pseudokirchneriella subcapitata

Pseudokirchneriella subcapitata is a unicellular green algae widely distributed in freshwater and soils. Due to its cosmopolitan characteristic, its use is recommended by national and international protocols in ecotoxicity studies. The alteration of phosphatase activities by agriculture pollutants like heavy metals has been extensively used as a biomarker in risk assessment and biomonitoring. In this study, we compared the extraction of acid phosphatase from P. subcapitata by different procedures and we studied the stability, substrates specificity, kinetics and the effect of Hg2+ in the crude extract. The freezing and thawing technique associated with probe sonication was the most suitable method of extraction. The enzyme was stable when frozen at -20ºC for at least six months, showed an optimum pH of 5 and a Km value of 0.27 mM for p-nitrophenylphosphate (pNPP) as substrate. Some natural organic substrates were cleaved by a similar extent as the synthetic substrate pNPP. Short term exposure (24 hours) to Hg2+ had little effect but inhibition of the specific activity was observed after 7 days with EC50 (concentration of Hg2+ that promotes 50% decrease of specific activity) value of 12.63 &#956;M Hg2+.<br>Pseudokirchneriella subcapitata é uma alga verde unicelular amplamente distribuída em corpos d´agua e solos. Devido a sua natureza cosmopolita, seu uso é recomendado por protocolos nacionais e internacionais na realização de estudos de ecotoxicidade. A alteração da atividade de fosfatases por agentes poluentes de origem agrícola, como metais pesados, tem sido largamente usada como um biomarcador na avaliação de risco e biomonitoramento. No presente trabalho foi comparada a extração da fosfatase ácida de P. subcapitata por diferentes métodos e estudada a sua estabilidade, especificidade por substratos, cinética e efeito do Hg2+ no extrato bruto. O congelamento e descongelamento, associado com ultrassom, foi o método que proporcionou maior rendimento de extração. A enzima, praticamente estável por armazenamento a -20ºC, durante aproximadamente seis meses, demonstrou uma atividade ótima em pH 5 e um valor de Km para o p-nitrofenilfostato (pNPP) de 0,27 mM. Alguns substratos naturais foram hidrolisados com uma intensidade semelhante à do substrato sintético pNPP. Diferentemente dos estudos de exposição a curto prazo (24 horas), observou-se inibição da atividade específica nas culturas expostas durante 7 dias, com um valor de CE50 (concentração de Hg2+ que promove 50% de decréscimo da atividade específica) equivalente a 12,63 &#956;M Hg2+

Comprovação do efeito antioxidante de plantas medicinais utilizadas no tratamento do Diabetes mellitus em animais: artigo de atualização Evidence of the antioxidant effect of medicinal plants used in the treatment of Diabetes mellitus in animals: an update

Diabetes mellitus (DM) é uma síndrome de etiologia múltipla caracterizada por hiperglicemia crônica. Esta hiperglicemia induz o aumento na produção de espécies reativas de oxigênio (ERO) e diminuição das defesas antioxidantes. Devido às complicações causadas pelo diabete, muitos indivíduos optam por terapias alternativas à base de plantas medicinais para amenizar seus efeitos. Sendo assim, nesta revisão de literatura, foram analisados e descritos diversos trabalhos experimentais com a utilização de animais diabéticos para comprovar os efeitos antioxidantes de algumas dessas plantas e verificar se os títulos e resumos disponibilizados nos artigos são compatíveis aos objetivos de nossa busca.<br>Diabetes mellitus (DM) is a syndrome of multiple etiology characterized by chronic hyperglycemia. This hyperglycemia induces increased production of reactive oxygen species (ROS) and decreased antioxidant defenses. Due to complications caused by diabetes, a large number of people have chosen medicinal plant-based alternative therapies to alleviate its effects. Thus, in this literature review, several experimental studies with the use of diabetic animals were analyzed to demonstrate the antioxidant effects of these plants and to verify if the titles and abstracts provided in the papers are compatible with the aims of our search