Calendula officinalis L. flower extract-mediated green synthesis of silver nanoparticles under LED light

Abstract Silver nanoparticles (AgNPs) are among the most known nanomaterials being used for several purposes, including medical applications. In this study, Calendula officinalis L. flower extract and silver nitrate were used for green synthesis of silver nanoparticles under red, green and blue light-emitting diodes. AgNPs were characterized by Ultraviolet-Visible Spectrophotometry, Field Emission Scanning Electron Microscopy, Dynamic Light Scattering, Electrophoretic Mobility, Fourier Transform Infrared Spectroscopy and X-ray Diffraction. Isotropic and anisotropic silver nanoparticles were obtained, presenting hydrodinamic diameters ranging 90 - 180 nm, polydispersity (PdI > 0.2) and moderate stability (zeta potential values around - 20 mV)

Potencial de extratos à base de Calendula officinalis L. na indução da síntese de fitoalexinas e no efeito fungistático sobre Botrytis cinerea, in vitro / Potential of Calendula officinalis L. extracts in inducing phytoalexin synthesis and fungistatic effect on Botrytis cinerea in vitro

Foram desenvolvidos três experimentos com o objetivo de avaliar o potencial de preparados a base de calêndula (Calendula officinalis L.) na indução de fitoalexinas em cotilédones de soja, na indução de mecanismos de resistência em frutos de morango, e o efeito fungistático sobre Botrytis cinerea in vitro. O delineamento experimental foi inteiramente casualizado com quatro repetições, para 15 tratamentos resultantes da combinação de três formas de extração (extrato alcoólico, infusão, e maceração) em cinco concentrações (zero; 1,25; 2,5; 5; e 10%). Os resultados demonstram que os preparados de C. officinalis apresentaram capacidade de indução das fitoalexinas gliceolinas em cotilédones de soja. Na aplicação dos preparados em pós-colheita de morangos ocorreu alteração no teor de flavonóides, bem como a atividade da enzima FAL foi estimulada pela aplicação dos extratos; no entanto, não foi constatado o controle de podridão dos frutos. O efeito fungistático foi observado na extração por maceração em todas as suas concentrações reduzindo o crescimento do fungo B. cinerea in vitro sendo que, a partir de 2,5%, observou-se inibição total. A extração por infusão também apresentou resposta positiva na redução do crescimento de B. cinerea, com melhor resposta na concentração de 10% do preparado.

Three experiments were carried out to evaluate the potential of calendula (Calendula officinalis L.) extracts for phytoalexin induction in soybean cotyledons, resistance mechanism induction in strawberry fruits and fungistatic effect on Botrytis cinerea in vitro. Experimental design was completely randomized with 15 treatments resulting from the combination of three forms of extraction (alcohol extract, infusion and maceration) at five concentrations (zero, 1.25, 2.5, 5 and 10%). Results showed that C. officinalis extracts could induce the phytoalexins glyceollins in soybean cotyledons. In the application of extracts during the strawberry postharvest, there was a change in flavonoid content, as well as in the activity of the enzyme PAL, which was stimulated by the application of extracts; however, fruit rot control was not noted. Fungistatic effect was observed for the extract obtained by maceration at all used concentrations, reducing in vitro the growth of the fungus B. cinerea, and from 2.5% there was total inhibition. The extract obtained by infusion also showed a positive response in reducing B. cinerea growth, with better response at the concentration of 10% extract.

Correlation between ovicidal effectiveness and egg-membrane penetration determined by chromatography in two modes of biomphalaria Alexandrina eggs exposure to certain plant and chemical molluscicides

The weak ovicidal effect of the plants having molluscicidal activity is a criterion against their field application in controlling the medically important snails. Chemical molluscicides are potent against snails and their eggs. This work is a trail to use bayluscide and CuSO4 [chemical molluscicides] in sub lethal concentrations to improve the ovicidal effect of Anagallis arvensis and Calendula micrantha plants against the eggs of Biomphalaria alexandrina snails through two modes of eggs exposure. The first was the pre-exposure of snail's eggs to sub lethal concentrations of chemical molluscicides followed by plant exposure and this improve the effect of plants against the snail's eggs with a synergistic ratio ranged from 1.5 to 4.49. While the second mode of exposure is to evaluate the toxicity of mixtures of chemical molluscicides and plants against snail's eggs. It was noticed that this moda resulted in 100% mortality when eggs exposed to mixture of LC15 of C. micrantha or LC25 of A. arvensis with sublethal concentrations of the molluscicides bayluscide or copper sulphate. TLC reveals that the number of the penetrated plant compounds increased in all copper sulphate treatments and in pre-exposure of C. micrantha by bayluscide while the same number of plant compounds were penetrated in the rest of bayluscide treatments as in the cese of the plant alone. So, the increase in plant potency was through chemicals that affect the eggs' membrane to be permeable for more active ingredients [more in number or concentration or both of them] of the tested plants to become in contact with the target embryos