Nanoremediation and Antioxidant Potential of Biogenic Silver Nanoparticles Synthesized Using Leucena's Leaves, Stem, and Fruits.

Synthetic dyes are persistent organic environmental pollutants that can cause extensive damage to living beings and to the ecosystem as a whole. Cost-effective, sustainable, and efficient strategies to deal with this type of pollution are necessary as it commonly resists conventional water treatment methods. Silver nanoparticles (AgNPs) synthesized using the aqueous extract from the leaves, stem, and fruits of Leucaena leucocephala (Leucena) were produced and characterized through UV-vis, TEM, EDS, SDL, XPS, XRD, and zeta potential, and they proved to be able to promote adsorption to remediate methylene blue and tartrazine pollution in water. The nanoremediation was performed and did not require direct exposure to sunlight or any special lamp or a specific reduction agent. The AgNPs produced using the extract from the leaves exhibited the best performance in nanoremediation and also presented antioxidant activity that surpassed the one from butylated hydroxytoluene (BHT). Consequently, it is an interesting nanotool to use in dye nanoremediation and/or as an antioxidant nanostructure.

Chemical characterization, antioxidant activity, and cytotoxicity of fatty acids methyl esters from Handroanthus impetiginosus (Mart. ex DC.) Mattos (Bignoniaceae) seeds.

Handroanthus impetiginosus, popularly known as "ipê-roxo", is used in folk medicine to treat skin inflammations, infections, stomach diseases, and cancer. Fatty acid methyl esters (FAMEs) obtained from the esterification reaction of fatty acids (FA) found in the hexane extract (HE) of seeds of H. impetiginosus were identified by gas chromatography-mass spectrometry (GC-MS). The antioxidant and cytotoxic activities of the HE and FAMEs were evaluated. Methyl palmitate, methyl linoleate, methyl oleate, and methyl stearate were the major FAMEs obtained from the HE. The samples, especially the HE, exhibited a significant antioxidant potential analyzed by ferric reducing ability power (FRAP) assay. In the A. salina larvae bioassay, the HE showed no cytotoxic effects, but the FAMEs exhibited a high toxicity. This study reported, for the first time, the antioxidant and cytotoxic activities of the HE and FAMEs obtained from H. impetiginosus seeds.

Characterisation of bioactive compounds from leaves of Smilax fluminensis Steud. by gc-MS and LC-DAD-MS, and analysis of its antioxidant and ecotoxicological activities.

Smilax fluminensis Steud. is distributed in Central and South America, commonly named as 'salsaparilha' or 'japicanga'. In the present work, the chemical composition was determined, antioxidant and cytotoxic effects were evaluated for the ethanol extract (EE) and fractions from leaves. Fatty acid esters and phytol were characterised in the hexane (HEX) fraction. O-glycosylated flavonols and flavones, caffeic acid derivatives, and steroidal saponins were annotated for EE, and dichloromethane (DCM), ethyl acetate (AC), and hydroethanol (HE) fractions. The samples contain flavonoids and phenolic compounds, and the AC fraction displayed the biggest concentration of these substances. Antioxidant potential was observed in all samples, being especially pronounced in the AC fraction by DPPH and FRAP assays, with IC50 values of 8.18 and 2.35 µg/mL, respectively. AC and HEX fractions showed 35% and 5% lethality at 1000 µg/mL, in the Artemia salina assay, and the other samples did not show a toxic effect.