Synthesis of Silver Nanoparticles Using Aqueous Leaf Extract of Mimosa albida (Mimosoideae): Characterization and Antioxidant Activity

Abstract

The search for sensitive and rapid analytical techniques for the determination of natural antioxidants is an area in constant growth due, among other aspects, to the complexity of plant matrices. In this study, silver nanoparticles prepared with the aqueous extract of Mimosa albida leaves were used to assess their polyphenolic content and antioxidant capacity. Silver nanoparticles were characterized by different techniques. As a result, nanoparticles of 6.5 ± 3.1 nm were obtained. The total phenolic content in the extract was 1320.4 ± 17.6 mg of gallic acid equivalents GAE· 100 g−1 and in the nanoparticles 257.3 ± 5.1 mg GAE· 100 g−1. From the phenolic profile analyzed by ultra high-performance liquid chromatography (UPLC) with a diode-array detector (DAD), the presence of apigenin and luteolin in the plant extract is postulated. The antioxidant capacity measured by oxygen radical absorbance capacity ORAC-fluorescein assay was 86917 ± 6287 and 7563 ± 967 µmol ET g−1 in the extract and nanoparticles respectively. Electrochemical analysis by cyclic voltammetry (CV) confirmed the effective reduction capacity of the Mimosa albida leaves extract to reduce Ag ions to AgNPs and differential pulse voltammetry (DPV) suggested the presence of two main reducing agents in the extract. From this study, it was concluded that the aqueous extract of Mimosa albida contains reducing agents capable of synthesizing silver nanoparticles, which can be used in the phytochemical industry.

Determination of Antioxidant Activity by Oxygen Radical Absorbance Capacity (ORAC-FL), Cellular Antioxidant Activity (CAA), Electrochemical and Microbiological Analyses of Silver Nanoparticles Using the Aqueous Leaf Extract of Solanum mammosum L.

“…The selected area electron diffraction (SAED) pattern of the as-prepared silver nanoparticles is shown in Figure 2D and confirms the nanoparticles’ crystalline nature and that the observed structure is silver. 3 , 66 The size measured by the DLS was 22.1 nm ± 2.3 nm, which indicates that the organic coating’s size is approximately 16.9 nm, 70 which is consistent with the nanoparticle size estimated by UV-Vis spectrophotometry. When comparing the size of the AgNPs-Sm obtained from the aqueous extract of S. mammosum fruit (15.3±4.8 nm) 59 to those from other Solanum species such as S. melongena L .…”

“…For the analysis, the protocol suggested by Pilaquinga et al was followed. 66 A CH-Instruments potentiostat, model 700D (Tennison Hill Drive Austin, TX, USA) coupled to a conventional 15 mL three-electrode reaction cell was used. Glassy carbon (GC) was used as a working electrode, Ag/AgCl as a reference electrode, and a platinum wire (0.5 cm in diameter and 3 cm long) as a counter electrode.…”

Dependence of the Ripeness Stage on the Antioxidant and Antimicrobial Properties of Walnut (Juglans regia L.) Green Husk Extracts from Industrial By-Products

“…After this time, 25 µL of APPH solution was added, resulting in a final volume of 200 µL in each plate. The blank was made using a phosphate-buffered solution at pH 7.4, instead of the sample, according to the methodology described by Pilaquinga et al [ 46 ].…”

Electrochemical Methods to Evaluate the Antioxidant Activity and Capacity of Foods: A Review

“…Generally, the peak current is used to estimate the antioxidant capacity or the concentration of antioxidants, whereas the peak potential can be used to identify the type of antioxidants. Applications of this technique for the measurement of antioxidants has been reported for tea [101][102][103][104], fruits, peels and pulps [78,[105][106][107][108][109], wines [67,[110][111][112][113][114][115], spices [116], herbal, plants or roots [79 ,87, 117, 118], dry fruits [119,120], honey [121] and propolis [75,122,123], meats [124], ginger [90], medicinal plant's leave and husk [125,126], beverage [127], coffees [128] and green coffee beans [62], fish oils [129], hops and malt [130] and algae [131].…”