Online HPLC-DPPH screening method for evaluation of radical scavenging phenols extracted from Moringa oleifera leaves

Optimization of the extraction of antioxidants from Moringa leaves: A comparative study between ultrasound‐ and ultra‐homogenizer‐assisted extractions

“…These results agree with several authors (Alves et al, 2016;Meneses et al, 2013;Viell et al, 2020), which have demonstrated that the extraction of antioxidant molecules is improved when used a mixture of solvents. Braham et al, (2019) found lower TFC values (0.472g QE.100 g -1 dry leaf) for extractions via mechanical agitation using the same solid/solvent and water/ ethanol ratio of UT5 and US5. Such comparison reinforce the superiority of the emerging extraction methods in relation to the traditional techniques.…”

“…However, it is important to highlight that the F I G U R E 1 Response surfaces (contour plots) for extraction yield (a), TPC (b), and DPPH (c) as a function of water/ethanol proportions and solid/solvent ratio for HAE extraction DPPH antioxidant activity values produced positive values for the linear coefficients of the water/ethanol ratio, which indicates that the increase in ethanol increased the antioxidant capacity. This fact could be associated with the DPPH method which estimates the antioxidant action of fat-soluble compounds that have an affinity for organic solvents such as ethanol(Sucupira et al, 2014) Braham et al, (2019). reported a lower DPPH antioxidant capacity value (56 µmol Trolox 100 g -1 of Moringa dry leaf) when investigating the extraction with a 1:1 ethanol-water solution using maceration with magnetic stirring.…”

Preparative isolation of 1,1‐diphenyl‐2‐picrylhydrazyl inhibitors from Ribes himalense using medium‐pressure and two‐dimensional reversed‐phase/reversed‐phase liquid chromatography guided by an online HPLC‐1, 1‐diphenyl‐2‐picrylhydrazyl assay

“…For such approaches, two HPLC are connected by a mixer and a reaction coil, with DPPH being added to the postcolumn flow such that antioxidants can be detected based on a reduction in absorbance at 517 nm. This approach has been utilized to discover antioxidative compounds in several plants and food products to date [14–16].…”

Preparative separation of 1,1-diphenyl-2-picrylhydrazyl inhibitors originating from Saxifraga sinomontana employing medium-pressure liquid chromatography in combination with reversed-phase liquid chromatography

“…DPPH inhibitors can be efficiently identied in extracts of various NPs using this technique. [25][26][27][28][29][30] Reversed-phase liquid chromatography (RPLC) is a technique of choice for isolating and purifying individual components from NPs. [31][32][33][34][35][36] As a technique with high reproducibility and real-time tracking of the chemical constitution of the eluent, it can largely be automated.…”