Screening and quantitative analysis of antioxidants in the fruits of Livistona chinensis R. Br using HPLC-DAD–ESI/MS coupled with pre-column DPPH assay

In Vitro Synergistic Antioxidant Activity and Identification of Antioxidant Components from Astragalus membranaceus and Paeonia lactiflora

“…Among the identified peaks, peaks 1, 3 and 4 were present in PL, while the others (6, 7, 9, 10 and 20) were from AME. Further characterization of these potential antioxidant components was carried out by HPLC-MS/MS, owing to it can provide affluent multistage fragment information for compounds with collision-induced dissociation [31]. As shown in Table 3, seven antioxidant components were unambiguously identified as Oxypaeoniflora (1), Catechin (3), Calycosin-7-O-β-D-glucopyranoside (6), Fomononetin-7-O-β-D-glucopyranoside (7), 9,10-dimethoxy-pterocarpan-3-O-β-D-glucopyranoside (9), 2′-dihydroxy-3′,4′-dimethyl–isoflavan-7-O-β-D-glucopyranoside (10), Quercetin (20), by comparing their UV maximum absorption wavelength, MS and MS/MS data with those of the standard references, as well as the previous reports [32], [33].…”

Strategies for differentiation of isobaric flavonoids using liquid chromatography coupled to electrospray ionization mass spectrometry

“…[35][36][37] Compound 32 which elutes on the tail of the fourth major peak, containing compound 30, was identified as kaempf-3-glu based on similar MRM signal profiles (287/153 and 287/121) as standard analyzed with method 1 (entry 11, Table 3 Table 4). Three different MRM transitions with m/z 317xxx where monitored with method 1 which according to literature [24,38] could correspond to isorhamnetin or petunidin. As only one MRM transition was seen for entry 30 identification could not be done.…”

“…287.1/213.1 (20) 287.1/137.1 (16) 128 (38) 157 (35) 139 (26) 121 (11) 213 (11) 449287 (100) 213 (23) 241 (23) 145 (15) 157 (12) (37) 127 (33) 173 (30) 115 (30) 465.1/303.1 (100) 627.1/303.1 (30) 465303 (100) 257 (11) 229 (10) 285 (8) 165 (5) 22 (47) 203 (47) 229 (27) 479.1/317.1 (100) 479317 (100) 285 (43) 302 (34) 139 (19) 261 (14) ? n.d. not detected.…”

Indirect identification of antioxidants in Polygalae Radix through their reaction with 2,2-diphenyl-1-picrylhydrazyl and subsequent HPLC–ESI-Q-TOF-MS/MS

“…Additionally, the activities of some natural antioxidants are often decreased during the isolation and purification processes due to their decomposition. LC-MS coupled with DPPH [8][9][10][11][12][13] or ABTS [14][15][16] assay methods have been used for the identification of antioxidants in Chinese medicinal herbs. For DPPH assay, the hypothesis is that upon reaction with DPPH.…”