MALDI-TOF/TOF Mass Spectrometric Determination and Antioxidative Activity of Purified Phosphatidylcholine Fractions from Shrimp Species

Abstract

Purification, characterization, and antioxidative activity in vitro of shrimp phosphatidylcholines (PCs) were investigated. The molecular structures of shrimp PCs were determined by MALDI-TOF/TOF MS. The MS fragments produced from protonated PC precursors and sodiated PC precursors were identified. The specific fragments including [M + Na - trimethylamine], [M + Na - 205], [M + Na - RCOOH - trimethylamine], and [M + H - RCOOH - trimethylamine] could distinguish the precursor type to confirm PC molecular structures. The antioxidative activities of purified shrimp PC fractions were evaluated by assay of DPPH free radical scavenging activity, and their effects on the oxidative stability of camellia oil were measured by monitoring changes in the peroxide value assay during oxidation. The PC fractions from Penaeus chinesis and Macrobranchium nipponense showed stronger antioxidative activities than those of other species. All of the shrimp PCs at 0.2% (w/w) improved the oxidative stability of camellia oil significantly (P < 0.05) compared to controls. The experimental findings suggest that shrimp PCs might be a valuable source of natural antioxidants for edible oils or other food dispersions.

Hexaricins, Pradimicin-like Polyketides from a Marine Sediment-Derived Streptosporangium sp. and Their Antioxidant Effects

“…The DPPH • scavenging assay was conducted with 96-well plates using a revised method . All tested compounds were dissolved in MeOH at concentrations of 1.875–120 μg/mL.…”

“…The DPPH • scavenging assay was conducted with 96-well plates using a revised method. 21 All tested compounds were dissolved in MeOH at concentrations of 1.875−120 μg/mL. The absorbance of the mixture was measured at 517 nm using a microplate reader (Multiskan GO, Thermo Scientific).…”

Exploration of natural phosphatidylcholine sources from six beans by UHPLC‐Q‐HRMS

“…A representative MS spectra and MS 2 fragmentation spectra of (18:2‐18:2)PC from common bean ( m/z 782.56671) is shown in Figure 2. The ion mass m/z 184.07301 corresponded to polar headgroup [C 5 H 14 NPO 4 H] + of PC and it was a characteristic fingerprint of PC class (Pacetti, Boselli, Hulan, & Frega, 2005; Zhou et al., 2017). The less intense m/z ions at 104.10732 choline [C 5 H 13 NOH] + , m/z 86.09683 dehydrocholine [C 5 H 12 N] + , and m/z 59.07380 trimethylamine group (TMA) (Al‐Saad, Siems, Hill, Zabrouskov, & Knowles, 2003).…”

“…Fatty acids methyl esters were obtained after transesterification of purified phospholipids according to our previous study (Zhou, Wang, Liang, Huang, & Zeng, 2017). GC (3400 Varian) equipped with an autosampler, a flame ionization detector, and an SP 2560 column [Nonbonded, poly(biscyanopropyl siloxane), 100 m × 0.25 mm, 0.2 µm, Supelco) was used.…”

Egg Yolk Phosphatidylethanolamine: Extraction Optimization, Antioxidative Activity, and Molecular Structure Profiling

“…A variety of ionization techniques are available, such as electrospray ionization (ESI) (Ali et al., ; Pulfer & Murphy, ), atmospheric pressure chemical ionization (APCI) (Lee, Williams, DuBois, & Blair, ), and matrix‐assisted laser desorption/ionization (MALDI) (Calvano, De, Aresta, Facchini, & Zambonin, ; Dong et al., ; Zhou et al., ). Although ESI and APCI are the most frequently used techniques in the analysis of phospholipid structure, MALDI time of flight MS (MALDI‐TOF MS) has been increasingly used to determine phospholipids due to its faster analysis, excellent sensitivity, and high tolerance to salts (Zhou et al., ). Although the length of the fatty alkyl chains and the degree of unsaturation can be analyzed by the assignment of the m / z peaks detected in positive ion MALDI‐TOF MS, the precise location of double bonds in the fatty alkyl chains of phospholipids cannot be determined using this method.…”