Application of electron spin resonance (ESR) spectrometry in nutraceutical and food research

Abstract

Electron spin resonance (ESR) spectroscopy is able to directly measure the chemical species with unpaired electrons and has been widely used in a number of research fields. This review focused on its application in nutraceutical and food research. Current status of ESR in free radical scavenging capacity estimation, food oxidative stability evaluation, Cu(2+) chelating capacity determination were summarized. Also discussed was the potential of ESR spin-label oximetry technique in examination of lipid peroxidation and oxygen diffusion-concentration products in liposomes, oxygen transport and depletion, and membrane structure and dynamic properties. In addition, ESR application in identifying and estimating irradiated foods including meat, fruits, vegetables, spices, cereal grains, and oil seeds was reviewed. Finally, the potential use of ESR technique in investigating microstructure change, phase transition and viscosity related properties during food formulation, processing, and storage was briefly mentioned, along with its potential in determination of radio-stability of food components. This review may provide some fundamental knowledge of ESR and its application in nutraceutical and food research.

Traditional Chinese medicine formula Qing Huo Yi Hao as superoxide anion scavenger in high glucose-treated endothelial cells

“…EPR is the only approach (other than enzymatic detection) that can provide direct evidence of the presence of a free radical [25] . Using spin traps, EPR allows the detection of free radicals with short life spans, such as HO • /O 2 •- [26] . In addition, because every free radical has its own typical EPR spectrum, EPR is a unique technique to identify the nature of free radi- cals.…”

“…The HO • free radical was generated through a Fenton reaction (Fe 2+ /H 2 O 2 ). A DMPO spin trap was used to form DMPO/HO • adducts with longer half-lives that were detectable with EPR [26,27] . The DMPO/HO • scavenging ability of QHYH was 82.2%, and it reduced DMPO/ HO • in a concentration-dependent manner (Figure 1 and 2).…”

Food-derived peptidic antioxidants: A review of their production, assessment, and potential applications

“…Electron spin resonance (ESR) spectrometry is a method that has emerged as a useful tool in studying radical-antioxidant interactions and estimating free radical scavenging capacities of antioxidants . This assay is specific with a clear reaction mechanism, simple, and free of interferences from sample matrix components such as pigments (Yu & Cheng, 2008). Direct ESR measurement can be performed using a stable radical species such as DPPH radical, whereas ESR spintrapping method with an exogenous spin-trapping molecule is used to measure short-lived reactive oxygen species (ROS) such as singlet oxygen, hydroxyl, and superoxide anion radicals (Yu & Cheng, 2008 As mentioned previously in Section 3, peptidic antioxidants interact differently with free radical species used in different in vitro chemical assay systems for the assessment of the radical scavenging activity.…”

Involvement of Ras and AP-1 in Helicobacter pylori-Induced Expression of COX-2 and iNOS in Gastric Epithelial AGS Cells

“…AP-1 regulates the gene expression program in response to signals generated by a wide array of extracellular stimuli including growth factors and tumor promoters [18]. AP-1 mediates the expression of COX-2 and iNOS in mouse epidermis [40] and iNOS in human lung carcinoma A549 cells [41]. In relation to H. pylori infection, transcription of COX-2 gene was mediated by the activation of NF-jB and AP-1 in H. pylori-infected human gastric epithelial AGS cells [42].…”