Evaluation of lipid oxidation mechanisms in beverages and cosmetics via analysis of lipid hydroperoxide isomers

Abstract

Understanding of lipid oxidation mechanisms (e.g., auto-oxidation and photo-oxidation) in foods and cosmetics is deemed essential to maintain the quality of such products. In this study, the oxidation mechanisms in foods and cosmetics were evaluated through analysis of linoleic acid hydroperoxide (LAOOH) and linoleic acid ethyl ester hydroperoxide (ELAOOH) isomers. Based on our previous method for analysis of LAOOH isomers, in this study, we developed a new HPLC-MS/MS method that enables analysis of ELAOOH isomers. The HPLC-MS/MS methods to analyze LAOOH and ELOOH isomers were applied to food (liquor) and cosmetic (skin cream) samples. As a result, LAOOH and ELAOOH isomers specific to photo-oxidation, and ELAOOH isomers characteristic to auto-oxidation were detected in some marketed liquor samples, suggesting that lipid oxidation of marketed liquor proceeds by both photo- and auto-oxidation during the manufacturing process and/or sales. In contrast, because only LAOOH and ELAOOH isomers specific to auto-oxidation were detected in skin cream stored under dark at different temperatures (−5 °C–40 °C) for different periods (2–15 months), auto-oxidation was considered to be the major oxidation mechanism in such samples. Therefore, our HPLC-MS/MS methods appear to be powerful tools to elucidate lipid oxidation mechanisms in food and cosmetic products.

Direct Separation of the Diastereomers of Cholesterol Ester Hydroperoxide Using LC-MS/MS to Evaluate Enzymatic Lipid Oxidation

“…The synthesized 13(RS)-HPODE-MxP CE was deprotected, and the resultant 13(RS)-HPODE CE was chromatographically purified. The cis-trans structure of the fatty acid chain was confirmed based on the results of 1 H NMR (data not shown), which was in agreement with previous studies [27]. The purity of the obtained 13(RS)-HPODE CE was high enough for use as a standard (>95%), as judged from the MS spectrum (Figure 2a).…”

“…Thus, to fully confirm the diastereoselective separation of 13(RS)-HPODE CE, detailed structural analysis with MS/MS and LC-MS/MS was conducted using the synthesized 13(RS)-HPODE CE standard. In previous studies, we identified that the use of Na + during MS/MS analysis affords structure-diagnostic fragment ions that can identify the position of the hydroperoxyl group of various lipid hydroperoxides (e.g., fatty acid hydroperoxide [17,19,27], triacylglycerol hydroperoxide [28], phospholipid hydroperoxide [18,20,23], and squalene hydroperoxide [29]). Hence, in this study, we expected that the method could also be applied to the analysis of CEOOH.…”

In vitro antioxidant and antihypertensive properties of sesame seed enzymatic protein hydrolysate and ultrafiltration peptide fractions

“…The blank with no added inhibitors showed a rapid increase in absorbance, which reached its maximum value (0.237) on the third day and began a down turn decline as the incubation period progressed to the end (0.089) on the sixth day, possibly due to the formation and accumulation of linoleic oxidation products (He, Girgih, et al., 2013). The observed steep decline in the absorbance of the blank with incubation period could be attributed to depletion of linoleic acid content or decomposition of the peroxides (Ito et al., 2019; Jayaprakasha et al., 2001). The test samples and GSH showed dose‐dependent ILAO.…”

Ferroptosis driven by radical oxidation of n-6 polyunsaturated fatty acids mediates acetaminophen-induced acute liver failure

“…In addition, although Fer-1 was previously considered to be a LOX inhibitor, it is now thought to be a radical trapping agent in membrane phospholipid 33 . In this regard, we and other researchers have developed new procedures to distinguish among oxidation mechanisms by analyzing the structural isomers of lipid hydroperoxides (i.e., PCOOH, fatty acid hydroperoxide, and triacylglycerol hydroperoxide) in foods as well as in serum or tissues in vivo 21,[43][44][45][46] . In the present study, we showed that the isomers characteristic of auto-oxidation were increased compared with those characteristic of other oxidation mechanisms.…”