Evaluating the In Vitro Potential of Natural Extracts to Protect Lipids from Oxidative Damage

Abstract

Lipid peroxidation is a chemical reaction known to have negative impacts on living organisms’ health and on consumer products’ quality and safety. Therefore, it has been the subject of extensive scientific research concerning the possibilities to reduce it, both in vivo and in nonliving organic matrices. It can be started by a variety of oxidants, by both ROS-dependent and -independent pathways, all of them reviewed in this document. Another feature of this reaction is the capacity of lipid peroxyl radicals to react with the non-oxidized lipids, propagating the reaction even in the absence of an external trigger. Due to these specificities of lipid peroxidation, regular antioxidant strategies—although being helpful in controlling oxidative triggers—are not tailored to tackle this challenge. Thus, more suited antioxidant compounds or technologies are required and sought after by researchers, either in the fields of medicine and physiology, or in product development and biotechnology. Despite the existence of several laboratory procedures associated with the study of lipid peroxidation, a methodology to perform bioprospecting of natural products to prevent lipid peroxidation (a Lipid Peroxidation Inhibitory Potential assay, LPIP) is not yet well established. In this review, a critical look into the possibility of testing the capacity of natural products to inhibit lipid peroxidation is presented. In vitro systems used to peroxidize a lipid sample are also reviewed on the basis of lipid substrate origin, and, for each of them, procedural insights, oxidation initiation strategies, and lipid peroxidation extent monitoring are discussed.

CG Demethylation Leads to Sequence Mutations in an Anther Culture of Barley Due to the Presence of Cu, Ag Ions in the Medium and Culture Time

“…Most probably, the pathways that require the presence of copper as a cofactor are affected. The two ions, among others, are involved in glycolysis [ 55 ], lipid peroxidation [ 56 , 57 ], and ethylene biosynthesis [ 46 ]. The mentioned pathways may contribute to DNA methylation change either via signaling mechanisms or modifying cytosine residues.…”

Milk Protein-Derived Antioxidant Tetrapeptides as Potential Hypopigmenting Agents

“…To identify the tetrapeptides that exhibit a dual antioxidant and tyrosinase inhibition activity, tetrapeptides that exhibit excellent tyrosinase inhibition activity are selected from each peptide family and these peptides are evaluated in terms of antioxidant activity. A lipid substrate (linoleic acid) formed a peroxide (R-O-O-R’) by oxidative degradation reaction and therefore, lipid peroxide quantification is used for evaluating antioxidant potential [ 39 ], which can be monitored by ferric thiocyanate complexation ( Figure S2 ). To facilitate comparison, we set the relative inhibition of lipid peroxidation of each original oligopeptide to 1.0 and calculated the relative antioxidant activity of the tetrapeptide fragments ( Figure 3 ).…”

Gender-Related Differences in Trimethylamine and Oxidative Blood Biomarkers in Cardiovascular Disease Patients

“…Lipid hydroperoxides are involved in the stress signaling that mediates several cellular responses (i.e., induction of antioxidant enzymes, apoptotic death) and may have gender-dependent regulations. Furthermore, the different level of hydroperoxides may also be related to differences in the metabolic pathways involved in the removal of lipid hydroperoxides and in the repairing reactions; indeed, lipid hydroperoxides should be removed to avoid the propagation of lipid peroxidation [42]. The excision/reduction/repair pathway comprises the activity of several enzymes like phospholipase A2, glutathione peroxidase (GPX), and an acyltransferase, which, as reported in the kinetic models, are less involved in hydroperoxide repair with respect to the enzymes phospholipid hydroperoxide glutathione peroxidase (PHGPX), phospholipase A2, and acyltransferase, that work through reduction/excision/repair reactions.…”

“…Transfected cells with PHGPX were particularly efficient in removing lipid hydroperoxides; PHGPH can interact more easily than GPX with polar (i.e., H 2 O 2 ) and lower polarity substrates (i.e., lipid hydroperoxides). Gender differences in glutathione peroxidase and phospholipase A2 activity have been observed, and they might contribute to partially explain the gender differences in lipid hydroperoxide levels [11,[42][43][44][45].…”