Analytical Strategies to Analyze the Oxidation Products of Phytosterols, and Formulation-Based Approaches to Reduce Their Generation

Abstract

Phytosterols are a class of lipid molecules present in plants that are structurally similar to cholesterol and have been widely utilized as cholesterol-lowering agents. However, the susceptibility of phytosterols to oxidation has led to concerns regarding their safety and tolerability. Phytosterol oxidation products (POPs) present in a variety of enriched and non-enriched foods can show pro-atherogenic and pro-inflammatory properties. Therefore, it is crucial to screen and analyze various phytosterol-containing products for the presence of POPs and ultimately design or modify phytosterols in such a way that prevents the generation of POPs and yet maintains their pharmacological activity. The main approaches for the analysis of POPs include the use of mass spectrometry (MS) linked to a suitable separation technique, notably gas chromatography (GC). However, liquid chromatography (LC)-MS has the potential to simplify the analysis due to the elimination of any derivatization step, usually required for GC-MS. To reduce the transformation of phytosterols to their oxidized counterparts, formulation strategies can theoretically be adopted, including the use of microemulsions, microcapsules, micelles, nanoparticles, and liposomes. In addition, co-formulation with antioxidants, such as tocopherols, may prove useful in substantially preventing POP generation. The main objectives of this review article are to evaluate the various analytical strategies that have been adopted for analyzing them. In addition, formulation approaches that can prevent the generation of these oxidation products are proposed.

Phytosterols and Novel Triterpenes Recovered from Industrial Fermentation Coproducts Exert In Vitro Anti-Inflammatory Activity in Macrophages

“…Due to the antioxidant properties of these compounds, such loss may indicate that oxidation reactions are taking place [ 49 ]. Phytosterols can be oxidized through auto- or photo-oxidation resulting in phytosterols oxidation products (POPs) [ 53 ]. On the one hand, these POPs can be nonpolar when derived by oxidation, dehydrogenation, or dehydration and, on the other hand, polar when derived by epoxidation, hydration, or interaction with oxygen or reactive free radicals.…”

Production, Characterization, Delivery, and Cholesterol-Lowering Mechanism of Phytosterols: A Review

“…49 Third, phytosterols are prone to chemically degrade when exposed to light, heat, or oxygen. The oxidation products generated have no effect on lowering blood lipids and can promote inflammation, 50 cytotoxicity, mutagenicity, and atherosclerosis. 16 These challenges can be overcome using colloidal delivery systems that increase the water-dispersibility, chemical stability, and bioavailability of the phytosterols (Figure 3).…”

Polyphenols, Saponins and Phytosterols in Lentils and Their Health Benefits: An Overview

“…Plant sterols/stanols, also known as phytosterols (PS), are sterols of plant origin, and are important constituents of plant cell membranes, with established health benefits [ 56 ]. Their structure is similar to cholesterol, with a typicalcyclopentane-perhydrophe- nanthrene ring system, an -OH group at position 3 and a side chain at position 17 ( Figure 3 ) [ 57 ].…”

“…The PS content in lentils can be reduced by prolonged heating processes and hrough their oxidation, leading to the formation of phytosterols oxidation products (POPs). Major POPs include 7α/β-hydroxysterols, 7-ketosterols, 5α,6α-/5β,6β-epoxysterols and 3β,5α,6β-triols, which demonstrate cytotoxic and pro-inflammatory effects [ 56 ]. However, to date, no study has reported the content of POPs in lentils.…”