Unveiling an unexpected superoxide-mediated photooxidation mechanism of squalene monohydroperoxides to squalene hydroperoxy cyclic peroxides through ESR and LC-MS/MS analyses.

Lipid cyclic peroxides are a rarely reported and documented class of compounds in the human organism. Recently, we reported the formation of squalene (SQ) hydroperoxy cyclic peroxides derived from SQ monohydroperoxide isomers (SQ-OOHs) for the first time. Notably, we successfully detected and quantified cis-2-OOH-3-(1,2-dioxane)-SQ in the human skin.

The inhibition of interaction with serum albumin enhances the physiological activity of curcumin by increasing its cellular uptake.

Based on the free drug hypothesis, we hypothesized that food compounds that bind stronger to BSA than CUR inhibit the binding between BSA and CUR, and that this results in an increase of the cellular uptake and physiological activities of CUR. To verify this hypothesis, food compounds that bind stronger to BSA than CUR were identified. When THP-1 monocytes were co-treated with the identified compounds (, piperine) and CUR, cell viability significantly decreased, suggesting that the physiological activity of CUR was enhanced.

Novel Photoinduced Squalene Cyclic Peroxide Identified, Detected, and Quantified in Human Skin Surface Lipids.

Skin surface lipids (SSLs) form the first barrier that protects the human organism from external stressors, disruption of the homeostasis of SSLs can result in severe skin abnormalities. One of the main causes of this disruption is oxidative stress that is primarily due to SSLs oxidation. Squalene (SQ), the most abundant lipid among SSLs, was shown to first undergo singlet molecular oxygen (O) oxidation to yield 6 SQ-monohydroperoxide (SQ-OOH) isomers as the primary oxidation products.

Investigation of Lipoproteins Oxidation Mechanisms by the Analysis of Lipid Hydroperoxide Isomers.

The continuous formation and accumulation of oxidized lipids (e.g., lipid hydroperoxides (LOOH)) which are present even in plasma lipoproteins of healthy subjects, are ultimately considered to be linked to various diseases.