Methods for efficient analysis of tocopherols, tocotrienols and their metabolites in animal samples with HPLC-EC

Synergistic integration of deep learning with protein docking in cardiovascular disease treatment strategies

This research delves into the exploration of the potential of tocopherol-based nanoemulsion as a therapeutic agent for cardiovascular diseases (CVD) through an in-depth molecular docking analysis. The study focuses on elucidating the molecular interactions between tocopherol and seven key proteins (1O8a, 4YAY, 4DLI, 1HW9, 2YCW, 1BO9 and 1CX2) that play pivotal roles in CVD development. Through rigorous in silico docking investigations, assessment was conducted on the binding affinities, inhibitory potentials and interaction patterns of tocopherol with these target proteins. The findings revealed significant interactions, particularly with 4YAY, displaying a robust binding energy of -6.39 kcal/mol and a promising Ki value of 20.84 μM. Notable interactions were also observed with 1HW9, 4DLI, 2YCW and 1CX2, further indicating tocopherol's potential therapeutic relevance. In contrast, no interaction was observed with 1BO9. Furthermore, an examination of the common residues of 4YAY bound to tocopherol was carried out, highlighting key intermolecular hydrophobic bonds that contribute to the interaction's stability. Tocopherol complies with pharmacokinetics (Lipinski's and Veber's) rules for oral bioavailability and proves safety non-toxic and non-carcinogenic. Thus, deep learning-based protein language models ESM1-b and ProtT5 were leveraged for input encodings to predict interaction sites between the 4YAY protein and tocopherol. Hence, highly accurate predictions of these critical protein-ligand interactions were achieved. This study not only advances the understanding of these interactions but also highlights deep learning's immense potential in molecular biology and drug discovery. It underscores tocopherol's promise as a cardiovascular disease management candidate, shedding light on its molecular interactions and compatibility with biomolecule-like characteristics.

Vitamin E in foodstuff: Nutritional, analytical, and food technology aspects

Vitamin E is a group of isoprenoid chromanols with different biological activities. It comprises eight oil-soluble compounds: four tocopherols, namely, α-, β-, γ-, and δ-tocopherols; and four tocotrienols, namely, α-, β-, γ, and δ-tocotrienols. Vitamin E isomers are well-known for their antioxidant activity, gene-regulation effects, and anti-inflammatory and nephroprotective properties. Considering that vitamin E is exclusively synthesized by photosynthetic organisms, animals can only acquire it through their diet. Plant-based food is the primary source of vitamin E; hence, oils, nuts, fruits, and vegetables with high contents of vitamin E are mostly consumed after processing, including industrial processes and home-cooking, which involve vitamin E profile and content alteration during their preparation. Accordingly, it is essential to identify the vitamin E content and profile in foodstuff to match daily intake requirements. This review summarizes recent advances in vitamin E chemistry, metabolism and metabolites, current knowledge on their contents and profiles in raw and processed plant foods, and finally, their modern developments in analytical methods.

Plasma, Prostate and Urine Levels of Tocopherols and Metabolites in Men after Supplementation with a γ-Tocopherol-Rich Vitamin E Mixture

The vitamin E forms γ- and δ-tocopherols (T) inhibit carcinogenesis in animal models; nevertheless, their cancer preventive activities in humans are uncertain. As an initial step to address this issue, we conducted a pilot phase 0 trial to determine the levels of tocopherols and their metabolites in prostate cancer patients undergoing radical prostatectomy. The patients were randomized to no supplementation or two capsules of a γ-T-rich vitamin E mixture daily for 7 or 14 day prior to prostatectomy. Blood and urine samples were collected before supplementation and on the day of surgery, along with prostate tissue, for analysis of tocopherols and their metabolites. Estimated blood loss during surgery was not significantly different across treatment arms and there were no reported adverse events. Prostate tissue levels of γ-T and δ-T were increased after 14 day of supplementation. Their side-chain degradation metabolites (CEHCs and CMBHCs) were significantly elevated in plasma, prostate and urine samples after supplementation for 7 or 14 day. In conclusion, supplementation with γ-T-rich vitamin E increased the prostate levels of γ-T and δ-T. The use of pure γ-T, δ-T or tocopherol mixtures with higher ratio of γ-T or δ-T to α-T is recommended for future studies.

α-Tocomonoenol Is Bioavailable in Mice and May Partly Be Regulated by the Function of the Hepatic α‑Tocopherol Transfer Protein

Tocomonoenols are vitamin E derivatives present in foods with a single double bond at carbon 11' in the sidechain. The α-tocopherol transfer protein (TTP) is required for the maintenance of normal α-tocopherol (αT) concentrations. Its role in the tissue distribution of α-11'-tocomonoenol (αT₁) is unknown. We investigated the tissue distribution of αT₁ and αT in wild-type (TTP^+/+) and TTP knockout (TTP^-/-) mice fed diets with either αT or αT₁ for two weeks. αT₁ was only found in blood, not tissues. αT concentrations in TTP^+/+ mice were in the order of adipose tissue > brain > heart > spleen > lungs > kidneys > small intestine > liver. Loss of TTP function depleted αT in all tissues. αT₁, contrary to αT, was still present in the blood of TTP^-/- mice (16% of αT₁ in TTP^+/+). Autoclaving and storage at room temperature reduced αT and αT₁ in experimental diets. In conclusion, αT₁ is bioavailable, reaches the blood in mice, and may not entirely depend on TTP function for secretion into the systemic circulation. However, due to instability of the test compounds in the experimental diets, further in vivo experiments are required to clarify the role of TTP in αT₁ secretion. Future research should consider compound stability during autoclaving of rodent feed.

Effects of antibiotics on degradation and bioavailability of different vitamin E forms in mice

Tocopherols (T) and tocotrienols (T3), all existing in α, β, γ, and δ-forms, are the eight forms of vitamin E (VE). In this study, we investigated the effects of gut microbiota on the degradation and tissue levels of different VE forms by treating mice with antibiotics in drinking water for 12 days. The mice also received an intragastric (i.g.) dose of VE mixture (mVE; α-T, γ-T, δ-T, γ-T3, and δ-T3, each at a dose of 75 mg/kg) every morning. Antibiotic treatment significantly increased the blood levels of all VE forms in mice that received an i.g. dose of mVE in the morning, 3 h before sacrifice. Without this morning dose, the blood levels of α-T were at the normal physiological levels, but those of the other VE forms were much lower; and the levels of all VE forms were not significantly affected by antibiotics. The liver levels of these VE forms were generally higher and followed the same pattern as the serum. On the contrary, the levels of most side-chain degradation metabolites of VE forms in the serum, liver, kidney, urine, and fecal samples were significantly decreased by antibiotics. The increased bioavailability of VE by antibiotics is probably due to increased absorption of VE or its decreased degradation by gut microbes. The results demonstrate the important roles of gut microbiota in the degradation of VE and in decreasing the bioavailabilities of VE forms. © 2019 BioFactors, 45(3):450-462, 2019.

Oxidative status of a yogurt-like fermented maize product containing phytosterols

This work describes the formulation of a functional yogurt-like product based on fermented maize with added phytosterols and its oxidative stability during cold storage. The technological challenge was to stabilize 3.5% esterified phytosterols (between 2 and 3 g of free sterols) in a low-fat emulsion and to preserve the obtained product throughout processing and storage. The natural bioactive compounds: lutein, zeaxanthin, β-cryptoxanthin, β-carotene and γ-tocopherol were detected in the yogurt, and remained stable during 12 days of refrigeration. Higher content of C18:1 n-9 and C18:3 n-3 (six and ninefold, respectively) were obtained in samples with phytosterols. This was desirable from a nutritional point of view, but at the same time it induced lipid oxidation that was 1.4-fold higher in the product with phytosterols than in the controls. The use of a multivariate approach served to find descriptors which were related to treatments, and to explain their behavior over time.