δ-Tocotrienol sensitizes and re-sensitizes ovarian cancer cells to cisplatin via induction of G1 phase cell cycle arrest and ROS/MAPK-mediated apoptosis

Fabrizio Fontana, Monica Marzagalli, Michela Raimondi, Valentina Zuco, Nadia Zaffaroni, Patrizia Limonta

Cell Prolif . 2021 Sep 14;e13111. doi: 10.1111/cpr.13111. Online ahead of print.


Objectives: Among gynaecologic malignancies, ovarian cancer (OC) represents the leading cause of death for women worldwide. Current OC treatment involves cytoreductive surgery followed by platinum-based chemotherapy, which is associated with severe side effects and development of drug resistance. Therefore, new therapeutic strategies are urgently needed. Herein, we evaluated the anti-tumour effects of Vitamin E-derived δ-tocotrienol (δ-TT) in two human OC cell lines, IGROV-1 and SKOV-3 cells.

Materials and methods: MTT and Trypan blue exclusion assays were used to assess δ-TT cytotoxicity, alone or in combination with other molecules. δ-TT effects on cell cycle, apoptosis, ROS generation and MAPK phosphorylation were investigated by flow cytometry, Western blot and immunofluorescence analyses. The synergism between δ-TT and chemotherapy was evaluated by isobologram analysis.

Results: We demonstrated that δ-TT could induce cell cycle block at G1-S phase and mitochondrial apoptosis in OC cell lines. In particular, we found that the proapoptotic activity of δ-TT correlated with mitochondrial ROS production and subsequent JNK and p38 activation. Finally, we observed that the compound was able to synergize with cisplatin, not only enhancing its cytotoxicity in IGROV-1 and SKOV-3 cells but also re-sensitizing IGROV-1/Pt1 cell line to its anti-tumour effects.

Conclusions: δ-TT triggers G1 phase cell cycle arrest and ROS/MAPK-mediated apoptosis in OC cells and sensitizes them to platinum treatment, thus representing an interesting option for novel chemopreventive/therapeutic strategies for OC.

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Oat ( Avena sativa) Extract against Oxidative Stress-Induced Apoptosis in Human Keratinocytes

Sooji Song, Yoon-Mi Lee, Yu Young Lee, Kyung-Jin Yeum

Molecules . 2021 Sep 13;26(18):5564. doi: 10.3390/molecules26185564.


Oat (Avena sativa) is well known for its various health benefits. The protective effect of oat extract against oxidative stress-induced apoptosis in human keratinocytes HaCaT was determined. First, extracts of two varieties of oat, Daeyang and Choyang, were analyzed for fat-soluble antioxidants such as α-tocotrienol, γ-oryzanols, lutein and zeaxanthin using an UPLC system and for antioxidant activity using a DPPH assay. Specifically, an 80% ethanol extract of Daeyang oat (Avena sativa cv. Daeyang), which had high amounts of antioxidants and potent radical scavenging activity, was further evaluated for protective effect against oxidative stress-induced cell death, intracellular reactive oxygen species levels, the phosphorylation of DNA damage mediating genes such as H2AX, checkpoint kinase 1 and 2, and p53 and the activation of apoptotic genes such as cleaved caspase-3 and 7 and poly (ADP-ribose) polymerase in HaCaT cells. The Daeyang and Choyang oat 80% ethanol extracts had 26.9 and 24.1 mg/100 g γ-oryzanols, 7.69 and 8.38 mg/100 g α-tocotrienol, 1.25 and 0.34 mg/100 g of lutein and 1.20 and 0.17 mg/100 g of zeaxanthin, respectively. The oat 80% ethanol extract treatment (Avena sativa cv. Daeyang) had a protective effect on oxidative stress-induced cell death in HaCaT cells. In addition, the oat 80% ethanol extracts led to a significant decrease in the intracellular ROS level at a concentration of 50-200 μg/mL, the attenuation of DNA damage mediating genes and the inhibition of apoptotic caspase activities in a dose dependent manner (50-200 μg/mL). Thus, the current study indicates that an oat (Avena sativa cv. Daeyang) extract rich in antioxidants, such as polyphenols, avenanthramides, γ-oryzanols, tocotrienols and carotenoids, has a protective role against oxidative stress-induced keratinocyte injuries and that oat may a useful source for oxidative stress-associated skin damage.

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Bioactive Electrospun Fibers of Poly(ε-Caprolactone) Incorporating α-Tocopherol for Food Packaging Applications

Raluca P Dumitriu, Elena Stoleru, Geoffrey R Mitchell, Cornelia Vasile, Mihai Brebu

Molecules . 2021 Sep 10;26(18):5498. doi: 10.3390/molecules26185498.


Antioxidant activity is an important feature for food contact materials such as packaging, aiming to preserve freshness and retard food spoilage. Common bioactive agents are highly susceptible to various forms of degradation; therefore, protection is required to maintain functionality and bioavailability. Poly(ε-caprolactone) (PCL), a biodegradable GRAS labeled polymer, was used in this study for encapsulation of α-tocopherol antioxidant, a major component of vitamin E, in the form of electrospun fibers. Rheological properties of the fiber forming solutions, which determine the electrospinning behavior, were correlated with the properties of electrospun fibers, e.g., morphology and surface properties. Interactions through hydrogen bonds were evidenced between the two components. These have strong effect on structuration of macromolecular chains, especially at low α-tocopherol amounts, decreasing viscosity and elastic modulus. Intra-molecular interactions in PCL strengthen at high α-tocopherol amounts due to decreased solvation, allowing good structural recovery after cease of mechanical stress. Morphologically homogeneous electrospun fibers were obtained, with ~6 μm average diameter. The obtained fibers were highly hydrophobic, with fast release in 95% ethanol as alternative simulant for fatty foods. This induced good in vitro antioxidant activity and significant in vivo reduction of microbial growth on cheese, as determined by respirometry. Therefore, the electrospun fibers from PCL entrapping α-tocopherol as bioactive agent showed potential use in food packaging materials.

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The effect of α-tocopherol, α- and γ-tocotrienols on amyloid-β aggregation and disaggregation in vitro

Nor Faeizah Ibrahim, Hamizah Shahirah Hamezah, Daijiro Yanagisawa, Mayumi Tsuji, Yuji Kiuchi, Kenjiro Ono, Ikuo Tooyama

Biochem Biophys Rep . 2021 Sep 10;28:101131. doi: 10.1016/j.bbrep.2021.101131. eCollection 2021 Dec.


One of the neuropathological hallmarks of Alzheimer’s disease (AD)-causing neurodegeneration and consequent memory deterioration, and eventually, cognitive decline-is amyloid-β (Aβ) aggregation forming amyloid plaques. Our previous study showed the potential of a tocotrienol-rich fraction-a mixture of naturally occurring of vitamin E analogs-to inhibit Aβ aggregation and restore cognitive function in an AD mouse model. The current study examined the effect of three vitamin E analogs-α-tocopherol (α-TOC), α-tocotrienol (α-T3), and γ-tocotrienol (γ-T3)-on Aβ aggregation, disaggregation, and oligomerization in vitro. Thioflavin T (ThT) assay showed α-T3 reduced Aβ aggregation at 10 μM concentration. Furthermore, both α-T3 and γ-T3 demonstrated Aβ disaggregation, as shown by the reduction of ThT fluorescence. However, α-TOC showed no significant effect. We confirmed the results for ThT assays with scanning electron microscopy imaging. Further investigation in photo-induced cross-linking of unmodified protein assay indicated a reduction in Aβ oligomerization by γ-T3. The present study thus revealed the individual effect of each tocotrienol analog in reducing Aβ aggregation and oligomerization as well as disaggregating preformed fibrils.

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Effects of eye drops containing a mixture of 3% diquafosol sodium and tocopherol acetate (vitamin E) on the ocular surface of murine dry eye

Lan Li, Rujun Jin, Ying Li, Hee Su Yoon, Hyeon Jeong Yoon, Kyung Chul Yoon

Cutan Ocul Toxicol . 2021 Sep 8;1-9. doi: 10.1080/15569527.2021.1973022. Online ahead of print.


Purpose: To investigate the efficacy of topical application of 3% diquafosol sodium (DQS) and tocopherol (TCP) acetate mixtures in a mouse model of experimental dry eye (EDE).

Methods: After exposure to desiccating stress for 5 days, eye drops consisting of 3% DQS alone, 0.01% TCP alone, or 3% DQS and 0.005% or 0.01% TCP mixture were applied for the treatment of EDE. Tear volume, tear film break-up time (TBUT), corneal fluorescein staining scores (CFSS), and tear film lipid layer grades (TFLLG) were measured at 0, 5 and 10 days after treatment. The 2′,7′-dichlorodihydrofluorescein diacetate assay (DCFDA) for reactive oxygen species (ROS) production, enzyme-linked immunosorbent assay (ELISA) for malondialdehyde (MDA), and flow cytometry for CD4 + interferon (IFN)-γ+ T cells were evaluated on the ocular surface at 10 days after treatment. In addition, levels of tumour necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and chemokine CC motif ligand 4 (CCL4) in the conjunctiva were measured using a multiplex immunobead assay, and conjunctival goblet cells were counted by periodic acid-Schiff staining at 10 days after treatment.

Results: Both the TCP mixture groups indicated a significant improvement in TBUT, ROS production, and MDA concentrations compared to those in the DQS alone group. Furthermore, the 0.01% TCP mixture group also showed higher tear film lipid layer grades and conjunctival goblet cell density and lower corneal fluorescein staining scores, number of CD4 + IFN-γ+ T cells, and levels of TNF-α, IL-1β, and CCL4 than the DQS alone group (P < 0.05).

Conclusions: Application of eye drops containing the mixture of DQS and TCP could stabilize the tear film lipid layer, improve TBUT and corneal epithelial damages, decrease ROS production, inflammatory molecules, and T cells, and increase conjunctival goblet cell density on the ocular surface. Topical DQS and TCP mixtures may have a greater therapeutic effect on clinical signs, oxidative damage, and inflammation of dry eye than DQS eye drops.

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Clarification of the Complexation Behaviour of 2,6-di-O-Methylated β-Cyclodextrin and Vitamin E and Radical Scavenging Ability of the Complex in Aqueous Solution

Shigesaburo Ogawa, Haruka Katsuragi, Katsuya Iuchi, Setsuko Hara

J Oleo Sci . 2021 Sep 8. doi: 10.5650/jos.ess21064. Online ahead of print.


The precise understanding of the behaviour of vitamin E (α-tocopherol; Toc) complexed with cyclodextrin (CD) additives in aqueous solution is a fundamental issue for further development of their aqua-related biological applications. In this study, the solubilisation and complexation behaviours of Toc with methyl-substituted CD derivatives and the radical scavenging ability of the resulting complexes were precisely investigated in water media. Several problems were encountered upon pre-dissolving Toc in an organic solvent prior to the addition to the water media, such as enhancement of the dispersibility and decrease in the complexation capacity. Additionally, dispersions were obtained in some cases when mixing CD and Toc even in the absence of an organic solvent; therefore, to perform the measurements, a transparent solution was prepared via filtration with a nanopore filter. Consequently, unexpectedly, the addition of certain CD methylated derivatives did not always enhance the solubility of Toc significantly. However, 2,6-di-O-methylated β-CD (2,6-DMCD) formed a water-soluble inclusion complex with Toc, effectively enhancing its solubility. A phase solubility study indicated the formation of 1:2 or 1:3 Toc/CD inclusion complexes, and the interaction of 2,6-DMCD with both the chromanol head and the phytol chain of Toc was revealed by 2D ROESY nuclear magnetic resonance analysis. The interaction between 2,6-DMCD and the chromanol head was also confirmed for a 2,6-DMCD-2,2,5,7,8-pentamethyl-6-chromanol inclusion complex. Additionally, a rapid scavenging effect for molecularly dissolved Toc was demonstrated even in a system comprising a chromanol head directly encapsulated by CD. Hence, this work elucidated the precise complexation and radical scavenging ability of 2,6-DMCD-Toc in an aqueous solution, which paves the way for its biological applications.

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Development and Validation of a Liquid Chromatography Mass Spectrometry Method for Simultaneous Measurement of 25(OH)D3, epi-25(OH)D3, 25(OH)D2, Vitamin A, α-Tocopherol, and γ-Tocopherol

Yi Xiao, Edward Ki Yun Leung

Am J Clin Pathol . 2021 Aug 31;aqab088. doi: 10.1093/ajcp/aqab088. Online ahead of print.


Objectives: Fat-soluble vitamins are measured to identify deficiencies that may lead to rickets, osteomalacia, night blindness, and reversible motor and sensory neuropathies. We present a rapid liquid chromatography-mass spectrometry (LC-MS/MS) method that simultaneously measures 25-hydroxyvitamin D3 (25[OH]D3), epi-25(OH)D3, 25(OH)D2, vitamin A, α-tocopherol, and γ-tocopherol.

Methods: We mixed 100 µL serum with internal standard and extracted it by using supported liquid extraction plates. Reconstituted specimens were analyzed by LC-MS/MS with a 10-minute gradient.

Results: The method was linear, covering physiological levels with r2 > 0.99, and the total precision was less than 15% at all quality control levels. The lower limit of the measuring intervals for 25(OH)D3, epi-25(OH)D3, 25(OH)D2, vitamin A, α-tocopherol, and γ-tocopherol were 4 ng/mL, 4 ng/mL, 4 ng/mL, 1 µg/dL, 0.2 µg/mL, and 0.2 µg/mL, respectively, with coefficient of variation of 20% or less. Recoveries were between 92% and 111% for National Institute of Standards and Technology reference materials and 81% and 122% for spike-recovery studies. Comparison studies for vitamin D total, vitamin A, and α-tocopherol demonstrated slopes between 1.04 and 1.11 and r2 between 0.94 and 0.96. Minimal matrix effect was observed for all analytes.

Conclusions: We developed and validated a rapid LC-MS/MS method for the simultaneous measurement of 25(OH)D3, epi-25(OH)D3, 25(OH)D2, vitamin A, α-tocopherol, and γ-tocopherol.

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Tocotrienols as an Anti-Breast Cancer Agent

Madison Trujillo, Anupreet Kharbanda, Christa Corley, Pilar Simmons, Antiño R Allen

Antioxidants (Basel) . 2021 Aug 29;10(9):1383. doi: 10.3390/antiox10091383.


In the past few years, breast cancer has become the most prevalent type of cancer. The majority of patients receive combinatorial chemotherapy treatments, which may result in increased risk of developing drug resistance, a reduced quality of life, and substantial side effects. Treatment modalities that could lessen the physical toll of standard treatments or act in synergy with chemotherapeutic treatments would benefit women worldwide. Research into tocotrienols has thus far demonstrated their potential to be such an agent, with tocotrienols surpassing the pharmacological potential of tocopherols. Further research using in vitro and preclinical breast cancer models to support clinical trials is needed. This review uses bibliometric analysis to highlight this gap in research and summarizes the current and future landscape of tocotrienols as an anti-breast cancer agent.

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The effects of vitamin E on colistin-induced nephrotoxicity in treatment of drug-resistant gram-negative bacterial infections: A randomized clinical trial

Maryam Samsami, Minoosh Shabani, Mohammadreza Hajiesmaeili, Maria Tavakoli-Ardakani, Seyed Hossein Ardehali, Alireza Fatemi, Saghar Barati, Omid Moradi, Zahra Sahraei

J Infect Chemother . 2021 Aug;27(8):1181-1185. doi: 10.1016/j.jiac.2021.03.013. Epub 2021 Apr 15.


Introduction: Nephrotoxicity remains a major long-standing concern for colistin, and it is critical to find agents that can prevent it. The present study aims to investigate the effect of vitamin E on the prevention of colistin-induced nephrotoxicity based on its antioxidant and free radical scavenging properties.

Methods: A randomized clinical trial was designed for 52 patients taking colistin. These patients were categorized into two groups of equal size, receiving colistin or colistin plus vitamin E (α-Tocopherol). Vitamin E with doses of 400 units was administrated daily either orally or by a nasogastric tube if needed. The incidence of Acute Kidney Injury (AKI) and its duration was recorded based on RIFLE criteria.

Results: The Incidence of AKI based on RIFLE criteria was 42.3% and 46.2% in intervention and control groups, respectively. The analysis showed no significant difference in the prevalence of AKI for the two groups (P = 0.78). There was no significant difference in the duration of AKI neither (P = 0.83).

Conclusion: Although vitamin E is a powerful biological antioxidant, the effects of Vitamin E prophylaxis on colistin-induced nephrotoxicity was not taken into consideration in this study.

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The plasma antioxidant vitamin status of the INTAPP cohort examined: The unsuspected importance of β-carotene and γ-tocopherol in preeclampsia

Jean-François Bilodeau, Amélie Gagné, Karine Greffard, François Audibert, William D Fraser, Pierre Julien

Pregnancy Hypertens . 2021 Aug;25:213-218. doi: 10.1016/j.preghy.2021.06.009. Epub 2021 Jun 12.


Objective: Examine the levels of plasma antioxidant vitamins before and during a treatment with placebo or vitamin E + C supplement to prevent preeclampsia (PE).

Study design: Per-protocol analysis of a subset group of pregnant women (n = 295) from the International Trial of Antioxidants for the Prevention of PE (INTAPP) randomized case-control study. Normotensive receiving placebo or vitamins (n = 115 and 87 respectively) were compared to gestational hypertension (GH) without proteinuria (n = 30 and 27) and PE (n = 21 and 15). Vitamin quantification was performed at 12-18, 24-26 and 32-34 weeks of gestation.

Main outcome measures: Coenzyme (Co) Q10, β-carotene and vitamins E (α and γ forms) plasma levels.

Results: Vitamin E + C supplementation was found to increase the α-tocopherol levels by 40% but was associated with a 57% decrease in the γ-tocopherol isoform for all study groups (p < 0.001). The β -carotene was lower in the PE than in the normotensive and GH groups (p < 0.001) while the level of CoQ10 remained unaffected.

Conclusions: A more personalized approach that target the suboptimal levels of specific antioxidants without disturbing the α/γ-tocopherol ratio could be a more successful approach to counteract oxidative stress in PE.

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