Suppression of Menthyl Anthranilate (UV-A Sunscreen)-Sensitized Singlet Oxygen Generation by Trolox and α-tocopherol

Shogo Kitasaka, Mikio Yagi, Azusa Kikuchi

Photochem Photobiol Sci . 2020 Jun 2. doi: 10.1039/d0pp00023j. Online ahead of print.


Menthyl anthranilate (MA, tradename meradimate) is a UV-A absorber. The interactions of ground-state molecular oxygen with the long-lived triplet state of MA produce singlet oxygen through energy transfer. The quantum yield of singlet oxygen generation is 0.12 in air-saturated ethanol. Kinetic traces of the near-IR phosphorescence of singlet oxygen generated by MA-photosensitization have been measured in the absence and presence of Trolox (a water-soluble analogue of vitamin E and a quencher of singlet oxygen) and α-tocopherol (vitamin E, a natural antioxidant) in ethanol. Fluorescence and transient absorption measurements suggest that Trolox and α-tocopherol quench the lowest excited singlet and triplet states of MA. As a result, Trolox and α-tocopherol suppress MA-photosensitized singlet oxygen generation. Not only the quenching of singlet oxygen but also the suppression of singlet oxygen generation is the mechanism of antioxidant properties of Trolox and α-tocopherol for MA. The ability of α-tocopherol to suppress the MA-photosensitized singlet oxygen generation in isododecane, used as a solvent for an oil-soluble UV absorber, is close to that in ethanol. Suppression of sunscreen-photosensitized singlet oxygen generation is an important method for the formulation of safe cosmetic sunscreens.

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Feasibility of Using Vitamin E-Loaded Poly(ε-caprolactone)/Gelatin Nanofibrous Mat to Prevent Oxidative Stress in Skin

Kalantary S, Golbabaei F, Latifi M, Shokrgozar MA, Yaseri M

J Nanosci Nanotechnol. 2020 Jun 1;20(6):3554-3562. doi: 10.1166/jnn.2020.17486.


Some occupational skin exposures lead to the formation of reactive oxygen species (ROS). The occupational exposure of workers to ROS has been found to be associated with an increased risk of developing skin injuries; therefore, it is essential to protect skin against ROS formation. Recently, some studies have been conducted on introducing better alternatives for skin protection. Nanofibers are good candidates for this purpose. The current study was carried out to assess vitamin E-loaded hybrid Poly(ε-caprolactone) (PCL)/gelatin (Gt) nanofibres mats as protective layers of skin exposed to occupational exposures. Vitamin E (VE) was successfully incorporated into PCL/Gt nanofibers while they were formed by electrospinning method. Nanofibers mats were characterized using scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FTIR). Their degradation behavior, in vitro release, biocompatibility, and antioxidant activity were studied. The diameters of the PCL/Gt/VE nanofibers decreased with the addition of vitamin E. The degradation rate of nanofibers was equal to 42.98 and 50.69% during 7 and 14 days, respectively. Nanofibers containing vitamin E showed an initial burst followed by a sustained release. The PCL/Gt/VE nanofibers exhibited good free radical scavenging activities despite being exposed to a high electrical potential during electrospinning. PCL/Gt/VE nanofibers supported a higher level of viability compared to PCL/Gt ones and significantly assisted human skin cells against tert-Butyl hydroperoxide (t-BHP) induced oxidative stress. Overall, PCL/Gt/VE nanofibers can potentially be used to protect skin against oxidative stress as a novel approach for worker’s healthcare.

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Effect of Anoectochilus roxburghii flavonoids extract on H2O2 – Induced oxidative stress in LO2 cells and D-gal induced aging mice model

Wang L, Chen Q, Zhuang S, Wen Y, Cheng W, Zeng Z, Jiang T, Tang C

J Ethnopharmacol. 2020 May 23;254:112670. doi: 10.1016/j.jep.2020.112670. Epub 2020 Mar 3.



Anoectochilus roxburghii (A. roxburghii) is a popular folk medicine in many Asian countries, which has been used traditionally for treatment of some diseases such as diabetes, tumors, hyperlipemia, and hepatitis. The ethanol extract from A. roxburghii was recently shown to exert better ability to scavenge free radicals in vitro and possess antioxidant on natural aging mice in vivo.


This study is to characterize the chemical composition, and investigate the protective effect of the A. roxburghii flavonoids extract (ARF) against hydrogen peroxide (H2O2)-induced oxidative stress in LO2 cells in vitro and D-galactose (D-gal)-induced aging mice model in vivo, and explore the underlying mechanisms.


The chemical components of the flavonoids extract fromA. roxburghii were detected by ultraperformance lipid chromatography coupled with quadrupole-time-of-flight mass spectrometry (UPLC-QTOF-MS/MS). H2O2 was used to establish an oxidative stress model in LO2 cells. Cytotoxic and protective effects of ARF on the LO2 cells were determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Moreover, the levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), and malondialdehyde (MDA) in cell supernatants were measured by commercial reagent kits. Kun-Ming mice were induced to aging with D-gal (400 mg/kg, BW) by subcutaneous injection for 58 days. From the 28th day to the 58th day of D-gal treatment, ARF (122.5, 245 and 490 mg/kg, BW) and vitamin E (100 mg/kg, BW) were orally administrated to aging mice once a day for consecutive 30 days. After 25 days of the treatment with ARF, learning and memory were assessed using Morris Water Maze (MWM). At the end of the test period, the animals were euthanized by cervical dislocation, and the levels of SOD, GSH-PX, and MDA in serum, liver homogenates and brain homogenates were measured. The levels of monoamine oxidase (MAO) and acetylcholinesterase (AchE) were determined in brain homogenates. Skin and liver histopathological morphology were observed by H&E staining. Furthermore, antioxidant-related gene expression levels in the liver were carried out by quantitative real-time polymerase chain reaction (qRT-PCR).


Nine flavonoids were identified in the extracts of A. roxburghii. In vitro assay, a high concentration of ARF (>612.5 μg/ml) reduced the survival rate and had toxic effects on LO2 cells. In addition, ARF (245 μg/ml, 490 μg/ml) and Vitamin C (200 μg/ml) markedly inhibited generations of MDA and increased activities of SOD, GSH-PX in H2O2-induced LO2 cells supernatants. In vivo assay, ARF (122.5 mg/kg, 245 mg/kg and 490 mg/kg) and Vitamin E (100 mg/kg) not only ameliorated learning and memory ability but also improved skin and liver pathological alterations. Strikingly, ARF significantly decreased MDA and MAO levels, markedly enhanced antioxidant enzyme (SOD and GSH-PX) activities. Further, compared to the D-gal group, ARF could obviously up-regulate glutathione peroxidase-1 (GPx-1) and glutathione peroxidase-4 (GPx-4) mRNA levels.


These findings suggested that ARF protects LO2 cells against H2O2-induced oxidative stress and exerts the potent anti-aging effects in D-gal aging mice model, which may be related to the inhibition of oxidative stress. Flavonoid compounds may contribute to the anti-oxidative capability and modulating aging.

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Nodular Panniculitis in a Cat With High Alpha Tocopherol Concentration in Serum

Martin Steffl, Nadine Nautscher, Alexander Kröpfl, Michael Granvogl

Vet Med Sci . 2020 May 18. doi: 10.1002/vms3.286. Online ahead of print.


A 5-year-old male neutered domestic shorthair cat suffered from recurrent solitary nodules in different subcutaneous body regions. Nodules were surgically removed and each time histopathological diagnosis was fat necrosis and fibrosing to pyogranulomatous panniculitis. After the second surgery the alpha (α)-tocopherol concentration in serum of the cat was examined and the result (21 mg/L) exceeded the upper limit of the reference interval (3-11 mg/L). Vitamin E amount in diet fed solely in the past was checked as studies have shown that vitamin E amounts in food significantly influence vitamin E concentrations in serum. For comparative purposes, α-tocopherol concentrations were determined in sera of healthy control cats. Additionally, vitamin E amount in wet food from different manufacturers was analysed using gas chromatography coupled to mass spectrometry (GC-MS). The results showed that the diet did not have higher vitamin E amounts compared to other diets. All control cats had similar high serum α-tocopherol concentrations. We conclude that panniculitis can occur despite high serum α-tocopherol concentrations in cats. Further studies are needed to redefine reference values of α-tocopherol in serum of cats.

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Microemulsion co-delivering vitamin A and vitamin E as a new platform for topical treatment of acute skin inflammation

Praça FG, Viegas JSR, Peh HY, Garbin TN, Medina WSG, Bentley MVLB

Mater Sci Eng C Mater Biol Appl. 2020 May;110:110639. doi: 10.1016/j.msec.2020.110639. Epub 2020 Jan 7.


In this study, we developed a water-in-oil microemulsion containing vitamin A (retinol) and vitamin E (α-tocopherol), which serves as a multifunctional nanosystem that co-delivers antioxidants and displayed additive effect against acute skin inflammation. Microemulsion (ME) was prepared by mixing a surfactant blend (Tween 80 and propylene glycol, 5:1) with isopropyl myristate and water (ratio of 50:40:10, respectively). Vitamin A (0.05% w/w concentration) and/or vitamin E (0.1% w/w concentration) were incorporated into the surfactant mixture of ME by stirring with a magnetic stirrer for 30 min. This multifunctional ME displayed physical stability, with low cytotoxicity in 3T3 cell line, as well as cellular internalization into the cytosol. In vivo treatments using ME delivering α-tocopherol reduced dermal expression of TNF-α by 1.3-fold (p < 0.01), when compared to unloaded ME treatment group. When retinol was added into the ME containing α-tocopherol, it further reduced TNF-α expression by 2-fold (p < 0.001), suggesting the additive effect of vitamin E and vitamin A in the treatment against skin inflammation. In conclusion, we successfully developed the use of water-in-oil ME to pack both vitamin E and vitamin A, and demonstrated for the first time its anti-inflammatory potential when applied topically to TPA-induced inflamed skin.

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Application of Vitamin E Acetate on Staple Lines and Anastomoses of Roux-en-Y Gastric Bypass: Impact on Postoperative Pain and Acute Phase Reactants

Jaime Ruiz-Tovar, Alejandro Garcia, Carlos Ferrigni, Manuel Duran

Obes Surg . 2020 Apr 27. doi: 10.1007/s11695-020-04635-9.


Purpose: Postoperative pain after laparoscopic surgery has 3 components: parietal, visceral, and associated with pneumoperitoneum. Visceral pain accounts for around 30% of the total pain and is less amenable to be controlled by multimodal analgesia. The topical application of vitamin E ointment has demonstrated an anti-inflammatory effect in the local inflammatory response against surgical aggression. Vitamin E has been also associated with a reduction in postoperative pain of skin wounds. The aim of this study was to evaluate the effect of the topical application of vitamin E acetate on staple lines and anastomoses of Roux-en-Y gastric bypass, as part of a multimodal analgesia scheme within an Enhanced Recovery After Surgery (ERAS) program.

Methods: A prospective randomized clinical trial was performed. Patients were divided into 2 groups: patients receiving a topical application of vitamin E on staple lines and anastomoses (G1) and patients not receiving it (G2). The primary endpoint was postoperative pain, as measured by VAS 24 h after surgery. Secondary outcomes include morphine rescue needs, acute phase reactants 24 h after surgery, and hospital stay.

Results: One hundred forty patients were included, 70 in each group. Postoperative pain was 10 mm in G1 and 21.8 mm in G2 (p < 0.001). Morphine needs within the first 24 h were 2.9% in G1 and 13.2% in G2 (p = 0.026). C-reactive protein levels were significantly lower in G1 (8.7 mg/dL vs 11.9; p = 0.016). Mean hospital stay was 2.1 days in G1 and 2.9 in G2 (p = 0.019).

Conclusion: Topical application of vitamin E reduces postoperative pain and acute phase reactants, allowing an earlier discharge.

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Topical Application of a Commercially Available Formulation of Vitamin C Stabilized by Vitamin E and Ferulic Acid Reduces Tissue Viability and Protein Synthesis in Ex Vivo Human Normal Skin

Bruna Romana-Souza, Welker Silva-Xavier, Andréa Monte-Alto-Costa

J Cosmet Dermatol . 2020 Apr 19. doi: 10.1111/jocd.13413.


Background: Aqueous formulations of vitamin C stabilized by vitamin E and ferulic acid at low pH effectively protect skin against reactive oxygen species-induced damage. However, the effects of these formulations on human skin have not clearly been described. The aim of this study was to investigate whether topical application of two commercially available formulations of vitamin C alter human skin using an ex vivo model.

Methods: Human skin explants were topically treated on alternate days with commercially available formulation 1 (15% vitamin C) at 100% (without dilution), 50%, or 10% diluted in saline or formulation 2 (20% vitamin C) at 100% (without dilution), 50%, or 10% diluted in saline. Only saline was applied to control skin explants.

Results: Topical formulation 1 at 100%, 50%, or 10%, but not formulation 2 at 100%, 50%, or 10%, reduced the viability of ex vivo human skin compared to the control after 7, 10, and 13 days. In addition, compared to the control, ex vivo human skin treated with formulation 1 at 50%, but not formulation 2 at 50%, also decreased mRNA levels of actin and ribosomal protein L10 and gene expression of extracellular matrix components after 10 days. Furthermore, after 10 days, topical application of formulation 1 at 50%, but not formulation 2 at 50%, decreased the protein expression of proliferating cellular nuclear antigen, lysyl oxidase, β-actin, and glyceraldehyde-3-phosphate dehydrogenase compared to the control.

Conclusions: Topical formulation 1, but not formulation 2, may reduce the viability of and protein synthesis in ex vivo human skin. Those effects might be due to action of vehicle of formulation 1 on ex vivo human skin.

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Injectable Enzyme-Based Hydrogel Matrix with Precisely Oxidative Stress Defense for Promoting Dermal Repair of Burn Wound

Zhang D, Wang B, Sun Y, Wang C, Mukherjee S, Yang C, Chen Y

Macromol Biosci. 2020 Apr 2:e2000036. doi: 10.1002/mabi.202000036. [Epub ahead of print]


Burn wound healing remains a challenging health problem worldwide due to the lack of efficient and precise therapy. Inherent oxidative stress following burn injury is importantly responsible for prolonged inflammation, fibrotic scar, and multiple organ failure. Herein, a bioinspired antioxidative defense system coupling with in situ forming hydrogel, namely, multiresponsive injectable catechol-Fe3+ coordination hydrogel (MICH) matrix, is engineered to promote burn-wound dermal repair by inhibiting tissue oxidative stress. This MICH matrix serves as the special traits of “Fe-superoxide dismutases,” small molecular antioxidant (vitamin E), and extracellular matrix (ECM) in alleviating cellular oxidative damage, which demonstrates precise scavenging on reactive oxygen species (ROS) of different cellular locations, blocking lipid peroxidation and cell apoptosis. In in vivo burn-wound treatment, this MICH promptly integrates with injured surrounding tissue to provide hydration microenvironment and physicochemical ECM for burn wounds. Importantly, the MICH matrix suppresses tissue ROS production, reducing the inflammatory response, prompting re-epithelization and neoangiogenesis during wound healing. Meanwhile, the remodeling skin treated with MICH matrix demonstrates low collagen deposition and normal dermal collagen architecture. Overall, the MICH prevents burn wound progression and enhances skin regeneration, which might be a promising biomaterial for burn-wound care and other disease therapy induced by oxidative stress.

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Fatty acids based α-Tocopherol loaded nanostructured lipid carrier gel: In vitro and in vivo evaluation for moisturizing and anti-aging effects

Ijaz M, Akhtar N

J Cosmet Dermatol. 2020 Mar 4. doi: 10.1111/jocd.13346. [Epub ahead of print]



α-Tocopherol is a potent antioxidant present in the skin. Its concentration decreases with age. Synthetically available α-tocopherol is viscous, irritating to skin and unstable toward oxidation and ultraviolet (UV) light.


To develop fatty acids based nanostructured lipid carrier (NLC) gel loaded with α-tocopherol and to evaluate its moisturizing and anti-aging properties.


Lauric acid, oleic acid, and Tween-80 were used as solid lipid, liquid lipid, and surfactant, respectively. Seven formulations (F0-F6) were developed by using different concentration of ingredients. Most optimized formulation (F2) was selected for further study on the basis of characterization. Dialysis tube method was used for release study. F2 was incorporated in gel, and then, in vitro and noninvasive in vivo study regarding skin moisture content by corneometer® and skin mechanical properties by cutometer® for 12 weeks on human volunteers (n = 13) was conducted.


Size, polydispersibility index (PDI), zeta potential, and %entrapment efficiency (%EE) of optimized formulation (F2) were found 82 nm, 0.261, -28.6, and 94.88 ± 1.16, respectively. Particles were spherical in shape. The release profile showed initial burst and then sustained release, and release data were best fitted to weibull model. α-tocopherol loaded NLC gel (NLCG) appeared physically stable for 12 weeks at room temperature and showed significant results in terms of skin capacitance and mechanical properties. Rheological assessment showed non-Newtonian behavior.


Fatty acids based NLC proved to be a promising carrier of photochemically unstable lipophilic vitamin E with enhanced moisturizing and anti-aging properties.

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Healing Properties of Epidermal Growth Factor and Tocotrienol-Rich Fraction in Deep Partial-Thickness Experimental Burn Wounds

Guo HF, Abd Hamid R, Mohd Ali R, Chang SK, Rahman MH, Zainal Z, Khaza'ai H

Antioxidants (Basel). 2020 Feb 3;9(2). pii: E130. doi: 10.3390/antiox9020130.


Background: An experimental study was undertaken to determine the efficacy of the epidermal growth factor (EGF) with tocotrienol-rich fraction (TRF) cream in the wound-healing process on skin with deep partial-thickness burn in rats. Methods: A total of 180 Sprague-Dawley rats were randomly divided into six groups of six each and were: untreated control, treated with Silverdin® cream, base cream, base cream with c% EGF, base cream with 3% TRF or base cream with c% EGF and 3% TRF, respectively. Creams were applied once daily for 21 consecutive days. Six animals from each group were sacrificed using anaesthetic overdose on the third, seventh, 11th, 14th and 21st day post-burn. Skin tissues with the wound to be examined were excised for macroscopic and microscopic evaluation and biochemical analyses. Results: EGF + TRF formulation decreased the number of neutrophils, lymphocytes and myofibroblasts post-burn. However, no effects on the number of adipose cells in the healing process were recorded. In addition, lipid peroxidation and nitrite production were found to be reduced post-burn, reducing oxidative stress. Conclusions: Results of the present study indicate that the addition of EGF with TRF have ameliorating effects on deep-partial thickness burn healing parameters.

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