Tocopheryl phosphate mixture (TPM) as a novel lipid-based transdermal drug delivery carrier: formulation and evaluation.

Gavin PD, El-Tamimy M, Keah HH, Boyd BJ.

Drug Deliv Transl Res. 2016 Sep 26. [Epub ahead of print]

Abstract

Transdermal drug delivery is a useful route of administration that avoids first-pass metabolism and more invasive delivery options. However, many drugs require enhancers to enable sufficient drug absorption to reach therapeutic effect. Alpha-tocopheryl phosphate (TP) and di-alpha-tocopheryl phosphate (T2P) are two phosphorylated forms of vitamin E which form tocopheryl phosphate mixture (TPM) when combined, and have been proposed to enhance the dermal and transdermal delivery of actives of interest. Here, we report the physicochemical characteristics and morphological properties of TPM formulations, including particle size, deformability and morphology, and its ability to facilitate the transport of carnosine, vitamin D3, CoEnzyme Q10 and caffeine into, and across, the skin. Results demonstrate that TPM self-assembles to form vesicular structures in hydroethanolic solutions ranging in mean size from 101 to 162 nM depending on the amount of TPM and ethanol present in the formulation. The ratio of TP to T2P in TPM formulations altered vesicle size and elasticity, with vesicles high in TP found to be more deformable than those rich in T2P. TPM produced a significant (p < 0.05) 2.4-3.4-fold increase in the absorption of carnosine, vitamin D3, CoEnzyme Q10 and caffeine into, or through, the skin. The TPM delivery platform was able to deliver a diverse range of actives with differing size and solubility profiles and therefore has significant potential to expand the number and types of drugs available for topical application and transdermal delivery.

Prasad S, Gupta SC, Tyagi AK, Aggarwal BB.

Br J Cancer. 2016 Sep 27;115(7):814-24. doi: 10.1038/bjc.2016.257.

Abstract

Colorectal cancer (CRC) is one of the most common malignancies worldwide and even develops resistance to chemotherapeutic agents over time. As a result survival for patients with CRC remains poor. We investigated both in vitro and in vivo effects of γ-tocotrienol (γ-T3) alone and in combination with capecitabine. Apoptosis and cytotoxicity assays were performed by MTT and FACS analysis, whereas expression of proteins was investigated using western blotting and immunohistochemistry. The γ-T3 inhibited the proliferation of CRC cells with wild-type or mutated KRAS. It also induced apoptosis, inhibited colony formation, and suppressed key regulators of cell survival, cell proliferation, invasion, angiogenesis, and metastasis. Furthermore, γ-T3 enhanced the anticancer effects of capecitabine in CRC cells. In a nude mouse xenograft model of human CRC, oral administration of γ-T3 inhibited tumour growth and enhanced the antitumour efficacy of capecitabine. Western blot and immunohistochemical analysis results indicated that expression of Ki-67, cyclin D1, MMP-9, CXCR4, NF-κB/p65, and VEGF was lower in tumour tissue from the combination treatment group. Combination treatment also downregulated NF-κB and NF-κB-regulated gene products. In conclusion, our findings suggest that γ-T3 inhibited the growth of human CRC and sensitised CRC to capecitabine by regulating proteins linked to tumourigenesis.

Chin KY, Pang KL, Soelaiman IN.

Adv Exp Med Biol. 2016;928:97-130.

Abstract

Tocotrienol is a member of vitamin E family and is well-known for its antioxidant and anti-inflammatory properties. It is also a suppressor of mevalonate pathway responsible for cholesterol and prenylated protein synthesis. This review aimed to discuss the health beneficial effects of tocotrienol, specifically in preventing or treating hyperlipidaemia, diabetes mellitus, osteoporosis and cancer with respect to these properties. Evidence from in vitro, in vivo and human studies has been examined. It is revealed that tocotrienolshows promising effects in preventing or treating the health conditions previously mentioned in in vivo and in vitro models. In some cases, alpha-tocopherol attenuates the biological activity of tocotrienol. Except for its cholesterol-lowering effects, data on the health-promoting effects of tocotrienol in human are limited. As a conclusion, the encouraging results on the health beneficial effects of tocotrienol should motivate researchers to explore its potential use in human.

Ourique GM, Saccol EM, Pês TS, Glanzner WG, Schiefelbein SH, Woehl VM, Baldisserotto B, Pavanato MA, Gonçalves PB, Barreto KP.

Food Chem Toxicol. 2016 Sep;95:159-67. doi: 10.1016/j.fct.2016.07.011.

Abstract

Long-term administration of valproic acid (VPA) is known to promote reproductive impairment mediated by increase in testicular oxidative stress. Vitamin E (VitE) is a lipophilic antioxidant known to be essential for mammalian spermatogenesis. However, the capacity of this vitamin to abrogate the VPA-mediated oxidative stress has not yet been assessed. In the current study, we evaluated the protective effect of VitE on functional abnormalities related to VPA-induced oxidative stress in the male reproductive system. VPA (400 mg kg(-1)) was administered by gavage and VitE (50 mg kg(-1)) intraperitoneally to male Wistar rats for 28 days. Analysis of spermatozoa from the cauda epididymides was performed. The testes and epididymides were collected for measurement of oxidative stress biomarkers. Treatment with VPA induced a decrease in sperm motility accompanied by an increase in oxidative damage to lipids and proteins, depletion of reduced glutathione and a decrease in total reactive antioxidant potential on testes and epididymides. Co-administration of VitE restored the antioxidant potential and prevented oxidative damage on testes and epididymides, restoring sperm motility. Thus, VitE protects the reproductive system from the VPA-induced damage, suggesting that it may be a useful compound to minimize the reproductive impairment in patients requiring long-term treatment with VPA.

Muddineti OS, Ghosh B, Biswas S.

Expert Opin Drug Deliv. 2016 Sep 6:1-12. [Epub ahead of print]

Abstract

Owing to the complexity of cancer pathogenesis, conventional chemotherapy can be an inadequate method of killing cancer cells effectively. Nanoparticle-based drug delivery systems have been widely exploited pre-clinically in recent years. Incorporation of vitamin-E in nanocarriers have the advantage of (1) improving the hydrophobicity of the drug delivery system, thereby improving the solubility of the loaded poorly soluble anticancer drugs, (2) enhancing the biocompatibility of the polymeric drug carriers, and (3) improving the anticancer potential of the chemotherapeutic agents by reversing the cellular drug resistance via simultaneous administration. In addition to being a powerful antioxidant, vitamin E demonstrated its anticancer potential by inducing apoptosis in various cancer cell lines. Various vitamin E analogs have proven their ability to cause marked inhibition of drug efflux transporters. The review discusses the potential of incorporating vitamin E in the polymeric micelles which are designed to carry poorly water-soluble anticancer drugs. Current applications of various vitamin E-based polymeric micelles with emphasis on the use of α-tocopherol, D-α-tocopheryl succinate (α-TOS) and its conjugates such as D-α-tocopheryl polyethylene glycol-succinate (TPGS) in micellar system is delineated. Advantages of utilizing polymeric micelles for drug delivery and the challenges to treat cancer, including multiple drug resistance have been discussed.

Pathak R, Bachri A, Ghosh SP, Koturbash I, Boerma M, Binz RK, Sawyer JR, Hauer-Jensen M.

Pharm Res. 2016 Sep;33(9):2117-25. doi: 10.1007/s11095-016-1950-0.

Abstract

Ionizing radiation (IR) generates reactive oxygen species (ROS), which cause DNA double-strand breaks (DSBs) that are responsible for cytogenetic alterations. Because antioxidants are potent ROS scavengers, we determined whether the vitamin E isoform γ-tocotrienol (GT3), a radio-protective multifunctional dietary antioxidant, can suppress IR-induced cytogenetic damage. We measured DSB formation in irradiated primary human umbilical vein endothelial cells (HUVECs) by quantifying the formation of γ-H2AX foci. Chromosomal aberrations (CAs) were analyzed in irradiated HUVECs and in the bone marrow cells of irradiated mice by conventional and fluorescence-based chromosome painting techniques. Gene expression was measured in HUVECs with quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). GT3 attenuates radiation-induced cytogenetic damage, possibly by affecting RAD50 expression. GT3 should be explored as a therapeutic to reduce the risk of developing genetic diseases after radiation exposure.

Eitsuka T, Tatewaki N, Nishida H, Nakagawa K, Miyazawa T.

Int J Mol Sci. 2016 Sep 22;17(10). pii: E1605. doi: 10.3390/ijms17101605. Review.

Abstract

Tocotrienol (T3), unsaturated vitamin E, is gaining a lot of attention owing to its potent anticancer effect, since its efficacy is much greater than that of tocopherol (Toc). Various factors are known to be involved in such antitumor action, including cell cycle arrest, apoptosis induction, antiangiogenesis, anti-metastasis, nuclear factor-κB suppression, and telomerase inhibition. Owing to a difference in the affinity of T3 and Toc for the α-tocopherol transfer protein, the bioavailability of orally ingested T3 is lower than that of Toc. Furthermore, cellular uptake of T3 is interrupted by coadministration of α-Toc in vitro and in vivo. Based on this, several studies are in progress to screen for molecules that can synergize with T3 in order to augment its potency. Combinations of T3 with chemotherapeutic drugs (e.g., statins, celecoxib, and gefitinib) or dietary components (e.g., polyphenols, sesamin, and ferulic acid) exhibit synergistic actions on cancer cell growth and signaling pathways. In this review, we summarize the current status of synergistic effects of T3 and an array of agents on cancer cells, and discuss their molecular mechanisms of action. These combination strategies would encourage further investigation and application in cancer prevention and therapy.

Parnan Emamverdikhan A, Golmakani N, Tabassi SA, Hassanzadeh M, Sharifi N, Shakeri MT.

Iran J Nurs Midwifery Res. 2016 Sep-Oct;21(5):475-481.

Abstract

Menopause is associated with various complications such as depression, sleep disorders, and genitourinary atrophy. Vaginal atrophy occurs due to the loss of steroid hormones, and its major symptoms include vaginal dryness, itching, dyspareunia, and bleeding after intercourse. According to the literature, vitamin E plays a key role in estrogen stability. The aim of this study was to compare the effects of vitamin E suppositories and conjugated estrogen vaginal cream on vaginal atrophy.

In this clinical trial, 52 postmenopausal women, who were referred to a gynecology clinic in 2013, were recruited and randomly divided into two groups (26 cases per group). One group received 100 IU of vitamin E suppositories (n = 26), whereas the other group applied 0.5 g of conjugated estrogen cream for 12 weeks. Vaginal maturation value (VMV) was compared between the two groups before and after the intervention. VMV ≤ 55 was regarded as a cut-off point for vaginal atrophy. Treatment success was defined as a 10-unit increase in VMV, compared to the baseline value. Data were analyzed by Friedman test and Mann-Whitney test. P value less than 0.05 was considered statistically significant.

The mean VMV in the vitamin E group before the treatment and after 4, 8, and 12 weeks of treatment was 43.78 ± 13.75, 69.07 ± 22.75, 77.86 ± 21.79, and 80.59 ± 19.23, respectively. The corresponding values in the estrogen cream group were 42.86 ± 14.40, 86.98 ± 12.58, 92.65 ± 15, and 91.57 ± 14.10, respectively. VMV significantly improved in both the treatment groups after the intervention, compared to the preintervention period (P < 0.001). Treatment success was reported in both groups, although estrogen cream (100%) appeared to be more effective after 4 weeks of treatment, compared to vitamin E suppositories (76.9%) (P = 0.01). Based on the findings, use of vitamin E suppositories could improve the laboratory criteria for vaginal atrophy and treatment success. Therefore, vitamin E suppositories are suggested for relieving the symptoms of vaginal atrophy, especially in women who are unable to use hormone therapy or cope with the associated side effects.

Kamezaki C, Nakashima A, Yamada A, Uenishi S, Ishibashi H, Shibuya N, Hama S, Hosoi S, Yamashita E, Kogure K.

J Clin Biochem Nutr. 2016 Sep;59(2):100-106. Epub 2016 Sep 1.

Abstract

Astaxanthin and vitamin E are both effective antioxidants that are frequently used in cosmetics, as food additives, and in to prevent oxidative damage. A combination of astaxanthin and vitamin E would be expected to show an additive anntioxidative effect. In this study, liposomes co-encapsulating astaxanthin and the vitamin E derivatives α-tocopherol (α-T) or tocotrienols (T3) were prepared, and the antioxidative activity of these liposomes toward singlet oxygen and hydroxyl radical was evaluated in vitro. Liposomes co-encapsulating astaxanthin and α-T showed no additive anntioxidative effect, while the actual scavenging activity of liposomes co-encapsulating astaxanthin and T3 was higher than the calculated additive activity. To clarify why this synergistic effect occurs, the most stable structure of astaxanthin in the presence of α-T or α-T3 was calculated. Only α-T3 was predicted to form hydrogen bonding with astaxanthin, and the astaxanthin polyene chain would partially interact with the α-T3 triene chain, which could explain why there was a synergistic effect between astaxanthin and T3 but not α-T. In conclusion, co-encapsulation of astaxanthin and T3 induces synergistic scavenging activity by intermolecular interactions between the two antioxidants.

Chia LL, Jantan I, Chua KH, Lam KW, Rullah K, Aluwi MF.

Front Pharmacol. 2016 Aug 30;7:291. doi: 10.3389/fphar.2016.00291.

Abstract

Tocotrienols (T3) are well-known for their antioxidant properties besides showing therapeutic potential in clinical complications such as hyperlipidemia induced by diabetes. The aim of this study was to determine the effects of δ-T3, γ-T3, and α-T3 on insulin secretion-associated genes expression of rat pancreatic islets in a dynamic culture. Pancreatic islets freshly isolated from male Wistar rats were treated with T3 for 1 h at 37°C in a microfluidic system with continuous operation. The cells were collected for total RNA extraction and reverse-transcribed, followed by measurement of insulin secretion-associated genes expression using quantitative real-time polymerase chain reaction. Molecular docking experiments were performed to gain insights on how the T3 bind to the receptors. Short-term exposure of δ- and γ-T3 to pancreatic β cells in a stimulant glucose condition (16.7 mM) significantly regulated preproinsulin mRNA levels and insulin gene transcription. In contrast, α-T3 possessed less ability in the activation of insulin synthesis level. Essentially, potassium chloride (KCl), a β cell membrane depolarising agent added into the treatment further enhanced the insulin production. δ- and γ-T3 revealed significantly higher quantitative expression in most of the insulin secretion-associated genes groups containing 16.7 mM glucose alone and 16.7 mM glucose with 30 mM KCl ranging from 600 to 1200 μM (p < 0.05). The findings suggest the potential of δ-T3 in regulating insulin synthesis and glucose-stimulated insulin secretion through triggering pathway especially in the presence of KCl.