Monthly Archives: September 2015

Current Technologies in the Extraction, Enrichment and Analytical Detection of Tocopherols and Tocotrienols: A Review.

Malekbala MR, Soltani SM, Hosseini S, Babadi FE, Darajeh N, Malekbala R

Crit Rev Food Sci Nutr. 2015 Jul 24

Abstract

During the past few years the scientific and medical community has been confronted with a continual interest in vitamin E with the interest prompted by new discoveries. Tocopherols and tocotrienols, commonly known as vitamin E, are extremely invaluable compounds and have various nutritional functionalities and benefits to human health. Great deals of research projects have been launched in order to develop effective methods for the extraction of vitamin E. By and large, three distinct extractive methods are usually employed: supercritical fluid extraction, molecular distillation and adsorption methods. These methods are sensitive to different experimental conditions such as pressure, temperature and flow rate with noticeable effects on the efficiency of the extraction and enrichment of vitamin E. This review has covered the most commonly-adapted extraction methods and has probed into the extraction yields under variable operational parameters.

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Vitamin E: A Role in Signal Transduction.

Zingg JM

Annu Rev Nutr. 2015 Jul 17;35:135-73

Abstract

Vitamin E modulates the activity of several signal transduction enzymes with consequent alterations of gene expression. At the molecular level, vitamin E may directly bind to these enzymes and compete with their substrates, or it may change their activity by redox regulation. The translocation of several of these enzymes to the plasma membrane is regulated by vitamin E, suggesting the modulation of protein-membrane interactions as a common mechanism for vitamin E action. Enzyme-membrane interactions can be affected by vitamin E by interference with binding to specific membrane lipids or by altering cellular structures such as membrane microdomains (lipid rafts). Moreover, competition by vitamin E for common binding sites within lipid transport proteins may alter the traffic of lipid mediators and thus affect their signaling and enzymatic conversion. In this review, the main effects of vitamin E on enzymes involved in signal transduction are summarized and possible molecular mechanisms leading to enzyme modulation are evaluated.

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Effect of palm oil (Elaeis guineensis) tocotrienols on mesenteric adipose tissue deposition and the expression of 11β-hydroxysteroid dehydrogenase type 1 enzyme (11β-HSD1) in adrenalectomized rats treated with dexamethasone.

Azwan K, Farihah HS, Fairus A, Elvy MR.

Clin Ter. 2015;166(3):99-104.

Abstract

OBJECTIVES:

A study was done to investigate the effect of palm oil (Elaeis guineensis) tocotrienols on (1) rats mesenteric adipose tissue deposition (2) and 11β-HSD1 enzyme expression in mesenteric adipocyte. There is a necessity to find an inhibitor for the 11β-HSD1 enzyme which enhances the proliferation of mesenteric adipocyte tissue therefore curbing the onset of metabolic syndrome.

MATERIAL AND METHODS:

A total of 35 male Spraque Dawley rats were divided into 5 different groups, i.e., a baseline control group (n=7), a sham operated group (n=7) and three experimental adrenalectomised groups (ADR) (n=21). Each of the experimental ADR group was given intramuscular dexamethasone (Dexa) with a dose of 120 μg/kg after 2 weeks post adrenalectomy and were divided into adrenalectomised control (n=7), Glycyrrhizic acid (GCA) treated (dose=120 mg/kg/day; n=7) and Palm Tocotrienol treated (dose=60 mg/kg/day; n=7) groups. These various treatments were given 6 days a week for 8 weeks via gastric gavage (following 2 weeks of adrenalectomy). Data is expressed as mean ± standard error mean (SEM), compared to each other using one-way analysis-of-variance (ANOVA) followed by Tukey’s post hoc test and then a t-test.

RESULTS:

The results show that palm tocotrienol tend to slightly increase mesenteric adipose tissue deposition in rats. However, palm tocotrienolwas also found to have potential in inhibiting the expression of 11β-HSD1 enzyme in mesenteric adipocytes.

CONCLUSIONS:

This study suggests palm tocotrienol inhibits 11β-HSD1 enzyme expression and activity.

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Synergistic anticancer effects of combined γ-tocotrienol and oridonin treatment is associated with the induction of autophagy.

Tiwari RV, Parajuli P, Sylvester PW.

Mol Cell Biochem. 2015 Jun 27

Abstract

γ-Tocotrienol and oridonin are natural phytochemicals that display potent anticancer activity. Studies showed that combined treatment with subeffective doses of γ-tocotrienol with oridonin resulted in synergistic autophagic and apoptotic effects in malignant +SA, but not normal CL-S1 mouse mammary epithelial cells in vitro. Specifically, combined treatment with low doses of γ-tocotrienol (8 µM) and oridonin (2 µM) for 24 h resulted in synergistic inhibition of +SA mammary cancer cells viability. This combination significantly enhanced the expression of autophagy cellular markers including the conversion of LC3B-I to LC3B-II, beclin-1, Atg3, Atg7, Atg5-Atg12, LAMP-1 and cathepsin-D, and pretreatment with the autophagy inhibitors 3-methyladenine (3-MA) or bafilomycin A1 (Baf1) blocked these effects. Furthermore, blockade of γ-tocotrienol and oridonin-induced autophagy with 3-MA or Baf1 induced a modest, but significant reduction in cytotoxicity resulting from the combined treatment of these phytochemicals. The anticancer effects of combination treatment was also associated with a large suppression in Akt/mTOR mitogenic signaling and corresponding increase in the levels of apoptotic cellular marker including cleaved caspase-3 and PARP, and Bax/Bcl-2 ratio in these tumor cells. These effects were also found to be selective against cancer cells, since similar combined treatment with γ-tocotrienol and oridonin did not induce autophagy or reduce viability of normal mouse CL-S1 mammary epithelial cells. These findings indicate that combined γ-tocotrienol and oridonin-induced autophagy plays a role in mediating the synergistic anticancer effects of these phytochemicals.

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Development and In Vitro Evaluation of Vitamin E-Enriched Nanoemulsion Vehicles Loaded with Genistein for Chemoprevention Against UVB-Induced Skin Damage.

Brownlow B, Nagaraj VJ, Nayel A, Joshi M, Elbayoumi T.

J Pharm Sci. 2015 Oct;104(10):3510-23.

Abstract

There is a great need for effective protection against cutaneous pathologies arising from chronic exposure to harmful solar UVB radiations. A promising pharmaceutical strategy to improve the efficacy of chemotherapeutic/preventative natural compounds (e.g., soy isoflavone Genistein, Gen) is to enhance their dermal delivery using nanoemulsion (NE) formulations. This report investigates the development of nanoemulsifiedtocotrienol(T3)-rich fraction of red palm oil (Tocomin®), to yield an optimal NE delivery system for dermal photoprotection (z-average size <150 nm, ζ-potential ≈ -30 mV, polydispersity index < 0.25). Physicochemical characterization and photostability studies indicate NE formulations utilizing surfactant mixture (Smix) of Solutol® HS-15 (SHS15) blended with vitamin E TPGS (TPGS) as cosurfactant was significantly superior to formulations that utilized Lutrol® F68 (LF68) as the cosurfactant. A ratio of 60:40 of SHS15-TPGS-NE was further identified as lead Tocomin® NE topical platform using in vitro pharmaceutical skin reactivity studies that assess cutaneous irritancy and cytotoxicity. Prototype Tocomin® NE loaded with the antiphotocarcinogenic molecule Gen (Gen-Tocomin® NE) showed slow-release profile in both liquid and cream forms. Gen-Tocomin® NE also showed excellent biocompatibility, and provided substantial UVB protection to cultured subcutaneous L929 fibroblasts, indicating the great potential of our Tocomin® NE warranting further prototype development as topical pharmaceutical platform for skin photoprotection applications.

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