Monthly Archives: November 2014

Tocotrienol-rich fraction, [6]-gingerol and epigallocatechin gallate inhibit proliferation and induce apoptosis of glioma cancer cells.

Amirah Abdul Rahman, Suzana Makpol, Rahman Jamal, Roslan Harun, Norfilza Mokhtar and Wan Zurinah Wan Ngah

Molecules 2014, 19(9), 14528-14541

Abstarct

Plant bioactives [6]-gingerol (GING), epigallocatechin gallate (EGCG) and asiaticoside (AS) and vitamin E, such as tocotrienol-rich fraction (TRF), have been reported to possess anticancer activity. In this study, we investigated the apoptotic properties of these bioactive compounds alone or in combination on glioma cancer cells. TRF, GING, EGCG and AS were tested for cytotoxicity on glioma cell lines 1321N1 (Grade II), SW1783 (Grade III) and LN18 (Grade IV) in culture by the (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxy-phenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt) (MTS) assay. With the exception of AS, combinations of two compounds were tested, and the interactions of each combination were evaluated by the combination index (CI) using an isobologram. Different grades of glioma cancer cells showed different cytotoxic responses to the compounds, where in 1321N1 and LN18 cells, the combination of EGCG + GING exhibited a synergistic effect with CI = 0.77 and CI = 0.55, respectively. In contrast, all combinations tested (TRF + GING, TRF + EGCG and EGCG + GING) were found to be antagonistic on SW1783 with CI values of 1.29, 1.39 and 1.39, respectively. Combined EGCG + GING induced apoptosis in both 1321N1 and LN18 cells, as evidenced by Annexin-V FITC/PI staining and increased active caspase-3. Our current data suggests that the combination of EGCG + GING synergistically induced apoptosis and inhibits the proliferation 1321N1 and LN18 cells, but not SW1783 cells, which may be due to their different genetic profiles.

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Antioxidant activities of annatto and palm tocotrienol-rich fractions in fish oil and structured lipid-based infant formula emulsion.

Zou L, Akoh CC

Food Chem. 2015 Feb 1; 168:504-11

Abstract

The abilities of annatto and palm tocotrienol-rich fractions (TRFs), as natural antioxidants, to inhibit lipid oxidation in menhaden fish oil and structured lipid-based infant formula emulsion, were evaluated and compared. The peroxide and anisidine values of the bulk oil and oil-in-water emulsion samples stored at 37°C were measured over a 28-day period. The results showed that annatto TRF was a more effective antioxidant than palm TRF and α-tocopherol in both food systems at 0.02% and 0.05%. Factors, including structural differences in chromanol head and isoprenoid tail, polarity, concentration, oxidation time, and the method used to monitor lipid oxidation, were responsible for the different behaviours of tocopherols and tocotrienols. In contrast to the reported findings in vivo, addition of α-tocopherol (0-75%) did not interfere with the antioxidant activity of tocopherol-free annatto TRF in foods. Our findings may lead to the development of new natural antioxidant products for food applications.

Distribution of Tocopherols and Tocotrienols in Guinea Pig Tissues Following Parenteral Lipid Emulsion Infusion.

Xu Z, Harvey KA, Pavlina TM, Zaloga GP, Siddiqui RA

J Parenter Enteral Nutr. 2014 Aug 28

Abstract:  Tocopherols and tocotrienols possess vitamin E activity and function as the major lipid-soluble antioxidants in the human body. Commercial lipid emulsions are composed of different oils and supply different amounts of vitamin E. The objective of this study was to measure all 8 vitamin E homologs within 4 different commercial lipid emulsions and evaluate their distribution in guinea pig tissues. Materials and Methods: The distribution of vitamin E homologs within plasma and guinea pig tissues was determined using a high-performance liquid chromatography (HPLC) system. Lipid hydroperoxides in lipid emulsions were determined using a commercial kit (Cayman Chemical Company, Ann Arbor, MI), and malondialdehyde tissue levels were determined using an HPLC system. Results: The lipid emulsions contained variable amounts of tocopherols, which were significantly different between emulsions. Tocotrienols were present at very low concentrations (≤0.3%). We found no correlation between the amount of vitamin E present in the lipid emulsions and lipid peroxidation. Hydroperoxides were the lowest with an olive oil-based emulsion and highest with a fish oil emulsion. The predominant vitamin E homolog in guinea pig tissues was α-tocopherol. No tissues had detectable levels of tocotrienols. Vitamin E levels (primarily α-tocopherol and γ-tocopherol) were highly variable among organ tissues. Plasma levels were a poor reflection of most tissue levels. Conclusion: Vitamin E levels within different lipid emulsions and plasma/tissues are highly variable, and no one tissue or plasma sample serves as a good proxy for levels in other tissues. All study emulsions were well tolerated and did not significantly increase systemic lipid peroxidation.