Samples of whole grain and 35% pearling flour of 20 different barley varieties grown in Alberta were analyzed for their lipid contents. Total lipid contents of whole grains were within 1.9% to 3.0% (w/w), whereas those of the 35% pearling flour were 4.3% to 7.9%. Lipids of 35% pearling flour fraction of Tercel barley were extracted using supercritical carbon dioxide (SC-CO2 ) at different pressures (24, 45, and 58 MPa) and temperatures (40 and 60 °C) for 3 h. Lipid recoveries of 73% to 97% were achieved using SC-CO2 extraction under different operational conditions. Tocol contents and compositions of whole grain, 35% pearling flour, and SC-CO2 extracts were analyzed using HPLC. Tocol content of the whole grain was 53.8 to 124.9 μg/g and that of the pearling flour was 195 to 363 μg/g of flour. The hulless barley varieties were higher in tocols, with waxy, double waxy and Tercel varieties having the highest levels (P < 0.05). The ratios of total tocotrienols to total tocopherols varied within 1.6 to 3.9 range. Tocol concentrations of SC-CO2 extract fractions varied from 1171 to 4391 μg/g extract depending on the operational conditions. Barley oil is a good natural source of different tocol isomers rich in tocotrienols.

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Phytochemical investigation of a dichloromethane extract from Garcinia amplexicaulis stem bark led to the isolation of four new tocotrienols (1-4); two known tocotrienols, two triterpenes, and a xanthone were also isolated. Their structures were mainly established using NMR and MS methods. The main compounds isolated, δ-amplexichromanol (1) and γ-amplexichromanol (2), were evaluated on VEGF-induced angiogenesis using a Matrigel assay. Compounds 1 and 2 inhibited in vitro angiogenesis of VEGF-induced human primary endothelial cells in the low nanomolar range. Their capacity to inhibit VEGF-induced proliferation of endothelial cells partially explained this activity, although δ-amplexichromanol (1) also prevented adhesion and migration processes.

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BACKGROUND:

The main component in tocotrienols (T3) from barley (Hordeum vulgare L.) is α-T3, the vitamer with the highest bioavailability, while palm oil T3 is particularly rich in γ-T3. Unlike tocopherols, T3 are known for their cholesterogenesis-inhibiting, neuroprotective, and anticarcinogenic properties. We compared the oral bioavailabilities of T3 from barley oil (3.98 mg day-1 ) and T3 from palm oil (3.36 mg day-1 ) in nanoemulsified formulations (NE) and self-emulsifying systems (SES) using hen’s eggs as a bioindicator. Furthermore, we compared the transfer efficiencies into egg yolk of barley oil T3 with that of palm oil T3, and the effects on egg cholesterol levels.

RESULTS:

Nanoemulsification led to T3 levels (132.9 µg egg-1 ) higher than with non-emulsified barley oil (112.8 µg egg-1 ) and barley oil SES (116.7 µg egg-1 ), due to the high proportions of α-T3 (99-117 µg egg-1 ), which has a particularly high transfer efficiency (4.32%-6.75%). T3 contents of eggs from hens fed barley oil supplements (112-132 µg egg-1 ) were significantly higher than those fed palm oil supplements (70-78 µg egg-1 ). Addition of barley and palm oils to laying hen feed decreased egg yolk cholesterol by 4% and 6%, respectively.

CONCLUSION:

Results from this animal study may help to establish T3 from barley as dietary supplement and to develop nutritionally improved hen eggs.

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Tocotrienol delays onset and progression of galactose-induced cataract in rat

Nurul Alimah ABDUL NASIR , Renu AGARWAL , Minaketan TRIPATHY, Renad ALYAUTDIN , Nafeeza MOHD ISMAIL

Aim: Tocotrienol (T3) is known to have potent antioxidant properties. Since
oxidative stress plays a major role in the cataract formation, we hypothesized that
T3 delays cataract development. We aimed to investigate effect of T3 eyedrop in
delaying onset and progression of galactose-induced cataract. Methods: 3 weeksold
Sprague-Dawley rats were divided into 8 groups. Group 1 received normal diet
while rest of the groups received 25% galactose diet. Groups 3-8 received one of 6
different doses of microemulsion of T3 ranges from 0.2-0.01% twice daily. Group
2 was similarly treated with vehicle. Pre-treatment was given for 3 weeks and was
continued for 4 weeks after starting the galactose diet. Slit lamp examination was
done biweekly to assess cataract progression. Cataractous changes were graded
from 0-4 according to progression of cortical vacuole formation to nuclear opacity.
Results: At week 1 of galactose diet, groups 3 and 4 had higher percentage of lenses
that progressed to stage 1B compared to group 2 in which progression was less
severe, whereas in groups 6 and 7, 10% and 25% lenses respectively remained in
stage 0. Groups 3 and 4 continued to show more advanced cataract progression
compared to group 2 in the following weeks until end of experimental period.
However, cataract progression was delayed in groups 6-8 during these subsequent
weeks. Conclusion: T3 delayed cataract progression at low doses but enhanced
cataract progression at higher doses.

Tocotrienol supplementation in postmenopausal osteoporosis: evidence from a laboratory study.

Muhammad N, Luke DA, Shuid AN, Mohamed N, Soelaiman IN.

OBJECTIVE:

Accelerated bone loss that occurs in postmenopausal women has been linked to oxidative stress and increased free radicals. We propose the use of antioxidants to prevent and reverse postmenopausal osteoporosis. This study aimed to examine the effects of tocotrienol, a vitamin E analog, on bone loss due to estrogen deficiency. Our previous study showed that tocotrienol increased the trabecular bone volume and trabecular number in ovariectomized rats. In the current study, we investigated the effects of tocotrienol supplementation on various biochemical parameters in a postmenopausal osteoporosis rat model.

MATERIALS AND METHODS:

A total of 32 female Wistar rats were randomly divided into four groups. The baseline group was sacrificed at the start of the study, and another group was sham operated. The remaining rats were ovariectomized and either given olive oil as a vehicle or treated with tocotrienol at a dose of 60 mg/kg body weight. After four weeks of treatment, blood was withdrawn for the measurement of interleukin-1 (IL1) and interleukin-6 (IL6) (bone resorbing cytokines), serum osteocalcin (a bone formation marker) and pyridinoline (a bone resorption marker).

RESULTS:

Tocotrienol supplementation in ovariectomized rats significantly reduced the levels of osteocalcin, IL1 and IL6. However, it did not alter the serum pyridinoline level.

CONCLUSION:

Tocotrienol prevented osteoporotic bone loss by reducing the high bone turnover rate associated with estrogen deficiency. Therefore, tocotrienol has the potential to be used as an anti-osteoporotic agent in postmenopausal women.

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γ-Tocotrienol-induced autophagy in malignant mammary cancer cells.

Tiwari RV, Parajuli P, Sylvester PW.

γ-Tocotrienol, a member of the vitamin E family of compounds, displays potent antiproliferative and cytotoxic effects in a variety of cancer cell types at treatment doses that have little or no effect on normal cell viability or growth. Autophagy is a tightly regulated lysosomal self-digested process that can either promote cell survival or programmed cell death, but the role of autophagy in mediating γ-tocotrienol-induced cytotoxicity in breast cancer is not presently completely understood. Mouse (+SA) and human (MCF-7 and MDA-MD-231) mammary tumor cells lines were exposed to 0-40 µmol/L γ-tocotrienol for a 24 h treatment period. γ-Tocotrienol treatment caused a relatively large increase in the accumulation of monodansylcadaverine (MDC)-labeled vacuoles, a marker of autophagosome formation, in all tumor cell lines. Results also showed that γ-tocotrienol treatment induced an increased conversion of microtubule-associated protein, 1A/1B-light chain 3, from its cytosolic form (LC3B-I) to its lipidated form (LC3B-II), increased Beclin-1 levels, and increased acridine orange staining as determined by flow cytometry analysis, providing further evidence of γ-tocotrienol-induced autophagy in these mammary cancer cell lines. In contrast, similar treatment with γ-tocotrienol was not found to increase autophagy marker expression in immortalized mouse (CL-S1) and human (MCF-10 A) normal mammary epithelial cell lines. Treatment with γ-tocotrienol also caused a reduction in PI3K/Akt/mTOR signaling and a corresponding increase in the Bax/Bcl-2 ratio, cleaved caspase-3, and cleaved poly (ADP-ribose) polymerase (PARP) levels in these cancer cell lines, suggesting that γ-tocotrienol-induced autophagy may be involved in the initiation of apoptosis. In summary, these findings demonstrate that the cytotoxic effects of γ-tocotrienol are associated with the induction of autophagy in a mouse and human mammary cancer cells.

Frataxin mRNA Isoforms in FRDA Patients and Normal Subjects: Effect of Tocotrienol Supplementation.

Abruzzo PM, Marini M, Bolotta A, Malisardi G, Manfredini S, Ghezzo A, Pini A, Tasco G, Casadio R.

Friedreich’s ataxia (FRDA) is caused by deficient expression of the mitochondrial protein frataxin involved in the formation of iron-sulphur complexes and by consequent oxidative stress. We analysed low-dose tocotrienol supplementation effects on the expression of the three splice variant isoforms (FXN-1, FXN-2, and FXN-3) in mononuclear blood cells of FRDA patients and healthy subjects. In FRDA patients, tocotrienol leads to a specific and significant increase of FXN-3 expression while not affecting FXN-1 and FXN-2 expression. Since no structural and functional details were available for FNX-2 and FXN-3, 3D models were built. FXN-1, the canonical isoform, was then docked on the human iron-sulphur complex, and functional interactions were computed; when FXN-1 was replaced by FXN-2 or FNX-3, we found that the interactions were maintained, thus suggesting a possible biological role for both isoforms in human cells. Finally, in order to evaluate whether tocotrienol enhancement of FXN-3 was mediated by an increase in peroxisome proliferator-activated receptor- γ (PPARG), PPARG expression was evaluated. At a low dose of tocotrienol, the increase of FXN-3 expression appeared to be independent of PPARG expression. Our data show that it is possible to modulate the mRNA expression of the minor frataxin isoforms and that they may have a functional role.

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