The Use of Delta-Tocotrienol and Lovastatin for Anti-Osteoporotic Therapy.

Abdul-Majeed S, Mohamed N, Soelaiman I.

Life Sci. 2014 Dec 19. pii: S0024-3205(14)00975-8

Abstract

AIMS:

Statins are competitive inhibitors of HMGCoA reductase and are commonly used as antihypercholesterolemic agents. Experimental studies clearly demonstrate the beneficial effects of statins on bone. Tocotrienols have also been shown to have anti-osteoporotic effects on the skeletal system. This study was conducted to observe the effect of a combination of delta-tocotrienol and lovastatin on structural bone histomorphometry and bone biomechanical strength in a postmenopausal rat model at clinically tolerable doses, and to compare it with the effect of delta-tocotrienol or lovastatin.

MAIN METHODS:

Forty-eight female Sprague Dawley rats were randomly divided into six groups: baseline control; sham-operated control; ovariectomised control; ovariectomised+11mg/kg lovastatin; ovariectomised+60mg/kg delta-tocotrienol and ovariectomised+60mg/kg delta-tocotrienol+11mg/kg lovastatin. These treatments were given via oral gavage daily for eight weeks. After sacrificing the rats, the left and right femurs were dissected and processed for bone histomorphometric analysis and a bone biomechanical test, respectively.

KEY FINDINGS:

Delta-tocotrienol in combination with lovastatin significantly improved the trabecular volume, trabecular number, trabecular thickness and trabecular separation; and it significantly increased bone strength in oestrogen-deficient rats. Delta-tocotrienol alone enhanced bone formation and maintained bone strength in ovariectomised rats. Delta-tocotrienol plus lovastatin treatment promoted better trabecular volume and trabecular number and received higher load than delta-tocotrienol alone. Lovastatin alone was not effective.

SIGNIFICANCE:

Thus, combination of delta-tocotrienol and lovastatin has the potential to be used for anti-osteoporotic therapy in postmenopausal women.

Tang Y, Li X, Chen PX, Zhang B, Hernandez M, Zhang H, Marcone MF, Liu R, Tsao R.

Food Chem. 2015 May 1;174:502-8

Abstract

Composition of fatty acids, tocopherols, tocotrienols, and carotenoids, and their contribution to antioxidant activities were investigated in seeds of three coloured quinoa cultivars (white, red and black). The major components and individual compounds were significantly different, and their concentrations were higher in darker seeds (p<0.05). The oil yield was 6.58-7.17% which contained predominantly unsaturated fatty acids (89.42%). The ratio of omega-6/omega-3 fatty acid was ca. 6/1. The total tocopherol content ranged from 37.49 to 59.82μg/g and mainly consisted of γ-tocopherol. Trace amount of α- and β-tocotrienols was also found. Black quinoa had the highest vitamin E followed by red and white quinoas. Carotenoids, mainly trans-lutein (84.7-85.6%) and zeaxanthin were confirmed for the first time in quinoa seeds, and the concentration was also the highest in black seeds. The antioxidant activities of lipophilic extracts were positively correlated with polyunsaturated fatty acids, total carotenoids and total tocopherols.

Ibrahim N', Khamis MF, Mod Yunoh MF, Abdullah S, Mohamed N, Shuid AN.

PLoS One. 2014; 9(12): e115595.

Abstract

Osteoporosis is becoming a major health problem that is associated with increased fracture risk. Previous studies have shown that osteoporosis could delay fracture healing. Although there are potential agents available to promote fracture healing of osteoporotic bone such as statins andtocotrienol, studies on direct delivery of these agents to the fracture site are limited. This study was designed to investigate the effects of two potential agents, lovastatin and tocotrienol using targeted drug delivery system on fracture healing of postmenopausal osteoporosis rats. The fracture healing was evaluated using micro CT and biomechanical parameters. Forty-eight Sprague-Dawley female rats were divided into 6 groups. The first group was sham-operated (SO), while the others were ovariectomized (OVx). After two months, the right tibiae of all rats were fractured at metaphysis region using pulsed ultrasound and were fixed with plates and screws. The SO and OVxC groups were given two single injections of lovastatin and tocotrienol carriers. The estrogen group (OVx+EST) was given daily oral gavages of Premarin (64.5 µg/kg). The Lovastatin treatment group (OVx+Lov) was given a single injection of 750 µg/kg lovastatin particles. The tocotrienol group (OVx+TT) was given a single injection of 60 mg/kg tocotrienol particles. The combination treatment group (OVx+Lov+TT) was given two single injections of 750 µg/kg lovastatin particles and 60 mg/kg tocotrienol particles. After 4 weeks of treatment, the fractured tibiae were dissected out for micro-CT and biomechanical assessments. The combined treatment group (OVx+Lov+TT) showed significantly higher callus volume and callus strength than the OVxC group (p<0.05). Both the OVx+Lov and OVx+TT groups showed significantly higher callus strength than the OVxC group (p<0.05), but not for callus volume. In conclusion, combined lovastatin and tocotrienol may promote better fracture healing of osteoporotic bone.

Abubakar IB, Lim KH, Loh HS.

Nat Prod Res. 2014 Dec 17:1-4.

Abstract

Tocotrienols have been reported to possess anticancer effects other than anti-inflammatory and antioxidant activities. This study explored the potential synergism of antiproliferative effects induced by individual alkaloid extracts of Ficus fistulosa, Ficus hispida and Ficus schwarzii combined with δ- and γ-tocotrienols against human brain glioblastoma (U87MG), lung adenocarcinoma (A549) and colorectal adenocarcinoma (HT-29) cells. Cell viability and morphological results demonstrated that extracts containing a mixture of alkaloids from the leaves and bark of F. schwarzii inhibited the proliferation of HT-29 cells, whereas the alkaloid extracts of F. fistulosa inhibited the proliferation of both U87MG and HT-29 cells and showed synergism in combined treatments with either δ- or γ-tocotrienol resulting in 2.2-34.7 fold of reduction in IC50 values of tocotrienols. The observed apoptotic cell characteristics in conjunction with the synergistic antiproliferative effects of Ficus species-derived alkaloids and tocotrienols assuredly warrant future investigations towards the development of a value-added chemotherapeutic regimen against cancers.

Lim SW, Loh HS, Ting KN, Bradshaw TD, Zeenathul NA.

BMC Complement Altern Med. 2014 Dec 6;14(1):469.

Abstract

BACKGROUND:

Tocotrienols, especially the gamma isomer was discovered to possess cytotoxic effects associated with the induction of apoptosis in numerous cancers. Individual tocotrienol isomers are believed to induce dissimilar apoptotic mechanisms in different cancer types. This study was aimed to compare the cytotoxic potency of alpha-, gamma- and delta-tocotrienols, and to explore their resultant apoptotic mechanisms in human lung adenocarcinoma A549 and glioblastoma U87MG cells which are scarcely researched.

METHODS:

The cytotoxic effects of alpha-, gamma- and delta-tocotrienols in both A549 and U87MG cancer cells were first determined at the cell viability and morphological aspects. DNA damage types were then identified by comet assay and flow cytometric study was carried out to support the incidence of apoptosis. The involvements of caspase-8, Bid, Bax and mitochondrial membrane permeability (MMP) in the execution of apoptosis were further expounded.

RESULTS:

All tocotrienols inhibited the growth of A549 and U87MG cancer cells in a concentration- and time-dependent manner. These treated cancer cells demonstrated some hallmarks of apoptotic morphologies, apoptosis was further confirmed by cell accumulation at the pre-G1 stage. Alltocotrienols induced only double strand DNA breaks (DSBs) and no single strand DNA breaks (SSBs) in both treated cancer cells. Activation of caspase-8 leading to increased levels of Bid and Bax as well as cytochrome c release attributed by the disruption of mitochondrial membrane permeability in both A549 and U87MG cells were evident.

CONCLUSIONS:

This study has shown that delta-tocotrienol, in all experimental approaches, possessed a higher efficacy (shorter induction period) and effectiveness (higher induction rate) in the execution of apoptosis in both A549 and U87MG cancer cells as compared to alpha- and gamma-tocotrienols. Tocotrienols in particular the delta isomer can be an alternative chemotherapeutic agent for treating lung and brain cancers.

Lim SW, Loh HS, Ting KN, Bradshaw TD, Zeenathul NA

Biomed Pharmacother. 2014 Oct 23. pii: S0753-3322(14)00132-2

Abstract

The pure vitamin isomer, β-tocotrienol has the least abundance among the other vitamin E isomers that are present in numerous plants. Hence, it is very scarcely studied for its bioactivity. In this study, the antiproliferative effects and primary apoptotic mechanisms of β-tocotrienol on human lung adenocarcinoma A549 and glioblastoma U87MG cells were investigated. It was evidenced that β-tocotrienol had inhibited the growth of both A549 (GI50=1.38±0.334μM) and U87MG (GI50=2.53±0.604μM) cells at rather low concentrations. Cancer cells incubated with β-tocotrienol were also found to exhibit hallmarks of apoptotic morphologies including membrane blebbing, chromatin condensation and formation of apoptotic bodies. The apoptotic properties of β-tocotrienol in both A549 and U87MG cells were the results of its capability to induce significant (P<0.05) double-strand DNA breaks (DSBs) without involving single-strand DNA breaks (SSBs). β-Tocotrienol is said to induce activation of caspase-8 in both A549 and U87MG cells guided by no activation when caspase-8 inhibitor, z-IETD-fmk was added. Besides, disruption on the mitochondrial membrane permeability of the cells in a concentration- and time-dependent manner had occurred. The induction of apoptosis by β-tocotrienol in A549 and U87MG cells was confirmed to involve both the death-receptor mediated and mitochondria-dependent apoptotic pathways. These findings could potentiate the palm oil derived β-tocotrienol to serve as a new anticancer agent for treating human lung and brain cancers.

Ahsan H, Ahad A, Iqbal J, Siddiqui WA

Nutr Metab (Lond). 2014 Nov 12;11(1):52

Abstract

Tocotrienols, members of the vitamin E family, are natural compounds found in a number of vegetable oils, wheat germ, barley, and certain types of nuts and grains. Like tocopherols, tocotrienols are also of four types viz. alpha, beta, gamma and delta. Unlike tocopherols, tocotrienols are unsaturated and possess an isoprenoid side chain. Tocopherols are lipophilic in nature and are found in association with lipoproteins, fat deposits and cellular membranes and protect the polyunsaturated fatty acids from peroxidation reactions. The unsaturated chain of tocotrienol allows an efficient penetration into tissues that have saturated fatty layers such as the brain and liver. Recent mechanistic studies indicate that other forms of vitamin E, such as γ-tocopherol, δ-tocopherol, and γ-tocotrienol, have unique antioxidant and anti-inflammatory properties that are superior to those of α-tocopherol against chronic diseases. These forms scavenge reactive nitrogen species, inhibit cyclooxygenase- and 5-lipoxygenase-catalyzed eicosanoids and suppress proinflammatory signalling, such as NF-κB and STAT. The animal and human studies show tocotrienols may be useful against inflammation-associated diseases. Many of the functions of tocotrienols are related to its antioxidant properties and its varied effects are due to it behaving as a signalling molecule. Tocotrienols exhibit biological activities that are also exhibited by tocopherols, such as neuroprotective, anti-cancer, anti-inflammatory and cholesterol lowering properties. Hence, effort has been made to compile the different functions and properties oftocotrienols in experimental model systems and humans. This article constitutes an in-depth review of the pharmacology, metabolism, toxicology and biosafety aspects of tocotrienols. Tocotrienols are detectable at appreciable levels in the plasma after supplementations. However, there is inadequate data on the plasma concentrations of tocotrienols that are sufficient to demonstrate significant physiological effect and biodistribution studies show their accumulation in vital organs of the body. Considering the wide range of benefits that tocotrienols possesses against some common human ailments and having a promising potential, the experimental analysis accounts for about a small fraction of all vitamin E research. The current state of knowledge deserves further investigation into this lesser known form of vitamin E.

Selvaraju TR, Khaza'ai H, Vidyadaran S, Abd Mutalib MS, Vasudevan R.

Bosn J Basic Med Sci. 2014 Nov 16;14(4):195-204.

Abstract

Tocotrienol rich fraction (TRF) is an extract of palm oil, which consists of 25% alpha tocopherol (α-TCP) and 75% tocotrienols. TRF has been shown to possess potent antioxidant, anti-inflammatory, anticancer, neuroprotection, and cholesterol lowering activities. Glutamate is the main excitatory amino acid neurotransmitter in the central nervous system of mammalian, which can be excitotoxic, and it has been suggested to play a key role in neurodegenerative disorders like Parkinson’s and Alzheimer’s diseases. In this present study, the effects of vitamin E (TRF and α-TCP) in protecting astrocytes against glutamate injury were elucidated. Astrocytes induced with 180 mM of glutamate lead to significant cell death. However, glutamate mediated cytotoxicity was diminished via pre and post supplementation of TRF and α-TCP. Hence, vitamin E acted as a potent antioxidant agent in recovering mitochondrial injury due to elevated oxidative stress, and enhanced better survivability upon glutamate toxicity.

Singh VK, Wise SY, Fatanmi OO, Scott J, Romaine PL, Newman VL, Verma A, Elliott TB, Seed TM.

PLoS One. 2014 Nov 25;9(11)

Abstract

The purpose of this study was to elucidate the role of gamma-tocotrienol (GT3)-mobilized progenitors in mitigating damage to mice exposed to a supralethal dose of cobalt-60 gamma-radiation. CD2F1 mice were transfused 24 h post-irradiation with whole blood or isolated peripheral blood mononuclear cells (PBMC) from donors that had received GT3 72 h prior to blood collection and recipient mice were monitored for 30 days. To understand the role of GT3-induced granulocyte colony-stimulating factor (G-CSF) in mobilizing progenitors, donor mice were administered a neutralizing antibody specific to G-CSF or its isotype before blood collection. Bacterial translocation from gut to heart, spleen and liver of irradiated recipient mice was evaluated by bacterial culture on enriched and selective agar media. Endotoxin in serum samples also was measured. We also analyzed the colony-forming units in the spleens of irradiated mice. Our results demonstrate that whole blood or PBMC from GT3-administered mice mitigated radiation injury when administered 24 h post-irradiation. Furthermore, administration of a G-CSF antibody to GT3-injected mice abrogated the efficacy of blood or PBMC obtained from such donors. Additionally, GT3-mobilized PBMC inhibited the translocation of intestinal bacteria to the heart, spleen, and liver, and increased colony forming unit-spleen (CFU-S) numbers in irradiated mice. Our data suggests that GT3 induces G-CSF, which mobilizes progenitors and these progenitors mitigate radiation injury in recipient mice. This approach using mobilized progenitor cells from GT3-injected donors could be a potential treatment for humans exposed to high doses of radiation.

Khanna S, Heigel M, Weist J, Gnyawali S, Teplitsky S, Roy S, Sen CK, Rink C.

FASEB J. 2014 Nov 19.

Abstract

The vitamin E family includes both tocopherols and tocotrienols, where α-tocopherol (αTOC) is the most bioavailable form. Clinical trials testing the therapeutic efficacy of high-dose αTOC against stroke have largely failed or reported negative outcomes when a “more is better” approach to supplementation (>400 IU/d) was used. This work addresses mechanisms by which supraphysiologic αTOC may contribute to stroke-induced brain injury. Ischemic stroke injury and the neuroinflammatory response were studied in tocopherol transfer protein-deficient mice maintained on a diet containing αTOC vitamin E at the equivalent human dose of 1680 IU/d. Ischemic stroke-induced brain injury was exacerbated in the presence of supraphysiologic brain αTOC levels. At 48 h after stroke, S100B and RAGE expression was increased in stroke-affected cortex of mice with elevated brain αTOC levels. Such increases were concomitant with aggravated microglial activation and neuroinflammatory signaling. A poststroke increase in markers of oxidative injury and neurodegeneration in the presence of elevated brain αTOC establish that at supraphysiologic levels, αTOC potentiates neuroinflammatory responses to acute ischemic stroke. Exacerbation of microglial activation by excessive αTOC likely depends on its unique cell signaling regulatory properties independent of antioxidant function. Against the background of clinical failure for high-dose αTOC, outcomes of this work identify risk for exacerbating stroke-induced brain injury as a result of supplementing diet with excessive levels of αTOC.-Khanna, S., Heigel, M., Weist, J., Gnyawali, S., Teplitsky, S., Roy, S., Sen, C. K., Rink, C. Excessive α-tocopherol exacerbates microglial activation and brain injury caused by acute ischemic stroke.