Tocotrienol Offers Better Protection Than Tocopherol From Free Radical‐induced Damage of Rat Bone

Abstract

1. Free radicals generated by ferric nitrilotriacetate (FeNTA) can activate osteoclastic activity and this is associated with elevation of the bone resorbing cytokines interleukin (IL)-1 and IL-6. In the present study, we investigated the effects of 2 mg/kg FeNTA (2 mg iron/kg) on the levels of serum IL-1 and IL-6 with or without supplementation with a palm oil tocotrienol mixture or alpha-tocopherol acetate in Wistar rats. 2. The FeNTA was found to elevate levels of IL-1 and IL-6. Only the palm oil tocotrienol mixture at doses of 60 and 100 mg/kg was able to prevent FeNTA-induced increases in IL-1 (P < 0.01). Both the palm oil tocotrienol mixture and alpha-tocopherol acetate, at doses of 30, 60 and 100 mg/kg, were able to reduce FeNTA-induced increases in IL-6 (P < 0.05). Therefore, the palm oil tocotrienol mixture was better than pure alpha-tocopherol acetate in protecting bone against FeNTA (free radical)-induced elevation of bone-resorbing cytokines. 3. Supplementation with the palm oil tocotrienol mixture or alpha-tocopherol acetate at 100 mg/kg restored the reduction in serum osteocalcin levels due to ageing, as seen in the saline (control) group (P< 0.05). All doses of the palm oil tocotrienol mixture decreased urine deoxypyridinoline cross-link (DPD) significantly compared with the control group, whereas a trend for decreased urine DPD was only seen for doses of 60 mg/kg onwards of alpha-tocopherol acetate (P < 0.05). 4. Bone histomorphometric analyses have shown that FeNTA injections significantly lowered mean osteoblast number (P < 0.001) and the bone formation rate (P < 0.001), but raised osteoclast number (P < 0.05) and the ratio of eroded surface/bone surface (P < 0.001) compared with the saline (control) group. Supplementation with 100 mg/kg palm oil tocotrienol mixture was able to prevent all these FeNTA-induced changes, but a similar dose of alpha-tocopherol acetate was found to be effective only for mean osteoclast number. Injections of FeNTA were also shown to reduce trabecular bone volume (P < 0.001) and trabecular thickness (P < 0.05), whereas only supplementation with 100 mg/kg palm oil tocotrienol mixture was able to prevent these FeNTA-induced changes.

γ-Tocotrienol Promotes TRAIL-Induced Apoptosis through Reactive Oxygen Species/Extracellular Signal-Regulated Kinase/p53–Mediated Upregulation of Death Receptors

“…Both T3 and TP exist in four isoforms, α, β, γ, and δ, and this classification is based on the number and location of the methyl groups on their chromanol rings (http://www.tocotrienol.org). Some evidence has suggested that T3s have greater potential physiologic functions than TPs (7,8). T3 has been shown to mediate its activity against a variety of chronic diseases, including cardiovascular diseases, neurologic diseases, diabetes, and cancer (9)(10)(11)(12)(13)(14).…”

Effects of vitamin E on bone turnover markers among US postmenopausal women

“…Few animal studies have examined the effects of alphatocopherol supplementation on bone health but their results are conflicting. Some studies suggest that alpha-tocopherol may improve bone quality and strength, (71,72) maintain BMD, (73) decrease bone resorption, (74) and increase bone formation. (75) Hypothesized mechanisms include preventing the accumulation of bone resorbing cytokines, (76) reducing the number of osteoclasts, (75) and increasing the number of osteoblasts.…”

Fenitrothion Alters Sperm Characteristics in Rats: Ameliorating Effects of Palm Oil Tocotrienol-Rich Fraction

“…mixtures of tocotrienol and tocopherol from palm oil showed better protection against free radical-induced bone damage in rats compared with pure α-tocopherol [1]. Palm oil TRF at the dose of 200 mg/kg also showed a protective effect against many pathological conditions including diabetes-induced atherosclerosis and red blood cells membrane damage [8,26] and oP-induced toxicity in the kidney and pancreas [6,7].…”