Tocotrienol (TRF) ethosomes were developed and evaluated in vitro for potential transdermal delivery against melanoma. The optimised TRF ethosomal size ranged between 64.9 ± 2.2 nm to 79.6 ± 3.9 nm and zeta potential (ZP) between -53.3 mV to -62.0 ± 2.6 mV. Characterisation of the ethosomes by ATR-FTIR indicated the successful formation of TRF-ethosomes. Scanning electron microscopy (SEM) images demonstrated the spherical shape of ethosomes, and the entrapment efficiencies of all the formulations were above 66%. In vitro permeation studies using full-thickness human skin showed that the permeation of gamma-T3 from the TRF ethosomal formulations was significantly higher (p
The drawbacks associated with chemical skin permeation enhancers such as skin irritation and toxicity necessitated the research to focus on potential permeation enhancers with a perceived lower toxicity. Crude palm oil (CPO) is obtained by direct compression of the mesocarp of the fruit of the oil palm belonging to the genus Elaeis. In this research, CPO and tocotrienol-rich fraction (TRF) of palm oil were evaluated for the first time as skin permeation enhancers using full-thickness human skin. The in vitro permeation experiments were conducted using excised human skin mounted in static upright 'Franz-type' diffusion cells. The drugs selected to evaluate the enhancing effects of these palm oil derivatives were 5-fluorouracil, lidocaine and ibuprofen: compounds covering a wide range of Log p values. It was demonstrated that CPO and TRF were capable of enhancing the percutaneous permeation of drugs across full-thickness human skin in vitro. Both TRF and CPO were shown to significantly enhance the permeation of ibuprofen with flux values of 30.6 µg/cm2 h and 23.0 µg/cm2 h respectively, compared to the control with a flux of 16.2 µg/cm2 h. The outcome of this research opens further scope for investigation on the transdermal penetration enhancement activity of pure compounds derived from palm oil.
Tocotrienols are forms of vitamin E that are present in several important food crops. Compared to tocopherols, less research has been conducted on these compounds because of their low bioavailability and distribution in plant tissues. Both tocotrienols and tocopherols are known for their antioxidant and anticancer activities, which are beneficial for both humans and animals. Moreover, tocotrienols possess certain properties which are not found in tocopherols, such as neuroprotective and cholesterol-lowering activities. The contents of tocotrienols in plants vary. Tocotrienols constitute more than 70% and tocopherols less than 30% of the total vitamin E content in palm oil, which is the best source of vitamin E. Accumulation of tocotrienols also occurs in non-photosynthetic tissues, such as the seeds, fruits and latex of some monocotyledonous and dicotyledonous plant species. The use of biotechnological techniques to increase the tocotrienol content in plants, their biological functions, and benefits to human health are discussed in this review.
The tocotrienol vitamin E has potent antioxidant property, however absorption is low due to high lipid solubility. A self emulsifying preparation of tocotrienol rich vitamin E (SF-TRE) had been reported to increase their bioavailability. This randomized, placebo controlled, blinded end point clinical study aimed to determine the effects of 50, 100 and 200 mg daily of SF-TRE and placebo for two months on arterial compliance and vitamin E blood levels. Assessment of arterial compliance by carotid femoral pulse wave velocity (PWV) and augmentation index (AI), plasma vitamin E, serum total cholesterol and low density lipoprotein cholesterol were taken before and after 2 months' treatment in 36 healthy males. Un-supplemented tocotrienol levels were low, after treatment, all SF-TRE treated groups had significantly higher plasma alpha, delta and delta tocotrienol concentrations compared to placebo. Augmentation index change from baseline to end of treatment for groups placebo, 50, 100, and 200 mg were 2.22+/-1.54, -6.59+/-2.84, -8.72+/-3.77, and -6.27+/-2.67% respectively (p=0.049, 0.049, and 0.047 respectively). Groups 100 and 200 mg showed significant improvement after treatment with pulse wave velocity reductions of 0.77 m/s and 0.65 m/s respectively (p=0.007 and p=0.002). There was no effect of SF-TRE on serum lipids. We conclude that there was a trend towards improvement in arterial compliance with 2 months' of SF-TRE.
Skeletal tissue undergoes continuous remodeling which makes it unique among other body tissues. Osteoporosis is a common bone metabolic disorder affecting both men and women. Osteoporosis and its complications mainly osteoporotic fractures, have a high impact on health and economy. Current approved medications are associated with numerous side effects, which limit their use. Identification of a new and safe therapy is mandatory. Statins, also known as HMGCoA reductase inhibitors, are frequently used for the treatment of hypercholesterolemia and for the prevention of morbidity and mortality associated with cardiovascular disease. Statins improved bone health status in intact and ovariectomised rodents following high clinically intolerable oral doses. However, this beneficial effect of statins could not be significantly demonstrated in humans. The reason behind this discrepancy might be due to the safety and bioavailability of the currently used oral statins. Vitamin E, especially the tocotrienols at the dose 60 mg/kg/day provided significant antiosteoporotic effects in different animal models of osteoporosis. The use of the aforementioned dose of tocotrienols was shown to be safe in both humans and animals. Enhancement of bone formation and reduction of bone resorption were achieved more effectively by a combination of tocotrienols and statins than by either treatment when supplemented separately at clinically tolerable doses. Therefore, the adverse effects associated with high statin doses might be avoided with the coadministration of tocotrienols. Moreover, the combination therapy strategy might be useful for patients who are at high risk of osteoporosis, cardiovascular events and hypercholesterolaemia.
Vitamin E has been recognized as an essential vitamin since their discovery in 1922. Although the functions of tocopherols are well established, tocotrienols have been the unsung heroes of vitamin E. Due to their structural differences, tocotrienols were reported to exert distinctive properties compared to tocopherols. While most vegetable oils contain higher amount of tocopherols, tocotrienols were found abundantly in palm oil. Nature has made palm vitamin E to contain up to 70% of total tocotrienols, among which alpha-, gamma- and delta-tocotrienols are the major constituents. Recent advancements have shown their biological properties in conferring protection against cancer, cardiovascular diseases, neurodegeneration, oxidative stress and immune regulation. Preclinical results of these physiological functions were translated into clinical trials gaining global attention. This review will discuss in detail the evidence in human studies to date in terms of efficacy, population, disease state and bioavailability. The review will serve as a platform to pave the future direction for tocotrienols in clinical settings.
Vitamin E, a natural antioxidant, is of interest to scientists, health care pundits and faddists; its nutritional and biomedical attributes may be validated, anecdotal or fantasy. Vitamin E is a mixture of tocopherols (TPs) and tocotrienols (T-3s), each class having four substitutional isomers (α-, β-, γ-, δ-). Vitamin E analogues attain only low concentrations in most tissues, necessitating exacting invasive techniques for analytical research. Quantitative positron emission tomography (PET) with an F-18-labeled molecular probe would expedite access to Vitamin E's biodistributions and pharmacokinetics via non-invasive temporal imaging. (R)-6-(3-[18F]Fluoropropoxy)-2,7,8-trimethyl-2-(4,8,12-trimethyltrideca-3,7,11-trien-1-yl)-chromane ([18F]F-γ-T-3) was prepared for this purpose. [18F]F-γ-T-3 was synthesized from γ-T-3 in two steps: (i) 1,3-di-O-tosylpropane was introduced at C6-O to form TsO-γ-T-3, and (ii) reaction of this tosylate with [18F]fluoride in DMF/K222. Non-radioactive F-γ-T-3 was synthesized by reaction of γ-T-3 with 3-fluoropropyl methanesulfonate. [18F]F-γ-T-3 biodistribution in a murine tumor model was imaged using a small-animal PET scanner. F-γ-T-3 was prepared in 61% chemical yield. [18F]F-γ-T-3 was synthesized in acceptable radiochemical yield (RCY 12%) with high radiochemical purity (>99% RCP) in 45 min. Preliminary F-18 PET images in mice showed upper abdominal accumulation with evidence of renal clearance, only low concentrations in the thorax (lung/heart) and head, and rapid clearance from blood. [18F]F-γ-T-3 shows promise as an F-18 PET tracer for detailed in vivo studies of Vitamin E. The labeling procedure provides acceptable RCY, high RCP and pertinence to all eight Vitamin E analogues.
A single dose comparative bioavailability study was conducted to evaluate the bioavailability of tocotrienols from two self-emulsifying formulations, one of which produced an emulsion that readily lipolysed under in vitro condition (SES-A), while the other produced a finer dispersion with negligible lipolysis (SES-B) in comparison with that of a non-self-emulsifying formulation in soya oil. The study was conducted according to a three-way crossover design using six healthy human volunteers. Statistically significant differences were observed between the logarithmic transformed peak plasma concentration (Cmax) and total area under the plasma concentration-time curve (AUC(0-infinity)) values of both SES-A and -B compared to NSES-C indicating that SES-A and -B achieved a higher extent of absorption compared to NSES-C. Moreover, the 90% confidence interval of the AUC(0-infinity) values of both SES-A and -B over those of NSES-C were between 2-3 suggesting an increase in bioavailability of about two-three times compared to NSES-C. Both SES-A and -B also achieved a faster onset of absorption. However, both SES-A and -B had comparable bioavailability, despite the fact that SES-B was able to form emulsions with smaller droplet size. Thus, it appeared that both droplet sizes as well as the rate and extent of lipolysis of the emulsion products formed were important for enhancing the bioavailability of the tocotrienols from the self-emulsifying systems.