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Quality assessment of palm products upon prolonged heat treatment

Tarmizi AH, Lin SW

J Oleo Sci, 2008;57(12):639-48.
PMID: 19001776

Extending the frying-life of oils is of commercial and economic importance. Due to this fact, assessment on the thermal stability of frying oils could provide considerable savings to the food processors. In this study, the physico-chemical properties of five palm products mainly palm oil, single-fractionated palm olein, double-fractionated palm olein, red palm olein and palm-based shortening during 80 hours of heating at 180 degrees C were investigated. Heating properties of these products were then compared with that of high oleic sunflower oil, which was used as reference oil. The indices applied in evaluating the quality changes of oils were free fatty acid, smoke point, p-anisidine value, tocols, polar and polymer compounds. Three palm products i.e. palm oil, single-fractionated palm olein and double-fractionated palm olein were identified to be the most stable in terms of lower formation of free fatty acid, polar and polymer compounds as well as preserving higher smoke point and tocols content compared to the other three oils. The low intensity of hydrolytic and oxidative changes due to prolonged heating, suggests that these palm products are inherently suitable for frying purposes.

Matched MeSH terms: Tocopherols/analysis
Separation of vitamin E (tocopherol, tocotrienol, and tocomonoenol) in palm oil

Ng MH, Choo YM, Ma AN, Chuah CH, Hashim MA

Lipids, 2004 Oct;39(10):1031-5.
PMID: 15691027

Previous reports showed that vitamin E in palm oil consists of various isomers of tocopherols and tocotrienols [alpha-tocopherol (alpha-T), alpha-tocotrienol, gamma-tocopherol, gamma-tocotrienol, and delta-tocotrienol), and this is normally analyzed using silica column HPLC with fluorescence detection. In this study, an HPLC-fluorescence method using a C30 silica stationary phase was developed to separate and analyze the vitamin E isomers present in palm oil. In addition, an alpha-tocomonoenol (alpha-T1) isomer was quantified and characterized by MS and NMR. (alpha-T1 constitutes about 3-4% (40+/-5 ppm) of vitamin E in crude palm oil (CPO) and is found in the phytonutrient concentrate (350+/-10 ppm) from palm oil, whereas its concentration in palm fiber oil (PFO) is about 11% (430+/-6 ppm). The relative content of each individual vitamin E isomer before and after interesterification/transesterification of CPO to CPO methyl esters, followed by vacuum distillation of CPO methyl esters to yield the residue, remained the same except for alpha-T and gamma-T3. Whereas alpha-T constitutes about 36% of the total vitamin E in CPO, it is present at a level of 10% in the phytonutrient concentrate. On the other hand, the composition of gamma-T3 increases from 31% in CPO to 60% in the phytonutrient concentrate. Vitamin is present at 1160+/-43 ppm, and its concentrations in PFO and the phytonutrient concentrate are 4,040+/-41 and 13,780+/-65 ppm, respectively. The separation and quantification of alpha-T1 in palm oil will lead to more in-depth knowledge of the occurrence of vitamin E in palm oil.

Matched MeSH terms: Tocopherols/isolation & purification
A developmental study on the appearance of tocopherols and tocotrienols in developing palm mesocarp (Elaeis guineensis)

Choo YM, Ma AN, Chuah CH, Khor HT, Bong SC

Lipids, 2004 Jun;39(6):561-4.
PMID: 15554155

The concentration of vitamin E isomers, namely, alpha-tocopherol (alpha-T), alpha-tocotrienol, gamma-tocotrienol, and delta-tocotrienol in palm mesocarp at 4, 8, 12, 16, and 20 wk after anthesis (WAA) were quantified using HPLC coupled with fluorescence detection. alpha-T was detected throughout the palm fruits' maturation process, whereas unsaturated tocotrienols were found only in ripe palm fruits. These developmental results indicate that tocotrienols are synthesized between 16 and 20 WAA.

Matched MeSH terms: Tocopherols/analysis*
Antioxidant status following postprandial challenge of two different doses of tocopherols and tocotrienols

Fairus S, Cheng HM, Sundram K

J Integr Med, 2020 Jan;18(1):68-79.
PMID: 31812339 DOI: 10.1016/j.joim.2019.11.005

OBJECTIVE: Tocotrienols (T3s) have been hypothesized to have greater antioxidant capacity than tocopherols (Ts) due to differences in biokinetics that affect their absorption and function. The present trial compares the antioxidant effectiveness following postprandial challenge of two different doses of α-T or palm T3-rich fraction (TRF) treatments and evaluates their dose-response effects on antioxidant status.
METHODS: Ten healthy volunteers were given four different doses of vitamin E formulations (268 mg α-T, 537 mg α-T, 263 mg TRF or 526 mg TRF) in a cross-over postprandial trial. Blood was sampled at 0, 2, 4, 5, 6 and 8 hours after meal consumption and plasma antioxidant status including total glutathione, superoxide dismutase, malondialdehyde (MDA), ferric reducing antioxidant potential and trolox-equivalent antioxidant capacity, was analyzed.
RESULTS: Supplementation with the different doses of either α-T or TRF did not significantly improve overall antioxidant status. There was no significant difference in overall antioxidant status among treatments at the different doses compared. However, a significant dose-response effect was observed for plasma MDA throughout the 8-hour postprandial period. MDA was significantly lower after the 537 mg α-T treatment, compared to the 268 mg α-T treatment; it was also lower after the 526 mg TRF treatment compared to the 263 mg TRF treatment (P

Matched MeSH terms: Tocopherols/administration & dosage*
Fulltext Thermal Stability and Sensory Acceptance of Cupcakes Containing Red Palm Olein

Loganathan R, Tarmizi AHA, Vethakkan SR, Teng KT

J Oleo Sci, 2020 Jul 02;69(7):671-676.
PMID: 32522941 DOI: 10.5650/jos.ess19253

The study was designed to evaluate the nutritive value, thermal stability and consumer acceptance of cupcakes baked with red palm olein compared to palm olein. Thermal stability was evaluated for acidity, peroxide, p-anisidine and total oxidation value (cumulative between peroxide and p-anisidine values), as well as fatty acid composition. The concentrations of phytonutrients including tocopherols and tocotrienols, alpha- and beta-carotene after baking were also determined. Acceptance of the cupcakes was assessed using a structured hedonic scale of five points by 29 panelists. As compared to initial test oil (red palm olein), acidity (red palm olein, 0.07±0.01% vs cupcakes containing red palm olein, 0.09±0.01%; P=0.0232), peroxide value (red palm olein, 0.33±0.05 meq O2 kg-1 vs cupcakes containing red palm olein 0.73±0.06 meq O2 kg-1; P=0.0011) and total oxidation value (red palm olein, 2.24±0.13 unit vs cupcakes containing red palm olein, 3.09±0.17 unit; P=0.0012) were found to be higher in cupcakes containing red palm olein, which is within the acceptable rancidity range (peroxide value < 7.5 meq O2 kg-1) for snack food category. No changes were found on oxidative parameters (acidity, peroxide, p-anisidine values and total oxidation value) in cupcakes containing palm olein. Cupcakes made with red palm olein retained nearly 100% of alpha- and beta-carotenes upon baking. Tocopherol homologues were stable in both comparisons, with 95% retention as compared to tocotrienol homologues (~85%). Cupcakes made from red palm olein received higher score (mean=3.29) in sensory evaluation as compared to cupcakes containing palm olein (mean=3.07). The study, therefore, encourages the inclusion of red palm olein in the formulation of bakery products.

Matched MeSH terms: Tocopherols/analysis
Fulltext Characterization of high-value bioactives in some selected varieties of Pakistani Rice (Oryza sativa L.)

Zubair M, Anwar F, Ashraf M, Uddin MK

Int J Mol Sci, 2012;13(4):4608-4622.
PMID: 22605998 DOI: 10.3390/ijms13044608

The present study reports the composition and variation of fatty acids, sterols, tocopherols and γ-oryzanol among selected varieties namely Basmati Super, Basmati 515, Basmati 198, Basmati 385, Basmati 2000, Basmati 370, Basmati Pak, KSK-139, KS-282 and Irri-6 of Pakistani rice (Oryza sativa L). Oil content extracted with n-hexane from different varieties of brown rice seed (unpolished rice) ranged from 1.92% to 2.72%. Total fatty acid contents among rice varieties tested varied between 18240 and 25840 mg/kg brown rice seed. The rice tested mainly contained oleic (6841-10952 mg/kg) linoleic (5453-7874 mg/kg) and palmitic acid (3613-5489 mg/kg). The amounts of total phytosterols (GC and GC-MS analysis), with main contribution from β-sitosterol (445-656 mg/kg), campesterol (116-242 mg/kg), Δ(5)-avenasterol (89-178 mg/kg) and stigmasterol (75-180 mg/kg) were established to be 739.4 to 1330.4 mg/kg rice seed. The content of α-, γ- and δ-tocopherols as analyzed by HPLC varied from 39.0-76.1, 21.6-28.1 and 6.5-16.5 mg/kg rice seed, respectively. The amounts of different γ-oryzanol components (HPLC data), identified as cycloartenyl ferulate, 24-methylene cycloartanyl ferulate, campesteryl ferulate and β-sitosteryl ferulate, were in the range of 65.5-103.6, 140.2-183.1, 29.8-45.5 and 8.6-10.4 mg/kg rice seed, respectively. Overall, the concentration of these bioactives was higher in the Basmati rice cultivars showing their functional food superiority. In conclusion, the tested varieties of Pakistani rice, especially the Basmati cultivars, can provide best ingredients for functional foods.

Matched MeSH terms: Tocopherols/metabolism*
Tocopherol and tocotrienol contents of different varieties of rice in Malaysia

Shammugasamy B, Ramakrishnan Y, Ghazali HM, Muhammad K

J Sci Food Agric, 2015 Mar 15;95(4):672-8.
PMID: 24841131 DOI: 10.1002/jsfa.6742

The present study examined the contents of tocopherols and tocotrienols and their distribution in 58 different varieties of whole rice cultivated in Malaysia. The analytical method used was saponification of samples followed by dispersive liquid-liquid microextraction and reverse phase high-performance liquid chromatography.

Matched MeSH terms: Tocopherols/analysis*; Tocopherols/metabolism
Characterization of phenolic compounds, carotenoids, vitamins and antioxidant activities of selected Malaysian wild edible plants

Wong JY, Matanjun P, Ooi YB, Chia KF

Int J Food Sci Nutr, 2013 Aug;64(5):621-31.
PMID: 23368987 DOI: 10.3109/09637486.2013.763910

This study was carried out to characterize phenolic compounds, carotenoids, vitamins and the antioxidant activity of selected wild edible plants. Plant extracts were purified, and phenolic compounds comprising 11 phenolic acids (hydroxybenzoic acid and hydrocinnamic acid) and 33 flavonoids (including catechin, glycosides and aglycones) were analysed using High Performance Liquid Chromatography - Diode Array Detector (HPLC-DAD). Furthermore, the contents of ascorbic acid and tocopherol ((α and γ tocopherol) and carotenoids (lutein and β-carotene) were also determined. The major phenolics identified consisted of glycosides of flavones (apigenin and luteolin) and flavonols (kaempferol and quercetin). Among the phenolic acids identified after hydrolysis, coumaric acid was the predominant phenolic acid in all the extracts of wild plants. Ascorbic acid [53.8 mg/100 g fresh weight (FW)] and β-carotene (656.5 mg/100 g FW) showed the highest content in the leaf of Heckeria umbellatum. In conclusion, the leaves of H. umbellatum, Aniseia martinicensis and Gonostegia hirta have excellent potential in the future to emerge as functional ingredients.

Matched MeSH terms: Tocopherols/analysis; Tocopherols/pharmacology
Fulltext Production of Nanoemulsions from Palm-Based Tocotrienol Rich Fraction by Microfluidization

Goh PS, Ng MH, Choo YM, Amru NB, Chuah CH

Molecules, 2015;20(11):19936-46.
PMID: 26556328 DOI: 10.3390/molecules201119666

In the present study, tocotrienol rich fraction (TRF) nanoemulsions were produced as an alternative approach to improve solubility and absorption of tocotrienols. In the present study, droplet size obtained after 10 cycles of homogenization with increasing pressure was found to decrease from 120 to 65.1 nm. Nanoemulsions stabilized with Tween series alone or emulsifier blend Brij 35:Span 80 (0.6:0.4 w/w) homogenized at 25,000 psi and 10 cycles, produced droplet size less than 100 nm and a narrow size distribution with a polydispersity index (PDI) value lower than 0.2. However blend of Tween series with Span 80 produced nanoemulsions with droplet size larger than 200 nm. This work has also demonstrated the amount of tocols losses in TRF nanoemulsion stabilized Tweens alone or emulsifier blend Brij 35:Span 80 (0.6:0.4 w/w) ranged between 3%-25%. This can be attributed to the interfacial film formed surrounding the droplets exhibited different level of oxidative stability against heat and free radicals created during high pressure emulsification.

Matched MeSH terms: Tocopherols
Lipidaemic effects of tocotrienols, tocopherols and squalene: studies in the hamster

Khor HT, Chieng DY

Asia Pac J Clin Nutr, 1997 Mar;6(1):36-40.
PMID: 24394651

Syrian Golden hamsters have been widely used as a experimental model for the investigation of the aetiology and development of atherosclerosis and cardiovascular disease. The responses of the hamster to dietary fat manipulations are in many ways similar to that observed in humans. The lipidaemic effect of a tocotrienol rich fraction (TRF) from palm oil on human trials has not been consistent. In this study, the cholesterolaemic effect of tocotrienols and tocopherols were differentiated by using pure tocotrienols (that were isolated from palm oil fatty acid distillate) and pure commercial tocopherols and squalene. A palm oil triacylglycerol fraction (POTG), free of all unsaponifiable matter, was used as the dietary fat in different feeding experiments. Tocotrienols added at 162 ppm to POTG (POTG-T3L) significantly (p<0.05) lowered serum total cholesterol (TC) level as compared to that of the POTG group; but the serum LDL-C , HDL-C and TG levels of the POTG-T3L group were not significantly lower than that of the POTG group (P>0.05). Increasing the level of tocotrienol supplementation to the diet (POTG-T3H) appeared to raise rather then reduce the serum TC, LDL-C and HDL-C levels as compared to that of POTG-T3L group. This observation that lower level of tocotrienol supplementation appeared to exhibit stronger hypocholesterolaemic effect than a higher level of tocotrienol supplementation is interesting; but its explanation is not yet forthcoming. When tocopherols were supplemented at 72 ppm to the POTG diet it was observed that the serum TC, LDL-C and HDL-C levels were all somewhat increased when compared to that of the POTG group. These results suggest that tocotrienols and tocopherols may have opposite cholesterolaemic effects in the hamster, and further experiments need to clarify the mode of action of these vitamin E isomers. In our second series of experiments the cholesterolaemic effects of tocotrienols and tocopherols were studied in the presence of squalene, a key intermediate in the cholesterol synthesis pathway and a controversial cholesterol lowering agent. Squalene added to the diet at 0.1% level significantly lowered (p<0.05) serum TC level when compared to that of the POTG group. The LDL-C, HDL-C and TG levels appeared to be lowered by the squalene supplementation also but the differences between the POTG-SQ and POTG groups were not statistically significant (P>0.05). When tocotrienols or tocopherols were added to the squalene-containing POTG diets, the serum TC and LDL-C levels were further reduced (p<0.01) when compared to that of the POTG and POTG-SQ groups. The HDL-C and TG levels were not affected by tocotrienol or tocopherol supplementation in the presence of squalene. These results indicate that in the presence of tocotrienols and squalene POTG exhibit hypocholesterolaemic action whereas tocopherols may have a hypercholesterolaemic effect in the hamster.

Matched MeSH terms: Tocopherols
The Effects of Palm Oil on Plasma and Serum Lipid Parameters: A Systematic Review on Animal Intervention Studies

Syarifah-Noratiqah SB, Fairus S, Zulfarina MS, Nasrullah Z, Qodriyah HMS, Naina-Mohamed I

Front Vet Sci, 2020;7:303.
PMID: 32775343 DOI: 10.3389/fvets.2020.00303

Background: Accumulative evidences on the beneficial effects of palm oil are progressively reported; however, there are still several controversies related to their effects on the risks of cardiovascular disease (CVD). This review explores the effects of palm oil and its liquid fraction namely palm olein, which is commonly used as cooking oil on four lipid parameters; total cholesterol (TC), triglyceride (TG), high-density lipoprotein-cholesterol (HDL-C) and low-density lipoprotein-cholesterol (LDL-C), which play an important role as CVD-related biomarkers. A systematic review of the literature was conducted to identify the relevant studies on palm oil and the lipid parameters specifically focusing on the in-vivo animal model. Methods: A comprehensive search was conducted in Medline via EBSCOhost, Medline via OVID and Scopus. Studies were limited to the English language published between the years of 2000 and 2019. The main inclusion criteria were as follows: (1) Study with in-vivo animal experiments [the animal should be limited to mammals] (2) Study should have evaluated the effects of palm oil or palm olein on plasma or serum lipid parameter (3) Study should have used palm oil or palm olein in the form of pure or refined oil (4) The treatment of palm oil or palm olein was assessed using the following outcomes: plasma or serum TC, TG, HDL-C, and LDL-C concentration (5) Study should have control group and (6) studies on specific fatty acid, fraction enriched tocotrienol and tocopherol, crude palm oil, kernel oil, red palm oil, thermally oxidized palm oil, hydrogenated palm oil, and palm oil or palm olein based products namely margarine, palm milk, butter and cream were excluded. The quality and the risk of bias on the selected studies were assessed using the ARRIVE Guideline and SYRCLE's Risk of Bias tools, respectively. Results: The literature search successfully identified 17 potentially relevant articles, whereby nine of them met the inclusion criteria. All research articles included in this review were in vivo studies comprising seven rats, one hamster and one mice model. Conclusion: Significant positive outcomes were observed in several lipid parameters such as TC and LDL-C. The evidence from this review supported that palm oil and palm olein possess high potential as lipid-lowering agents.

Matched MeSH terms: Tocopherols
Fulltext Differences in chemical components and antioxidant-related substances in virgin coconut oil from coconut hybrids and their parents

Arlee, R., Suanphairoch, S., Pakdeechanuan, P.

International Food Research Journal, 2013;20(5):0-0.
MyJurnal

Chumphon Horticultural Research Centre (CHRC) is Thailand’s main coconut research unit. CHRC has developed three coconut cultivars: Sawi Hybrid No. 1 (Malayan Yellow Dwarf x West African Tall: MYD x WAT), Chumphon Hybrid No. 60 (Thai Tall: THT x WAT) and Chumphon Hybrid No. 2 (MYD x THT). This study compared some chemical components in virgin coconut oil (VCO) from coconut hybrids with their parents. The VCO was extracted by cold pressing and fermentation methods, and was analyzed for fatty acid profiles, triacylglycerol profile, acid value, tocopherol content, total phenolic content, and antioxidant activity against DPPH (1,1-diphenyl-2-picrylhydrazyl) radicals. The findings showed that hybrids contained lauric acid ranging from 46.63 to 48.34% of total fatty acid. Chumphon 60 had the highest lauric acid content, 48.34% of total fatty acids, which was not significantly different (p > 0.05) from that of the parents. In contrast, the cultivars from MYD, Sawi 1 and Chumphon 2, had significantly greater lauric acid content than the parent MYD (p ≤ 0.05). Cold pressing and fermentation provided an oil extraction yield of 25 and 20%, respectively. The proportions of lauric acid in VCO from these two methods were not significantly different (p > 0.05), but the cold pressing method resulted in higher tocopherol content (p ≤ 0.05). The VCO of Chumphon 60 from the cold pressed method had tocopherol content close to that of the parent WAT (p > 0.05) but significantly higher than that of the other parent THT (p ≤ 0.05). In addition, it contained the highest total phenolic contents among the three cultivars, 57.89 mg GAE/100 g oil, leading to antioxidant activity with a low EC50 of 0.53 mg GAE/ml. Overall, the hybrid of WAT x THT, Chumphon 60, was outstanding among the cultivars; it had the highest levels of lauric acid, total phenolic compounds, and antioxidant activity.

Matched MeSH terms: Tocopherols
Fulltext Percutaneous absorption of triacyglycerols (TAGs), tocols and carotenoids: comparison studies of crude and refined palm oil

Prasanthi Sri, Senthil Adimoolam, Ahmad Mahmud

Malaysian Journal of Pharmaceutical Science, 2013;11(1):33-48.
MyJurnal

Studies were conducted to assess the percutaneous absorption of the triacyglycerols (TAGs), tocols and carotenoids present in crude and refined palm oil. In vitro experiments using upright Franz diffusion cells were employed to investigate the permeability of these compounds across full thickness human skin and into the receptor solution. Cetrimide, a cationic surfactant was chosen to be used as a solubilising agent in the receptor phase with an optimum concentration of 3.0 mg/mL and was able to provide sink conditions throughout the permeation. TAGs, tocols and carotenoids all permeated human skin from crude palm oil (CPO), whereas only TAGs permeated when refined palm oil (RPO) was used. Of the TAGs, oleic acid-containing TAGs was preferentially absorbed despite palmitic acid being the most prevalent fatty acid (FA) in TAGs. Tocols in the form of α-T3 showed the highest permeation followed by γ-T3, α-T and the lowest permeation was observed for δ-T3. Carotenoids (α-carotene and β-carotene) also showed an appreciable amount of permeation from CPO.

Matched MeSH terms: Tocopherols
Fulltext Bioactive compounds and "in vitro" antioxidant activity of some traditional and non-traditional cold-pressed edible oils from Macedonia

Kostadinović Veličkovska S, Catalin Moţ A, Mitrev S, Gulaboski R, Brühl L, Mirhosseini H, et al.

J Food Sci Technol, 2018 May;55(5):1614-1623.
PMID: 29666513 DOI: 10.1007/s13197-018-3050-0

The bioactive compounds and "in vitro" antioxidant activity measured by three antioxidant assays of some traditional and non-traditional cold-pressed edible oils from Macedonia were object of this study. The fatty acid composition showed dominance of monounsaturated oleic acid in "sweet" and "bitter" apricot kernel oils with percentages of 66.7 ± 0.5 and 57.8 ± 0.3%, respectively. The most dominant fatty acid in paprika seed oil was polyunsaturated linoleic acid with abundance of 69.6 ± 2.3%. The most abundant tocopherol was γ-tocopherol with the highest quantity in sesame seed oil (57.6 ± 0.1 mg/100 g oil). Paprika seed oil, sesame seed oil and sweet apricot oil were the richest source of phytosterols. DPPH assay was the most appropriate for the determination of the antioxidant activity of cold-pressed sunflower oil due to high abundance of α-tocopherol with a level of 22.8 ± 1.1 mg/100 g of oil. TEAC assay is the best for the determination of the antioxidant activity of sesame seed oil and paprika seed oils as the richest sources of phenolic compounds. β-carotene assay was the most suitable assay for oils obtained from high pigmented plant material. Triacylglycerols and phytosterol profiles can be used as useful markers for the origin, variety and purity of the oils.

Matched MeSH terms: Tocopherols
Fulltext Cellular Uptake and Bioavailability of Tocotrienol-Rich Fraction in SIRT1-Inhibited Human Diploid Fibroblasts

Jaafar F, Abdullah A, Makpol S

Sci Rep, 2018 Jul 11;8(1):10471.
PMID: 29992988 DOI: 10.1038/s41598-018-28708-z

Tocotrienol-rich fraction (TRF) is palm vitamin E that consists of tocopherol and tocotrienol. TRF is involved in important cellular regulation including delaying cellular senescence. A key regulator of cellular senescence, Sirtuin 1 (SIRT1) is involved in lipid metabolism. Thus, SIRT1 may regulate vitamin E transportation and bioavailability at cellular level. This study aimed to determine the role of SIRT1 on cellular uptake and bioavailability of TRF in human diploid fibroblasts (HDFs). SIRT1 gene in young HDFs was silenced by small interference RNA (siRNA) while SIRT1 activity was inhibited by sirtinol. TRF treatment was given for 24 h before or after SIRT1 inhibition. Cellular concentration of TRF isomers was determined according to the time points of before and after TRF treatment at 0, 24, 48, 72 and 96 h. Our results showed that all tocotrienol isomers were significantly taken up by HDFs after 24 h of TRF treatment and decreased 24 h after TRF treatment was terminated but remained in the cell up to 72 h. The uptake of α-tocopherol, α-tocotrienol and β-tocotrienol was significantly higher in senescent cells as compared to young HDFs indicating higher requirement for vitamin E in senescent cells. Inhibition of SIRT1 gene increased the uptake of all tocotrienol isomers but not α-tocopherol. However, SIRT1 inhibition at protein level decreased tocotrienol concentration. In conclusion, SIRT1 may regulate the cellular uptake and bioavailability of tocotrienol isomers in human diploid fibroblast cells while a similar regulation was not shown for α-tocopherol.

Matched MeSH terms: Tocopherols
Fulltext Effect of microwave heating with different exposure times on the degradation of corn oil

Abbas Ali, Hadi Mesran, M., Nik Mahmood, N.A., Abd Latip, R.

International Food Research Journal, 2016;23(2):842-848.
MyJurnal

In the present work, the influence of microwave power and heating times on the quality
degradation of corn oil was evaluated. Microwave heating test was carried out using a domestic
microwave oven for different periods at low- and medium-power settings for the corn oil sample.
The changes in physicochemical characteristics related to oil degradation of the samples during
heating were determined by standard methods. In this study, refractive index, free fatty acid
content, peroxide value, p-anisidine value, TOTOX value, viscosity and total polar compound
of the oils all increased with increasing heating power and time of exposure. In GLC analysis,
the percentage of linoleic acid tended to decrease, whereas the percentage of palmitic, stearic
and oleic acids increased. The C18:2/C16:0 ratio decreased in all oil samples with increasing
heating times. Exposing the corn oil to various microwave power settings and heating periods
caused the formation of hydroperoxides and secondary oxidation products. The heating reduced
the various tocopherol isomers in corn oil and highest reduction was detected in γ-tocopherol.
Longer microwave heating times resulted in a greater degree of oil deterioration. Microwave
heating caused the formation of comparatively lower amounts of some degradative products in
the oil samples heated at low-power setting compared to medium-power setting. The present
analysis indicated that oil quality was affected by both microwave power and heating time.

Matched MeSH terms: Tocopherols
Fulltext Variations in Antioxidant Capacity, Oxidative Stability, and Physicochemical Quality Parameters of Walnut (Juglans regia) Oil with Roasting and Accelerated Storage Conditions

Elouafy Y, El Idrissi ZL, El Yadini A, Harhar H, Alshahrani MM, Al Awadh AA, et al.

Molecules, 2022 Nov 09;27(22).
PMID: 36431794 DOI: 10.3390/molecules27227693

Walnut oil, like all vegetable oils, is chemically unstable because of the sensitivity of its unsaturated fatty acids to the oxidation phenomenon. This phenomenon is based on a succession of chemical reactions, under the influence of temperature or storage conditions, that always lead to a considerable change in the quality of the oil by promoting the oxidation of unsaturated fatty acids through the degradation of their C-C double bonds, leading to the formation of secondary oxidation products that reduce the nutritional values of the oil. This research examines the oxidative stability of roasted and unroasted cold-pressed walnut oils under accelerated storage conditions. The oxidative stability of both oils was evaluated using physicochemical parameters: chemical composition (fatty acids, phytosterols, and tocopherols), pigment content (chlorophyll and carotenoids), specific extinction coefficients (K232 and K270), and quality indicators (acid and peroxide value) as well as the evaluation of radical scavenging activity by the DPPH method. The changes in these parameters were evaluated within 60 days at 60 ± 2 °C. The results showed that the levels of total phytosterols, the parameters of the acid and peroxide value, K232 and K270, increased slightly for both oils as well as the total tocopherol content and the antioxidant activity affected by the roasting process. In contrast, the fatty acid profiles did not change considerably during the 60 days of our study. After two months of oil treatment at 60 °C, the studied oils still showed an excellent physicochemical profile, which allows us to conclude that these oils are stable and can withstand such conditions. This may be due to the considerable content of tocopherols (vitamin E), which acts as an antioxidant.

Matched MeSH terms: Tocopherols
Fulltext Optimal antioxidant activity with moderate concentrations of Tocotrienol rich fraction (TRF) in in vitro assays

Muid, S., Ali, A.M., Yusoff, K., Nawawi, H.M.

International Food Research Journal, 2013;20(2):687-694.
MyJurnal

Vitamin E is known to have potent antioxidant activity and plays an important role in reducing oxidative stress, a pivotal step in atherogenesis. However, several randomised clinical trials using α-tocopherol have failed to demonstrate consistent beneficial effects of antioxidants against atherosclerosis and clinical endpoints. Tocotrienol, a vitamin E compound analogue is shown to have more potent antioxidant activity compared to tocopherol. Finding the optimal anti-oxidative dose is crucial and may effectively be applied for cardioprotection in human. The objective of this study was to determine the optimal dose of tocotrienol rich fraction (TRF) with highest antioxidant activity in vitro using the ferric thiocyanate (FTC), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and 2’, 7’- dichlorofluorescein diacetate (DCFHDA) assays. It was found that TRF exhibited potent antioxidant and free radical scavenging activities with an IC50 of 22.10 + 0.01 µg/ml. In all assays, TRF had optimal antioxidant activity at moderate concentrations (10-100 µg/ml). In conclusion, TRF has potent antioxidant activity, which is optimal at moderate concentrations.

Matched MeSH terms: Tocopherols
Fulltext Tocotrienols and breast cancer: the evidence to date

Nesaretnam K, Meganathan P, Veerasenan SD, Selvaduray KR

Genes Nutr, 2012 Jan;7(1):3-9.
PMID: 21516480 DOI: 10.1007/s12263-011-0224-z

Breast cancer is the second most frequent cancer affecting women worldwide after lung cancer. The toxicity factor associated with synthetic drugs has turned the attention toward natural compounds as the primary focus of interest as anticancer agents. Vitamin E derivatives consisting of the well-established tocopherols and their analogs namely tocotrienols have been extensively studied due to their remarkable biological properties. While tocopherols have failed to offer protection, tocotrienols, in particular, α-, δ-, and γ-tocotrienols alone and in combination have demonstrated anticancer properties. The discovery of the antiangiogenic, antiproliferative, and apoptotic effects of tocotrienols, as well as their role as an inducer of immunological functions, not only reveals a new horizon as a potent antitumor agent but also reinforces the notion that tocotrienols are indeed more than antioxidants. On the basis of a transcriptomic platform, we have recently demonstrated a novel mechanism for tocotrienol activity that involves estrogen receptor (ER) signaling. In silico simulations and in vitro binding analyses indicate a high affinity of specific forms of tocotrienols for ERβ, but not for ERα. Moreover, we have demonstrated that specific tocotrienols increase ERβ translocation into the nucleus which, in turn, activates the expression of estrogen-responsive genes (MIC-1, EGR-1 and Cathepsin D) in breast cancer cells only expressing ERβ cells (MDA-MB-231) and in cells expressing both ER isoforms (MCF-7). The binding of specific tocotrienol forms to ERβ is associated with the alteration of cell morphology, caspase-3 activation, DNA fragmentation, and apoptosis. Furthermore, a recently concluded clinical trial seems to suggest that tocotrienols in combination with tamoxifen may have the potential to extend breast cancer-specific survival.

Matched MeSH terms: Tocopherols
Fulltext Evaluation of topical tocopherol cream on cutaneous wound healing in streptozotocin-induced diabetic rats

Lin TS, Abd Latiff A, Abd Hamid NA, Wan Ngah WZ, Mazlan M

Evid Based Complement Alternat Med, 2012;2012:491027.
PMID: 23097676 DOI: 10.1155/2012/491027

Diabetes is a common cause of delayed wound healing. The aim of the study was to determine the effect of topical administration of tocopherol cream on the wound healing process in diabetic rats. The study was conducted using 18 male Sprague Dawley rats which were divided into three groups: (I) diabetic rats receiving control cream (n = 6), (II) diabetic rats receiving 0.06% tocopherol cream (n = 6), and (III) diabetic rats receiving 0.29% tocopherol cream (n = 6). Four cutaneous wounds were created at the dorsal region of the rats. Wound healing was assessed by total protein content, rate of wound closure estimation, and histological studies on the tenth day after wounding. Tocopherol treatment enhanced the wound healing process by increasing rate of wound closure and total protein content significantly (P < 0.05) compared to the control group. Histological observation also showed better organized epithelium and more collagen fibers in the tocopherol treated groups. Application of tocopherol cream enhances wound healing process in diabetic condition which is known to cause delay in wound healing.

Matched MeSH terms: Tocopherols

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