We have adapted to erythrocytes a method for the determination of alpha- and gamma-tocopherols in plasma and platelets. Erythrocytes (50 microL) were extracted with methanol containing tocol (internal standard) and pyrogallol. Tocopherols were partitioned into chloroform, washed, and injected in methanol onto a reversed-phase (C18) "high-performance" liquid-chromatographic column. The mobile ph...

Relationship among malondialdehyde (MDA), 2-thiobarbituric acid (TBA)-reactive substances (TBA-RS), and tocopherols in the oxidation of rapeseed oil was investigated. MDA was determined by a new HPLC method with chemical derivatization. When the oil was heated at 170 degrees C, TBA-RS and MDA increased. The contents of TBA-RS were approximately 1.6 times higher than those of MDA. Correlation be...

Initially discovered in 1938 as a "fertility factor," vitamin E now refers to eight different isoforms that belong to two categories, four saturated analogues (α, β, γ, and δ) called tocopherols and four unsaturated analogues referred to as tocotrienols. While the tocopherols have been investigated extensively, little is known about the tocotrienols. Very limited studies suggest that both the m...

Tocopherols and tocotrienols, collectively known as tocochromanols, are lipid-soluble molecules that belong to the group of vitamin E compounds and are essential in the human diet. Not surprisingly, most of what is known about the biological functions of tocochromanols comes from studies of mammalian systems, yet they have been shown to be synthesized only by photosynthetic organisms. The last ...

Vitamin E (alpha-tocopherol or alphaT) has long been recognized as a classic free radical scavenging antioxidant whose deficiency impairs mammalian fertility. In actuality, alpha-tocopherol is one member of a class of phytochemicals that are distinguished by varying methylation of a chroman head group. Early studies conducted between 1922 and 1950 indicated that alpha-tocopherol was specific am...

Tocol-related compounds, tocopherols and tocotrienols, are important bioactive constituents of vegetable oils. They belong to the family of vitamin E active substances. The term “vitamin E” usually refers to a group of compounds occurring naturally in plants, all deriving from 6-chromanol with a 2-phytyl substituent. Tocopherols are vitamin E compounds with a saturated phytyl chain, while tocot...

BACKGROUND Compromised immunity and chronic inflammation are thought to contribute to the development of non-Hodgkin lymphoma (NHL). Because tocopherols protect cells through antioxidant mechanisms, they may play a role in NHL etiology. METHODS This nested case-control study within the Multiethnic Cohort examined the association of prediagnostic serum tocopherols levels measured in 271 NHL ca...

Tissue-specific accumulation of tocopherols and tocotrienols in turkey tissues during embryonic development and their susceptibility to lipid peroxidation were investigated. Fertile turkey eggs were incubated using standard commercial conditions. Embryonic tissues were collected at 16, 22, 25 d of incubation and from day-old poults (referred to as day 29) and alpha-; beta- + gamma- and delta-to...

A quick and direct method for measuring tocopherols (alpha, beta+gamma and delta) in vegetable oils has been developed using RP-HPLC with UV detection. Previous extraction of tocopherols is not required. The oil is diluted in hexane and an aliquot is mixed with ethanol containing an internal standard (alpha-tocopherol acetate). The chromatographic system consists of an ODS-2 column with a metha...

A thin-layer chromatography-gas-liquid chromatography system has made it possible to separate the individual tocopherols for qualitative and quantitative determination in blood plasma and red blood cells. The peak of the individual tocopherols found in plasma and red blood cells were identified by their RF values and comparing their relative retention times with that of 5,7-dimethyltocol which ...