When most people think of vitamin E, more often than not they think of tocopherols—the most prominent being alpha-tocopherol. However, vitamin E refers to a family of eight distinct compounds: four tocopherols and four tocotrienols. While most people are familiar with alpha-tocopherol, other tocopherol forms include beta-, gamma-, and delta-. Similarly, the vitamin E family includes alpha-, bet...

Gamma-tocopherol along with the other forms of vitamin E plays a vital role in maintaining tissue homeostasis and protecting against oxidative stress and lipid peroxidation. Recent evidences suggest that gamma-tocopherol has characteristics that are not shared by alpha-tocopherol. In present study, based on the significant role of gammatocopherol as a particular antioxidant and its substantial ...

Although vitamin E can block mutagenesis and cell transformation in vitro and can reduce the number of chemically induced colonic adenomas in mice, previous clinical trials have found no protective effect of vitamin E supplements against colorectal adenomas, and epidemiological studies have found only weak protective effects of dietary or plasma alpha-tocopherol against colorectal cancer. We pr...

To study the mechanisms of discrimination between various forms of vitamin E, four normal subjects, one patient with lipoprotein lipase deficiency, and three patients with abnormal apolipoprotein B-100 production were given an oral dose containing three tocopherols labeled with differing amounts of deuterium (2R,4'R,8'R-alpha-(5,7-(C2H3)2)tocopheryl acetate (d6-RRR-alpha-tocopheryl acetate), 2S...

BACKGROUND Programmed cell death (apoptosis) is a physiological process needed to remove unwanted or damaged cells. It has been hypothesized that any failure of programmed cell death leads to the development of neoplasm. Identifying new agents which induce apoptosis in tumor cells is of great significance in treatment of neoplasms. Numerous studies suggest that exposure of tumor cells to statin...

BACKGROUND It has long been assumed that newly absorbed vitamin A and E enter the body only via enterocyte-produced chylomicrons. However, recent results in cell cultures have shown that a fraction of alpha-tocopherol is secreted with intestinal HDL. OBJECTIVES The aims of this study were to identify this transporter and to assess whether it is significantly implicated in the in vivo intestin...

BACKGROUND Oxidative stress during HIV infection may impair immune function, cause more rapid disease progression, and increase requirements for dietary antioxidants such as vitamins C and E. OBJECTIVES The study had 2 principal objectives. The first was to ascertain whether HIV infection and immune activation were associated with lower plasma concentrations of ascorbate, urate, and alpha- an...

We have shown that phenolic antioxidant tocopherols are oxidized to nonarylating alpha-tocopheryl quinone (alpha-TQ) and arylating gamma- and delta-TQ electrophiles. The arylating quinones stimulate apoptosis and are highly cytotoxic in mammalian cells. Some xenobiotic phenolic antioxidants are mutagens, and it has been suggested that their arylating quinone metabolites are the active agents in...