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[33] Assessment of prooxidant activity of vitamin E in human low-density lipoprotein and plasma

1999; Academic Press; Linguagem: Inglês

10.1016/s0076-6879(99)99036-5

1557-7988

Paul K. Witting, Detlef Mohr, Roland Stocker,

Vitamin C and Antioxidants Research

This chapter discusses the assessment of pro-oxidant activity of vitamin E in human low-density lipoprotein and plasma. The chapter discusses a series of simple tests that manipulate both the phase- and the chain-transfer activity of α-tocopherol (α-TOH) in low-density lipoprotein (LDL). While these tests can provide useful information on the mechanism of action of α -TOH in vitro, they do not give information on the action of vitamin E in vivo, nor propose that α -TOH acts as a prooxidant in vivo. The chapter presents various procedures for testing the pro-oxidant activity of α-TOH in lipoproteins and lipid emulsions. The methods described in the chapter allow investigations on the mechanism of in vitro lipoprotein lipid peroxidation and the way this process is affected by various (co-)antioxidants surrounding or associated with lipoproteins. The methods discussed also allow investigation of a possible role of tocopherol-mediated peroxidation (TMP) in cellular lipid peroxidation and antioxidation, particularly once analytical tools comparable to those for lipoproteins are available for the assessment of cellular lipid peroxidation.