Lipid peroxidation recent developments

Peroxidation of polyunsaturated lipids is thought to be an important pathological event involved in the development of tissue damage and dysfimction. In recent studies, Rubbo and colleagues [113] demonstrated that NO inhibits lipid peroxidation and therefore may be important in the modulation of the inflammatory response by inhibiting the formation of proinflammatory lipids. 

Much recent work has focused on defining the bioactivity of the individual lipid peroxidation products and will be the topic of chapters following in this volume. Important recent mechanistic discoveries include the refinement of radical clocks that are used for determination of rate constants of peroxyl radical reactions, insight into the limitation of dietary antioxidants to prevent or reduce lipid peroxidation, and the development of super-antioxidants. Each of these will be discussed briefly. 

Currently, it has been proven through several results that tea polyphenols can reduce the risk of cancer by suppressing chronic inflammation at the molecular, cellular, and whole-animal levels. Stress, a recently discovered cause of cancer [125], can be reduced with tea, in turn reducing the risk of developing cancer. Several studies have mentioned that tea consiunption could be related to a decrease in psychological and physiological responses, such as lower post-stress cortisol levels, inhibition of eortieal neuron excitation, lower lipid peroxide levels, and decreased DNA damage [126,127]. 

Lipids. Most of the recently published EPR studies on lipid peroxidation have been concerned with developments in spin-trapping methodology e.g. radical-adduct extraction and separation by HPLC, - the use of novel spin traps and the reassignment of peroxyl adducts to alkoxyl adducts ) and are covered in Chapter 2 this volume by Davies. 

More recently, another series of di-r-butyl phenol antioxidants represented by LY231617 has been developed. These compounds inhibit iron-dependent lipid j>eroxidation and antagonize hydrogen peroxide-induced cortical neuronal injury [at 5 /iM LY231617 increased neuron viability fiom 20% (untreated) to 70%]. Interestingly, LY231617 does not inhibit the key enzymes of... 

In recent years, modern instrumental methods have been developed to monitor lipid oxidation in biological samples, including dairy products. These include use of electron spin resonance (ESR) spectrometry, direct measurement of secondary oxidative products such as malonaldehyde, static and dynamic GC/MS methods. ESR spectrometry permits detection of free radicals formed in the very early stages of oxidation prior to the formation of peroxides. The method has been applied successfully to dairy products such as milk powders and processed cheese (Nielsen et al., 1997 Stapelfeldt... 

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