Assay for lipid peroxides in animal tissues by thiobarbituric acid reaction

中枢神経系疾患の治療は正常細胞（ニューロン）の機能維持を目的とするが，脳血管障害のように機能障害の原因が細胞の死滅に基づくことは多い．一方，脳腫瘍の治療においては薬物療法や放射線療法といった腫瘍細胞の死滅を目標とするものが大きな位置を占める．いずれの場合にも，細胞死の機序を理解することは各種病態や治療法の理解のうえで重要である．現在のところ最も研究の進んでいる細胞死の型はアポトーシスである．そのなかで重要な位置を占めるミトコンドリアにおける反応および抗アポトーシス因子について概要を紹介する．

Neuroscience 細胞死：最近の知見

http://www.uniroma2.it/didattica/piante_medicinali/deposito/Carotenoidi.pdf

Carotenoids and human health

This article is a review of the fundamental chemistry of the tocopherols and tocotrienols relevant to their antioxidant action. Despite the general agreement that α-tocopherol is the most efficient antioxidant and vitamin E homologuein vivo, there was always a considerable discrepancy in its “absolute” and “relative” antioxidant effectivenessin vitro, especially when compared to γ-tocopherol. Many chemical, physical, biochemical, physicochemical, and other factors seem responsible for the observed discrepancy between the relative antioxidant potencies of the tocopherolsin vivo andin vitro. This paper aims at highlighting some possible reasons for the observed differences between the tocopherols (α-, β-, γ-, and δ-) in relation to their interactions with the important chemical species involved in lipid peroxidation, specifically trace metal ions, singlet oxygen, nitrogen oxides, and antioxidant synergists. Although literature reports related to the chemistry of the tocotrienols are quite meager, they also were included in the discussion in virtue of their structural and functional resemblance to the tocopherols.

The chemistry and antioxidant properties of tocopherols and tocotrienols

The epidemiologic literature in the English language regarding intake of tomatoes and tomato-based products and blood lycopene (a compound derived predominantly from tomatoes) level in relation to the risk of various cancers was reviewed. Among 72 studies identified, 57 reported inverse associations between tomato intake or blood lycopene level and the risk of cancer at a defined anatomic site; 35 of these inverse associations were statistically significant. No study indicated that higher tomato consumption or blood lycopene level statistically significantly increased the risk of cancer at any of the investigated sites. About half of the relative risks for comparisons of high with low intakes or levels for tomatoes or lycopene were approximately 0.6 or lower. The evidence for a benefit was strongest for cancers of the prostate, lung, and stomach. Data were also suggestive of a benefit for cancers of the pancreas, colon and rectum, esophagus, oral cavity, breast, and cervix. Because the data are from observational studies, a cause-effect relationship cannot be established definitively. However, the consistency of the results across numerous studies in diverse populations, for case-control and prospective studies, and for dietary-based and blood-based investigations argues against bias or confounding as the explanation for these findings. Lycopene may account for or contribute to these benefits, but this possibility is not yet proven and requires further study. Numerous other potentially beneficial compounds are present in tomatoes, and, conceivably, complex interactions among multiple components may contribute to the anticancer properties of tomatoes. The consistently lower risk of cancer for a variety of anatomic sites that is associated with higher consumption of tomatoes and tomato-based products adds further support for current dietary recommendations to increase fruit and vegetable consumption.

/pdf/tomatoes-tomato-based-products-lycopene-and-cancer-review-of-58ewr3o8rf.pdf

Tomatoes, Tomato-Based Products, Lycopene, and Cancer: Review of the Epidemiologic Literature

Carotenoids are currently under intense scrutiny regarding their potential to modulate chronic disease risk and prevent vitamin A deficiency, and renewed emphasis has been placed on achieving a better understanding of the metabolic fate of these compounds in humans. The development of new animal models, and use of human metabolic studies and stable tracer methods have greatly improved our knowledge of how carotenoids are absorbed, metabolized, and transported to tissues; however, many important issues remain unresolved. For example, intestinal uptake of carotenoids occurs by passive diffusion, but the lumenal or intracellular factors limiting this process are obscure. The intestinal mucosa plays a key role in the metabolism of provitamin A carotenoids such as beta-carotene, thus greatly influencing their bioavailability. Most recent evidence supports a central oxidation mechanism of cleavage of beta-carotene to retinal in the intestinal mucosa, but the extent and site(s) of postabsorptive metabolism in th...

Absorption, metabolism, and transport of carotenoids.

Cytochrome P450 ω-Hydroxylase Pathway of Tocopherol Catabolism NOVEL MECHANISM OF REGULATION OF VITAMIN E STATUS

The occurrence of carotenoid pigments in human blood and tissues has recently become an area of renewed interest due to the observed inverse relationship between consumption of carotenoid-rich fruits and vegetables and risk of certain cancers. This article reviews current knowledge of the kinds and concentrations of carotenoids in human plasma (or serum) and solid tissues. Most reports have focused on the hydrocarbon carotenoids (lycopene, alpha-carotene, and beta-carotene) with fewer dealing with the more polar xanthophyll pigments. The available literature indicates substantial interindividual heterogeneity with respect to blood levels of both total and individual carotenoids. Reports of solid tissue levels are few, but also indicate large variation, with adipose tissue and liver seemingly the major sites of deposition. The relationship between the types and concentrations of circulating carotenoids and those in solid tissues of the same individuals is not known, but preliminary investigations in our laboratory show considerable qualitative homology between the carotenoids in fasting serum and those in fatty tissue.

Carotenoids in human blood and tissues.

In egg-laying animals, mothers can influence the development of their offspring via the suite of biochemicals they incorporate into the nourishing yolk (eg lipids, hormones) However, the long-lasting fitness consequences of this early nutritional environment have often proved elusive Here, we show that the colorful carotenoid pigments that female zebra finches (Taeniopygia guttata) deposit into egg yolks influence embryonic and nestling survival, the sex ratio of fledged offspring, and the eventual ornamental coloration displayed by their offspring as adults Mothers experimentally supplemented with dietary carotenoids prior to egg-laying incorporated more carotenoids into eggs, which, due to the antioxidant activity of carotenoids, rendered their embryos less susceptible to free-radical attack during development These eggs were subsequently more likely to hatch, fledge offspring, produce more sons than daughters, and produce sons who exhibited more brightly colored carotenoid-based beak pigmentation Provisioned mothers also acquired more colorful beaks, which directly predicted levels of carotenoids found in eggs, thus indicating that these pigments may function not only as physiological ‘damage-protectants’ in adults and offspring but also as morphological signals of maternal reproductive capabilities

/pdf/maternally-derived-carotenoid-pigments-affect-offspring-4edpm5mmct.pdf

Robert S. Parker

Papers

Absorption, metabolism, and transport of carotenoids.

Cytochrome P450 ω-Hydroxylase Pathway of Tocopherol Catabolism NOVEL MECHANISM OF REGULATION OF VITAMIN E STATUS

Carotenoids in human blood and tissues.

Maternally derived carotenoid pigments affect offspring survival, sex ratio, and sexual attractiveness in a colorful songbird

Cytochrome P4503A-Dependent Metabolism of Tocopherols and Inhibition by Sesamin☆☆☆