A fine structural demonstration that some benzopyrones act as vitamin P in the rat.

In rats fed a diet lacking flavonoids (but which had supplementary vitamin C) definite fine structural alterations were found in blood capillaries and tissues. These fine structural alterations were quite different from those reported in C-avitaminosis and imply a different deficiency. They were largely prevented by feeding the benzopyrones, coumarin or coumarin plus troxerutin, thus pointing to the specificity of the lesions. This implies that, for the rat, benzopyrones are vitamins and that vitamin C and "vitamin P"-deficiency states are qute distinct. In "P-avitaminosis" the basic lesion is the opening of some blood capillary endothelial intercellular junctions. Unlike in C-avitaminosis, the endothelial cells are intact, without pale, grossly swollen cytoplasms.

[Changes in the activity of antioxidant enzymes in an experimental peroxidation syndrome in the rabbit]. / Izmenenie aktivnosti antioksidantnykh fermentov pri éksperimental'nom sindrome peroksidatsii u krolikov.

Activity of the antioxidant enzymes under conditions of experimental syndrome of peroxidation was studied in rabbits maintained at a diet deprived of antioxidants. Peroxidation of lipids was increased in the animals; at the same time, content of the vitamin-antioxidants was decreased in their tissues. Activity of the antioxidant enzymes was distinctly increased within the first steps of the experiment after which it was decreased. The data obtained suggest that deficiency of the vitamin-antioxidants may be transitory compensated by an increase in activity of the antioxidant enzymes; long-term deprivation of bioantioxidants led, however, to inhibition of biosynthesis of the antioxidant enzymes.

[Alimentary factors in the genesis of atherosclerosis]. / Alimentarnye faktory v geneze ateroskleroza.

A peroxidized model of atherosclerosis devised by the authors and the results of using antioxidants in these conditions as well as of literature sources on the deficiency of the antioxidant action substances in the current ration, on the peroxidation syndrome in this illness in man and animals, all this allowed the following concept to be formulated. Overeating, continued deficiency of antioxidants in natural products and hypodynamia contribute to the derangement of the physiological antioxidant system. An intensified free-radical oxidation calls forth decomposition of the beta-lipoproteids, lipoid infiltration of the intima, destruction of the elasticity, fibrosis and calcinosis. An alimentary prophylaxis of atherosclerosis should repose on the utilization of food mixtures representing complexes of the antioxidants of the direct and indirect action and trace elements entering the composition of the antiperoxidized enzymes.

Increased sensitivity to pentobarbital in rats fed a diet lacking flavonoids.

Pentobarbital-sensitivity is highly increased in rats fed a diet lacking flavonoids; sleeping time was found to be increased by 42 and 30% as compared with rats fed a normal diet. These studies confirm our previous statement according to which for the rat, benzopyrones are vitamins.

Analysis of Arabidopsis mutants deficient in flavonoid biosynthesis.

Eleven loci that play a role in the synthesis of flavonoids in Arabidopsis are described. Mutations at these loci, collectively named transparent testa (tt), disrupt the synthesis of brown pigments in the seed coat (testa). Several of these loci (tt3, tt4, tt5 and ttg) are also required for the accumulation of purple anthocyanins in leaves and stems and one locus (ttg) plays additional roles in trichome and root hair development. Specific functions were previously assigned to tt1-7 and ttg. Here, the results of additional genetic, biochemical and molecular analyses of these mutants are described. Genetic map positions were determined for tt8, tt9 and tt10. Thin-layer chromatography identified tissue- and locus-specific differences in the flavonols and anthocyanidins synthesized by mutant and wild-type plants. It was found that UV light reveals distinct differences in the floral tissues of tt3, tt4, tt5, tt6 and ttg, even though these tissues are indistinguishable under visible light. Evidence was also uncovered that tt8 and ttg specifically affect dihydroflavonol reductase gene expression. A summary of these and previously published results are incorporated into an overview of the genetics of flavonoid biosynthesis in Arabidopsis.

Prolonged action of drugs in rats with flavonoid-deficiency.

In flavonoid-deficient Wistar-rats, the action of caffeine, harmine, hexobarbital, morphine and pentobarbital is enhanced. In contrast, the thiopental sleeping time is shortened. These observations may indicate impaired drug metabolism as a consequence of the flavonoid-deficiency state.