FLAVONOIDS

From Big Medical Encyclopedia

FLAVONOIDS — big group of structurally related aromatic oxygen-containing heterocyclic compounds. Many flavonoids possess fiziol. activity (see Bioflavonoida) are also mother compounds for receiving the pharmaceuticals possessing antiinflammatory, cholagogue, diuretic, spasmolytic, vasodilating or antisclero-tichesky action. The flavonoids containing two hydroxylic groups in orto-and para-provisions, are antioxidants (see Antioxidants) and are used at conservation of food stuffs. Flavonoids in vegetable fabrics — the active metabolites connected with implementation of the major vital signs of plants and participating in control of their growth and development. The important role of flavonoids consists in ensuring various coloring of plants. One of functions of flavonoids is absorption of a part ultra-violet (330 — 350 nanometers) and parts seen (520 — 560 nanometers) light and protection of plants against excess radiation. Assume participation of flavonoids in redoxreactions in vegetable fabrics. Flavonoids as a part of wood give it resistance to defeat by pathogenic fungi.

It is described apprx. 2 thousand various flavonoids, hl. obr. the vegetable pigments which are found in flowers, fruits, leaves, roots, seeds and wood of plants. Flavonoids meet also in the form of a white mealy plaque on leaves, stalks and seed boxes of primroses of different types.

Treat the most known flavonoids apigenin, hrizin, lyuteolin, fizetin, kempferol, mo-rin, miretsitin, meletin, remnetin, etc. In plants they usually contain in a type of O-glycosides, is more rare in the form of S-glycosides (see Glycosides), and most often are exposed to a glycosylation IT - groups at

the 3rd and 7th carbon atoms in their molecules. A glyconew part (di - or trisaccharides) flavonoids is constructed of glucose, pectine sugar, rhamnose, a galactose, xylose, glucuronic and galacturonic to - t. Sometimes molecules hydroxy-cinnamic or hydroxybenzoic to - t join the carbohydrate remains.

Flavonoids, to-rykh the structure of flavones is the cornerstone (see), and also aurona and chalcones are painted in yellow and orange colors.

Various flavonoids are connected by the general ways of their biosynthesis in plants. Animals are not capable to synthesize flavonoids. Flavonoids get to an organism of animals and the person with vegetable food.

Bibliography: Zaprometov M. N.

Fundamentals of biochemistry of phenolic connections, M., 1974; The flavonoids, ed. by J. Century of Har-bone and. lake, N. Y., 1975; Flavonoids and bioflavonoids, 1981, ed. by L. Farkas a. o., Budapest, 1982; Harborne J. B. Comparative biochemistry of the flavonoids, L. — N. Y4, 1967. H. V. Gulyaeva.

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