ANTHOCYANS (grech, anthos color + kyanos azure) — group of vegetable pigments, well water soluble. By the chemical nature And. — glycosides (see); at hydrolysis they are split on sugar and agglucon — a component of not sugar nature. Sugar component A. the remains of glucose, a galactose, rhamnose, in certain cases — the remains of disaccharides can serve. Agglucon are antotsianidina — the connections close on the structure to derivatives of flavanol (see. Flavones ) and to catechins (see). K A. belong. besides, antoksantina — the pigments painted in pale yellow color.
And. are eurysynusic in the nature: meet in fabrics of leaves, flowers, fruits; they have red, orange, violet or blue coloring, contain in cellular juice. A big variety of coloring of vegetable fabrics is caused first of all by chemical structure of a pigment. Coloring changes also depending on acidity of the environment and some other factors.
Light — a necessary condition for acquisition by fruits (peaches, apricots, apples, etc.) normal coloring. Some And. are capable to be synthesized for lack of light (a pigment of roots of table beet, sprouts of red cabbage, etc.).
Biological role And. it is studied insufficiently. Most likely, that And. because of the ability to reversible oxidation and recovery can take active part in exchange processes of living tissue. In processes of photosynthesis And. do not participate. And. in combination with tanning agents play an important role in the production technology of table red wines.
Antotsianidina (e.g., meletin, etc.) are widely used in medicine as the means reducing (similar to citrin) permeability of capillaries.
Besides, ability of colourless catechin to turning into brightly painted And. it is the basis for an exact method of discovery of catechins in urine and other biological liquids. See also Pigments .
Bibliography: Kochetkov Η. To., Torgov I. V. and Botvinik M. M. Chemistry of natural compounds, page 96, M., 1961; Kretovich V. L. Fundamentals of phytochemistry, M., 1971; Geissman T. A. The chemistry of flavonoid compounds, Oxford a. o., 1962, bibliogr.; Phe-nolics in plants in health and disease, ed. by J. B. Pridham, Oxford a. o., 1960.
B. A. Rubin.