Bioflavonoids

Literature References: A group of compounds which contribute to the maintenance of normal blood vessel conditions by decreasing capillary permeability and fragility. Widely distributed among plants: J. B. Harborne, Comparative Biochemistry of the Flavonoids (Academic Press, New York, 1967). Biosynthesis: Grisebach, Barz, Naturwissenschaften 56, 538 (1969). High concentrates can be obtained from all citrus fruits, rose hips, and black currants. Commercial methods extract the rinds of oranges, tangerines, lemons, limes, kumquats, and grapefruits. Solvents used in the extraction processes are aqueous alkalies, hot water, or water-miscible organic solvents, such as isopropanol: Freedman et al., US 2888381 (1959 to U.S. Vitamin). Early interest in the compounds developed because of their synergistic effect with ascorbic acid. Other pharmacologic effects such as inhibition of adrenaline autooxidation and of enzyme action are also under study: several authors in The Pharmacology of Plant Phenolics, J. W. Fairbairn, Ed. (Academic Press, New York, 1959); several authors in Angiologica 9, 133-446 (1972). Metabolism: DeEds, "Flavonoid Metabolism" in Comprehensive Biology Vol. 20, M. Florkin, E. H. Stotz, Eds. (Elsevier, New York, 1968). Reviews: Scarborough, Bacharach, Vitam. Horm. 7, 1-55 (1949); Baier et al., Ann. N.Y. Acad. Sci. 61, (Art. 3), 637-736 (1955); T. Robinson, The Organic Constituents of Higher Plants (Burgess, Minneapolis, 1967) pp 178-209; H. Geiger, C. Quinn in Flavonoids, J. B. Harborne et al., Eds. (Academic Press, New York, 1975) pp 692-742.