Polyphenols and tannins

Polyphenols and Tannins Tannic acid Quercetin Catechin Ellagic acid Rutin... 

Casalini, C., Lodovici, M., Briani, C., Paganelli, G., Remy, S., Cheynier, V., and Dolara, P., Effect of complex polyphenols and tannins from red wine (WCPT) on chemically induced oxidative DNA damage in the rat, Eur. J. Nutr., 38, 190, 1999. 

Crozier A, Jaganath IB, Clifford MN. 2006b. Phenols, polyphenols and tannins An overview. In Crozier A, Ashihara H, Clifford MN, Eds. Plant Secondary Metabolites and the Human Diet. Oxford Blackwell Publishing, PP. 1-31. 

TABLE 6.2 Total polyphenol and tannin estimated in finger millet. (ND, not detectable)... 

Adsorption and removal of the polyphenols and tannins from tinctures and plant extracts (Section 3.4.6)... 

Teucrium riparium Hochst. umnunu (Lamiaceae) root bark infusion is used in the treatment of diarrhoea. The root bark contains alkaloids, flavonoids, polyphenols and tannins 15). The plant is also used for snakebites 28). 

Cephalantus natalensis Oliv. [umfomfo, tree strawbeny] (Rubiaceae) root bark decoction is nsed for infertility in women and to increase libido. The root bark contains alkaloids, cardenolides, glycosides, polyphenols and taimins 18). The fresh beny is eaten for malaria fever 28). The root bark contains alkaloids, cardenolides, glycosides, polyphenols and tannins 18). 

Margaritaria discoidea (Baill.) Webster [madlozini. Pheasant berry] (Euphorbiaceae) root bark decoction is used for headache. The root bark contains flavonoids, glycosides, polyphenols and tannins (15). The plant also has strong anti-Candida activity (64). 

Anthospermum rigidum Eckl. Zeyh. [sambulela] (Rubiaceae) leaf infusion is also used for pubic lice. The leaf contains flavonoids, polyphenols and tannins (75). Studies have also shown that apart from the antibacterial properties of these plants, they also have additional medicinal values. The root bark of Andrachne ovalis shows insecticidal activity and is a remedy for snake bites and epilepsy (16,28). The alcohohc extract of the leaves is strongly molluscicidal and can be used in the vector control of hilharzia (67). The leaf decoction is used for persistent dizziness (11). The stem bark contains alkaloids, anthranoids, cardenolides and polyphenols. The root bark contains alkaloids, cardenohdes, polyphenols and saponins (50). 

The polyphenols and tannins in hardwoods largely contribute to wood colour, particularly heartwood colour, and in earlier times some hardwoods were sought after for dyestuffs. Colour change is undesirable with darker timbers that are rich in extractives, where they are to be used for joinery or furniture. With light-coloured woods such as pines the effect of ultraviolet light is complex (Hon, 1991). Some pines can have very pale sapwood. Unfortunately the attractive white surface can yellow where directly exposed to sunlight (Sinclair and Vincent, 1964). 

The presence of polyphenols and tannins in woods such as oaks, western red cedar, eucalypts and Nothofagus sp. leads to blue-black tannin stains during sawing of moist timber, or in the grain around metallic wood fastenings when the wood remains moist. 

Catechins, polyphenols, and tannins in tea Catechins and related flavanols are water soluble, and can be extracted by boiling with water, or by shaking with aqueous acetone. 

Crozier, A., Jaganath, LB. Cliford, M.N. (2006). Phenols, polyphenols and tannins An overview. In Plant Secondary Metabolites (eds A. Crozier, M.N. Clifford H. Ashihara), pp. 1-24. Blackwell, Oxford. 

Crozier, A., Jaganath, I.B., and M.N.C. 2006. Phenols, polyphenols and tannins an overview. In Plant secondary metabolites occurrence, structure and role in the human diet. Wiley-Black-well, Oxford U.K., 1-24. 

There have been a number of studies of protein-polyphenol and -tannin binding, the results of which have been summarized by Haslam and co-workers (79) as follows ... 

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