Avtor/Urednik		Perharič-Walton, Lucija
Naslov		Studies on the teratogenicity of tea extract polyphenols
Tip		monografija
Kraj izdaje		London
Založnik		Medical research council experimental embriology and Teratology unit St. Georges's Medical School
Leto izdaje		1990
Obseg		str. 52
Jezik		eng
Abstrakt		Maternal tea drinking has been associated with the incidence of neural tube defects. Tea is a complex substance; polyphenols represent nearly half the constituents of tea extract solids. Very little is known about their tetragenic potential and this study attempted to assess this potential. Gallic acid a tea-extract polyphenol, its metabolites pyrogallol and purpurogallin, synergic acid a common plant polyphenol, and five structural analogues of phenol: catechol, resorcinol, hydroquinoone, benzenetriol and phloroglucinol were assessed for their tetragenicity in whole rat embryo culture. Embryo culture assay is particularly suitable for the studies of neural tube defects, because neural tube closure in the rat occurs during the culture period. Due to readiness of polyphenols to oxidize, ascorbate was added to the culture medium. The results suggest that gallic acid (tested at 100 uM), pyrogallol (tested at 50 uM), purpurogallin (tested at 10 uM, 50 uM and 100 uM), synergic acid (tested at 100 uM) and 1000 uM) all possess a weak teratogenic potential. Synergic acid and purpurogallin exhibited detrimental effects on rat embryos at high concentrations. However, the concentrations used in this study are most likely to be many times higher than those found in vivo. The rsults of exposure of rat ambryos to structural analogues of phenol: catechol, hydroquinone, resorcinol, benzenetriol and phloroglucinol, confirmed the rsults of previos studies with these compounds. Firstly that the placing of hydroxyl groups is an important determinant of toxicity of dihydroxyphenols, and secondly that a third hydroxyl group on the benzene ring renders the compound less toxic. Two potential mechanisms of the action of polyphenols are discussed: inhibition of catechol-O-methyl transferase and induction of free radicals.
Deskriptorji		NEURAL TUBE DEFECTS TEA GALLIC ACID PYROGALLOL PHENOLS RATS EMBRYO