TITLE:
Concentrated Extract of Green Tea Polyphenols Enhances the Toxicity of the Elderberry Lectin Nigrin b to Mice
AUTHORS:
Pilar Jiménez, Patricia Cabrero, Jesús Tejero, Manuel J. Gayoso, Manuel Garrosa, Damián Cordoba-Diaz, Manuel Cordoba-Diaz, Tomás Girbés
KEYWORDS:
Green Tea Polyphenols; Nigrin b Model; Ribosome-Inactivating Protein; Lectin; Small Intestine; Liver; Apoptosis
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.5 No.5,
February
26,
2014
ABSTRACT: The effect of
the administration of large amounts of green tea polyphenols is a matter of
controversy. We explored whether a polyphenol mixture from a concentrated green
tea extract (Polyphenon 60) could alter the effects on mice of the type 2 (two
chains) ribosome-inactivating protein nigrin b isolated from Sambucus nigra L. Nigrin b triggers
specific reversible toxic effects on the mouse intestines featured by apoptosis
of mice Lieberkühn crypt cells upon parenteral administration of sub-lethal
amounts. Independent administration to mice of 30 mg/kg body weight of
Polyphenon 60 by oral gavage or 10 mg/kg body weight of nigrin b administered
via the intraperitoneal route (i.p.) did not affect survival. In contrast, the
simultaneous treatment greatly enhanced nigrin b toxicity leading to the death
of some animals. The histological analysis revealed that the most serious
injury was inflicted on the small intestine crypts, which disappeared, and on
the liver, which evidenced hepatotoxicity showing haemorrhagic areas. These
findings raise concerns about the abuse of high concentrations of green tea
polyphenols especially when the intestinal mucosa is damaged, for instance by
toxins or therapeutic drugs.