Glycyrrhizin stimulates growth of Eubacterium sp. strain GLH, a human intestinal anaerobe

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Abstract
Eubacterium sp. strain GLH was isolated from human feces and produced two kinds of .beta.-D-glucuronidase (EC 3.2.1.31), one new enzyme specific for glycyrrhizin (GL) and the other for phenyl .beta.-D-glucuronides. GL or p-nitrophenyl-mono-.beta.-D-glucuronide (pNPG) stimulated the production of GL or pNPG .beta.-glucuronidases and the growth of strain GLH in a basal medium lacking carbohydrate. D-Glucuronic acid also stimulated the growth of the bacterium, but glycyrrhetic acid did not. The increase of GL .beta.-glucuronidase paralleled the growth of the Eubacterium strain in pure culture. These results suggest that glucuronides such as GL and pNPG stimulate the growth of the Eubacterium strain in a nutrient-poor medium by providing D-glucuronic acid through the activity of .beta.-glucuronidases. The increase in GL .beta.-glucuronidase activity in the presence of GL was observed during the cultivation of human intestinal flora in a general anaerobic medium. During mixed cultivation of the Eubacterium strain with Streptococcus faecalis, which does not produce GL .beta.-glucuronidase, GL .beta.-glucuronidase was also increased by GL or pNPG, but not by glycyrrhetic acid and p-nitrophenol. It is suggested that GL stimulates the growth of strain GLH even in the mixed culture.