Effects and mechanisms of Aspergillus oryzae-fermented grain germ on constipation in rats treated with loperamide

Abstract

Purpose: Gut Working Tablet (GWT) is a Japanese traditional fermented medicine based on Aspergillus oryzae NK-fermented grain germ. Although GWT has been used by Japanese patients with constipation, the mechanism has not been investigated. The aim of this study was to examine the possible mechanisms of GWT on constipation.

Methods: Sprague-Dawley rats were fed with or without 5% of GWT for 2 weeks and administered loperamide. Number and weight of feces were measured for 24h after administration of loperamide. The concentration of short chain fatty acids (SCFA) in the cecal contents was measured. We measured stimulating effects of A. oryzae NK-fermented grain germ water extracts on the growth of B. longum and other intestinal bacteria in vitro.

Results: The decrease of feces caused by loperamide was improved by GWT administration. The decrease of butyric acid in feces and cecal contents induced by the administration of loperamide was inhibited by GWT. The growth of B. longum was increased in the presence of GWT and A. oryzae NK-fermented grain germ water extracts in a dose-dependent manner.

Conclusion: Administration of GWT restored constipation induced by loperamide. A. oryzae NK-fermented grain germ would be a useful prebiotics to stimulate the growth of Bifidobacterium.