Metabolism of Plant Lignans by Human Intestinal Bacteria

Abstract

Dietary plant lignans have been implicated in the prevention of several chronic diseases including breast cancer, colon cancer, and cardiovascular disease. Plant lignans can be converted to the physiologically active enterolignans enterodiol and enterolactone by anaerobic bacteria residing in the intestine. Significant interindividual variation has been observed regarding the ability of intestinal bacterial communities to metabolize plant lignans to enterolignans. However, little is known about what characterizes a high enterolignan-producing community from a low enterolignan-producing community. This work presents the development of a platform that can be used to study communities of lignan-converting intestinal bacteria in vitro. Variables that were tested include media type, fecal inoculum concentration, stool processing, and sample headspace. Optimal conditions for enterolignan production and reproducibility consisted of a simple media containing sodium acetate and sodium formate, a total fecal concentration of greater than 1.0%, homogenized slurry processed in a batch, and a headspace-slurry ratio of 3:2.