Thymol is a natural product that exhibits antimicrobial activity in vitro but in vivo results indicate that absorption within the proximal alimentary tract precludes its delivery to the distal gut. Presently, the anti-Campylobacter activity of thymol was compared against that of thymol-beta-D-glucopyranoside, the latter being resistant to absorption. When treated with 1 mM thymol, Campylobacter coli and jejuni were reduced during pure or co-culture with a beta-glycoside-hydrolysing Parabacteroides distasonis. Thymol-beta-D-glucopyranoside treatment (1 mM) did not reduce C coli and jejuni during pure culture but did during co-culture with P. distasonis or during mixed culture with porcine or bovine faecal microbes possessing beta-glycoside-hydrolysing activity. Fermentation acid production was reduced by thymol-beta-D-glucopyranoside treatment, indicating that fermentation was inhibited, which may limit its application to just before harvest. Results suggest that thymol-beta-D-glucopyranoside or similar beta-glycosides may be able to escape absorption within the proximal gut and become activated by bacterial beta-glycosidases in the distal gut. Published by Elsevier Ltd.
