Data from St. John's Wort Attenuates Colorectal Carcinogenesis in Mice through Suppression of Inflammatory Signaling

Abstract

<div>Abstract<p>Despite widespread use as well as epidemiologic indications, there have been no investigations into the effect of St. John's wort (SJW) extract on colorectal carcinogenesis <i>in vivo</i>. This study reports a systematic evaluation of the impact of dietary supplementation of SJW extract on azoxymethane-induced colorectal carcinogenesis in mice. Mice were fed with either AIN-93G (control) diet or SJW extract–supplemented diet (SJW diet) prior to azoxymethane treatment. SJW diet was found to significantly improve the overall survival of azoxymethane-treated mice. Pretreatment with the SJW diet significantly reduced body weight loss as well as decrease of serum albumin and cholesterol levels associated with azoxymethane-induced colorectal tumorigenesis. SJW diet–fed mice showed a significant decrease in tumor multiplicity along with a decrease in incidence of large tumors and a trend toward decreased total tumor volume in a dose-dependent manner. A short-term study, which examined the effect of SJW prior to rectal bleeding, also showed decrease in colorectal polyps in SJW diet–fed mice. Nuclear factor kappa B (NF-κB) and extracellular signal–regulated kinase (ERK1/2) pathways were attenuated by SJW administration. SJW extract resulted in early and continuous attenuation of these pathways in the colon epithelium of SJW diet–fed mice under both short-term and long-term treatment regimens. In conclusion, this study demonstrated the chemopreventive potential of SJW extract against colorectal cancer through attenuation of proinflammatory processes. <i>Cancer Prev Res; 8(9); 786–95. ©2015 AACR</i>.</p></div>