3′-Hydroxypterostilbene Suppresses Colitis-Associated Tumorigenesis by Inhibition of IL-6/STAT3 Signaling in Mice

3′-Hydroxypterostilbene (trans-3,5-dimethoxy-3′,4′-hydroxystilbene) presents in Sphaerophysa salsula, Pterocarpus marsupium, and honey bee propolis and has been reported to exhibit several biological activities. Herein, we aimed to explore the chemopreventive effects of dietary 3′-hydroxypterostilbene and underlying molecular mechanisms on colitis-associated cancer using the azoxymethane (AOM)/dextran sodium sulfate (DSS) model. 3′-Hydroxypterostilbene administration effectively ameliorated the colon shortening and number of tumors in AOM/DSS-treated mice (3.2 ± 1.2 of the high-dose treatment versus 13.8 ± 5.3 of the AOM/DSS group, p < 0.05). Molecular analysis exhibited the anti-inflammatory activity of 3′-hydroxypterostilbene by a significant decrease in the levels of inducible nitric oxide synthase, cyclooxygenase-2, and interleukin-6 (IL-6) (p < 0.05). Moreover, dietary 3′-hydroxypterostilbene also significantly diminished IL-6/signal transducer and activator of transcription signaling and restored colonic suppressor of cytokine signaling 3 levels in the colonic tissue of mice (p < 0.05). Collectively, these results demonstrated for the first time the in vivo chemopreventive efficacy and molecular mechanisms of dietary 3′-hydroxypterostilbene against colitis-associated colonic tumorigenesis.